Introduce gsl::span. Bound checking at compile time, no overhead at runtime

See https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md

src/algorithms/acquisition/adapters/beidou_b1i_pcps_acquisition.cc

@@ -206,7 +206,7 @@ void BeidouB1iPcpsAcquisition::set_local_code()
 {
     auto* code = new std::complex<float>[code_length_];
 
-    beidou_b1i_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_, 0);
+    beidou_b1i_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, fs_in_, 0);
 
     for (uint32_t i = 0; i < sampled_ms_; i++)
         {
@@ -331,6 +331,7 @@ gr::basic_block_sptr BeidouB1iPcpsAcquisition::get_right_block()
     return acquisition_;
 }
 
+
 void BeidouB1iPcpsAcquisition::set_resampler_latency(uint32_t latency_samples)
 {
     acquisition_->set_resampler_latency(latency_samples);

src/algorithms/acquisition/adapters/beidou_b3i_pcps_acquisition.cc

@@ -143,6 +143,7 @@ void BeidouB3iPcpsAcquisition::stop_acquisition()
 {
 }
 
+
 void BeidouB3iPcpsAcquisition::set_threshold(float threshold)
 {
     float pfa = configuration_->property(role_ + ".pfa", 0.0);
@@ -203,7 +204,7 @@ void BeidouB3iPcpsAcquisition::set_local_code()
 {
     auto* code = new std::complex<float>[code_length_];
 
-    beidou_b3i_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_, 0);
+    beidou_b3i_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, fs_in_, 0);
 
     for (unsigned int i = 0; i < sampled_ms_; i++)
         {

src/algorithms/acquisition/adapters/galileo_e1_pcps_8ms_ambiguous_acquisition.cc

@@ -217,8 +217,10 @@ void GalileoE1Pcps8msAmbiguousAcquisition::set_local_code()
                 "Acquisition" + std::to_string(channel_) + ".cboc", false);
 
             auto* code = new std::complex<float>[code_length_];
+            std::array<char, 3> Signal_;
+            std::memcpy(Signal_.data(), gnss_synchro_->Signal, 3);
 
-            galileo_e1_code_gen_complex_sampled(code, gnss_synchro_->Signal,
+            galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), Signal_,
                 cboc, gnss_synchro_->PRN, fs_in_, 0, false);
 
             for (unsigned int i = 0; i < sampled_ms_ / 4; i++)

src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.cc

@@ -247,28 +247,30 @@ void GalileoE1PcpsAmbiguousAcquisition::set_local_code()
     if (acquire_pilot_ == true)
         {
             //set local signal generator to Galileo E1 pilot component (1C)
-            char pilot_signal[3] = "1C";
+            std::array<char, 3> pilot_signal = {{'1', 'C', '\0'}};
             if (acq_parameters_.use_automatic_resampler)
                 {
-                    galileo_e1_code_gen_complex_sampled(code, pilot_signal,
+                    galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), pilot_signal,
                         cboc, gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0, false);
                 }
             else
                 {
-                    galileo_e1_code_gen_complex_sampled(code, pilot_signal,
+                    galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), pilot_signal,
                         cboc, gnss_synchro_->PRN, fs_in_, 0, false);
                 }
         }
     else
         {
+            std::array<char, 3> Signal_;
+            std::memcpy(Signal_.data(), gnss_synchro_->Signal, 3);
             if (acq_parameters_.use_automatic_resampler)
                 {
-                    galileo_e1_code_gen_complex_sampled(code, gnss_synchro_->Signal,
+                    galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), Signal_,
                         cboc, gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0, false);
                 }
             else
                 {
-                    galileo_e1_code_gen_complex_sampled(code, gnss_synchro_->Signal,
+                    galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), Signal_,
                         cboc, gnss_synchro_->PRN, fs_in_, 0, false);
                 }
         }

src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition_fpga.cc

@@ -122,14 +122,14 @@ GalileoE1PcpsAmbiguousAcquisitionFpga::GalileoE1PcpsAmbiguousAcquisitionFpga(
             if (acquire_pilot_ == true)
                 {
                     //set local signal generator to Galileo E1 pilot component (1C)
-                    char pilot_signal[3] = "1C";
+                    std::array<char, 3> pilot_signal = {{'1', 'C', '\0'}};
-                    galileo_e1_code_gen_complex_sampled(code, pilot_signal,
+                    galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, nsamples_total), pilot_signal,
                         cboc, PRN, fs_in, 0, false);
                 }
             else
                 {
-                    char data_signal[3] = "1B";
+                    std::array<char, 3> data_signal = {{'1', 'B', '\0'}};
-                    galileo_e1_code_gen_complex_sampled(code, data_signal,
+                    galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, nsamples_total), data_signal,
                         cboc, PRN, fs_in, 0, false);
                 }
 

src/algorithms/acquisition/adapters/galileo_e1_pcps_cccwsr_ambiguous_acquisition.cc

@@ -203,16 +203,14 @@ void GalileoE1PcpsCccwsrAmbiguousAcquisition::set_local_code()
             bool cboc = configuration_->property(
                 "Acquisition" + std::to_string(channel_) + ".cboc", false);
 
-            char signal[3];
+            std::array<char, 3> signal = {{'1', 'B', '\0'}};
 
-            strcpy(signal, "1B");
+            galileo_e1_code_gen_complex_sampled(gsl::span<gr_complex>(code_data_, vector_length_), signal,
-
-            galileo_e1_code_gen_complex_sampled(code_data_, signal,
                 cboc, gnss_synchro_->PRN, fs_in_, 0, false);
 
-            strcpy(signal, "1C");
+            std::array<char, 3> signal_C = {{'1', 'C', '\0'}};
 
-            galileo_e1_code_gen_complex_sampled(code_pilot_, signal,
+            galileo_e1_code_gen_complex_sampled(gsl::span<gr_complex>(code_pilot_, vector_length_), signal_C,
                 cboc, gnss_synchro_->PRN, fs_in_, 0, false);
 
             acquisition_cc_->set_local_code(code_data_, code_pilot_);

src/algorithms/acquisition/adapters/galileo_e1_pcps_quicksync_ambiguous_acquisition.cc

@@ -251,8 +251,10 @@ void GalileoE1PcpsQuickSyncAmbiguousAcquisition::set_local_code()
                 "Acquisition" + std::to_string(channel_) + ".cboc", false);
 
             auto* code = new std::complex<float>[code_length_];
+            std::array<char, 3> Signal_;
+            std::memcpy(Signal_.data(), gnss_synchro_->Signal, 3);
 
-            galileo_e1_code_gen_complex_sampled(code, gnss_synchro_->Signal,
+            galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), Signal_,
                 cboc, gnss_synchro_->PRN, fs_in_, 0, false);
 
 

src/algorithms/acquisition/adapters/galileo_e1_pcps_tong_ambiguous_acquisition.cc

@@ -221,8 +221,9 @@ void GalileoE1PcpsTongAmbiguousAcquisition::set_local_code()
                 "Acquisition" + std::to_string(channel_) + ".cboc", false);
 
             auto* code = new std::complex<float>[code_length_];
-
+            std::array<char, 3> Signal_;
-            galileo_e1_code_gen_complex_sampled(code, gnss_synchro_->Signal,
+            std::memcpy(Signal_.data(), gnss_synchro_->Signal, 3);
+            galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), Signal_,
                 cboc, gnss_synchro_->PRN, fs_in_, 0, false);
 
             for (unsigned int i = 0; i < sampled_ms_ / 4; i++)

src/algorithms/acquisition/adapters/galileo_e5a_noncoherent_iq_acquisition_caf.cc

@@ -228,18 +228,18 @@ void GalileoE5aNoncoherentIQAcquisitionCaf::set_local_code()
 
             if (gnss_synchro_->Signal[0] == '5' && gnss_synchro_->Signal[1] == 'X')
                 {
-                    char a[3];
+                    std::array<char, 3> a = {{'5', 'I', '\0'}};
-                    strcpy(a, "5I");
+                    galileo_e5_a_code_gen_complex_sampled(gsl::span<std::complex<float>>(codeI, code_length_), a,
-                    galileo_e5_a_code_gen_complex_sampled(codeI, a,
                         gnss_synchro_->PRN, fs_in_, 0);
 
-                    strcpy(a, "5Q");
+                    std::array<char, 3> b = {{'5', 'Q', '\0'}};
-                    galileo_e5_a_code_gen_complex_sampled(codeQ, a,
+                    galileo_e5_a_code_gen_complex_sampled(gsl::span<std::complex<float>>(codeQ, code_length_), b,
                         gnss_synchro_->PRN, fs_in_, 0);
                 }
             else
                 {
-                    galileo_e5_a_code_gen_complex_sampled(codeI, gnss_synchro_->Signal,
+                    std::array<char, 3> signal_type_ = {{'5', 'X', '\0'}};
+                    galileo_e5_a_code_gen_complex_sampled(gsl::span<std::complex<float>>(codeI, code_length_), signal_type_,
                         gnss_synchro_->PRN, fs_in_, 0);
                 }
             // WARNING: 3ms are coherently integrated. Secondary sequence (1,1,1)

src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition.cc

@@ -236,28 +236,30 @@ void GalileoE5aPcpsAcquisition::init()
 void GalileoE5aPcpsAcquisition::set_local_code()
 {
     auto* code = new gr_complex[code_length_];
-    char signal_[3];
+    std::array<char, 3> signal_;
+    signal_[0] = '5';
+    signal_[2] = '\0';
 
     if (acq_iq_)
         {
-            strcpy(signal_, "5X");
+            signal_[1] = 'X';
         }
     else if (acq_pilot_)
         {
-            strcpy(signal_, "5Q");
+            signal_[1] = 'Q';
         }
     else
         {
-            strcpy(signal_, "5I");
+            signal_[1] = 'I';
         }
 
     if (acq_parameters_.use_automatic_resampler)
         {
-            galileo_e5_a_code_gen_complex_sampled(code, signal_, gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0);
+            galileo_e5_a_code_gen_complex_sampled(gsl::span<gr_complex>(code, code_length_), signal_, gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0);
         }
     else
         {
-            galileo_e5_a_code_gen_complex_sampled(code, signal_, gnss_synchro_->PRN, fs_in_, 0);
+            galileo_e5_a_code_gen_complex_sampled(gsl::span<gr_complex>(code, code_length_), signal_, gnss_synchro_->PRN, fs_in_, 0);
         }
 
     for (unsigned int i = 0; i < sampled_ms_; i++)

src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition_fpga.cc

@@ -119,22 +119,24 @@ GalileoE5aPcpsAcquisitionFpga::GalileoE5aPcpsAcquisitionFpga(ConfigurationInterf
 
     for (uint32_t PRN = 1; PRN <= GALILEO_E5A_NUMBER_OF_CODES; PRN++)
         {
-            char signal_[3];
+            std::array<char, 3> signal_;
+            signal_[0] = '5';
+            signal_[2] = '\0';
 
             if (acq_iq_)
                 {
-                    strcpy(signal_, "5X");
+                    signal_[1] = 'X';
                 }
             else if (acq_pilot_)
                 {
-                    strcpy(signal_, "5Q");
+                    signal_[1] = 'Q';
                 }
             else
                 {
-                    strcpy(signal_, "5I");
+                    signal_[1] = 'I';
                 }
 
-            galileo_e5_a_code_gen_complex_sampled(code, signal_, PRN, fs_in, 0);
+            galileo_e5_a_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, nsamples_total), signal_, PRN, fs_in, 0);
 
             for (uint32_t s = code_length; s < 2 * code_length; s++)
                 {

src/algorithms/acquisition/adapters/glonass_l1_ca_pcps_acquisition.cc

@@ -208,7 +208,7 @@ void GlonassL1CaPcpsAcquisition::set_local_code()
 {
     auto* code = new std::complex<float>[code_length_];
 
-    glonass_l1_ca_code_gen_complex_sampled(code, /* gnss_synchro_->PRN,*/ fs_in_, 0);
+    glonass_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), /* gnss_synchro_->PRN,*/ fs_in_, 0);
 
     for (unsigned int i = 0; i < sampled_ms_; i++)
         {

src/algorithms/acquisition/adapters/glonass_l2_ca_pcps_acquisition.cc

@@ -208,7 +208,7 @@ void GlonassL2CaPcpsAcquisition::set_local_code()
 {
     auto* code = new std::complex<float>[code_length_];
 
-    glonass_l2_ca_code_gen_complex_sampled(code, /* gnss_synchro_->PRN,*/ fs_in_, 0);
+    glonass_l2_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), /* gnss_synchro_->PRN,*/ fs_in_, 0);
 
     for (unsigned int i = 0; i < sampled_ms_; i++)
         {

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition.cc

@@ -41,6 +41,7 @@
 #include "gps_sdr_signal_processing.h"
 #include <boost/math/distributions/exponential.hpp>
 #include <glog/logging.h>
+#include <gsl/gsl>
 
 
 GpsL1CaPcpsAcquisition::GpsL1CaPcpsAcquisition(
@@ -230,11 +231,11 @@ void GpsL1CaPcpsAcquisition::set_local_code()
 
     if (acq_parameters_.use_automatic_resampler)
         {
-            gps_l1_ca_code_gen_complex_sampled(code, gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0);
+            gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0);
         }
     else
         {
-            gps_l1_ca_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_, 0);
+            gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, fs_in_, 0);
         }
     for (unsigned int i = 0; i < sampled_ms_; i++)
         {

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition_fine_doppler.cc

@@ -163,7 +163,7 @@ void GpsL1CaPcpsAcquisitionFineDoppler::init()
 
 void GpsL1CaPcpsAcquisitionFineDoppler::set_local_code()
 {
-    gps_l1_ca_code_gen_complex_sampled(code_, gnss_synchro_->PRN, fs_in_, 0);
+    gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(code_, vector_length_), gnss_synchro_->PRN, fs_in_, 0);
     acquisition_cc_->set_local_code(code_);
 }
 

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition_fpga.cc

@@ -113,7 +113,7 @@ GpsL1CaPcpsAcquisitionFpga::GpsL1CaPcpsAcquisitionFpga(
     // temporary maxima search
     for (uint32_t PRN = 1; PRN <= NUM_PRNs; PRN++)
         {
-            gps_l1_ca_code_gen_complex_sampled(code, PRN, fs_in, 0);  // generate PRN code
+            gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, nsamples_total), PRN, fs_in, 0);  // generate PRN code
 
             for (uint32_t s = code_length; s < 2 * code_length; s++)
                 {

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_assisted_acquisition.cc

@@ -154,7 +154,7 @@ void GpsL1CaPcpsAssistedAcquisition::init()
 
 void GpsL1CaPcpsAssistedAcquisition::set_local_code()
 {
-    gps_l1_ca_code_gen_complex_sampled(code_, gnss_synchro_->PRN, fs_in_, 0);
+    gps_l1_ca_code_gen_complex_sampled(gsl::span<gr_complex>(code_, vector_length_), gnss_synchro_->PRN, fs_in_, 0);
     acquisition_cc_->set_local_code(code_);
 }
 

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_opencl_acquisition.cc

@@ -209,7 +209,7 @@ void GpsL1CaPcpsOpenClAcquisition::set_local_code()
         {
             auto* code = new std::complex<float>[code_length_];
 
-            gps_l1_ca_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_, 0);
+            gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, fs_in_, 0);
 
             for (unsigned int i = 0; i < sampled_ms_; i++)
                 {

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_quicksync_acquisition.cc

@@ -238,7 +238,7 @@ void GpsL1CaPcpsQuickSyncAcquisition::set_local_code()
         {
             auto* code = new std::complex<float>[code_length_]();
 
-            gps_l1_ca_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_, 0);
+            gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, fs_in_, 0);
 
             for (unsigned int i = 0; i < (sampled_ms_ / folding_factor_); i++)
                 {

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_tong_acquisition.cc

@@ -199,7 +199,7 @@ void GpsL1CaPcpsTongAcquisition::set_local_code()
         {
             auto* code = new std::complex<float>[code_length_];
 
-            gps_l1_ca_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_, 0);
+            gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, fs_in_, 0);
 
             for (unsigned int i = 0; i < sampled_ms_; i++)
                 {

src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition.cc

@@ -241,17 +241,15 @@ void GpsL2MPcpsAcquisition::set_local_code()
 {
     auto* code = new std::complex<float>[code_length_];
 
-
     if (acq_parameters_.use_automatic_resampler)
         {
-            gps_l2c_m_code_gen_complex_sampled(code, gnss_synchro_->PRN, acq_parameters_.resampled_fs);
+            gps_l2c_m_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, acq_parameters_.resampled_fs);
         }
     else
         {
-            gps_l2c_m_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_);
+            gps_l2c_m_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, fs_in_);
         }
 
-
     for (unsigned int i = 0; i < num_codes_; i++)
         {
             memcpy(&(code_[i * code_length_]), code,
@@ -268,6 +266,7 @@ void GpsL2MPcpsAcquisition::reset()
     acquisition_->set_active(true);
 }
 
+
 void GpsL2MPcpsAcquisition::set_state(int state)
 {
     acquisition_->set_state(state);

src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition_fpga.cc

@@ -113,7 +113,7 @@ GpsL2MPcpsAcquisitionFpga::GpsL2MPcpsAcquisitionFpga(
 
     for (unsigned int PRN = 1; PRN <= NUM_PRNs; PRN++)
         {
-            gps_l2c_m_code_gen_complex_sampled(code, PRN, fs_in_);
+            gps_l2c_m_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, nsamples_total), PRN, fs_in_);
             // fill in zero padding
             for (unsigned int s = code_length; s < nsamples_total; s++)
                 {

src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition.cc

@@ -237,11 +237,11 @@ void GpsL5iPcpsAcquisition::set_local_code()
 
     if (acq_parameters_.use_automatic_resampler)
         {
-            gps_l5i_code_gen_complex_sampled(code, gnss_synchro_->PRN, acq_parameters_.resampled_fs);
+            gps_l5i_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, acq_parameters_.resampled_fs);
         }
     else
         {
-            gps_l5i_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_);
+            gps_l5i_code_gen_complex_sampled(gsl::span<std::complex<float>>(code, code_length_), gnss_synchro_->PRN, fs_in_);
         }
 
     for (unsigned int i = 0; i < num_codes_; i++)

src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition_fpga.cc

@@ -118,7 +118,7 @@ GpsL5iPcpsAcquisitionFpga::GpsL5iPcpsAcquisitionFpga(
 
     for (uint32_t PRN = 1; PRN <= NUM_PRNs; PRN++)
         {
-            gps_l5i_code_gen_complex_sampled(code, PRN, fs_in);
+            gps_l5i_code_gen_complex_sampled(gsl::span<gr_complex>(code, nsamples_total), PRN, fs_in);
 
             for (uint32_t s = code_length; s < 2 * code_length; s++)
                 {

src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc

@@ -510,11 +510,11 @@ void pcps_acquisition::dump_results(int32_t effective_fft_size)
 
             dims[0] = static_cast<size_t>(1);
             dims[1] = static_cast<size_t>(1);
-            matvar = Mat_VarCreate("doppler_max", MAT_C_UINT32, MAT_T_UINT32, 1, dims, &acq_parameters.doppler_max, 0);
+            matvar = Mat_VarCreate("doppler_max", MAT_C_INT32, MAT_T_INT32, 1, dims, &acq_parameters.doppler_max, 0);
             Mat_VarWrite(matfp, matvar, MAT_COMPRESSION_ZLIB);  // or MAT_COMPRESSION_NONE
             Mat_VarFree(matvar);
 
-            matvar = Mat_VarCreate("doppler_step", MAT_C_UINT32, MAT_T_UINT32, 1, dims, &d_doppler_step, 0);
+            matvar = Mat_VarCreate("doppler_step", MAT_C_INT32, MAT_T_INT32, 1, dims, &d_doppler_step, 0);
             Mat_VarWrite(matfp, matvar, MAT_COMPRESSION_ZLIB);  // or MAT_COMPRESSION_NONE
             Mat_VarFree(matvar);
 
@@ -552,7 +552,7 @@ void pcps_acquisition::dump_results(int32_t effective_fft_size)
             Mat_VarWrite(matfp, matvar, MAT_COMPRESSION_ZLIB);  // or MAT_COMPRESSION_NONE
             Mat_VarFree(matvar);
 
-            matvar = Mat_VarCreate("num_dwells", MAT_C_UINT32, MAT_T_UINT32, 1, dims, &d_num_noncoherent_integrations_counter, 0);
+            matvar = Mat_VarCreate("num_dwells", MAT_C_INT32, MAT_T_INT32, 1, dims, &d_num_noncoherent_integrations_counter, 0);
             Mat_VarWrite(matfp, matvar, MAT_COMPRESSION_ZLIB);  // or MAT_COMPRESSION_NONE
             Mat_VarFree(matvar);
 

src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition_fine_doppler_cc.cc

@@ -430,7 +430,7 @@ int pcps_acquisition_fine_doppler_cc::estimate_Doppler()
     //1. generate local code aligned with the acquisition code phase estimation
     auto *code_replica = static_cast<gr_complex *>(volk_gnsssdr_malloc(signal_samples * sizeof(gr_complex), volk_gnsssdr_get_alignment()));
 
-    gps_l1_ca_code_gen_complex_sampled(code_replica, d_gnss_synchro->PRN, d_fs_in, 0);
+    gps_l1_ca_code_gen_complex_sampled(gsl::span<gr_complex>(code_replica, signal_samples * sizeof(gr_complex)), d_gnss_synchro->PRN, d_fs_in, 0);
 
     int shift_index = static_cast<int>(d_gnss_synchro->Acq_delay_samples);
 
@@ -705,11 +705,11 @@ void pcps_acquisition_fine_doppler_cc::dump_results(int effective_fft_size)
 
             dims[0] = static_cast<size_t>(1);
             dims[1] = static_cast<size_t>(1);
-            matvar = Mat_VarCreate("doppler_max", MAT_C_UINT32, MAT_T_UINT32, 1, dims, &d_config_doppler_max, 0);
+            matvar = Mat_VarCreate("doppler_max", MAT_C_INT32, MAT_T_INT32, 1, dims, &d_config_doppler_max, 0);
             Mat_VarWrite(matfp, matvar, MAT_COMPRESSION_ZLIB);  // or MAT_COMPRESSION_NONE
             Mat_VarFree(matvar);
 
-            matvar = Mat_VarCreate("doppler_step", MAT_C_UINT32, MAT_T_UINT32, 1, dims, &d_doppler_step, 0);
+            matvar = Mat_VarCreate("doppler_step", MAT_C_INT32, MAT_T_INT32, 1, dims, &d_doppler_step, 0);
             Mat_VarWrite(matfp, matvar, MAT_COMPRESSION_ZLIB);  // or MAT_COMPRESSION_NONE
             Mat_VarFree(matvar);
 

src/algorithms/libs/CMakeLists.txt

@@ -92,6 +92,15 @@ else()
     target_link_libraries(algorithms_libs PRIVATE Boost::filesystem Boost::system)
 endif()
 
+if(NOT (CMAKE_CXX_STANDARD VERSION_LESS 20))
+    target_compile_definitions(algorithms_libs PUBLIC -DHAS_SPAN=1)
+else()
+    target_include_directories(algorithms_libs
+        PUBLIC
+            ${CMAKE_SOURCE_DIR}/src/algorithms/libs/gsl/include
+    )
+endif()
+
 target_link_libraries(algorithms_libs
     PUBLIC
         Armadillo::armadillo

src/algorithms/libs/beidou_b1i_signal_processing.cc

@@ -34,7 +34,7 @@
 
 auto auxCeil = [](float x) { return static_cast<int32_t>(static_cast<int64_t>((x) + 1)); };
 
-void beidou_b1i_code_gen_int(int32_t* _dest, int32_t _prn, uint32_t _chip_shift)
+void beidou_b1i_code_gen_int(gsl::span<int32_t> _dest, int32_t _prn, uint32_t _chip_shift)
 {
     const uint32_t _code_length = 2046;
     bool G1[_code_length];
@@ -112,12 +112,12 @@ void beidou_b1i_code_gen_int(int32_t* _dest, int32_t _prn, uint32_t _chip_shift)
 }
 
 
-void beidou_b1i_code_gen_float(float* _dest, int32_t _prn, uint32_t _chip_shift)
+void beidou_b1i_code_gen_float(gsl::span<float> _dest, int32_t _prn, uint32_t _chip_shift)
 {
     uint32_t _code_length = 2046;
     int32_t b1i_code_int[_code_length];
 
-    beidou_b1i_code_gen_int(b1i_code_int, _prn, _chip_shift);
+    beidou_b1i_code_gen_int(gsl::span<int32_t>(b1i_code_int, _code_length), _prn, _chip_shift);
 
     for (uint32_t ii = 0; ii < _code_length; ++ii)
         {
@@ -126,12 +126,12 @@ void beidou_b1i_code_gen_float(float* _dest, int32_t _prn, uint32_t _chip_shift)
 }
 
 
-void beidou_b1i_code_gen_complex(std::complex<float>* _dest, int32_t _prn, uint32_t _chip_shift)
+void beidou_b1i_code_gen_complex(gsl::span<std::complex<float>> _dest, int32_t _prn, uint32_t _chip_shift)
 {
     uint32_t _code_length = 2046;
     int32_t b1i_code_int[_code_length];
 
-    beidou_b1i_code_gen_int(b1i_code_int, _prn, _chip_shift);
+    beidou_b1i_code_gen_int(gsl::span<int32_t>(b1i_code_int, _code_length), _prn, _chip_shift);
 
     for (uint32_t ii = 0; ii < _code_length; ++ii)
         {
@@ -143,7 +143,7 @@ void beidou_b1i_code_gen_complex(std::complex<float>* _dest, int32_t _prn, uint3
 /*
  *  Generates complex GPS L1 C/A code for the desired SV ID and sampled to specific sampling frequency
  */
-void beidou_b1i_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift)
+void beidou_b1i_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift)
 {
     // This function is based on the GNU software GPS for MATLAB in the Kay Borre book
     std::complex<float> _code[2046];

src/algorithms/libs/beidou_b1i_signal_processing.h

@@ -36,20 +36,27 @@
 #include <complex>
 #include <cstdint>
 
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 
 //! Generates int32_t GPS L1 C/A code for the desired SV ID and code shift
-void beidou_b1i_code_gen_int(int32_t* _dest, int32_t _prn, uint32_t _chip_shift);
+void beidou_b1i_code_gen_int(gsl::span<int32_t> _dest, int32_t _prn, uint32_t _chip_shift);
 
 //! Generates float GPS L1 C/A code for the desired SV ID and code shift
-void beidou_b1i_code_gen_float(float* _dest, int32_t _prn, uint32_t _chip_shift);
+void beidou_b1i_code_gen_float(gsl::span<float> _dest, int32_t _prn, uint32_t _chip_shift);
 
 //! Generates complex GPS L1 C/A code for the desired SV ID and code shift, and sampled to specific sampling frequency
-void beidou_b1i_code_gen_complex(std::complex<float>* _dest, int32_t _prn, uint32_t _chip_shift);
+void beidou_b1i_code_gen_complex(gsl::span<std::complex<float>> _dest, int32_t _prn, uint32_t _chip_shift);
 
 //! Generates N complex GPS L1 C/A codes for the desired SV ID and code shift
-void beidou_b1i_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift, uint32_t _ncodes);
+void beidou_b1i_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift, uint32_t _ncodes);
 
 //! Generates complex GPS L1 C/A code for the desired SV ID and code shift
-void beidou_b1i_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift);
+void beidou_b1i_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift);
 
 #endif /* BEIDOU_B1I_SDR_SIGNAL_PROCESSING_H_ */

src/algorithms/libs/beidou_b3i_signal_processing.cc

@@ -34,7 +34,7 @@
 
 auto auxCeil = [](float x) { return static_cast<int>(static_cast<long>((x) + 1)); };
 
-void beidou_b3i_code_gen_int(int* _dest, signed int _prn, unsigned int _chip_shift)
+void beidou_b3i_code_gen_int(gsl::span<int> _dest, signed int _prn, unsigned int _chip_shift)
 {
     const unsigned int _code_length = 10230;
     bool G1[_code_length];
@@ -170,7 +170,7 @@ void beidou_b3i_code_gen_int(int* _dest, signed int _prn, unsigned int _chip_shi
 }
 
 
-void beidou_b3i_code_gen_float(float* _dest, signed int _prn, unsigned int _chip_shift)
+void beidou_b3i_code_gen_float(gsl::span<float> _dest, signed int _prn, unsigned int _chip_shift)
 {
     unsigned int _code_length = 10230;
     int b3i_code_int[10230];
@@ -184,7 +184,7 @@ void beidou_b3i_code_gen_float(float* _dest, signed int _prn, unsigned int _chip
 }
 
 
-void beidou_b3i_code_gen_complex(std::complex<float>* _dest, signed int _prn, unsigned int _chip_shift)
+void beidou_b3i_code_gen_complex(gsl::span<std::complex<float>> _dest, signed int _prn, unsigned int _chip_shift)
 {
     unsigned int _code_length = 10230;
     int b3i_code_int[10230];
@@ -198,7 +198,7 @@ void beidou_b3i_code_gen_complex(std::complex<float>* _dest, signed int _prn, un
 }
 
 
-void beidou_b3i_code_gen_complex_sampled(std::complex<float>* _dest, unsigned int _prn, int _fs, unsigned int _chip_shift)
+void beidou_b3i_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, unsigned int _prn, int _fs, unsigned int _chip_shift)
 {
     // This function is based on the GNU software GPS for MATLAB in the Kay Borre book
     std::complex<float> _code[10230];

src/algorithms/libs/beidou_b3i_signal_processing.h

@@ -39,19 +39,26 @@
 #include <array>
 #include <algorithm>
 
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 //! Generates int BeiDou B3I code for the desired SV ID and code shift
-void beidou_b3i_code_gen_int(int* _dest, signed int _prn, unsigned int _chip_shift);
+void beidou_b3i_code_gen_int(gsl::span<int> _dest, signed int _prn, unsigned int _chip_shift);
 
 //! Generates float BeiDou B3I code for the desired SV ID and code shift
-void beidou_b3i_code_gen_float(float* _dest, signed int _prn, unsigned int _chip_shift);
+void beidou_b3i_code_gen_float(gsl::span<float> _dest, signed int _prn, unsigned int _chip_shift);
 
 //! Generates complex BeiDou B3I code for the desired SV ID and code shift, and sampled to specific sampling frequency
-void beidou_b3i_code_gen_complex(std::complex<float>* _dest, signed int _prn, unsigned int _chip_shift);
+void beidou_b3i_code_gen_complex(gsl::span<std::complex<float>> _dest, signed int _prn, unsigned int _chip_shift);
 
 //! Generates N complex BeiDou B3I codes for the desired SV ID and code shift
-void beidou_b3i_code_gen_complex_sampled(std::complex<float>* _dest, unsigned int _prn, int _fs, unsigned int _chip_shift, unsigned int _ncodes);
+void beidou_b3i_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, unsigned int _prn, int _fs, unsigned int _chip_shift, unsigned int _ncodes);
 
 //! Generates complex BeiDou B3I code for the desired SV ID and code shift
-void beidou_b3i_code_gen_complex_sampled(std::complex<float>* _dest, unsigned int _prn, int _fs, unsigned int _chip_shift);
+void beidou_b3i_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, unsigned int _prn, int _fs, unsigned int _chip_shift);
 
 #endif /* GNSS_SDR_BEIDOU_B3I_SIGNAL_PROCESSING_H_ */

src/algorithms/libs/galileo_e1_signal_processing.cc

@@ -37,9 +37,9 @@
 #include <string>
 
 
-void galileo_e1_code_gen_int(int* _dest, char _Signal[3], int32_t _prn)
+void galileo_e1_code_gen_int(gsl::span<int> _dest, std::array<char, 3> _Signal, int32_t _prn)
 {
-    std::string _galileo_signal = _Signal;
+    std::string _galileo_signal = _Signal.data();
     int32_t prn = _prn - 1;
     int32_t index = 0;
 
@@ -68,10 +68,10 @@ void galileo_e1_code_gen_int(int* _dest, char _Signal[3], int32_t _prn)
 }
 
 
-void galileo_e1_sinboc_11_gen_int(int* _dest, const int* _prn, uint32_t _length_out)
+void galileo_e1_sinboc_11_gen_int(gsl::span<int> _dest, gsl::span<const int> _prn)
 {
     const uint32_t _length_in = GALILEO_E1_B_CODE_LENGTH_CHIPS;
-    auto _period = static_cast<uint32_t>(_length_out / _length_in);
+    auto _period = static_cast<uint32_t>(_dest.size() / _length_in);
     for (uint32_t i = 0; i < _length_in; i++)
         {
             for (uint32_t j = 0; j < (_period / 2); j++)
@@ -86,10 +86,10 @@ void galileo_e1_sinboc_11_gen_int(int* _dest, const int* _prn, uint32_t _length_
 }
 
 
-void galileo_e1_sinboc_61_gen_int(int* _dest, const int* _prn, uint32_t _length_out)
+void galileo_e1_sinboc_61_gen_int(gsl::span<int> _dest, gsl::span<const int> _prn)
 {
     const uint32_t _length_in = GALILEO_E1_B_CODE_LENGTH_CHIPS;
-    auto _period = static_cast<uint32_t>(_length_out / _length_in);
+    auto _period = static_cast<uint32_t>(_dest.size() / _length_in);
 
     for (uint32_t i = 0; i < _length_in; i++)
         {
@@ -105,9 +105,9 @@ void galileo_e1_sinboc_61_gen_int(int* _dest, const int* _prn, uint32_t _length_
 }
 
 
-void galileo_e1_code_gen_sinboc11_float(float* _dest, char _Signal[3], uint32_t _prn)
+void galileo_e1_code_gen_sinboc11_float(gsl::span<float> _dest, std::array<char, 3> _Signal, uint32_t _prn)
 {
-    std::string _galileo_signal = _Signal;
+    std::string _galileo_signal = _Signal.data();
     const auto _codeLength = static_cast<uint32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS);
     int32_t primary_code_E1_chips[4092];                            // _codeLength not accepted by Clang
     galileo_e1_code_gen_int(primary_code_E1_chips, _Signal, _prn);  //generate Galileo E1 code, 1 sample per chip
@@ -119,18 +119,20 @@ void galileo_e1_code_gen_sinboc11_float(float* _dest, char _Signal[3], uint32_t
 }
 
 
-void galileo_e1_gen_float(float* _dest, int* _prn, char _Signal[3])
+void galileo_e1_gen_float(gsl::span<float> _dest, gsl::span<int> _prn, std::array<char, 3> _Signal)
 {
-    std::string _galileo_signal = _Signal;
+    std::string _galileo_signal = _Signal.data();
     const uint32_t _codeLength = 12 * GALILEO_E1_B_CODE_LENGTH_CHIPS;
     const float alpha = sqrt(10.0 / 11.0);
     const float beta = sqrt(1.0 / 11.0);
 
     int32_t sinboc_11[12 * 4092] = {0};  //  _codeLength not accepted by Clang
     int32_t sinboc_61[12 * 4092] = {0};
+    gsl::span<int32_t> sinboc_11_(sinboc_11, _codeLength);
+    gsl::span<int32_t> sinboc_61_(sinboc_61, _codeLength);
 
-    galileo_e1_sinboc_11_gen_int(sinboc_11, _prn, _codeLength);  //generate sinboc(1,1) 12 samples per chip
+    galileo_e1_sinboc_11_gen_int(sinboc_11_, _prn);  //generate sinboc(1,1) 12 samples per chip
-    galileo_e1_sinboc_61_gen_int(sinboc_61, _prn, _codeLength);  //generate sinboc(6,1) 12 samples per chip
+    galileo_e1_sinboc_61_gen_int(sinboc_61_, _prn);  //generate sinboc(6,1) 12 samples per chip
 
     if (_galileo_signal.rfind("1B") != std::string::npos && _galileo_signal.length() >= 2)
         {
@@ -151,12 +153,12 @@ void galileo_e1_gen_float(float* _dest, int* _prn, char _Signal[3])
 }
 
 
-void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
+void galileo_e1_code_gen_float_sampled(gsl::span<float> _dest, std::array<char, 3> _Signal,
     bool _cboc, uint32_t _prn, int32_t _fs, uint32_t _chip_shift,
     bool _secondary_flag)
 {
     // This function is based on the GNU software GPS for MATLAB in Kay Borre's book
-    std::string _galileo_signal = _Signal;
+    std::string _galileo_signal = _Signal.data();
     uint32_t _samplesPerCode;
     const int32_t _codeFreqBasis = GALILEO_E1_CODE_CHIP_RATE_HZ;  // Hz
     auto _codeLength = static_cast<uint32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS);
@@ -167,7 +169,7 @@ void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
 
     const uint32_t delay = ((static_cast<int32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS) - _chip_shift) % static_cast<int32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS)) * _samplesPerCode / GALILEO_E1_B_CODE_LENGTH_CHIPS;
 
-    galileo_e1_code_gen_int(primary_code_E1_chips, _Signal, _prn);  // generate Galileo E1 code, 1 sample per chip
+    galileo_e1_code_gen_int(gsl::span<int32_t>(primary_code_E1_chips, static_cast<uint32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS)), _Signal, _prn);  // generate Galileo E1 code, 1 sample per chip
 
     float* _signal_E1;
 
@@ -176,12 +178,12 @@ void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
 
     if (_cboc == true)
         {
-            galileo_e1_gen_float(_signal_E1, primary_code_E1_chips, _Signal);  // generate cboc 12 samples per chip
+            galileo_e1_gen_float(gsl::span<float>(_signal_E1, _codeLength), gsl::span<int>(primary_code_E1_chips, static_cast<uint32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS)), _Signal);  // generate cboc 12 samples per chip
         }
     else
         {
             auto* _signal_E1_int = static_cast<int32_t*>(volk_gnsssdr_malloc(_codeLength * sizeof(int32_t), volk_gnsssdr_get_alignment()));
-            galileo_e1_sinboc_11_gen_int(_signal_E1_int, primary_code_E1_chips, _codeLength);  // generate sinboc(1,1) 2 samples per chip
+            galileo_e1_sinboc_11_gen_int(gsl::span<int32_t>(_signal_E1_int, _codeLength), gsl::span<int>(primary_code_E1_chips, static_cast<uint32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS)));  // generate sinboc(1,1) 2 samples per chip
 
             for (uint32_t ii = 0; ii < _codeLength; ++ii)
                 {
@@ -194,8 +196,7 @@ void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
         {
             auto* _resampled_signal = new float[_samplesPerCode];
 
-            resampler(_signal_E1, _resampled_signal, _samplesPerChip * _codeFreqBasis, _fs,
+            resampler(gsl::span<float>(_signal_E1, _codeLength), gsl::span<float>(_resampled_signal, _samplesPerCode), _samplesPerChip * _codeFreqBasis, _fs);  // resamples code to fs
-                _codeLength, _samplesPerCode);  // resamples code to fs
 
             delete[] _signal_E1;
             _signal_E1 = _resampled_signal;
@@ -229,11 +230,11 @@ void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
 }
 
 
-void galileo_e1_code_gen_complex_sampled(std::complex<float>* _dest, char _Signal[3],
+void galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, std::array<char, 3> _Signal,
     bool _cboc, uint32_t _prn, int32_t _fs, uint32_t _chip_shift,
     bool _secondary_flag)
 {
-    std::string _galileo_signal = _Signal;
+    std::string _galileo_signal = _Signal.data();
     const int32_t _codeFreqBasis = GALILEO_E1_CODE_CHIP_RATE_HZ;  // Hz
     auto _samplesPerCode = static_cast<uint32_t>(static_cast<double>(_fs) /
                                                  (static_cast<double>(_codeFreqBasis) / static_cast<double>(GALILEO_E1_B_CODE_LENGTH_CHIPS)));
@@ -245,7 +246,7 @@ void galileo_e1_code_gen_complex_sampled(std::complex<float>* _dest, char _Signa
 
     auto* real_code = static_cast<float*>(volk_gnsssdr_malloc(_samplesPerCode * sizeof(float), volk_gnsssdr_get_alignment()));
 
-    galileo_e1_code_gen_float_sampled(real_code, _Signal, _cboc, _prn, _fs, _chip_shift, _secondary_flag);
+    galileo_e1_code_gen_float_sampled(gsl::span<float>(real_code, _samplesPerCode), _Signal, _cboc, _prn, _fs, _chip_shift, _secondary_flag);
 
     for (uint32_t ii = 0; ii < _samplesPerCode; ++ii)
         {
@@ -255,14 +256,14 @@ void galileo_e1_code_gen_complex_sampled(std::complex<float>* _dest, char _Signa
 }
 
 
-void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
+void galileo_e1_code_gen_float_sampled(gsl::span<float> _dest, std::array<char, 3> _Signal,
     bool _cboc, uint32_t _prn, int32_t _fs, uint32_t _chip_shift)
 {
     galileo_e1_code_gen_float_sampled(_dest, _Signal, _cboc, _prn, _fs, _chip_shift, false);
 }
 
 
-void galileo_e1_code_gen_complex_sampled(std::complex<float>* _dest, char _Signal[3],
+void galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, std::array<char, 3> _Signal,
     bool _cboc, uint32_t _prn, int32_t _fs, uint32_t _chip_shift)
 {
     galileo_e1_code_gen_complex_sampled(_dest, _Signal, _cboc, _prn, _fs, _chip_shift, false);

src/algorithms/libs/galileo_e1_signal_processing.h

@@ -32,21 +32,29 @@
 #ifndef GNSS_SDR_GALILEO_E1_SIGNAL_PROCESSING_H_
 #define GNSS_SDR_GALILEO_E1_SIGNAL_PROCESSING_H_
 
+#include <array>
 #include <complex>
 #include <cstdint>
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 
 /*!
  * \brief This function generates Galileo E1 code (can select E1B or E1C sinboc).
  *
  */
-void galileo_e1_code_gen_sinboc11_float(float* _dest, char _Signal[3], uint32_t _prn);
+void galileo_e1_code_gen_sinboc11_float(gsl::span<float> _dest, std::array<char, 3> _Signal, uint32_t _prn);
 
 /*!
  * \brief This function generates Galileo E1 code (can select E1B or E1C, cboc or sinboc
  * and the sample frequency _fs).
  *
  */
-void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
+void galileo_e1_code_gen_float_sampled(gsl::span<float> _dest, std::array<char, 3> _Signal,
     bool _cboc, uint32_t _prn, int32_t _fs, uint32_t _chip_shift,
     bool _secondary_flag);
 
@@ -55,7 +63,7 @@ void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
  * and the sample frequency _fs).
  *
  */
-void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
+void galileo_e1_code_gen_float_sampled(gsl::span<float> _dest, std::array<char, 3> _Signal,
     bool _cboc, uint32_t _prn, int32_t _fs, uint32_t _chip_shift);
 
 /*!
@@ -63,14 +71,14 @@ void galileo_e1_code_gen_float_sampled(float* _dest, char _Signal[3],
  * and the sample frequency _fs).
  *
  */
-void galileo_e1_code_gen_complex_sampled(std::complex<float>* _dest, char _Signal[3],
+void galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, std::array<char, 3> _Signal,
     bool _cboc, uint32_t _prn, int32_t _fs, uint32_t _chip_shift,
     bool _secondary_flag);
 
 /*!
  * \brief galileo_e1_code_gen_complex_sampled without _secondary_flag for backward compatibility.
  */
-void galileo_e1_code_gen_complex_sampled(std::complex<float>* _dest, char _Signal[3],
+void galileo_e1_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, std::array<char, 3> _Signal,
     bool _cboc, uint32_t _prn, int32_t _fs, uint32_t _chip_shift);
 
 #endif /* GNSS_SDR_GALILEO_E1_SIGNAL_PROCESSING_H_ */

src/algorithms/libs/galileo_e5_signal_processing.cc

@@ -37,7 +37,7 @@
 #include <gnuradio/gr_complex.h>
 
 
-void galileo_e5_a_code_gen_complex_primary(std::complex<float>* _dest, int32_t _prn, const char _Signal[3])
+void galileo_e5_a_code_gen_complex_primary(gsl::span<std::complex<float>> _dest, int32_t _prn, std::array<char, 3> _Signal)
 {
     uint32_t prn = _prn - 1;
     uint32_t index = 0;
@@ -100,7 +100,7 @@ void galileo_e5_a_code_gen_complex_primary(std::complex<float>* _dest, int32_t _
 }
 
 
-void galileo_e5_a_code_gen_complex_sampled(std::complex<float>* _dest, char _Signal[3],
+void galileo_e5_a_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, std::array<char, 3> _Signal,
     uint32_t _prn, int32_t _fs, uint32_t _chip_shift)
 {
     uint32_t _samplesPerCode;
@@ -110,7 +110,7 @@ void galileo_e5_a_code_gen_complex_sampled(std::complex<float>* _dest, char _Sig
 
     auto* _code = new std::complex<float>[_codeLength]();
 
-    galileo_e5_a_code_gen_complex_primary(_code, _prn, _Signal);
+    galileo_e5_a_code_gen_complex_primary(gsl::span<std::complex<float>>(_code, _codeLength), _prn, _Signal);
 
     _samplesPerCode = static_cast<uint32_t>(static_cast<double>(_fs) / (static_cast<double>(_codeFreqBasis) / static_cast<double>(_codeLength)));
 
@@ -122,7 +122,7 @@ void galileo_e5_a_code_gen_complex_sampled(std::complex<float>* _dest, char _Sig
             if (posix_memalign(reinterpret_cast<void**>(&_resampled_signal), 16, _samplesPerCode * sizeof(gr_complex)) == 0)
                 {
                 };
-            resampler(_code, _resampled_signal, _codeFreqBasis, _fs, _codeLength, _samplesPerCode);  // resamples code to fs
+            resampler(gsl::span<std::complex<float>>(_code, _codeLength), gsl::span<std::complex<float>>(_resampled_signal, _samplesPerCode), _codeFreqBasis, _fs);  // resamples code to fs
             delete[] _code;
             _code = _resampled_signal;
         }

src/algorithms/libs/galileo_e5_signal_processing.h

@@ -36,22 +36,27 @@
 
 #include <complex>
 #include <cstdint>
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 
 
 /*!
  * \brief Generates Galileo E5a code at 1 sample/chip
  * bool _pilot generates E5aQ code if true and E5aI (data signal) if false.
  */
-void galileo_e5_a_code_gen_complex_primary(std::complex<float>* _dest, int32_t _prn, const char _Signal[3]);
+void galileo_e5_a_code_gen_complex_primary(gsl::span<std::complex<float>> _dest, int32_t _prn, std::array<char, 3> _Signal);
-
-void galileo_e5_a_code_gen_tiered(std::complex<float>* _dest, std::complex<float>* _primary, uint32_t _prn, char _Signal[3]);
 
 /*!
  * \brief Generates Galileo E5a complex code, shifted to the desired chip and sampled at a frequency fs
  * bool _pilot generates E5aQ code if true and E5aI (data signal) if false.
  */
-void galileo_e5_a_code_gen_complex_sampled(std::complex<float>* _dest,
+void galileo_e5_a_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest,
-    char _Signal[3], uint32_t _prn, int32_t _fs, uint32_t _chip_shift);
+    std::array<char, 3> _Signal, uint32_t _prn, int32_t _fs, uint32_t _chip_shift);
 
 
 #endif /* GNSS_SDR_GALILEO_E5_SIGNAL_PROCESSING_H_ */

src/algorithms/libs/glonass_l1_signal_processing.cc

@@ -34,7 +34,7 @@
 
 auto auxCeil = [](float x) { return static_cast<int32_t>(static_cast<int64_t>((x) + 1)); };
 
-void glonass_l1_ca_code_gen_complex(std::complex<float>* _dest, /* int32_t  _prn,*/ uint32_t _chip_shift)
+void glonass_l1_ca_code_gen_complex(gsl::span<std::complex<float>> _dest, /* int32_t  _prn,*/ uint32_t _chip_shift)
 {
     const uint32_t _code_length = 511;
     bool G1[_code_length];
@@ -104,7 +104,7 @@ void glonass_l1_ca_code_gen_complex(std::complex<float>* _dest, /* int32_t  _prn
 /*
  *  Generates complex GLONASS L1 C/A code for the desired SV ID and sampled to specific sampling frequency
  */
-void glonass_l1_ca_code_gen_complex_sampled(std::complex<float>* _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift)
+void glonass_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift)
 {
     // This function is based on the GNU software GPS for MATLAB in the Kay Borre book
     std::complex<float> _code[511];
@@ -121,7 +121,7 @@ void glonass_l1_ca_code_gen_complex_sampled(std::complex<float>* _dest, /* uint3
     //--- Find time constants --------------------------------------------------
     _ts = 1.0 / static_cast<float>(_fs);                                                      // Sampling period in sec
     _tc = 1.0 / static_cast<float>(_codeFreqBasis);                                           // C/A chip period in sec
-    glonass_l1_ca_code_gen_complex(_code, _chip_shift);  //generate C/A code 1 sample per chip
+    glonass_l1_ca_code_gen_complex(gsl::span<std::complex<float>>(_code, 511), _chip_shift);  //generate C/A code 1 sample per chip
 
     for (int32_t i = 0; i < _samplesPerCode; i++)
         {

src/algorithms/libs/glonass_l1_signal_processing.h

@@ -36,13 +36,20 @@
 #include <complex>
 #include <cstdint>
 
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 //!Generates complex GLONASS L1 C/A code for the desired SV ID and code shift, and sampled to specific sampling frequency
-void glonass_l1_ca_code_gen_complex(std::complex<float>* _dest, /*int32_t  _prn,*/ uint32_t _chip_shift);
+void glonass_l1_ca_code_gen_complex(gsl::span<std::complex<float>> _dest, /*int32_t  _prn,*/ uint32_t _chip_shift);
 
 //! Generates N complex GLONASS L1 C/A codes for the desired SV ID and code shift
-void glonass_l1_ca_code_gen_complex_sampled(std::complex<float>* _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift, uint32_t _ncodes);
+void glonass_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift, uint32_t _ncodes);
 
 //! Generates complex GLONASS L1 C/A code for the desired SV ID and code shift
-void glonass_l1_ca_code_gen_complex_sampled(std::complex<float>* _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift);
+void glonass_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift);
 
 #endif /* GNSS_SDR_GLONASS_SDR_SIGNAL_PROCESSING_H_ */

src/algorithms/libs/glonass_l2_signal_processing.cc

@@ -34,7 +34,7 @@
 
 auto auxCeil = [](float x) { return static_cast<int32_t>(static_cast<int64_t>((x) + 1)); };
 
-void glonass_l2_ca_code_gen_complex(std::complex<float>* _dest, /* int32_t _prn,*/ uint32_t _chip_shift)
+void glonass_l2_ca_code_gen_complex(gsl::span<std::complex<float>> _dest, /* int32_t _prn,*/ uint32_t _chip_shift)
 {
     const uint32_t _code_length = 511;
     bool G1[_code_length];
@@ -104,7 +104,7 @@ void glonass_l2_ca_code_gen_complex(std::complex<float>* _dest, /* int32_t _prn,
 /*
  *  Generates complex GLONASS L2 C/A code for the desired SV ID and sampled to specific sampling frequency
  */
-void glonass_l2_ca_code_gen_complex_sampled(std::complex<float>* _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift)
+void glonass_l2_ca_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift)
 {
     // This function is based on the GNU software GPS for MATLAB in the Kay Borre book
     std::complex<float> _code[511];
@@ -121,7 +121,7 @@ void glonass_l2_ca_code_gen_complex_sampled(std::complex<float>* _dest, /* uint3
     //--- Find time constants --------------------------------------------------
     _ts = 1.0 / static_cast<float>(_fs);                                                      // Sampling period in sec
     _tc = 1.0 / static_cast<float>(_codeFreqBasis);                                           // C/A chip period in sec
-    glonass_l2_ca_code_gen_complex(_code, _chip_shift);  //generate C/A code 1 sample per chip
+    glonass_l2_ca_code_gen_complex(gsl::span<std::complex<float>>(_code, 511), _chip_shift);  //generate C/A code 1 sample per chip
 
     for (int32_t i = 0; i < _samplesPerCode; i++)
         {

src/algorithms/libs/glonass_l2_signal_processing.h

@@ -36,13 +36,20 @@
 #include <complex>
 #include <cstdint>
 
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 //!Generates complex GLONASS L2 C/A code for the desired SV ID and code shift, and sampled to specific sampling frequency
-void glonass_l2_ca_code_gen_complex(std::complex<float>* _dest, /*int32_t  _prn,*/ uint32_t _chip_shift);
+void glonass_l2_ca_code_gen_complex(gsl::span<std::complex<float>> _dest, /*int32_t  _prn,*/ uint32_t _chip_shift);
 
 //! Generates N complex GLONASS L2 C/A codes for the desired SV ID and code shift
-void glonass_l2_ca_code_gen_complex_sampled(std::complex<float>* _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift, uint32_t _ncodes);
+void glonass_l2_ca_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift, uint32_t _ncodes);
 
 //! Generates complex GLONASS L2 C/A code for the desired SV ID and code shift
-void glonass_l2_ca_code_gen_complex_sampled(std::complex<float>* _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift);
+void glonass_l2_ca_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, /* uint32_t _prn,*/ int32_t _fs, uint32_t _chip_shift);
 
 #endif /* GNSS_SDR_GLONASS_L2_SIGNAL_PROCESSING_H_ */

src/algorithms/libs/gnss_signal_processing.cc

@@ -38,19 +38,19 @@
 
 auto auxCeil2 = [](float x) { return static_cast<int32_t>(static_cast<int64_t>((x) + 1)); };
 
-void complex_exp_gen(std::complex<float>* _dest, double _f, double _fs, uint32_t _samps)
+void complex_exp_gen(gsl::span<std::complex<float>> _dest, double _f, double _fs)
 {
     gr::fxpt_nco d_nco;
     d_nco.set_freq((GPS_TWO_PI * _f) / _fs);
-    d_nco.sincos(_dest, _samps, 1);
+    d_nco.sincos(_dest.data(), _dest.size(), 1);
 }
 
 
-void complex_exp_gen_conj(std::complex<float>* _dest, double _f, double _fs, uint32_t _samps)
+void complex_exp_gen_conj(gsl::span<std::complex<float>> _dest, double _f, double _fs)
 {
     gr::fxpt_nco d_nco;
     d_nco.set_freq(-(GPS_TWO_PI * _f) / _fs);
-    d_nco.sincos(_dest, _samps, 1);
+    d_nco.sincos(_dest.data(), _dest.size(), 1);
 }
 
 
@@ -158,15 +158,15 @@ void hex_to_binary_converter(int32_t* _dest, char _from)
 }
 
 
-void resampler(const float* _from, float* _dest, float _fs_in,
+void resampler(const gsl::span<float> _from, gsl::span<float> _dest, float _fs_in,
-    float _fs_out, uint32_t _length_in, uint32_t _length_out)
+    float _fs_out)
 {
     uint32_t _codeValueIndex;
     float aux;
     //--- Find time constants --------------------------------------------------
     const float _t_in = 1 / _fs_in;    // Incoming sampling  period in sec
     const float _t_out = 1 / _fs_out;  // Out sampling period in sec
-    for (uint32_t i = 0; i < _length_out - 1; i++)
+    for (uint32_t i = 0; i < _dest.size() - 1; i++)
         {
             //=== Digitizing =======================================================
             //--- compute index array to read sampled values -------------------------
@@ -178,19 +178,19 @@ void resampler(const float* _from, float* _dest, float _fs_in,
             _dest[i] = _from[_codeValueIndex];
         }
     //--- Correct the last index (due to number rounding issues) -----------
-    _dest[_length_out - 1] = _from[_length_in - 1];
+    _dest[_dest.size() - 1] = _from[_from.size() - 1];
 }
 
 
-void resampler(const std::complex<float>* _from, std::complex<float>* _dest, float _fs_in,
+void resampler(gsl::span<const std::complex<float>> _from, gsl::span<std::complex<float>> _dest, float _fs_in,
-    float _fs_out, uint32_t _length_in, uint32_t _length_out)
+    float _fs_out)
 {
     uint32_t _codeValueIndex;
     float aux;
     //--- Find time constants --------------------------------------------------
     const float _t_in = 1 / _fs_in;    // Incoming sampling  period in sec
     const float _t_out = 1 / _fs_out;  // Out sampling period in sec
-    for (uint32_t i = 0; i < _length_out - 1; i++)
+    for (uint32_t i = 0; i < _dest.size() - 1; i++)
         {
             //=== Digitizing =======================================================
             //--- compute index array to read sampled values -------------------------
@@ -202,5 +202,5 @@ void resampler(const std::complex<float>* _from, std::complex<float>* _dest, flo
             _dest[i] = _from[_codeValueIndex];
         }
     //--- Correct the last index (due to number rounding issues) -----------
-    _dest[_length_out - 1] = _from[_length_in - 1];
+    _dest[_dest.size() - 1] = _from[_from.size() - 1];
 }

src/algorithms/libs/gnss_signal_processing.h

@@ -38,21 +38,25 @@
 #include <complex>
 #include <cstdint>
 
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 
 /*!
  * \brief This function generates a complex exponential in _dest.
  *
  */
-void complex_exp_gen(std::complex<float>* _dest, double _f, double _fs,
+void complex_exp_gen(gsl::span<std::complex<float>> _dest, double _f, double _fs);
-    uint32_t _samps);
 
 /*!
  * \brief This function generates a conjugate complex exponential in _dest.
  *
  */
-void complex_exp_gen_conj(std::complex<float>* _dest, double _f, double _fs,
+void complex_exp_gen_conj(gsl::span<std::complex<float>> _dest, double _f, double _fs);
-    uint32_t _samps);
-
 
 /*!
  * \brief This function makes a conversion from hex (the input is a char)
@@ -65,15 +69,14 @@ void hex_to_binary_converter(int32_t* _dest, char _from);
  * \brief This function resamples a sequence of float values.
  *
  */
-void resampler(const float* _from, float* _dest,
+void resampler(const gsl::span<float> _from, gsl::span<float> _dest,
-    float _fs_in, float _fs_out, uint32_t _length_in,
+    float _fs_in, float _fs_out);
-    uint32_t _length_out);
+
 /*!
  * \brief This function resamples a sequence of complex values.
  *
  */
-void resampler(const std::complex<float>* _from, std::complex<float>* _dest,
+void resampler(gsl::span<const std::complex<float>> _from, gsl::span<std::complex<float>> _dest,
-    float _fs_in, float _fs_out, uint32_t _length_in,
+    float _fs_in, float _fs_out);
-    uint32_t _length_out);
 
 #endif /* GNSS_SDR_GNSS_SIGNAL_PROCESSING_H_ */

src/algorithms/libs/gps_l2c_signal.cc

@@ -41,7 +41,7 @@ int32_t gps_l2c_m_shift(int32_t x)
 }
 
 
-void gps_l2c_m_code(int32_t* _dest, uint32_t _prn)
+void gps_l2c_m_code(gsl::span<int32_t> _dest, uint32_t _prn)
 {
     int32_t x;
     x = GPS_L2C_M_INIT_REG[_prn - 1];
@@ -53,13 +53,13 @@ void gps_l2c_m_code(int32_t* _dest, uint32_t _prn)
 }
 
 
-void gps_l2c_m_code_gen_complex(std::complex<float>* _dest, uint32_t _prn)
+void gps_l2c_m_code_gen_complex(gsl::span<std::complex<float>> _dest, uint32_t _prn)
 {
     auto* _code = new int32_t[GPS_L2_M_CODE_LENGTH_CHIPS];
 
     if (_prn > 0 and _prn < 51)
         {
-            gps_l2c_m_code(_code, _prn);
+            gps_l2c_m_code(gsl::span<int32_t>(_code, GPS_L2_M_CODE_LENGTH_CHIPS), _prn);
         }
 
     for (int32_t i = 0; i < GPS_L2_M_CODE_LENGTH_CHIPS; i++)
@@ -71,13 +71,13 @@ void gps_l2c_m_code_gen_complex(std::complex<float>* _dest, uint32_t _prn)
 }
 
 
-void gps_l2c_m_code_gen_float(float* _dest, uint32_t _prn)
+void gps_l2c_m_code_gen_float(gsl::span<float> _dest, uint32_t _prn)
 {
     auto* _code = new int32_t[GPS_L2_M_CODE_LENGTH_CHIPS];
 
     if (_prn > 0 and _prn < 51)
         {
-            gps_l2c_m_code(_code, _prn);
+            gps_l2c_m_code(gsl::span<int32_t>(_code, GPS_L2_M_CODE_LENGTH_CHIPS), _prn);
         }
 
     for (int32_t i = 0; i < GPS_L2_M_CODE_LENGTH_CHIPS; i++)
@@ -92,12 +92,12 @@ void gps_l2c_m_code_gen_float(float* _dest, uint32_t _prn)
 /*
  *  Generates complex GPS L2C M code for the desired SV ID and sampled to specific sampling frequency
  */
-void gps_l2c_m_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs)
+void gps_l2c_m_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs)
 {
     auto* _code = new int32_t[GPS_L2_M_CODE_LENGTH_CHIPS];
     if (_prn > 0 and _prn < 51)
         {
-            gps_l2c_m_code(_code, _prn);
+            gps_l2c_m_code(gsl::span<int32_t>(_code, GPS_L2_M_CODE_LENGTH_CHIPS), _prn);
         }
 
     int32_t _samplesPerCode, _codeValueIndex;

src/algorithms/libs/gps_l2c_signal.h

@@ -36,12 +36,19 @@
 #include <complex>
 #include <cstdint>
 
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 
 //! Generates complex GPS L2C M code for the desired SV ID
-void gps_l2c_m_code_gen_complex(std::complex<float>* _dest, uint32_t _prn);
+void gps_l2c_m_code_gen_complex(gsl::span<std::complex<float>> _dest, uint32_t _prn);
-void gps_l2c_m_code_gen_float(float* _dest, uint32_t _prn);
+void gps_l2c_m_code_gen_float(gsl::span<float> _dest, uint32_t _prn);
 
 //! Generates complex GPS L2C M code for the desired SV ID, and sampled to specific sampling frequency
-void gps_l2c_m_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs);
+void gps_l2c_m_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs);
 
 #endif /* GNSS_GPS_L2C_SIGNAL_H_ */

src/algorithms/libs/gps_l5_signal.cc

@@ -131,7 +131,7 @@ std::deque<bool> make_l5q_xb()
 }
 
 
-void make_l5i(int32_t* _dest, int32_t prn)
+void make_l5i(gsl::span<int32_t> _dest, int32_t prn)
 {
     int32_t xb_offset = GPS_L5I_INIT_REG[prn];
 
@@ -151,7 +151,7 @@ void make_l5i(int32_t* _dest, int32_t prn)
 }
 
 
-void make_l5q(int32_t* _dest, int32_t prn)
+void make_l5q(gsl::span<int32_t> _dest, int32_t prn)
 {
     int32_t xb_offset = GPS_L5Q_INIT_REG[prn];
 
@@ -171,13 +171,13 @@ void make_l5q(int32_t* _dest, int32_t prn)
 }
 
 
-void gps_l5i_code_gen_complex(std::complex<float>* _dest, uint32_t _prn)
+void gps_l5i_code_gen_complex(gsl::span<std::complex<float>> _dest, uint32_t _prn)
 {
     auto* _code = new int32_t[GPS_L5I_CODE_LENGTH_CHIPS];
 
     if (_prn > 0 and _prn < 51)
         {
-            make_l5i(_code, _prn - 1);
+            make_l5i(gsl::span<int32_t>(_code, GPS_L5I_CODE_LENGTH_CHIPS), _prn - 1);
         }
 
     for (int32_t i = 0; i < GPS_L5I_CODE_LENGTH_CHIPS; i++)
@@ -189,13 +189,13 @@ void gps_l5i_code_gen_complex(std::complex<float>* _dest, uint32_t _prn)
 }
 
 
-void gps_l5i_code_gen_float(float* _dest, uint32_t _prn)
+void gps_l5i_code_gen_float(gsl::span<float> _dest, uint32_t _prn)
 {
     auto* _code = new int32_t[GPS_L5I_CODE_LENGTH_CHIPS];
 
     if (_prn > 0 and _prn < 51)
         {
-            make_l5i(_code, _prn - 1);
+            make_l5i(gsl::span<int32_t>(_code, GPS_L5I_CODE_LENGTH_CHIPS), _prn - 1);
         }
 
     for (int32_t i = 0; i < GPS_L5I_CODE_LENGTH_CHIPS; i++)
@@ -210,12 +210,12 @@ void gps_l5i_code_gen_float(float* _dest, uint32_t _prn)
 /*
  *  Generates complex GPS L5i code for the desired SV ID and sampled to specific sampling frequency
  */
-void gps_l5i_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs)
+void gps_l5i_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs)
 {
     auto* _code = new int32_t[GPS_L5I_CODE_LENGTH_CHIPS];
     if (_prn > 0 and _prn < 51)
         {
-            make_l5i(_code, _prn - 1);
+            make_l5i(gsl::span<int32_t>(_code, GPS_L5I_CODE_LENGTH_CHIPS), _prn - 1);
         }
 
     int32_t _samplesPerCode, _codeValueIndex;
@@ -252,13 +252,13 @@ void gps_l5i_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn,
 }
 
 
-void gps_l5q_code_gen_complex(std::complex<float>* _dest, uint32_t _prn)
+void gps_l5q_code_gen_complex(gsl::span<std::complex<float>> _dest, uint32_t _prn)
 {
     auto* _code = new int32_t[GPS_L5Q_CODE_LENGTH_CHIPS];
 
     if (_prn > 0 and _prn < 51)
         {
-            make_l5q(_code, _prn - 1);
+            make_l5q(gsl::span<int32_t>(_code, GPS_L5Q_CODE_LENGTH_CHIPS), _prn - 1);
         }
 
     for (int32_t i = 0; i < GPS_L5Q_CODE_LENGTH_CHIPS; i++)
@@ -270,13 +270,13 @@ void gps_l5q_code_gen_complex(std::complex<float>* _dest, uint32_t _prn)
 }
 
 
-void gps_l5q_code_gen_float(float* _dest, uint32_t _prn)
+void gps_l5q_code_gen_float(gsl::span<float> _dest, uint32_t _prn)
 {
     auto* _code = new int32_t[GPS_L5Q_CODE_LENGTH_CHIPS];
 
     if (_prn > 0 and _prn < 51)
         {
-            make_l5q(_code, _prn - 1);
+            make_l5q(gsl::span<int32_t>(_code, GPS_L5Q_CODE_LENGTH_CHIPS), _prn - 1);
         }
 
     for (int32_t i = 0; i < GPS_L5Q_CODE_LENGTH_CHIPS; i++)
@@ -291,12 +291,12 @@ void gps_l5q_code_gen_float(float* _dest, uint32_t _prn)
 /*
  *  Generates complex GPS L5Q code for the desired SV ID and sampled to specific sampling frequency
  */
-void gps_l5q_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs)
+void gps_l5q_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs)
 {
     auto* _code = new int32_t[GPS_L5Q_CODE_LENGTH_CHIPS];
     if (_prn > 0 and _prn < 51)
         {
-            make_l5q(_code, _prn - 1);
+            make_l5q(gsl::span<int32_t>(_code, GPS_L5Q_CODE_LENGTH_CHIPS), _prn - 1);
         }
 
     int32_t _samplesPerCode, _codeValueIndex;

src/algorithms/libs/gps_l5_signal.h

@@ -36,23 +36,30 @@
 #include <complex>
 #include <cstdint>
 
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 //! Generates complex GPS L5I code for the desired SV ID
-void gps_l5i_code_gen_complex(std::complex<float>* _dest, uint32_t _prn);
+void gps_l5i_code_gen_complex(gsl::span<std::complex<float>> _dest, uint32_t _prn);
 
 //! Generates real GPS L5I code for the desired SV ID
-void gps_l5i_code_gen_float(float* _dest, uint32_t _prn);
+void gps_l5i_code_gen_float(gsl::span<float> _dest, uint32_t _prn);
 
 //! Generates complex GPS L5Q code for the desired SV ID
-void gps_l5q_code_gen_complex(std::complex<float>* _dest, uint32_t _prn);
+void gps_l5q_code_gen_complex(gsl::span<std::complex<float>> _dest, uint32_t _prn);
 
 //! Generates real GPS L5Q code for the desired SV ID
-void gps_l5q_code_gen_float(float* _dest, uint32_t _prn);
+void gps_l5q_code_gen_float(gsl::span<float> _dest, uint32_t _prn);
 
 //! Generates complex GPS L5I code for the desired SV ID, and sampled to specific sampling frequency
-void gps_l5i_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs);
+void gps_l5i_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs);
 
 //! Generates complex GPS L5Q code for the desired SV ID, and sampled to specific sampling frequency
-void gps_l5q_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs);
+void gps_l5q_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs);
 
 
 #endif /* GNSS_SDR_GPS_L5_SIGNAL_H_ */

src/algorithms/libs/gps_sdr_signal_processing.cc

@@ -34,7 +34,7 @@
 
 auto auxCeil = [](float x) { return static_cast<int32_t>(static_cast<int64_t>((x) + 1)); };
 
-void gps_l1_ca_code_gen_int(int32_t* _dest, int32_t _prn, uint32_t _chip_shift)
+void gps_l1_ca_code_gen_int(gsl::span<int32_t> _dest, int32_t _prn, uint32_t _chip_shift)
 {
     const uint32_t _code_length = 1023;
     bool G1[_code_length];
@@ -116,7 +116,7 @@ void gps_l1_ca_code_gen_int(int32_t* _dest, int32_t _prn, uint32_t _chip_shift)
 }
 
 
-void gps_l1_ca_code_gen_float(float* _dest, int32_t _prn, uint32_t _chip_shift)
+void gps_l1_ca_code_gen_float(gsl::span<float> _dest, int32_t _prn, uint32_t _chip_shift)
 {
     const uint32_t _code_length = 1023;
     int32_t ca_code_int[_code_length];
@@ -130,7 +130,7 @@ void gps_l1_ca_code_gen_float(float* _dest, int32_t _prn, uint32_t _chip_shift)
 }
 
 
-void gps_l1_ca_code_gen_complex(std::complex<float>* _dest, int32_t _prn, uint32_t _chip_shift)
+void gps_l1_ca_code_gen_complex(gsl::span<std::complex<float>> _dest, int32_t _prn, uint32_t _chip_shift)
 {
     const uint32_t _code_length = 1023;
     int32_t ca_code_int[_code_length] = {0};
@@ -148,7 +148,7 @@ void gps_l1_ca_code_gen_complex(std::complex<float>* _dest, int32_t _prn, uint32
  *  Generates complex GPS L1 C/A code for the desired SV ID and sampled to specific sampling frequency
  *  NOTICE: the number of samples is rounded towards zero (integer truncation)
  */
-void gps_l1_ca_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift)
+void gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift)
 {
     // This function is based on the GNU software GPS for MATLAB in the Kay Borre book
     std::complex<float> _code[1023];

src/algorithms/libs/gps_sdr_signal_processing.h

@@ -36,19 +36,26 @@
 #include <complex>
 #include <cstdint>
 
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
+
 //! Generates int GPS L1 C/A code for the desired SV ID and code shift
-void gps_l1_ca_code_gen_int(int32_t* _dest, int32_t _prn, uint32_t _chip_shift);
+void gps_l1_ca_code_gen_int(gsl::span<int32_t> _dest, int32_t _prn, uint32_t _chip_shift);
 
 //! Generates float GPS L1 C/A code for the desired SV ID and code shift
-void gps_l1_ca_code_gen_float(float* _dest, int32_t _prn, uint32_t _chip_shift);
+void gps_l1_ca_code_gen_float(gsl::span<float> _dest, int32_t _prn, uint32_t _chip_shift);
 
 //! Generates complex GPS L1 C/A code for the desired SV ID and code shift, and sampled to specific sampling frequency
-void gps_l1_ca_code_gen_complex(std::complex<float>* _dest, int32_t _prn, uint32_t _chip_shift);
+void gps_l1_ca_code_gen_complex(gsl::span<std::complex<float>> _dest, int32_t _prn, uint32_t _chip_shift);
 
 //! Generates N complex GPS L1 C/A codes for the desired SV ID and code shift
-void gps_l1_ca_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift, uint32_t _ncodes);
+void gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift, uint32_t _ncodes);
 
 //! Generates complex GPS L1 C/A code for the desired SV ID and code shift
-void gps_l1_ca_code_gen_complex_sampled(std::complex<float>* _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift);
+void gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>> _dest, uint32_t _prn, int32_t _fs, uint32_t _chip_shift);
 
 #endif /* GNSS_SDR_GPS_SDR_SIGNAL_PROCESSING_H_ */

src/algorithms/libs/gsl/include/gsl/gsl

@@ -0,0 +1,29 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_GSL_H
+#define GSL_GSL_H
+
+#include <gsl/gsl_algorithm> // copy
+#include <gsl/gsl_assert>    // Ensures/Expects
+#include <gsl/gsl_byte>      // byte
+#include <gsl/gsl_util>      // finally()/narrow()/narrow_cast()...
+#include <gsl/multi_span>    // multi_span, strided_span...
+#include <gsl/pointers>      // owner, not_null
+#include <gsl/span>          // span
+#include <gsl/string_span>   // zstring, string_span, zstring_builder...
+
+#endif // GSL_GSL_H

src/algorithms/libs/gsl/include/gsl/gsl_algorithm

@@ -0,0 +1,61 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_ALGORITHM_H
+#define GSL_ALGORITHM_H
+
+#include <gsl/gsl_assert> // for Expects
+#include <gsl/span>       // for dynamic_extent, span
+
+#include <algorithm>   // for copy_n
+#include <cstddef>     // for ptrdiff_t
+#include <type_traits> // for is_assignable
+
+#ifdef _MSC_VER
+#pragma warning(push)
+
+// turn off some warnings that are noisy about our Expects statements
+#pragma warning(disable : 4127) // conditional expression is constant
+#pragma warning(disable : 4996) // unsafe use of std::copy_n
+
+#endif // _MSC_VER
+
+namespace gsl
+{
+// Note: this will generate faster code than std::copy using span iterator in older msvc+stl
+// not necessary for msvc since VS2017 15.8 (_MSC_VER >= 1915)
+template <class SrcElementType, std::ptrdiff_t SrcExtent, class DestElementType,
+          std::ptrdiff_t DestExtent>
+void copy(span<SrcElementType, SrcExtent> src, span<DestElementType, DestExtent> dest)
+{
+    static_assert(std::is_assignable<decltype(*dest.data()), decltype(*src.data())>::value,
+                  "Elements of source span can not be assigned to elements of destination span");
+    static_assert(SrcExtent == dynamic_extent || DestExtent == dynamic_extent ||
+                      (SrcExtent <= DestExtent),
+                  "Source range is longer than target range");
+
+    Expects(dest.size() >= src.size());
+    GSL_SUPPRESS(stl.1) // NO-FORMAT: attribute
+    std::copy_n(src.data(), src.size(), dest.data());
+}
+
+} // namespace gsl
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif // _MSC_VER
+
+#endif // GSL_ALGORITHM_H

src/algorithms/libs/gsl/include/gsl/gsl_assert

@@ -0,0 +1,177 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_CONTRACTS_H
+#define GSL_CONTRACTS_H
+
+#include <exception>
+#include <stdexcept> // for logic_error
+
+//
+// make suppress attributes parse for some compilers
+// Hopefully temporary until suppression standardization occurs
+//
+#if defined(__clang__)
+#define GSL_SUPPRESS(x) [[gsl::suppress("x")]]
+#else
+#if defined(_MSC_VER)
+#define GSL_SUPPRESS(x) [[gsl::suppress(x)]]
+#else
+#define GSL_SUPPRESS(x)
+#endif // _MSC_VER
+#endif // __clang__
+
+//
+// Temporary until MSVC STL supports no-exceptions mode.
+// Currently terminate is a no-op in this mode, so we add termination behavior back
+//
+#if defined(_MSC_VER) && defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS
+#define GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND
+#include <intrin.h>
+#define RANGE_CHECKS_FAILURE 0
+
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Winvalid-noreturn"
+#endif
+
+#endif
+
+//
+// There are three configuration options for this GSL implementation's behavior
+// when pre/post conditions on the GSL types are violated:
+//
+// 1. GSL_TERMINATE_ON_CONTRACT_VIOLATION: std::terminate will be called (default)
+// 2. GSL_THROW_ON_CONTRACT_VIOLATION: a gsl::fail_fast exception will be thrown
+// 3. GSL_UNENFORCED_ON_CONTRACT_VIOLATION: nothing happens
+//
+#if !(defined(GSL_THROW_ON_CONTRACT_VIOLATION) || defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION) ||  \
+      defined(GSL_UNENFORCED_ON_CONTRACT_VIOLATION))
+#define GSL_TERMINATE_ON_CONTRACT_VIOLATION
+#endif
+
+#define GSL_STRINGIFY_DETAIL(x) #x
+#define GSL_STRINGIFY(x) GSL_STRINGIFY_DETAIL(x)
+
+#if defined(__clang__) || defined(__GNUC__)
+#define GSL_LIKELY(x) __builtin_expect(!!(x), 1)
+#define GSL_UNLIKELY(x) __builtin_expect(!!(x), 0)
+#else
+#define GSL_LIKELY(x) (!!(x))
+#define GSL_UNLIKELY(x) (!!(x))
+#endif
+
+//
+// GSL_ASSUME(cond)
+//
+// Tell the optimizer that the predicate cond must hold. It is unspecified
+// whether or not cond is actually evaluated.
+//
+#ifdef _MSC_VER
+#define GSL_ASSUME(cond) __assume(cond)
+#elif defined(__GNUC__)
+#define GSL_ASSUME(cond) ((cond) ? static_cast<void>(0) : __builtin_unreachable())
+#else
+#define GSL_ASSUME(cond) static_cast<void>((cond) ? 0 : 0)
+#endif
+
+//
+// GSL.assert: assertions
+//
+
+namespace gsl
+{
+struct fail_fast : public std::logic_error
+{
+    explicit fail_fast(char const* const message) : std::logic_error(message) {}
+};
+
+namespace details
+{
+#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
+
+    typedef void  (__cdecl *terminate_handler)();
+
+    GSL_SUPPRESS(f.6) // NO-FORMAT: attribute
+    [[noreturn]] inline void __cdecl default_terminate_handler()
+    {
+        __fastfail(RANGE_CHECKS_FAILURE);
+    }
+
+    inline gsl::details::terminate_handler& get_terminate_handler() noexcept
+    {
+        static terminate_handler handler = &default_terminate_handler;
+        return handler;
+    }
+
+#endif
+
+    [[noreturn]] inline void terminate() noexcept
+    {
+#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
+        (*gsl::details::get_terminate_handler())();
+#else
+        std::terminate();
+#endif
+    }
+
+#if defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION)
+
+    template <typename Exception>
+    [[noreturn]] void throw_exception(Exception&&) noexcept
+    {
+        gsl::details::terminate();
+    }
+
+#else
+
+    template <typename Exception>
+    [[noreturn]] void throw_exception(Exception&& exception)
+    {
+        throw std::forward<Exception>(exception);
+    }
+
+#endif // GSL_TERMINATE_ON_CONTRACT_VIOLATION
+
+} // namespace details
+} // namespace gsl
+
+#if defined(GSL_THROW_ON_CONTRACT_VIOLATION)
+
+#define GSL_CONTRACT_CHECK(type, cond)                                                             \
+    (GSL_LIKELY(cond) ? static_cast<void>(0)                                                       \
+                      : gsl::details::throw_exception(gsl::fail_fast(                              \
+                            "GSL: " type " failure at " __FILE__ ": " GSL_STRINGIFY(__LINE__))))
+
+#elif defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION)
+
+#define GSL_CONTRACT_CHECK(type, cond)                                                             \
+    (GSL_LIKELY(cond) ? static_cast<void>(0) : gsl::details::terminate())
+
+#elif defined(GSL_UNENFORCED_ON_CONTRACT_VIOLATION)
+
+#define GSL_CONTRACT_CHECK(type, cond) GSL_ASSUME(cond)
+
+#endif // GSL_THROW_ON_CONTRACT_VIOLATION
+
+#define Expects(cond) GSL_CONTRACT_CHECK("Precondition", cond)
+#define Ensures(cond) GSL_CONTRACT_CHECK("Postcondition", cond)
+
+#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND) && defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+
+#endif // GSL_CONTRACTS_H

src/algorithms/libs/gsl/include/gsl/gsl_byte

@@ -0,0 +1,203 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_BYTE_H
+#define GSL_BYTE_H
+
+//
+// make suppress attributes work for some compilers
+// Hopefully temporary until suppression standardization occurs
+//
+#if defined(__clang__)
+#define GSL_SUPPRESS(x) [[gsl::suppress("x")]]
+#else
+#if defined(_MSC_VER)
+#define GSL_SUPPRESS(x) [[gsl::suppress(x)]]
+#else
+#define GSL_SUPPRESS(x)
+#endif // _MSC_VER
+#endif // __clang__
+
+#include <type_traits>
+
+#ifdef _MSC_VER
+
+#pragma warning(push)
+
+// Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.
+#pragma warning(disable : 26493) // don't use c-style casts // TODO: MSVC suppression in templates does not always work
+
+#ifndef GSL_USE_STD_BYTE
+// this tests if we are under MSVC and the standard lib has std::byte and it is enabled
+#if defined(_HAS_STD_BYTE) && _HAS_STD_BYTE
+
+#define GSL_USE_STD_BYTE 1
+
+#else // defined(_HAS_STD_BYTE) && _HAS_STD_BYTE
+
+#define GSL_USE_STD_BYTE 0
+
+#endif // defined(_HAS_STD_BYTE) && _HAS_STD_BYTE
+#endif // GSL_USE_STD_BYTE
+
+#else // _MSC_VER
+
+#ifndef GSL_USE_STD_BYTE
+// this tests if we are under GCC or Clang with enough -std:c++1z power to get us std::byte
+// also check if libc++ version is sufficient (> 5.0) or libstc++ actually contains std::byte
+#if defined(__cplusplus) && (__cplusplus >= 201703L) && \
+  (defined(__cpp_lib_byte) && (__cpp_lib_byte >= 201603)  || \
+   defined(_LIBCPP_VERSION) && (_LIBCPP_VERSION >= 5000))
+
+#define GSL_USE_STD_BYTE 1
+#include <cstddef>
+
+#else // defined(__cplusplus) && (__cplusplus >= 201703L) &&
+      //   (defined(__cpp_lib_byte) && (__cpp_lib_byte >= 201603)  ||
+      //    defined(_LIBCPP_VERSION) && (_LIBCPP_VERSION >= 5000))
+
+#define GSL_USE_STD_BYTE 0
+
+#endif //defined(__cplusplus) && (__cplusplus >= 201703L) &&
+       //   (defined(__cpp_lib_byte) && (__cpp_lib_byte >= 201603)  ||
+       //    defined(_LIBCPP_VERSION) && (_LIBCPP_VERSION >= 5000))
+#endif // GSL_USE_STD_BYTE
+
+#endif // _MSC_VER
+
+// Use __may_alias__ attribute on gcc and clang
+#if defined __clang__ || (defined(__GNUC__) && __GNUC__ > 5)
+#define byte_may_alias __attribute__((__may_alias__))
+#else // defined __clang__ || defined __GNUC__
+#define byte_may_alias
+#endif // defined __clang__ || defined __GNUC__
+
+namespace gsl
+{
+#if GSL_USE_STD_BYTE
+
+using std::byte;
+using std::to_integer;
+
+#else // GSL_USE_STD_BYTE
+
+// This is a simple definition for now that allows
+// use of byte within span<> to be standards-compliant
+enum class byte_may_alias byte : unsigned char
+{
+};
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr byte& operator<<=(byte& b, IntegerType shift) noexcept
+{
+    return b = byte(static_cast<unsigned char>(b) << shift);
+}
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr byte operator<<(byte b, IntegerType shift) noexcept
+{
+    return byte(static_cast<unsigned char>(b) << shift);
+}
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr byte& operator>>=(byte& b, IntegerType shift) noexcept
+{
+    return b = byte(static_cast<unsigned char>(b) >> shift);
+}
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr byte operator>>(byte b, IntegerType shift) noexcept
+{
+    return byte(static_cast<unsigned char>(b) >> shift);
+}
+
+constexpr byte& operator|=(byte& l, byte r) noexcept
+{
+    return l = byte(static_cast<unsigned char>(l) | static_cast<unsigned char>(r));
+}
+
+constexpr byte operator|(byte l, byte r) noexcept
+{
+    return byte(static_cast<unsigned char>(l) | static_cast<unsigned char>(r));
+}
+
+constexpr byte& operator&=(byte& l, byte r) noexcept
+{
+    return l = byte(static_cast<unsigned char>(l) & static_cast<unsigned char>(r));
+}
+
+constexpr byte operator&(byte l, byte r) noexcept
+{
+    return byte(static_cast<unsigned char>(l) & static_cast<unsigned char>(r));
+}
+
+constexpr byte& operator^=(byte& l, byte r) noexcept
+{
+    return l = byte(static_cast<unsigned char>(l) ^ static_cast<unsigned char>(r));
+}
+
+constexpr byte operator^(byte l, byte r) noexcept
+{
+    return byte(static_cast<unsigned char>(l) ^ static_cast<unsigned char>(r));
+}
+
+constexpr byte operator~(byte b) noexcept { return byte(~static_cast<unsigned char>(b)); }
+
+template <class IntegerType, class = std::enable_if_t<std::is_integral<IntegerType>::value>>
+constexpr IntegerType to_integer(byte b) noexcept
+{
+    return static_cast<IntegerType>(b);
+}
+
+#endif // GSL_USE_STD_BYTE
+
+template <bool E, typename T>
+constexpr byte to_byte_impl(T t) noexcept
+{
+    static_assert(
+        E, "gsl::to_byte(t) must be provided an unsigned char, otherwise data loss may occur. "
+           "If you are calling to_byte with an integer contant use: gsl::to_byte<t>() version.");
+    return static_cast<byte>(t);
+}
+template <>
+// NOTE: need suppression since c++14 does not allow "return {t}"
+// GSL_SUPPRESS(type.4) // NO-FORMAT: attribute // TODO: suppression does not work
+constexpr byte to_byte_impl<true, unsigned char>(unsigned char t) noexcept
+{
+    return byte(t);
+}
+
+template <typename T>
+constexpr byte to_byte(T t) noexcept
+{
+    return to_byte_impl<std::is_same<T, unsigned char>::value, T>(t);
+}
+
+template <int I>
+constexpr byte to_byte() noexcept
+{
+    static_assert(I >= 0 && I <= 255,
+                  "gsl::byte only has 8 bits of storage, values must be in range 0-255");
+    return static_cast<byte>(I);
+}
+
+} // namespace gsl
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif // _MSC_VER
+
+#endif // GSL_BYTE_H

src/algorithms/libs/gsl/include/gsl/gsl_util

@@ -0,0 +1,175 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_UTIL_H
+#define GSL_UTIL_H
+
+#include <gsl/gsl_assert> // for Expects
+
+#include <array>
+#include <cstddef>          // for ptrdiff_t, size_t
+#include <exception>        // for exception
+#include <initializer_list> // for initializer_list
+#include <type_traits>      // for is_signed, integral_constant
+#include <utility>          // for forward
+
+#if defined(_MSC_VER) && !defined(__clang__)
+
+#pragma warning(push)
+#pragma warning(disable : 4127) // conditional expression is constant
+
+#if _MSC_VER < 1910
+#pragma push_macro("constexpr")
+#define constexpr /*constexpr*/
+#endif            // _MSC_VER < 1910
+#endif            // _MSC_VER
+
+#if (defined(_MSC_VER) && _MSC_VER < 1910) || (!defined(__clang__) && defined(__GNUC__) && __GUNC__ < 6)
+#define GSL_CONSTEXPR_NARROW 0
+#else
+#define GSL_CONSTEXPR_NARROW 1
+#endif
+
+namespace gsl
+{
+//
+// GSL.util: utilities
+//
+
+// index type for all container indexes/subscripts/sizes
+using index = std::ptrdiff_t;
+
+// final_action allows you to ensure something gets run at the end of a scope
+template <class F>
+class final_action
+{
+public:
+    explicit final_action(F f) noexcept : f_(std::move(f)) {}
+
+    final_action(final_action&& other) noexcept : f_(std::move(other.f_)), invoke_(other.invoke_)
+    {
+        other.invoke_ = false;
+    }
+
+    final_action(const final_action&) = delete;
+    final_action& operator=(const final_action&) = delete;
+    final_action& operator=(final_action&&) = delete;
+
+    GSL_SUPPRESS(f.6) // NO-FORMAT: attribute // terminate if throws
+    ~final_action() noexcept
+    {
+        if (invoke_) f_();
+    }
+
+private:
+    F f_;
+    bool invoke_{true};
+};
+
+// finally() - convenience function to generate a final_action
+template <class F>
+final_action<F> finally(const F& f) noexcept
+{
+    return final_action<F>(f);
+}
+
+template <class F>
+final_action<F> finally(F&& f) noexcept
+{
+    return final_action<F>(std::forward<F>(f));
+}
+
+// narrow_cast(): a searchable way to do narrowing casts of values
+template <class T, class U>
+GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+constexpr T narrow_cast(U&& u) noexcept
+{
+    return static_cast<T>(std::forward<U>(u));
+}
+
+struct narrowing_error : public std::exception
+{
+};
+
+namespace details
+{
+    template <class T, class U>
+    struct is_same_signedness
+        : public std::integral_constant<bool, std::is_signed<T>::value == std::is_signed<U>::value>
+    {
+    };
+} // namespace details
+
+// narrow() : a checked version of narrow_cast() that throws if the cast changed the value
+template <class T, class U>
+GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+GSL_SUPPRESS(f.6) // NO-FORMAT: attribute // TODO: MSVC /analyze does not recognise noexcept(false)
+#if GSL_CONSTEXPR_NARROW
+constexpr
+#endif
+T narrow(U u) noexcept(false)
+{
+    T t = narrow_cast<T>(u);
+    if (static_cast<U>(t) != u) gsl::details::throw_exception(narrowing_error());
+    if (!details::is_same_signedness<T, U>::value && ((t < T{}) != (u < U{})))
+        gsl::details::throw_exception(narrowing_error());
+    return t;
+}
+
+//
+// at() - Bounds-checked way of accessing builtin arrays, std::array, std::vector
+//
+template <class T, std::size_t N>
+GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
+GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
+constexpr T& at(T (&arr)[N], const index i)
+{
+    Expects(i >= 0 && i < narrow_cast<index>(N));
+    return arr[narrow_cast<std::size_t>(i)];
+}
+
+template <class Cont>
+GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
+GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
+constexpr auto at(Cont& cont, const index i) -> decltype(cont[cont.size()])
+{
+    Expects(i >= 0 && i < narrow_cast<index>(cont.size()));
+    using size_type = decltype(cont.size());
+    return cont[narrow_cast<size_type>(i)];
+}
+
+template <class T>
+GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+constexpr T at(const std::initializer_list<T> cont, const index i)
+{
+    Expects(i >= 0 && i < narrow_cast<index>(cont.size()));
+    return *(cont.begin() + i);
+}
+
+} // namespace gsl
+
+#if defined(_MSC_VER) && !defined(__clang__)
+#if _MSC_VER < 1910
+#undef constexpr
+#pragma pop_macro("constexpr")
+
+#endif // _MSC_VER < 1910
+
+#pragma warning(pop)
+
+#endif // _MSC_VER
+
+#endif // GSL_UTIL_H

src/algorithms/libs/gsl/include/gsl/pointers

@@ -0,0 +1,294 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_POINTERS_H
+#define GSL_POINTERS_H
+
+#include <gsl/gsl_assert>  // for Ensures, Expects
+
+#include <algorithm>    // for forward
+#include <iosfwd>       // for ptrdiff_t, nullptr_t, ostream, size_t
+#include <memory>       // for shared_ptr, unique_ptr
+#include <system_error> // for hash
+#include <type_traits>  // for enable_if_t, is_convertible, is_assignable
+
+#if defined(_MSC_VER) && _MSC_VER < 1910 && !defined(__clang__)
+#pragma push_macro("constexpr")
+#define constexpr /*constexpr*/
+
+#endif                          // defined(_MSC_VER) && _MSC_VER < 1910
+
+namespace gsl
+{
+
+//
+// GSL.owner: ownership pointers
+//
+using std::unique_ptr;
+using std::shared_ptr;
+
+//
+// owner
+//
+// owner<T> is designed as a bridge for code that must deal directly with owning pointers for some reason
+//
+// T must be a pointer type
+// - disallow construction from any type other than pointer type
+//
+template <class T, class = std::enable_if_t<std::is_pointer<T>::value>>
+using owner = T;
+
+//
+// not_null
+//
+// Restricts a pointer or smart pointer to only hold non-null values.
+//
+// Has zero size overhead over T.
+//
+// If T is a pointer (i.e. T == U*) then
+// - allow construction from U*
+// - disallow construction from nullptr_t
+// - disallow default construction
+// - ensure construction from null U* fails
+// - allow implicit conversion to U*
+//
+template <class T>
+class not_null
+{
+public:
+    static_assert(std::is_assignable<T&, std::nullptr_t>::value, "T cannot be assigned nullptr.");
+
+    template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
+    constexpr not_null(U&& u) : ptr_(std::forward<U>(u))
+    {
+        Expects(ptr_ != nullptr);
+    }
+
+    template <typename = std::enable_if_t<!std::is_same<std::nullptr_t, T>::value>>
+    constexpr not_null(T u) : ptr_(u)
+    {
+        Expects(ptr_ != nullptr);
+    }
+
+    template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
+    constexpr not_null(const not_null<U>& other) : not_null(other.get())
+    {
+    }
+
+    not_null(not_null&& other) = default;
+    not_null(const not_null& other) = default;
+    not_null& operator=(const not_null& other) = default;
+
+    constexpr T get() const
+    {
+        Ensures(ptr_ != nullptr);
+        return ptr_;
+    }
+
+    constexpr operator T() const { return get(); }
+    constexpr T operator->() const { return get(); }
+    constexpr decltype(auto) operator*() const { return *get(); } 
+
+    // prevents compilation when someone attempts to assign a null pointer constant
+    not_null(std::nullptr_t) = delete;
+    not_null& operator=(std::nullptr_t) = delete;
+
+    // unwanted operators...pointers only point to single objects!
+    not_null& operator++() = delete;
+    not_null& operator--() = delete;
+    not_null operator++(int) = delete;
+    not_null operator--(int) = delete;
+    not_null& operator+=(std::ptrdiff_t) = delete;
+    not_null& operator-=(std::ptrdiff_t) = delete;
+    void operator[](std::ptrdiff_t) const = delete;
+
+private:
+    T ptr_;
+};
+
+template <class T>
+auto make_not_null(T&& t) {
+    return not_null<std::remove_cv_t<std::remove_reference_t<T>>>{std::forward<T>(t)};
+}
+
+template <class T>
+std::ostream& operator<<(std::ostream& os, const not_null<T>& val)
+{
+    os << val.get();
+    return os;
+}
+
+template <class T, class U>
+auto operator==(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() == rhs.get())
+{
+    return lhs.get() == rhs.get();
+}
+
+template <class T, class U>
+auto operator!=(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() != rhs.get())
+{
+    return lhs.get() != rhs.get();
+}
+
+template <class T, class U>
+auto operator<(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() < rhs.get())
+{
+    return lhs.get() < rhs.get();
+}
+
+template <class T, class U>
+auto operator<=(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() <= rhs.get())
+{
+    return lhs.get() <= rhs.get();
+}
+
+template <class T, class U>
+auto operator>(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() > rhs.get())
+{
+    return lhs.get() > rhs.get();
+}
+
+template <class T, class U>
+auto operator>=(const not_null<T>& lhs, const not_null<U>& rhs) -> decltype(lhs.get() >= rhs.get())
+{
+    return lhs.get() >= rhs.get();
+}
+
+// more unwanted operators
+template <class T, class U>
+std::ptrdiff_t operator-(const not_null<T>&, const not_null<U>&) = delete;
+template <class T>
+not_null<T> operator-(const not_null<T>&, std::ptrdiff_t) = delete;
+template <class T>
+not_null<T> operator+(const not_null<T>&, std::ptrdiff_t) = delete;
+template <class T>
+not_null<T> operator+(std::ptrdiff_t, const not_null<T>&) = delete;
+
+} // namespace gsl
+
+namespace std
+{
+template <class T>
+struct hash<gsl::not_null<T>>
+{
+    std::size_t operator()(const gsl::not_null<T>& value) const { return hash<T>{}(value); }
+};
+
+} // namespace std
+
+namespace gsl
+{
+
+//
+// strict_not_null
+//
+// Restricts a pointer or smart pointer to only hold non-null values,
+//
+// - provides a strict (i.e. explicit contructor from T) wrapper of not_null
+// - to be used for new code that wishes the design to be cleaner and make not_null
+//   checks intentional, or in old code that would like to make the transition.
+//
+//   To make the transition from not_null, incrementally replace not_null
+//   by strict_not_null and fix compilation errors
+//
+//   Expect to
+//   - remove all unneded conversions from raw pointer to not_null and back
+//   - make API clear by specifyning not_null in parameters where needed
+//   - remove unnesessary asserts
+//
+template <class T>
+class strict_not_null: public not_null<T>
+{
+public:
+
+    template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
+    constexpr explicit strict_not_null(U&& u) :
+        not_null<T>(std::forward<U>(u))
+    {}
+
+    template <typename = std::enable_if_t<!std::is_same<std::nullptr_t, T>::value>>
+    constexpr explicit strict_not_null(T u) :
+        not_null<T>(u)
+    {}
+
+    template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
+    constexpr strict_not_null(const not_null<U>& other) :
+        not_null<T>(other)
+    {}
+
+    template <typename U, typename = std::enable_if_t<std::is_convertible<U, T>::value>>
+    constexpr strict_not_null(const strict_not_null<U>& other) :
+        not_null<T>(other)
+    {}
+
+    strict_not_null(strict_not_null&& other) = default;
+    strict_not_null(const strict_not_null& other) = default;
+    strict_not_null& operator=(const strict_not_null& other) = default;
+    strict_not_null& operator=(const not_null<T>& other)
+    {
+        not_null<T>::operator=(other);
+        return *this;
+    }
+
+    // prevents compilation when someone attempts to assign a null pointer constant
+    strict_not_null(std::nullptr_t) = delete;
+    strict_not_null& operator=(std::nullptr_t) = delete;
+
+    // unwanted operators...pointers only point to single objects!
+    strict_not_null& operator++() = delete;
+    strict_not_null& operator--() = delete;
+    strict_not_null operator++(int) = delete;
+    strict_not_null operator--(int) = delete;
+    strict_not_null& operator+=(std::ptrdiff_t) = delete;
+    strict_not_null& operator-=(std::ptrdiff_t) = delete;
+    void operator[](std::ptrdiff_t) const = delete;
+};
+
+// more unwanted operators
+template <class T, class U>
+std::ptrdiff_t operator-(const strict_not_null<T>&, const strict_not_null<U>&) = delete;
+template <class T>
+strict_not_null<T> operator-(const strict_not_null<T>&, std::ptrdiff_t) = delete;
+template <class T>
+strict_not_null<T> operator+(const strict_not_null<T>&, std::ptrdiff_t) = delete;
+template <class T>
+strict_not_null<T> operator+(std::ptrdiff_t, const strict_not_null<T>&) = delete;
+
+template <class T>
+auto make_strict_not_null(T&& t) {
+    return strict_not_null<std::remove_cv_t<std::remove_reference_t<T>>>{std::forward<T>(t)};
+}
+
+} // namespace gsl
+
+namespace std
+{
+template <class T>
+struct hash<gsl::strict_not_null<T>>
+{
+    std::size_t operator()(const gsl::strict_not_null<T>& value) const { return hash<T>{}(value); }
+};
+
+} // namespace std
+
+#if defined(_MSC_VER) && _MSC_VER < 1910 && !defined(__clang__)
+
+#undef constexpr
+#pragma pop_macro("constexpr")
+
+#endif // defined(_MSC_VER) && _MSC_VER < 1910 && !defined(__clang__)
+
+#endif // GSL_POINTERS_H

src/algorithms/libs/gsl/include/gsl/span

@@ -0,0 +1,793 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_SPAN_H
+#define GSL_SPAN_H
+
+#include <gsl/gsl_assert> // for Expects
+#include <gsl/gsl_byte>   // for byte
+#include <gsl/gsl_util>   // for narrow_cast, narrow
+
+#include <algorithm> // for lexicographical_compare
+#include <array>     // for array
+#include <cstddef>   // for ptrdiff_t, size_t, nullptr_t
+#include <iterator>  // for reverse_iterator, distance, random_access_...
+#include <limits>
+#include <stdexcept>
+#include <type_traits> // for enable_if_t, declval, is_convertible, inte...
+#include <utility>
+#include <memory> // for std::addressof
+
+#if defined(_MSC_VER) && !defined(__clang__)
+#pragma warning(push)
+
+// turn off some warnings that are noisy about our Expects statements
+#pragma warning(disable : 4127) // conditional expression is constant
+#pragma warning(disable : 4702) // unreachable code
+
+// Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.
+#pragma warning(disable : 26495) // uninitalized member when constructor calls constructor
+#pragma warning(disable : 26446) // parser bug does not allow attributes on some templates
+
+#if _MSC_VER < 1910
+#pragma push_macro("constexpr")
+#define constexpr /*constexpr*/
+#define GSL_USE_STATIC_CONSTEXPR_WORKAROUND
+
+#endif // _MSC_VER < 1910
+#endif // _MSC_VER
+
+// See if we have enough C++17 power to use a static constexpr data member
+// without needing an out-of-line definition
+#if !(defined(__cplusplus) && (__cplusplus >= 201703L))
+#define GSL_USE_STATIC_CONSTEXPR_WORKAROUND
+#endif // !(defined(__cplusplus) && (__cplusplus >= 201703L))
+
+// GCC 7 does not like the signed unsigned missmatch (size_t ptrdiff_t)
+// While there is a conversion from signed to unsigned, it happens at
+// compiletime, so the compiler wouldn't have to warn indiscriminently, but
+// could check if the source value actually doesn't fit into the target type
+// and only warn in those cases.
+#if defined(__GNUC__) && __GNUC__ > 6
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#endif
+
+namespace gsl
+{
+
+// [views.constants], constants
+constexpr const std::ptrdiff_t dynamic_extent = -1;
+
+template <class ElementType, std::ptrdiff_t Extent = dynamic_extent>
+class span;
+
+// implementation details
+namespace details
+{
+    template <class T>
+    struct is_span_oracle : std::false_type
+    {
+    };
+
+    template <class ElementType, std::ptrdiff_t Extent>
+    struct is_span_oracle<gsl::span<ElementType, Extent>> : std::true_type
+    {
+    };
+
+    template <class T>
+    struct is_span : public is_span_oracle<std::remove_cv_t<T>>
+    {
+    };
+
+    template <class T>
+    struct is_std_array_oracle : std::false_type
+    {
+    };
+
+    template <class ElementType, std::size_t Extent>
+    struct is_std_array_oracle<std::array<ElementType, Extent>> : std::true_type
+    {
+    };
+
+    template <class T>
+    struct is_std_array : public is_std_array_oracle<std::remove_cv_t<T>>
+    {
+    };
+
+    template <std::ptrdiff_t From, std::ptrdiff_t To>
+    struct is_allowed_extent_conversion
+        : public std::integral_constant<bool, From == To || From == gsl::dynamic_extent ||
+                                                  To == gsl::dynamic_extent>
+    {
+    };
+
+    template <class From, class To>
+    struct is_allowed_element_type_conversion
+        : public std::integral_constant<bool, std::is_convertible<From (*)[], To (*)[]>::value>
+    {
+    };
+
+    template <class Span, bool IsConst>
+    class span_iterator
+    {
+        using element_type_ = typename Span::element_type;
+
+    public:
+#ifdef _MSC_VER
+        // Tell Microsoft standard library that span_iterators are checked.
+        using _Unchecked_type = typename Span::pointer;
+#endif
+
+        using iterator_category = std::random_access_iterator_tag;
+        using value_type = std::remove_cv_t<element_type_>;
+        using difference_type = typename Span::index_type;
+
+        using reference = std::conditional_t<IsConst, const element_type_, element_type_>&;
+        using pointer = std::add_pointer_t<reference>;
+
+        span_iterator() = default;
+
+        constexpr span_iterator(const Span* span, typename Span::index_type idx) noexcept
+            : span_(span), index_(idx)
+        {}
+
+        friend span_iterator<Span, true>;
+        template <bool B, std::enable_if_t<!B && IsConst>* = nullptr>
+        constexpr span_iterator(const span_iterator<Span, B>& other) noexcept
+            : span_iterator(other.span_, other.index_)
+        {}
+
+        GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+        constexpr reference operator*() const
+        {
+            Expects(index_ != span_->size());
+            return *(span_->data() + index_);
+        }
+
+        constexpr pointer operator->() const
+        {
+            Expects(index_ != span_->size());
+            return span_->data() + index_;
+        }
+
+        constexpr span_iterator& operator++()
+        {
+            Expects(0 <= index_ && index_ != span_->size());
+            ++index_;
+            return *this;
+        }
+
+        constexpr span_iterator operator++(int)
+        {
+            auto ret = *this;
+            ++(*this);
+            return ret;
+        }
+
+        constexpr span_iterator& operator--()
+        {
+            Expects(index_ != 0 && index_ <= span_->size());
+            --index_;
+            return *this;
+        }
+
+        constexpr span_iterator operator--(int)
+        {
+            auto ret = *this;
+            --(*this);
+            return ret;
+        }
+
+        constexpr span_iterator operator+(difference_type n) const
+        {
+            auto ret = *this;
+            return ret += n;
+        }
+
+        friend constexpr span_iterator operator+(difference_type n, span_iterator const& rhs)
+        {
+            return rhs + n;
+        }
+
+        constexpr span_iterator& operator+=(difference_type n)
+        {
+            Expects((index_ + n) >= 0 && (index_ + n) <= span_->size());
+            index_ += n;
+            return *this;
+        }
+
+        constexpr span_iterator operator-(difference_type n) const
+        {
+            auto ret = *this;
+            return ret -= n;
+        }
+
+        constexpr span_iterator& operator-=(difference_type n) { return *this += -n; }
+
+        constexpr difference_type operator-(span_iterator rhs) const
+        {
+            Expects(span_ == rhs.span_);
+            return index_ - rhs.index_;
+        }
+
+        constexpr reference operator[](difference_type n) const { return *(*this + n); }
+
+        constexpr friend bool operator==(span_iterator lhs, span_iterator rhs) noexcept
+        {
+            return lhs.span_ == rhs.span_ && lhs.index_ == rhs.index_;
+        }
+
+        constexpr friend bool operator!=(span_iterator lhs, span_iterator rhs) noexcept
+        {
+            return !(lhs == rhs);
+        }
+
+        constexpr friend bool operator<(span_iterator lhs, span_iterator rhs) noexcept
+        {
+            return lhs.index_ < rhs.index_;
+        }
+
+        constexpr friend bool operator<=(span_iterator lhs, span_iterator rhs) noexcept
+        {
+            return !(rhs < lhs);
+        }
+
+        constexpr friend bool operator>(span_iterator lhs, span_iterator rhs) noexcept
+        {
+            return rhs < lhs;
+        }
+
+        constexpr friend bool operator>=(span_iterator lhs, span_iterator rhs) noexcept
+        {
+            return !(rhs > lhs);
+        }
+
+#ifdef _MSC_VER
+        // MSVC++ iterator debugging support; allows STL algorithms in 15.8+
+        // to unwrap span_iterator to a pointer type after a range check in STL
+        // algorithm calls
+        friend constexpr void _Verify_range(span_iterator lhs, span_iterator rhs) noexcept
+        { // test that [lhs, rhs) forms a valid range inside an STL algorithm
+            Expects(lhs.span_ == rhs.span_        // range spans have to match
+                    && lhs.index_ <= rhs.index_); // range must not be transposed
+        }
+
+        constexpr void _Verify_offset(const difference_type n) const noexcept
+        { // test that the iterator *this + n is a valid range in an STL
+            // algorithm call
+            Expects((index_ + n) >= 0 && (index_ + n) <= span_->size());
+        }
+
+        GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+        constexpr pointer _Unwrapped() const noexcept
+        { // after seeking *this to a high water mark, or using one of the
+            // _Verify_xxx functions above, unwrap this span_iterator to a raw
+            // pointer
+            return span_->data() + index_;
+        }
+
+        // Tell the STL that span_iterator should not be unwrapped if it can't
+        // validate in advance, even in release / optimized builds:
+#if defined(GSL_USE_STATIC_CONSTEXPR_WORKAROUND)
+        static constexpr const bool _Unwrap_when_unverified = false;
+#else
+        static constexpr bool _Unwrap_when_unverified = false;
+#endif
+        GSL_SUPPRESS(con.3) // NO-FORMAT: attribute // TODO: false positive
+        constexpr void _Seek_to(const pointer p) noexcept
+        { // adjust the position of *this to previously verified location p
+            // after _Unwrapped
+            index_ = p - span_->data();
+        }
+#endif
+
+    protected:
+        const Span* span_ = nullptr;
+        std::ptrdiff_t index_ = 0;
+    };
+
+    template <std::ptrdiff_t Ext>
+    class extent_type
+    {
+    public:
+        using index_type = std::ptrdiff_t;
+
+        static_assert(Ext >= 0, "A fixed-size span must be >= 0 in size.");
+
+        constexpr extent_type() noexcept {}
+
+        template <index_type Other>
+        constexpr extent_type(extent_type<Other> ext)
+        {
+            static_assert(Other == Ext || Other == dynamic_extent,
+                          "Mismatch between fixed-size extent and size of initializing data.");
+            Expects(ext.size() == Ext);
+        }
+
+        constexpr extent_type(index_type size) { Expects(size == Ext); }
+
+        constexpr index_type size() const noexcept { return Ext; }
+    };
+
+    template <>
+    class extent_type<dynamic_extent>
+    {
+    public:
+        using index_type = std::ptrdiff_t;
+
+        template <index_type Other>
+        explicit constexpr extent_type(extent_type<Other> ext) : size_(ext.size())
+        {}
+
+        explicit constexpr extent_type(index_type size) : size_(size) { Expects(size >= 0); }
+
+        constexpr index_type size() const noexcept { return size_; }
+
+    private:
+        index_type size_;
+    };
+
+    template <class ElementType, std::ptrdiff_t Extent, std::ptrdiff_t Offset, std::ptrdiff_t Count>
+    struct calculate_subspan_type
+    {
+        using type = span<ElementType, Count != dynamic_extent
+                                           ? Count
+                                           : (Extent != dynamic_extent ? Extent - Offset : Extent)>;
+    };
+} // namespace details
+
+// [span], class template span
+template <class ElementType, std::ptrdiff_t Extent>
+class span
+{
+public:
+    // constants and types
+    using element_type = ElementType;
+    using value_type = std::remove_cv_t<ElementType>;
+    using index_type = std::ptrdiff_t;
+    using pointer = element_type*;
+    using reference = element_type&;
+
+    using iterator = details::span_iterator<span<ElementType, Extent>, false>;
+    using const_iterator = details::span_iterator<span<ElementType, Extent>, true>;
+    using reverse_iterator = std::reverse_iterator<iterator>;
+    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+
+    using size_type = index_type;
+
+#if defined(GSL_USE_STATIC_CONSTEXPR_WORKAROUND)
+    static constexpr const index_type extent{Extent};
+#else
+    static constexpr index_type extent{Extent};
+#endif
+
+    // [span.cons], span constructors, copy, assignment, and destructor
+    template <bool Dependent = false,
+              // "Dependent" is needed to make "std::enable_if_t<Dependent || Extent <= 0>" SFINAE,
+              // since "std::enable_if_t<Extent <= 0>" is ill-formed when Extent is greater than 0.
+              class = std::enable_if_t<(Dependent || Extent <= 0)>>
+    constexpr span() noexcept : storage_(nullptr, details::extent_type<0>())
+    {}
+
+    constexpr span(pointer ptr, index_type count) : storage_(ptr, count) {}
+
+    constexpr span(pointer firstElem, pointer lastElem)
+        : storage_(firstElem, std::distance(firstElem, lastElem))
+    {}
+
+    template <std::size_t N>
+    constexpr span(element_type (&arr)[N]) noexcept
+        : storage_(KnownNotNull{std::addressof(arr[0])}, details::extent_type<N>())
+    {}
+
+    template <std::size_t N, class = std::enable_if_t<(N > 0)>>
+    constexpr span(std::array<std::remove_const_t<element_type>, N>& arr) noexcept
+        : storage_(KnownNotNull{arr.data()}, details::extent_type<N>())
+    {
+    }
+
+    constexpr span(std::array<std::remove_const_t<element_type>, 0>&) noexcept
+        : storage_(static_cast<pointer>(nullptr), details::extent_type<0>())
+    {
+    }
+
+    template <std::size_t N, class = std::enable_if_t<(N > 0)>>
+    constexpr span(const std::array<std::remove_const_t<element_type>, N>& arr) noexcept
+        : storage_(KnownNotNull{arr.data()}, details::extent_type<N>())
+    {
+    }
+
+    constexpr span(const std::array<std::remove_const_t<element_type>, 0>&) noexcept
+        : storage_(static_cast<pointer>(nullptr), details::extent_type<0>())
+    {
+    }
+
+    // NB: the SFINAE here uses .data() as a incomplete/imperfect proxy for the requirement
+    // on Container to be a contiguous sequence container.
+    template <class Container,
+              class = std::enable_if_t<
+                  !details::is_span<Container>::value && !details::is_std_array<Container>::value &&
+                  std::is_convertible<typename Container::pointer, pointer>::value &&
+                  std::is_convertible<typename Container::pointer,
+                                      decltype(std::declval<Container>().data())>::value>>
+    constexpr span(Container& cont) : span(cont.data(), narrow<index_type>(cont.size()))
+    {}
+
+    template <class Container,
+              class = std::enable_if_t<
+                  std::is_const<element_type>::value && !details::is_span<Container>::value &&
+                  std::is_convertible<typename Container::pointer, pointer>::value &&
+                  std::is_convertible<typename Container::pointer,
+                                      decltype(std::declval<Container>().data())>::value>>
+    constexpr span(const Container& cont) : span(cont.data(), narrow<index_type>(cont.size()))
+    {}
+
+    constexpr span(const span& other) noexcept = default;
+
+    template <
+        class OtherElementType, std::ptrdiff_t OtherExtent,
+        class = std::enable_if_t<
+            details::is_allowed_extent_conversion<OtherExtent, Extent>::value &&
+            details::is_allowed_element_type_conversion<OtherElementType, element_type>::value>>
+    constexpr span(const span<OtherElementType, OtherExtent>& other)
+        : storage_(other.data(), details::extent_type<OtherExtent>(other.size()))
+    {}
+
+    ~span() noexcept = default;
+    constexpr span& operator=(const span& other) noexcept = default;
+
+    // [span.sub], span subviews
+    template <std::ptrdiff_t Count>
+    constexpr span<element_type, Count> first() const
+    {
+        Expects(Count >= 0 && Count <= size());
+        return {data(), Count};
+    }
+
+    template <std::ptrdiff_t Count>
+    GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+    constexpr span<element_type, Count> last() const
+    {
+        Expects(Count >= 0 && size() - Count >= 0);
+        return {data() + (size() - Count), Count};
+    }
+
+    template <std::ptrdiff_t Offset, std::ptrdiff_t Count = dynamic_extent>
+    GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+    constexpr auto subspan() const ->
+        typename details::calculate_subspan_type<ElementType, Extent, Offset, Count>::type
+    {
+        Expects((Offset >= 0 && size() - Offset >= 0) &&
+                (Count == dynamic_extent || (Count >= 0 && Offset + Count <= size())));
+
+        return {data() + Offset, Count == dynamic_extent ? size() - Offset : Count};
+    }
+
+    constexpr span<element_type, dynamic_extent> first(index_type count) const
+    {
+        Expects(count >= 0 && count <= size());
+        return {data(), count};
+    }
+
+    constexpr span<element_type, dynamic_extent> last(index_type count) const
+    {
+        return make_subspan(size() - count, dynamic_extent, subspan_selector<Extent>{});
+    }
+
+    constexpr span<element_type, dynamic_extent> subspan(index_type offset,
+                                                         index_type count = dynamic_extent) const
+    {
+        return make_subspan(offset, count, subspan_selector<Extent>{});
+    }
+
+    // [span.obs], span observers
+    constexpr index_type size() const noexcept { return storage_.size(); }
+    constexpr index_type size_bytes() const noexcept
+    {
+        return size() * narrow_cast<index_type>(sizeof(element_type));
+    }
+    constexpr bool empty() const noexcept { return size() == 0; }
+
+    // [span.elem], span element access
+    GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+    constexpr reference operator[](index_type idx) const
+    {
+        Expects(CheckRange(idx, storage_.size()));
+        return data()[idx];
+    }
+
+    constexpr reference at(index_type idx) const { return this->operator[](idx); }
+    constexpr reference operator()(index_type idx) const { return this->operator[](idx); }
+    constexpr pointer data() const noexcept { return storage_.data(); }
+
+    // [span.iter], span iterator support
+    constexpr iterator begin() const noexcept { return {this, 0}; }
+    constexpr iterator end() const noexcept { return {this, size()}; }
+
+    constexpr const_iterator cbegin() const noexcept { return {this, 0}; }
+    constexpr const_iterator cend() const noexcept { return {this, size()}; }
+
+    constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator{end()}; }
+    constexpr reverse_iterator rend() const noexcept { return reverse_iterator{begin()}; }
+
+    constexpr const_reverse_iterator crbegin() const noexcept
+    {
+        return const_reverse_iterator{cend()};
+    }
+    constexpr const_reverse_iterator crend() const noexcept
+    {
+        return const_reverse_iterator{cbegin()};
+    }
+
+#ifdef _MSC_VER
+    // Tell MSVC how to unwrap spans in range-based-for
+    constexpr pointer _Unchecked_begin() const noexcept { return data(); }
+    constexpr pointer _Unchecked_end() const noexcept
+    {
+        GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+        return data() + size();
+    }
+#endif // _MSC_VER
+
+private:
+    static constexpr bool CheckRange(index_type idx, index_type size) noexcept
+    {
+        // Optimization:
+        //
+        // idx >= 0 && idx < size
+        // =>
+        // static_cast<size_t>(idx) < static_cast<size_t>(size)
+        //
+        // because size >=0 by span construction, and negative idx will
+        // wrap around to a value always greater than size when casted.
+
+        // check if we have enough space to wrap around
+#if defined(__cpp_if_constexpr)
+        if constexpr (sizeof(index_type) <= sizeof(size_t))
+#else
+        if (sizeof(index_type) <= sizeof(size_t))
+#endif
+        {
+            return narrow_cast<size_t>(idx) < narrow_cast<size_t>(size);
+        }
+        else
+        {
+            return idx >= 0 && idx < size;
+        }
+    }
+
+    // Needed to remove unnecessary null check in subspans
+    struct KnownNotNull
+    {
+        pointer p;
+    };
+
+    // this implementation detail class lets us take advantage of the
+    // empty base class optimization to pay for only storage of a single
+    // pointer in the case of fixed-size spans
+    template <class ExtentType>
+    class storage_type : public ExtentType
+    {
+    public:
+        // KnownNotNull parameter is needed to remove unnecessary null check
+        // in subspans and constructors from arrays
+        template <class OtherExtentType>
+        constexpr storage_type(KnownNotNull data, OtherExtentType ext)
+            : ExtentType(ext), data_(data.p)
+        {
+            Expects(ExtentType::size() >= 0);
+        }
+
+        template <class OtherExtentType>
+        constexpr storage_type(pointer data, OtherExtentType ext) : ExtentType(ext), data_(data)
+        {
+            Expects(ExtentType::size() >= 0);
+            Expects(data || ExtentType::size() == 0);
+        }
+
+        constexpr pointer data() const noexcept { return data_; }
+
+    private:
+        pointer data_;
+    };
+
+    storage_type<details::extent_type<Extent>> storage_;
+
+    // The rest is needed to remove unnecessary null check
+    // in subspans and constructors from arrays
+    constexpr span(KnownNotNull ptr, index_type count) : storage_(ptr, count) {}
+
+    template <std::ptrdiff_t CallerExtent>
+    class subspan_selector
+    {
+    };
+
+    template <std::ptrdiff_t CallerExtent>
+    span<element_type, dynamic_extent> make_subspan(index_type offset, index_type count,
+                                                    subspan_selector<CallerExtent>) const
+    {
+        const span<element_type, dynamic_extent> tmp(*this);
+        return tmp.subspan(offset, count);
+    }
+
+    GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
+    span<element_type, dynamic_extent> make_subspan(index_type offset, index_type count,
+                                                    subspan_selector<dynamic_extent>) const
+    {
+        Expects(offset >= 0 && size() - offset >= 0);
+
+        if (count == dynamic_extent) { return {KnownNotNull{data() + offset}, size() - offset}; }
+
+        Expects(count >= 0 && size() - offset >= count);
+        return {KnownNotNull{data() + offset}, count};
+    }
+};
+
+#if defined(GSL_USE_STATIC_CONSTEXPR_WORKAROUND)
+template <class ElementType, std::ptrdiff_t Extent>
+constexpr const typename span<ElementType, Extent>::index_type span<ElementType, Extent>::extent;
+#endif
+
+// [span.comparison], span comparison operators
+template <class ElementType, std::ptrdiff_t FirstExtent, std::ptrdiff_t SecondExtent>
+constexpr bool operator==(span<ElementType, FirstExtent> l, span<ElementType, SecondExtent> r)
+{
+    return std::equal(l.begin(), l.end(), r.begin(), r.end());
+}
+
+template <class ElementType, std::ptrdiff_t Extent>
+constexpr bool operator!=(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return !(l == r);
+}
+
+template <class ElementType, std::ptrdiff_t Extent>
+constexpr bool operator<(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return std::lexicographical_compare(l.begin(), l.end(), r.begin(), r.end());
+}
+
+template <class ElementType, std::ptrdiff_t Extent>
+constexpr bool operator<=(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return !(l > r);
+}
+
+template <class ElementType, std::ptrdiff_t Extent>
+constexpr bool operator>(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return r < l;
+}
+
+template <class ElementType, std::ptrdiff_t Extent>
+constexpr bool operator>=(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return !(l < r);
+}
+
+namespace details
+{
+    // if we only supported compilers with good constexpr support then
+    // this pair of classes could collapse down to a constexpr function
+
+    // we should use a narrow_cast<> to go to std::size_t, but older compilers may not see it as
+    // constexpr
+    // and so will fail compilation of the template
+    template <class ElementType, std::ptrdiff_t Extent>
+    struct calculate_byte_size
+        : std::integral_constant<std::ptrdiff_t,
+                                 static_cast<std::ptrdiff_t>(sizeof(ElementType) *
+                                                             static_cast<std::size_t>(Extent))>
+    {
+    };
+
+    template <class ElementType>
+    struct calculate_byte_size<ElementType, dynamic_extent>
+        : std::integral_constant<std::ptrdiff_t, dynamic_extent>
+    {
+    };
+} // namespace details
+
+// [span.objectrep], views of object representation
+template <class ElementType, std::ptrdiff_t Extent>
+span<const byte, details::calculate_byte_size<ElementType, Extent>::value>
+as_bytes(span<ElementType, Extent> s) noexcept
+{
+    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    return {reinterpret_cast<const byte*>(s.data()), s.size_bytes()};
+}
+
+template <class ElementType, std::ptrdiff_t Extent,
+          class = std::enable_if_t<!std::is_const<ElementType>::value>>
+span<byte, details::calculate_byte_size<ElementType, Extent>::value>
+as_writeable_bytes(span<ElementType, Extent> s) noexcept
+{
+    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    return {reinterpret_cast<byte*>(s.data()), s.size_bytes()};
+}
+
+//
+// make_span() - Utility functions for creating spans
+//
+template <class ElementType>
+constexpr span<ElementType> make_span(ElementType* ptr,
+                                      typename span<ElementType>::index_type count)
+{
+    return span<ElementType>(ptr, count);
+}
+
+template <class ElementType>
+constexpr span<ElementType> make_span(ElementType* firstElem, ElementType* lastElem)
+{
+    return span<ElementType>(firstElem, lastElem);
+}
+
+template <class ElementType, std::size_t N>
+constexpr span<ElementType, N> make_span(ElementType (&arr)[N]) noexcept
+{
+    return span<ElementType, N>(arr);
+}
+
+template <class Container>
+constexpr span<typename Container::value_type> make_span(Container& cont)
+{
+    return span<typename Container::value_type>(cont);
+}
+
+template <class Container>
+constexpr span<const typename Container::value_type> make_span(const Container& cont)
+{
+    return span<const typename Container::value_type>(cont);
+}
+
+template <class Ptr>
+constexpr span<typename Ptr::element_type> make_span(Ptr& cont, std::ptrdiff_t count)
+{
+    return span<typename Ptr::element_type>(cont, count);
+}
+
+template <class Ptr>
+constexpr span<typename Ptr::element_type> make_span(Ptr& cont)
+{
+    return span<typename Ptr::element_type>(cont);
+}
+
+// Specialization of gsl::at for span
+template <class ElementType, std::ptrdiff_t Extent>
+constexpr ElementType& at(span<ElementType, Extent> s, index i)
+{
+    // No bounds checking here because it is done in span::operator[] called below
+    return s[i];
+}
+
+} // namespace gsl
+
+#if defined(_MSC_VER) && !defined(__clang__)
+#if _MSC_VER < 1910
+#undef constexpr
+#pragma pop_macro("constexpr")
+
+#endif // _MSC_VER < 1910
+
+#pragma warning(pop)
+#endif // _MSC_VER
+
+#if defined(__GNUC__) && __GNUC__ > 6
+#pragma GCC diagnostic pop
+#endif // __GNUC__ > 6
+
+#endif // GSL_SPAN_H

src/algorithms/libs/gsl/include/gsl/string_span

@@ -0,0 +1,722 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+//
+// This code is licensed under the MIT License (MIT).
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_STRING_SPAN_H
+#define GSL_STRING_SPAN_H
+
+#include <gsl/gsl_assert> // for Ensures, Expects
+#include <gsl/gsl_util>   // for narrow_cast
+#include <gsl/span>       // for operator!=, operator==, dynamic_extent
+#include <gsl/pointers>   // for not_null
+
+#include <algorithm> // for equal, lexicographical_compare
+#include <array>     // for array
+#include <cstddef>   // for ptrdiff_t, size_t, nullptr_t
+#include <cstdint>   // for PTRDIFF_MAX
+#include <cstring>
+#include <string>      // for basic_string, allocator, char_traits
+#include <type_traits> // for declval, is_convertible, enable_if_t, add_...
+
+#if defined(_MSC_VER) && !defined(__clang__)
+#pragma warning(push)
+
+// Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.
+#pragma warning(disable : 26446) // TODO: bug in parser - attributes and templates
+#pragma warning(disable : 26481) // TODO: suppress does not work inside templates sometimes
+
+#if _MSC_VER < 1910
+#pragma push_macro("constexpr")
+#define constexpr /*constexpr*/
+
+#endif // _MSC_VER < 1910
+#endif // _MSC_VER
+
+namespace gsl
+{
+//
+// czstring and wzstring
+//
+// These are "tag" typedefs for C-style strings (i.e. null-terminated character arrays)
+// that allow static analysis to help find bugs.
+//
+// There are no additional features/semantics that we can find a way to add inside the
+// type system for these types that will not either incur significant runtime costs or
+// (sometimes needlessly) break existing programs when introduced.
+//
+
+template <typename CharT, std::ptrdiff_t Extent = dynamic_extent>
+using basic_zstring = CharT*;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using czstring = basic_zstring<const char, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using cwzstring = basic_zstring<const wchar_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using cu16zstring = basic_zstring<const char16_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using cu32zstring = basic_zstring<const char32_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using zstring = basic_zstring<char, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using wzstring = basic_zstring<wchar_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using u16zstring = basic_zstring<char16_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using u32zstring = basic_zstring<char32_t, Extent>;
+
+namespace details
+{
+    template <class CharT>
+    std::ptrdiff_t string_length(const CharT* str, std::ptrdiff_t n)
+    {
+        if (str == nullptr || n <= 0) return 0;
+
+        const span<const CharT> str_span{str, n};
+
+        std::ptrdiff_t len = 0;
+        while (len < n && str_span[len]) len++;
+
+        return len;
+    }
+} // namespace details
+
+//
+// ensure_sentinel()
+//
+// Provides a way to obtain an span from a contiguous sequence
+// that ends with a (non-inclusive) sentinel value.
+//
+// Will fail-fast if sentinel cannot be found before max elements are examined.
+//
+template <typename T, const T Sentinel>
+span<T, dynamic_extent> ensure_sentinel(T* seq, std::ptrdiff_t max = PTRDIFF_MAX)
+{
+    Ensures(seq != nullptr);
+
+    GSL_SUPPRESS(f.23) // NO-FORMAT: attribute // TODO: false positive // TODO: suppress does not work
+    auto cur = seq;
+    Ensures(cur != nullptr); // workaround for removing the warning
+
+    GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute // TODO: suppress does not work
+    while ((cur - seq) < max && *cur != Sentinel) ++cur;
+    Ensures(*cur == Sentinel);
+    return {seq, cur - seq};
+}
+
+//
+// ensure_z - creates a span for a zero terminated strings.
+// Will fail fast if a null-terminator cannot be found before
+// the limit of size_type.
+//
+template <typename CharT>
+span<CharT, dynamic_extent> ensure_z(CharT* const& sz, std::ptrdiff_t max = PTRDIFF_MAX)
+{
+    return ensure_sentinel<CharT, CharT(0)>(sz, max);
+}
+
+template <typename CharT, std::size_t N>
+span<CharT, dynamic_extent> ensure_z(CharT (&sz)[N])
+{
+    return ensure_z(&sz[0], narrow_cast<std::ptrdiff_t>(N));
+}
+
+template <class Cont>
+span<typename std::remove_pointer<typename Cont::pointer>::type, dynamic_extent>
+ensure_z(Cont& cont)
+{
+    return ensure_z(cont.data(), narrow_cast<std::ptrdiff_t>(cont.size()));
+}
+
+template <typename CharT, std::ptrdiff_t>
+class basic_string_span;
+
+namespace details {
+    template <typename T>
+    struct is_basic_string_span_oracle : std::false_type
+    {
+    };
+
+    template <typename CharT, std::ptrdiff_t Extent>
+    struct is_basic_string_span_oracle<basic_string_span<CharT, Extent>> : std::true_type
+    {
+    };
+
+    template <typename T>
+    struct is_basic_string_span : is_basic_string_span_oracle<std::remove_cv_t<T>>
+    {
+    };
+} // namespace details
+
+//
+// string_span and relatives
+//
+template <typename CharT, std::ptrdiff_t Extent = dynamic_extent>
+class basic_string_span
+{
+public:
+    using element_type = CharT;
+    using value_type = std::remove_cv_t<element_type>;
+    using pointer = std::add_pointer_t<element_type>;
+    using reference = std::add_lvalue_reference_t<element_type>;
+    using const_reference = std::add_lvalue_reference_t<std::add_const_t<element_type>>;
+    using impl_type = span<element_type, Extent>;
+
+    using index_type = typename impl_type::index_type;
+    using iterator = typename impl_type::iterator;
+    using const_iterator = typename impl_type::const_iterator;
+    using reverse_iterator = typename impl_type::reverse_iterator;
+    using const_reverse_iterator = typename impl_type::const_reverse_iterator;
+
+    using size_type = index_type;
+
+    // default (empty)
+    constexpr basic_string_span() noexcept = default;
+
+    // copy
+    constexpr basic_string_span(const basic_string_span& other) noexcept = default;
+
+    // assign
+    constexpr basic_string_span& operator=(const basic_string_span& other) noexcept = default;
+
+    constexpr basic_string_span(pointer ptr, index_type length) : span_(ptr, length) {}
+    constexpr basic_string_span(pointer firstElem, pointer lastElem) : span_(firstElem, lastElem) {}
+
+    // From static arrays - if 0-terminated, remove 0 from the view
+    // All other containers allow 0s within the length, so we do not remove them
+    template <std::size_t N>
+    constexpr basic_string_span(element_type (&arr)[N]) : span_(remove_z(arr))
+    {}
+
+    template <std::size_t N, class ArrayElementType = std::remove_const_t<element_type>>
+    constexpr basic_string_span(std::array<ArrayElementType, N>& arr) noexcept : span_(arr)
+    {}
+
+    template <std::size_t N, class ArrayElementType = std::remove_const_t<element_type>>
+    constexpr basic_string_span(const std::array<ArrayElementType, N>& arr) noexcept : span_(arr)
+    {}
+
+    // Container signature should work for basic_string after C++17 version exists
+    template <class Traits, class Allocator>
+    // GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute // TODO: parser bug
+    constexpr basic_string_span(std::basic_string<element_type, Traits, Allocator>& str)
+        : span_(&str[0], narrow_cast<std::ptrdiff_t>(str.length()))
+    {}
+
+    template <class Traits, class Allocator>
+    constexpr basic_string_span(const std::basic_string<element_type, Traits, Allocator>& str)
+        : span_(&str[0], str.length())
+    {}
+
+    // from containers. Containers must have a pointer type and data() function signatures
+    template <class Container,
+              class = std::enable_if_t<
+                  !details::is_basic_string_span<Container>::value &&
+                  std::is_convertible<typename Container::pointer, pointer>::value &&
+                  std::is_convertible<typename Container::pointer,
+                                      decltype(std::declval<Container>().data())>::value>>
+    constexpr basic_string_span(Container& cont) : span_(cont)
+    {}
+
+    template <class Container,
+              class = std::enable_if_t<
+                  !details::is_basic_string_span<Container>::value &&
+                  std::is_convertible<typename Container::pointer, pointer>::value &&
+                  std::is_convertible<typename Container::pointer,
+                                      decltype(std::declval<Container>().data())>::value>>
+    constexpr basic_string_span(const Container& cont) : span_(cont)
+    {}
+
+    // from string_span
+    template <
+        class OtherValueType, std::ptrdiff_t OtherExtent,
+        class = std::enable_if_t<std::is_convertible<
+            typename basic_string_span<OtherValueType, OtherExtent>::impl_type, impl_type>::value>>
+    constexpr basic_string_span(basic_string_span<OtherValueType, OtherExtent> other)
+        : span_(other.data(), other.length())
+    {}
+
+    template <index_type Count>
+    constexpr basic_string_span<element_type, Count> first() const
+    {
+        return {span_.template first<Count>()};
+    }
+
+    constexpr basic_string_span<element_type, dynamic_extent> first(index_type count) const
+    {
+        return {span_.first(count)};
+    }
+
+    template <index_type Count>
+    constexpr basic_string_span<element_type, Count> last() const
+    {
+        return {span_.template last<Count>()};
+    }
+
+    constexpr basic_string_span<element_type, dynamic_extent> last(index_type count) const
+    {
+        return {span_.last(count)};
+    }
+
+    template <index_type Offset, index_type Count>
+    constexpr basic_string_span<element_type, Count> subspan() const
+    {
+        return {span_.template subspan<Offset, Count>()};
+    }
+
+    constexpr basic_string_span<element_type, dynamic_extent>
+    subspan(index_type offset, index_type count = dynamic_extent) const
+    {
+        return {span_.subspan(offset, count)};
+    }
+
+    constexpr reference operator[](index_type idx) const { return span_[idx]; }
+    constexpr reference operator()(index_type idx) const { return span_[idx]; }
+
+    constexpr pointer data() const { return span_.data(); }
+
+    constexpr index_type length() const noexcept { return span_.size(); }
+    constexpr index_type size() const noexcept { return span_.size(); }
+    constexpr index_type size_bytes() const noexcept { return span_.size_bytes(); }
+    constexpr index_type length_bytes() const noexcept { return span_.length_bytes(); }
+    constexpr bool empty() const noexcept { return size() == 0; }
+
+    constexpr iterator begin() const noexcept { return span_.begin(); }
+    constexpr iterator end() const noexcept { return span_.end(); }
+
+    constexpr const_iterator cbegin() const noexcept { return span_.cbegin(); }
+    constexpr const_iterator cend() const noexcept { return span_.cend(); }
+
+    constexpr reverse_iterator rbegin() const noexcept { return span_.rbegin(); }
+    constexpr reverse_iterator rend() const noexcept { return span_.rend(); }
+
+    constexpr const_reverse_iterator crbegin() const noexcept { return span_.crbegin(); }
+    constexpr const_reverse_iterator crend() const noexcept { return span_.crend(); }
+
+private:
+    static impl_type remove_z(pointer const& sz, std::ptrdiff_t max)
+    {
+        return {sz, details::string_length(sz, max)};
+    }
+
+    template <std::size_t N>
+    static impl_type remove_z(element_type (&sz)[N])
+    {
+        return remove_z(&sz[0], narrow_cast<std::ptrdiff_t>(N));
+    }
+
+    impl_type span_;
+};
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using string_span = basic_string_span<char, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using cstring_span = basic_string_span<const char, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using wstring_span = basic_string_span<wchar_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using cwstring_span = basic_string_span<const wchar_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using u16string_span = basic_string_span<char16_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using cu16string_span = basic_string_span<const char16_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using u32string_span = basic_string_span<char32_t, Extent>;
+
+template <std::ptrdiff_t Extent = dynamic_extent>
+using cu32string_span = basic_string_span<const char32_t, Extent>;
+
+//
+// to_string() allow (explicit) conversions from string_span to string
+//
+
+template <typename CharT, std::ptrdiff_t Extent>
+std::basic_string<typename std::remove_const<CharT>::type>
+to_string(basic_string_span<CharT, Extent> view)
+{
+    return {view.data(), narrow_cast<std::size_t>(view.length())};
+}
+
+template <typename CharT, typename Traits = typename std::char_traits<CharT>,
+          typename Allocator = std::allocator<CharT>, typename gCharT, std::ptrdiff_t Extent>
+std::basic_string<CharT, Traits, Allocator> to_basic_string(basic_string_span<gCharT, Extent> view)
+{
+    return {view.data(), narrow_cast<std::size_t>(view.length())};
+}
+
+template <class ElementType, std::ptrdiff_t Extent>
+basic_string_span<const byte, details::calculate_byte_size<ElementType, Extent>::value>
+as_bytes(basic_string_span<ElementType, Extent> s) noexcept
+{
+    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    return {reinterpret_cast<const byte*>(s.data()), s.size_bytes()};
+}
+
+template <class ElementType, std::ptrdiff_t Extent,
+          class = std::enable_if_t<!std::is_const<ElementType>::value>>
+basic_string_span<byte, details::calculate_byte_size<ElementType, Extent>::value>
+as_writeable_bytes(basic_string_span<ElementType, Extent> s) noexcept
+{
+    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
+    return {reinterpret_cast<byte*>(s.data()), s.size_bytes()};
+}
+
+// zero-terminated string span, used to convert
+// zero-terminated spans to legacy strings
+template <typename CharT, std::ptrdiff_t Extent = dynamic_extent>
+class basic_zstring_span {
+public:
+    using value_type = CharT;
+    using const_value_type = std::add_const_t<CharT>;
+
+    using pointer = std::add_pointer_t<value_type>;
+    using const_pointer = std::add_pointer_t<const_value_type>;
+
+    using zstring_type = basic_zstring<value_type, Extent>;
+    using const_zstring_type = basic_zstring<const_value_type, Extent>;
+
+    using impl_type = span<value_type, Extent>;
+    using string_span_type = basic_string_span<value_type, Extent>;
+
+    constexpr basic_zstring_span(impl_type s) : span_(s)
+    {
+        // expects a zero-terminated span
+        Expects(s[s.size() - 1] == '\0');
+    }
+
+    // copy
+    constexpr basic_zstring_span(const basic_zstring_span& other) = default;
+
+    // move
+    constexpr basic_zstring_span(basic_zstring_span&& other) = default;
+
+    // assign
+    constexpr basic_zstring_span& operator=(const basic_zstring_span& other) = default;
+
+    // move assign
+    constexpr basic_zstring_span& operator=(basic_zstring_span&& other) = default;
+
+    constexpr bool empty() const noexcept { return span_.size() == 0; }
+
+    constexpr string_span_type as_string_span() const noexcept
+    {
+        const auto sz = span_.size();
+        return {span_.data(), sz > 1 ? sz - 1 : 0};
+    }
+    constexpr string_span_type ensure_z() const { return gsl::ensure_z(span_); }
+
+    constexpr const_zstring_type assume_z() const noexcept { return span_.data(); }
+
+private:
+    impl_type span_;
+};
+
+template <std::ptrdiff_t Max = dynamic_extent>
+using zstring_span = basic_zstring_span<char, Max>;
+
+template <std::ptrdiff_t Max = dynamic_extent>
+using wzstring_span = basic_zstring_span<wchar_t, Max>;
+
+template <std::ptrdiff_t Max = dynamic_extent>
+using u16zstring_span = basic_zstring_span<char16_t, Max>;
+
+template <std::ptrdiff_t Max = dynamic_extent>
+using u32zstring_span = basic_zstring_span<char32_t, Max>;
+
+template <std::ptrdiff_t Max = dynamic_extent>
+using czstring_span = basic_zstring_span<const char, Max>;
+
+template <std::ptrdiff_t Max = dynamic_extent>
+using cwzstring_span = basic_zstring_span<const wchar_t, Max>;
+
+template <std::ptrdiff_t Max = dynamic_extent>
+using cu16zstring_span = basic_zstring_span<const char16_t, Max>;
+
+template <std::ptrdiff_t Max = dynamic_extent>
+using cu32zstring_span = basic_zstring_span<const char32_t, Max>;
+
+// operator ==
+template <class CharT, std::ptrdiff_t Extent, class T,
+          class = std::enable_if_t<
+              details::is_basic_string_span<T>::value ||
+              std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>>>::value>>
+bool operator==(const gsl::basic_string_span<CharT, Extent>& one, const T& other)
+{
+    const gsl::basic_string_span<std::add_const_t<CharT>> tmp(other);
+    return std::equal(one.begin(), one.end(), tmp.begin(), tmp.end());
+}
+
+template <class CharT, std::ptrdiff_t Extent, class T,
+          class = std::enable_if_t<
+              !details::is_basic_string_span<T>::value &&
+              std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>>>::value>>
+bool operator==(const T& one, const gsl::basic_string_span<CharT, Extent>& other)
+{
+    const gsl::basic_string_span<std::add_const_t<CharT>> tmp(one);
+    return std::equal(tmp.begin(), tmp.end(), other.begin(), other.end());
+}
+
+// operator !=
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+          typename = std::enable_if_t<std::is_convertible<
+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
+bool operator!=(gsl::basic_string_span<CharT, Extent> one, const T& other)
+{
+    return !(one == other);
+}
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename = std::enable_if_t<
+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
+        !gsl::details::is_basic_string_span<T>::value>>
+bool operator!=(const T& one, gsl::basic_string_span<CharT, Extent> other)
+{
+    return !(one == other);
+}
+
+// operator<
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+          typename = std::enable_if_t<std::is_convertible<
+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
+bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other)
+{
+    const gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
+    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());
+}
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename = std::enable_if_t<
+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
+        !gsl::details::is_basic_string_span<T>::value>>
+bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other)
+{
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
+    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());
+}
+
+#ifndef _MSC_VER
+
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename DataType = typename T::value_type,
+    typename = std::enable_if_t<
+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
+        std::is_convertible<DataType*, CharT*>::value &&
+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
+                     DataType>::value>>
+bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other)
+{
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
+    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());
+}
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename DataType = typename T::value_type,
+    typename = std::enable_if_t<
+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
+        std::is_convertible<DataType*, CharT*>::value &&
+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
+                     DataType>::value>>
+bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other)
+{
+    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
+    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());
+}
+#endif
+
+// operator <=
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+          typename = std::enable_if_t<std::is_convertible<
+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
+bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other)
+{
+    return !(other < one);
+}
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename = std::enable_if_t<
+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
+        !gsl::details::is_basic_string_span<T>::value>>
+bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other)
+{
+    return !(other < one);
+}
+
+#ifndef _MSC_VER
+
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename DataType = typename T::value_type,
+    typename = std::enable_if_t<
+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
+        std::is_convertible<DataType*, CharT*>::value &&
+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
+                     DataType>::value>>
+bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other)
+{
+    return !(other < one);
+}
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename DataType = typename T::value_type,
+    typename = std::enable_if_t<
+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
+        std::is_convertible<DataType*, CharT*>::value &&
+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
+                     DataType>::value>>
+bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other)
+{
+    return !(other < one);
+}
+#endif
+
+// operator>
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+          typename = std::enable_if_t<std::is_convertible<
+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
+bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other)
+{
+    return other < one;
+}
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename = std::enable_if_t<
+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
+        !gsl::details::is_basic_string_span<T>::value>>
+bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other)
+{
+    return other < one;
+}
+
+#ifndef _MSC_VER
+
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename DataType = typename T::value_type,
+    typename = std::enable_if_t<
+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
+        std::is_convertible<DataType*, CharT*>::value &&
+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
+                     DataType>::value>>
+bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other)
+{
+    return other < one;
+}
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename DataType = typename T::value_type,
+    typename = std::enable_if_t<
+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
+        std::is_convertible<DataType*, CharT*>::value &&
+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
+                     DataType>::value>>
+bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other)
+{
+    return other < one;
+}
+#endif
+
+// operator >=
+template <typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+          typename = std::enable_if_t<std::is_convertible<
+              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
+bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other)
+{
+    return !(one < other);
+}
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename = std::enable_if_t<
+        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
+        !gsl::details::is_basic_string_span<T>::value>>
+bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other)
+{
+    return !(one < other);
+}
+
+#ifndef _MSC_VER
+
+// VS treats temp and const containers as convertible to basic_string_span,
+// so the cases below are already covered by the previous operators
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename DataType = typename T::value_type,
+    typename = std::enable_if_t<
+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
+        std::is_convertible<DataType*, CharT*>::value &&
+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
+                     DataType>::value>>
+bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other)
+{
+    return !(one < other);
+}
+
+template <
+    typename CharT, std::ptrdiff_t Extent = gsl::dynamic_extent, typename T,
+    typename DataType = typename T::value_type,
+    typename = std::enable_if_t<
+        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
+        std::is_convertible<DataType*, CharT*>::value &&
+        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
+                     DataType>::value>>
+bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other)
+{
+    return !(one < other);
+}
+#endif
+} // namespace gsl
+
+#if defined(_MSC_VER) && !defined(__clang__)
+#pragma warning(pop)
+
+#if _MSC_VER < 1910
+#undef constexpr
+#pragma pop_macro("constexpr")
+
+#endif // _MSC_VER < 1910
+#endif // _MSC_VER
+
+#endif // GSL_STRING_SPAN_H

src/algorithms/signal_generator/gnuradio_blocks/signal_generator_c.cc

@@ -208,10 +208,9 @@ void signal_generator_c::generate_codes()
                 {
                     if (signal_[sat].at(0) == '5')
                         {
-                            char signal[3];
+                            std::array<char, 3> signal = {{'5', 'X', '\0'}};
-                            strcpy(signal, "5X");
 
-                            galileo_e5_a_code_gen_complex_sampled(sampled_code_data_[sat], signal, PRN_[sat], fs_in_,
+                            galileo_e5_a_code_gen_complex_sampled(gsl::span<gr_complex>(sampled_code_data_[sat], vector_length_), signal, PRN_[sat], fs_in_,
                                 static_cast<int>(GALILEO_E5A_CODE_LENGTH_CHIPS) - delay_chips_[sat]);
                             //noise
                             if (noise_flag_)
@@ -226,10 +225,9 @@ void signal_generator_c::generate_codes()
                         {
                             // Generate one code-period of E1B signal
                             bool cboc = true;
-                            char signal[3];
+                            std::array<char, 3> signal = {{'1', 'B', '\0'}};
-                            strcpy(signal, "1B");
 
-                            galileo_e1_code_gen_complex_sampled(code, signal, cboc, PRN_[sat], fs_in_,
+                            galileo_e1_code_gen_complex_sampled(gsl::span<gr_complex>(code, 64000), signal, cboc, PRN_[sat], fs_in_,
                                 static_cast<int>(GALILEO_E1_B_CODE_LENGTH_CHIPS) - delay_chips_[sat]);
 
                             // Obtain the desired CN0 assuming that Pn = 1.
@@ -251,9 +249,9 @@ void signal_generator_c::generate_codes()
                             // Generate E1C signal (25 code-periods, with secondary code)
                             sampled_code_pilot_[sat] = static_cast<gr_complex *>(std::malloc(vector_length_ * sizeof(gr_complex)));
 
-                            strcpy(signal, "1C");
+                            std::array<char, 3> signal_1C = {{'1', 'C', '\0'}};
 
-                            galileo_e1_code_gen_complex_sampled(sampled_code_pilot_[sat], signal, cboc, PRN_[sat], fs_in_,
+                            galileo_e1_code_gen_complex_sampled(gsl::span<gr_complex>(sampled_code_pilot_[sat], vector_length_), signal_1C, cboc, PRN_[sat], fs_in_,
                                 static_cast<int>(GALILEO_E1_B_CODE_LENGTH_CHIPS) - delay_chips_[sat], true);
 
                             // Obtain the desired CN0 assuming that Pn = 1.

src/algorithms/tracking/adapters/galileo_e1_dll_pll_veml_tracking_fpga.cc

@@ -227,12 +227,12 @@ GalileoE1DllPllVemlTrackingFpga::GalileoE1DllPllVemlTrackingFpga(
 
     for (uint32_t PRN = 1; PRN <= GALILEO_E1_NUMBER_OF_CODES; PRN++)
         {
-            char data_signal[3] = "1B";
+            std::array<char, 3> data_signal = {'1', 'B', '\0'};
             if (d_track_pilot)
                 {
-                    char pilot_signal[3] = "1C";
+                    std::array<char, 3> pilot_signal = {'1', 'C', '\0'};
-                    galileo_e1_code_gen_sinboc11_float(ca_codes_f, pilot_signal, PRN);
+                    galileo_e1_code_gen_sinboc11_float(gsl::span<float>(ca_codes_f, static_cast<int32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS) * code_samples_per_chip), pilot_signal, PRN);
-                    galileo_e1_code_gen_sinboc11_float(data_codes_f, data_signal, PRN);
+                    galileo_e1_code_gen_sinboc11_float(gsl::span<float>(data_codes_f, static_cast<uint32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS) * code_samples_per_chip), data_signal, PRN);
 
                     // The code is generated as a series of 1s and -1s. In order to store the values using only one bit, a -1 is stored as a 0 in the FPGA
                     for (uint32_t s = 0; s < 2 * GALILEO_E1_B_CODE_LENGTH_CHIPS; s++)
@@ -255,7 +255,7 @@ GalileoE1DllPllVemlTrackingFpga::GalileoE1DllPllVemlTrackingFpga(
                 }
             else
                 {
-                    galileo_e1_code_gen_sinboc11_float(ca_codes_f, data_signal, PRN);
+                    galileo_e1_code_gen_sinboc11_float(gsl::span<float>(ca_codes_f, static_cast<int32_t>(GALILEO_E1_B_CODE_LENGTH_CHIPS) * code_samples_per_chip), data_signal, PRN);
 
                     // The code is generated as a series of 1s and -1s. In order to store the values using only one bit, a -1 is stored as a 0 in the FPGA
                     for (uint32_t s = 0; s < 2 * GALILEO_E1_B_CODE_LENGTH_CHIPS; s++)

src/algorithms/tracking/adapters/galileo_e5a_dll_pll_tracking_fpga.cc

@@ -217,7 +217,8 @@ GalileoE5aDllPllTrackingFpga::GalileoE5aDllPllTrackingFpga(
 
     for (uint32_t PRN = 1; PRN <= GALILEO_E5A_NUMBER_OF_CODES; PRN++)
         {
-            galileo_e5_a_code_gen_complex_primary(aux_code, PRN, const_cast<char *>(sig_));
+            std::array<char, 3> sig_a = {'5', 'X', '\0'};
+            galileo_e5_a_code_gen_complex_primary(gsl::span<gr_complex>(aux_code, code_length_chips * code_samples_per_chip), PRN, sig_a);
 
             if (trk_param_fpga.track_pilot)
                 {

src/algorithms/tracking/adapters/gps_l1_ca_dll_pll_tracking_fpga.cc

@@ -212,7 +212,7 @@ GpsL1CaDllPllTrackingFpga::GpsL1CaDllPllTrackingFpga(
     d_ca_codes = static_cast<int32_t*>(volk_gnsssdr_malloc(static_cast<int32_t>(GPS_L1_CA_CODE_LENGTH_CHIPS * NUM_PRNs) * sizeof(int32_t), volk_gnsssdr_get_alignment()));
     for (uint32_t PRN = 1; PRN <= NUM_PRNs; PRN++)
         {
-            gps_l1_ca_code_gen_int(&d_ca_codes[(int32_t(GPS_L1_CA_CODE_LENGTH_CHIPS)) * (PRN - 1)], PRN, 0);
+            gps_l1_ca_code_gen_int(gsl::span<int32_t>(&d_ca_codes[static_cast<int32_t>(GPS_L1_CA_CODE_LENGTH_CHIPS) * (PRN - 1)], &d_ca_codes[static_cast<int32_t>(GPS_L1_CA_CODE_LENGTH_CHIPS) * (PRN)]), PRN, 0);
 
             // The code is generated as a series of 1s and -1s. In order to store the values using only one bit, a -1 is stored as a 0 in the FPGA
             for (uint32_t k = 0; k < GPS_L1_CA_CODE_LENGTH_CHIPS; k++)

src/algorithms/tracking/adapters/gps_l2_m_dll_pll_tracking_fpga.cc

@@ -128,7 +128,7 @@ GpsL2MDllPllTrackingFpga::GpsL2MDllPllTrackingFpga(
     d_ca_codes = static_cast<int*>(volk_gnsssdr_malloc(static_cast<int>(GPS_L2_M_CODE_LENGTH_CHIPS * NUM_PRNs) * sizeof(int), volk_gnsssdr_get_alignment()));
     for (unsigned int PRN = 1; PRN <= NUM_PRNs; PRN++)
         {
-            gps_l2c_m_code_gen_float(ca_codes_f, PRN);
+            gps_l2c_m_code_gen_float(gsl::span<float>(ca_codes_f, static_cast<unsigned int>(GPS_L2_M_CODE_LENGTH_CHIPS)), PRN);
             for (unsigned int s = 0; s < 2 * static_cast<unsigned int>(GPS_L2_M_CODE_LENGTH_CHIPS); s++)
                 {
                     d_ca_codes[static_cast<int>(GPS_L2_M_CODE_LENGTH_CHIPS) * (PRN - 1) + s] = static_cast<int>(ca_codes_f[s]);

src/algorithms/tracking/adapters/gps_l5_dll_pll_tracking_fpga.cc

@@ -236,8 +236,8 @@ GpsL5DllPllTrackingFpga::GpsL5DllPllTrackingFpga(
         {
             if (track_pilot)
                 {
-                    gps_l5q_code_gen_float(tracking_code, PRN);
+                    gps_l5q_code_gen_float(gsl::span<float>(tracking_code, code_length_chips), PRN);
-                    gps_l5i_code_gen_float(data_code, PRN);
+                    gps_l5i_code_gen_float(gsl::span<float>(data_code, code_length_chips), PRN);
 
                     // The code is generated as a series of 1s and -1s. In order to store the values using only one bit, a -1 is stored as a 0 in the FPGA
                     for (uint32_t s = 0; s < code_length_chips; s++)
@@ -261,7 +261,7 @@ GpsL5DllPllTrackingFpga::GpsL5DllPllTrackingFpga(
                 }
             else
                 {
-                    gps_l5i_code_gen_float(tracking_code, PRN);
+                    gps_l5i_code_gen_float(gsl::span<float>(tracking_code, code_length_chips), PRN);
 
                     // The code is generated as a series of 1s and -1s. In order to store the values using only one bit, a -1 is stored as a 0 in the FPGA
                     for (uint32_t s = 0; s < code_length_chips; s++)

src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.cc

@@ -63,6 +63,7 @@
 #include <algorithm>  // for fill_n
 #include <cmath>      // for fmod, round, floor
 #include <exception>  // for exception
+#include <gsl/gsl>
 #include <iostream>  // for cout, cerr
 #include <map>
 #include <numeric>
@@ -587,48 +588,52 @@ void dll_pll_veml_tracking::start_tracking()
     d_carrier_phase_rate_step_rad = 0.0;
     d_carr_ph_history.clear();
     d_code_ph_history.clear();
+    std::array<char, 3> Signal_;
+    std::memcpy(Signal_.data(), d_acquisition_gnss_synchro->Signal, 3);
 
     if (systemName == "GPS" and signal_type == "1C")
         {
-            gps_l1_ca_code_gen_float(d_tracking_code, d_acquisition_gnss_synchro->PRN, 0);
+            gps_l1_ca_code_gen_float(gsl::span<float>(d_tracking_code, 2 * d_code_length_chips), d_acquisition_gnss_synchro->PRN, 0);
         }
     else if (systemName == "GPS" and signal_type == "2S")
         {
-            gps_l2c_m_code_gen_float(d_tracking_code, d_acquisition_gnss_synchro->PRN);
+            gps_l2c_m_code_gen_float(gsl::span<float>(d_tracking_code, 2 * d_code_length_chips), d_acquisition_gnss_synchro->PRN);
         }
     else if (systemName == "GPS" and signal_type == "L5")
         {
             if (trk_parameters.track_pilot)
                 {
-                    gps_l5q_code_gen_float(d_tracking_code, d_acquisition_gnss_synchro->PRN);
+                    gps_l5q_code_gen_float(gsl::span<float>(d_tracking_code, 2 * d_code_length_chips), d_acquisition_gnss_synchro->PRN);
-                    gps_l5i_code_gen_float(d_data_code, d_acquisition_gnss_synchro->PRN);
+                    gps_l5i_code_gen_float(gsl::span<float>(d_data_code, 2 * d_code_length_chips), d_acquisition_gnss_synchro->PRN);
                     d_Prompt_Data[0] = gr_complex(0.0, 0.0);
                     correlator_data_cpu.set_local_code_and_taps(d_code_length_chips, d_data_code, d_prompt_data_shift);
                 }
             else
                 {
-                    gps_l5i_code_gen_float(d_tracking_code, d_acquisition_gnss_synchro->PRN);
+                    gps_l5i_code_gen_float(gsl::span<float>(d_tracking_code, 2 * d_code_length_chips), d_acquisition_gnss_synchro->PRN);
                 }
         }
     else if (systemName == "Galileo" and signal_type == "1B")
         {
             if (trk_parameters.track_pilot)
                 {
-                    char pilot_signal[3] = "1C";
+                    std::array<char, 3> pilot_signal = {{'1', 'C', '\0'}};
-                    galileo_e1_code_gen_sinboc11_float(d_tracking_code, pilot_signal, d_acquisition_gnss_synchro->PRN);
+
-                    galileo_e1_code_gen_sinboc11_float(d_data_code, d_acquisition_gnss_synchro->Signal, d_acquisition_gnss_synchro->PRN);
+                    galileo_e1_code_gen_sinboc11_float(gsl::span<float>(d_tracking_code, 2 * d_code_length_chips), pilot_signal, d_acquisition_gnss_synchro->PRN);
+                    galileo_e1_code_gen_sinboc11_float(gsl::span<float>(d_data_code, 2 * d_code_length_chips), Signal_, d_acquisition_gnss_synchro->PRN);
                     d_Prompt_Data[0] = gr_complex(0.0, 0.0);
                     correlator_data_cpu.set_local_code_and_taps(d_code_samples_per_chip * d_code_length_chips, d_data_code, d_prompt_data_shift);
                 }
             else
                 {
-                    galileo_e1_code_gen_sinboc11_float(d_tracking_code, d_acquisition_gnss_synchro->Signal, d_acquisition_gnss_synchro->PRN);
+                    galileo_e1_code_gen_sinboc11_float(gsl::span<float>(d_tracking_code, 2 * d_code_length_chips), Signal_, d_acquisition_gnss_synchro->PRN);
                 }
         }
     else if (systemName == "Galileo" and signal_type == "5X")
         {
             auto *aux_code = static_cast<gr_complex *>(volk_gnsssdr_malloc(sizeof(gr_complex) * d_code_length_chips, volk_gnsssdr_get_alignment()));
-            galileo_e5_a_code_gen_complex_primary(aux_code, d_acquisition_gnss_synchro->PRN, const_cast<char *>(signal_type.c_str()));
+            std::array<char, 3> signal_type_ = {{'5', 'X', '\0'}};
+            galileo_e5_a_code_gen_complex_primary(gsl::span<gr_complex>(aux_code, d_code_length_chips), d_acquisition_gnss_synchro->PRN, signal_type_);
             if (trk_parameters.track_pilot)
                 {
                     d_secondary_code_string = const_cast<std::string *>(&GALILEO_E5A_Q_SECONDARY_CODE[d_acquisition_gnss_synchro->PRN - 1]);
@@ -651,7 +656,7 @@ void dll_pll_veml_tracking::start_tracking()
         }
     else if (systemName == "Beidou" and signal_type == "B1")
         {
-            beidou_b1i_code_gen_float(d_tracking_code, d_acquisition_gnss_synchro->PRN, 0);
+            beidou_b1i_code_gen_float(gsl::span<float>(d_tracking_code, 2 * d_code_length_chips), d_acquisition_gnss_synchro->PRN, 0);
             // Update secondary code settings for geo satellites
             if (d_acquisition_gnss_synchro->PRN > 0 and d_acquisition_gnss_synchro->PRN < 6)
                 {
@@ -691,7 +696,7 @@ void dll_pll_veml_tracking::start_tracking()
 
     else if (systemName == "Beidou" and signal_type == "B3")
         {
-            beidou_b3i_code_gen_float(d_tracking_code, d_acquisition_gnss_synchro->PRN, 0);
+            beidou_b3i_code_gen_float(gsl::span<float>(d_tracking_code, 2 * d_code_length_chips), d_acquisition_gnss_synchro->PRN, 0);
             // Update secondary code settings for geo satellites
             if (d_acquisition_gnss_synchro->PRN > 0 and d_acquisition_gnss_synchro->PRN < 6)
                 {

src/algorithms/tracking/gnuradio_blocks/galileo_e1_tcp_connector_tracking_cc.cc

@@ -188,10 +188,12 @@ void Galileo_E1_Tcp_Connector_Tracking_cc::start_tracking()
     d_acq_code_phase_samples = d_acquisition_gnss_synchro->Acq_delay_samples;
     d_acq_carrier_doppler_hz = d_acquisition_gnss_synchro->Acq_doppler_hz;
     d_acq_sample_stamp = d_acquisition_gnss_synchro->Acq_samplestamp_samples;
+    std::array<char, 3> Signal_;
+    std::memcpy(Signal_.data(), d_acquisition_gnss_synchro->Signal, 3);
 
     // generate local reference ALWAYS starting at chip 1 (2 samples per chip)
-    galileo_e1_code_gen_complex_sampled(d_ca_code,
+    galileo_e1_code_gen_complex_sampled(gsl::span<gr_complex>(d_ca_code, (2 * GALILEO_E1_B_CODE_LENGTH_CHIPS)),
-        d_acquisition_gnss_synchro->Signal,
+        Signal_,
         false,
         d_acquisition_gnss_synchro->PRN,
         2 * GALILEO_E1_CODE_CHIP_RATE_HZ,

src/algorithms/tracking/gnuradio_blocks/glonass_l1_ca_dll_pll_c_aid_tracking_cc.cc

@@ -272,7 +272,7 @@ void glonass_l1_ca_dll_pll_c_aid_tracking_cc::start_tracking()
     d_code_loop_filter.initialize();                           // initialize the code filter
 
     // generate local reference ALWAYS starting at chip 1 (1 sample per chip)
-    glonass_l1_ca_code_gen_complex(d_ca_code, 0);
+    glonass_l1_ca_code_gen_complex(gsl::span<gr_complex>(d_ca_code, GLONASS_L1_CA_CODE_LENGTH_CHIPS), 0);
 
     multicorrelator_cpu.set_local_code_and_taps(static_cast<int32_t>(GLONASS_L1_CA_CODE_LENGTH_CHIPS), d_ca_code, d_local_code_shift_chips);
     for (int32_t n = 0; n < d_n_correlator_taps; n++)

src/algorithms/tracking/gnuradio_blocks/glonass_l1_ca_dll_pll_c_aid_tracking_sc.cc

@@ -266,7 +266,7 @@ void glonass_l1_ca_dll_pll_c_aid_tracking_sc::start_tracking()
     d_code_loop_filter.initialize();                           // initialize the code filter
 
     // generate local reference ALWAYS starting at chip 1 (1 sample per chip)
-    glonass_l1_ca_code_gen_complex(d_ca_code, 0);
+    glonass_l1_ca_code_gen_complex(gsl::span<gr_complex>(d_ca_code, GLONASS_L1_CA_CODE_LENGTH_CHIPS), 0);
     volk_gnsssdr_32fc_convert_16ic(d_ca_code_16sc, d_ca_code, static_cast<int32_t>(GLONASS_L1_CA_CODE_LENGTH_CHIPS));
 
     multicorrelator_cpu_16sc.set_local_code_and_taps(static_cast<int32_t>(GLONASS_L1_CA_CODE_LENGTH_CHIPS), d_ca_code_16sc, d_local_code_shift_chips);

src/algorithms/tracking/gnuradio_blocks/glonass_l1_ca_dll_pll_tracking_cc.cc

@@ -226,7 +226,7 @@ void Glonass_L1_Ca_Dll_Pll_Tracking_cc::start_tracking()
     d_code_loop_filter.initialize();     // initialize the code filter
 
     // generate local reference ALWAYS starting at chip 1 (1 sample per chip)
-    glonass_l1_ca_code_gen_complex(d_ca_code, 0);
+    glonass_l1_ca_code_gen_complex(gsl::span<gr_complex>(d_ca_code, GLONASS_L1_CA_CODE_LENGTH_CHIPS), 0);
 
     multicorrelator_cpu.set_local_code_and_taps(static_cast<int32_t>(GLONASS_L1_CA_CODE_LENGTH_CHIPS), d_ca_code, d_local_code_shift_chips);
     for (int32_t n = 0; n < d_n_correlator_taps; n++)

src/algorithms/tracking/gnuradio_blocks/glonass_l2_ca_dll_pll_c_aid_tracking_cc.cc

@@ -269,7 +269,7 @@ void glonass_l2_ca_dll_pll_c_aid_tracking_cc::start_tracking()
     d_code_loop_filter.initialize();                           // initialize the code filter
 
     // generate local reference ALWAYS starting at chip 1 (1 sample per chip)
-    glonass_l2_ca_code_gen_complex(d_ca_code, 0);
+    glonass_l2_ca_code_gen_complex(gsl::span<gr_complex>(d_ca_code, static_cast<int32_t>(GLONASS_L2_CA_CODE_LENGTH_CHIPS)), 0);
 
     multicorrelator_cpu.set_local_code_and_taps(static_cast<int32_t>(GLONASS_L2_CA_CODE_LENGTH_CHIPS), d_ca_code, d_local_code_shift_chips);
     for (int32_t n = 0; n < d_n_correlator_taps; n++)

src/algorithms/tracking/gnuradio_blocks/glonass_l2_ca_dll_pll_c_aid_tracking_sc.cc

@@ -265,7 +265,7 @@ void glonass_l2_ca_dll_pll_c_aid_tracking_sc::start_tracking()
     d_code_loop_filter.initialize();                           // initialize the code filter
 
     // generate local reference ALWAYS starting at chip 1 (1 sample per chip)
-    glonass_l2_ca_code_gen_complex(d_ca_code, 0);
+    glonass_l2_ca_code_gen_complex(gsl::span<gr_complex>(d_ca_code, static_cast<int32_t>(GLONASS_L2_CA_CODE_LENGTH_CHIPS)), 0);
     volk_gnsssdr_32fc_convert_16ic(d_ca_code_16sc, d_ca_code, static_cast<int32_t>(GLONASS_L2_CA_CODE_LENGTH_CHIPS));
 
     multicorrelator_cpu_16sc.set_local_code_and_taps(static_cast<int32_t>(GLONASS_L2_CA_CODE_LENGTH_CHIPS), d_ca_code_16sc, d_local_code_shift_chips);

src/algorithms/tracking/gnuradio_blocks/glonass_l2_ca_dll_pll_tracking_cc.cc

@@ -226,7 +226,7 @@ void Glonass_L2_Ca_Dll_Pll_Tracking_cc::start_tracking()
     d_code_loop_filter.initialize();     // initialize the code filter
 
     // generate local reference ALWAYS starting at chip 1 (1 sample per chip)
-    glonass_l2_ca_code_gen_complex(d_ca_code, 0);
+    glonass_l2_ca_code_gen_complex(gsl::span<gr_complex>(d_ca_code, static_cast<int32_t>(GLONASS_L2_CA_CODE_LENGTH_CHIPS)), 0);
 
     multicorrelator_cpu.set_local_code_and_taps(static_cast<int32_t>(GLONASS_L2_CA_CODE_LENGTH_CHIPS), d_ca_code, d_local_code_shift_chips);
     for (int32_t n = 0; n < d_n_correlator_taps; n++)

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_tracking_gpu_cc.cc

@@ -217,7 +217,7 @@ void Gps_L1_Ca_Dll_Pll_Tracking_GPU_cc::start_tracking()
     d_code_loop_filter.initialize();                             // initialize the code filter
 
     // generate local reference ALWAYS starting at chip 1 (1 sample per chip)
-    gps_l1_ca_code_gen_complex(d_ca_code, d_acquisition_gnss_synchro->PRN, 0);
+    gps_l1_ca_code_gen_complex(gsl::span<gr_complex>(d_ca_code, static_cast<int32_t>(GPS_L1_CA_CODE_LENGTH_CHIPS)), d_acquisition_gnss_synchro->PRN, 0);
 
     multicorrelator_gpu->set_local_code_and_taps(static_cast<int32_t>(GPS_L1_CA_CODE_LENGTH_CHIPS), d_ca_code, d_local_code_shift_chips, d_n_correlator_taps);
 

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_kf_tracking_cc.cc

@@ -49,6 +49,7 @@
 #include <volk_gnsssdr/volk_gnsssdr.h>
 #include <cmath>
 #include <exception>
+#include <gsl/gsl>
 #include <iostream>
 #include <memory>
 #include <sstream>
@@ -320,7 +321,7 @@ void Gps_L1_Ca_Kf_Tracking_cc::start_tracking()
     d_code_loop_filter.initialize();  // initialize the code filter
 
     // generate local reference ALWAYS starting at chip 1 (1 sample per chip)
-    gps_l1_ca_code_gen_float(d_ca_code, d_acquisition_gnss_synchro->PRN, 0);
+    gps_l1_ca_code_gen_float(gsl::span<float>(d_ca_code, static_cast<int>(GPS_L1_CA_CODE_LENGTH_CHIPS) * sizeof(float)), d_acquisition_gnss_synchro->PRN, 0);
 
     multicorrelator_cpu.set_local_code_and_taps(static_cast<int>(GPS_L1_CA_CODE_LENGTH_CHIPS), d_ca_code, d_local_code_shift_chips);
     for (int32_t n = 0; n < d_n_correlator_taps; n++)

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_tcp_connector_tracking_cc.cc

@@ -223,7 +223,7 @@ void Gps_L1_Ca_Tcp_Connector_Tracking_cc::start_tracking()
     d_carrier_doppler_hz = d_acq_carrier_doppler_hz;
 
     // generate local reference ALWAYS starting at chip 1 (1 sample per chip)
-    gps_l1_ca_code_gen_complex(d_ca_code, d_acquisition_gnss_synchro->PRN, 0);
+    gps_l1_ca_code_gen_complex(gsl::span<gr_complex>(d_ca_code, (GPS_L1_CA_CODE_LENGTH_CHIPS) * sizeof(gr_complex)), d_acquisition_gnss_synchro->PRN, 0);
 
     multicorrelator_cpu.set_local_code_and_taps(static_cast<int32_t>(GPS_L1_CA_CODE_LENGTH_CHIPS), d_ca_code, d_local_code_shift_chips);
     for (int32_t n = 0; n < d_n_correlator_taps; n++)

src/tests/unit-tests/arithmetic/code_generation_test.cc

@@ -33,6 +33,12 @@
 #include "gps_sdr_signal_processing.h"
 #include <chrono>
 #include <complex>
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
 
 
 TEST(CodeGenerationTest, CodeGenGPSL1Test)
@@ -48,7 +54,7 @@ TEST(CodeGenerationTest, CodeGenGPSL1Test)
 
     for (int i = 0; i < iterations; i++)
         {
-            gps_l1_ca_code_gen_complex(_dest, _prn, _chip_shift);
+            gps_l1_ca_code_gen_complex(gsl::span<std::complex<float>>(_dest, 1023), _prn, _chip_shift);
         }
 
     end = std::chrono::system_clock::now();
@@ -77,7 +83,7 @@ TEST(CodeGenerationTest, CodeGenGPSL1SampledTest)
 
     for (int i = 0; i < iterations; i++)
         {
-            gps_l1_ca_code_gen_complex_sampled(_dest, _prn, _fs, _chip_shift);
+            gps_l1_ca_code_gen_complex_sampled(gsl::span<std::complex<float>>(_dest, _samplesPerCode), _prn, _fs, _chip_shift);
         }
 
     end = std::chrono::system_clock::now();
@@ -105,7 +111,7 @@ TEST(CodeGenerationTest, ComplexConjugateTest)
 
     for (int i = 0; i < iterations; i++)
         {
-            complex_exp_gen_conj(_dest, _f, _fs, _samplesPerCode);
+            complex_exp_gen_conj(gsl::span<std::complex<float>>(_dest, _samplesPerCode), _f, _fs);
         }
 
     end = std::chrono::system_clock::now();

src/tests/unit-tests/arithmetic/complex_carrier_test.cc

@@ -34,6 +34,12 @@
 #include <armadillo>
 #include <chrono>
 #include <complex>
+#if HAS_SPAN
+#include <span>
+namespace gsl = std;
+#else
+#include <gsl/gsl>
+#endif
 
 DEFINE_int32(size_carrier_test, 100000, "Size of the arrays used for complex carrier testing");
 
@@ -120,7 +126,7 @@ TEST(ComplexCarrierTest, OwnComplexImplementation)
     std::chrono::time_point<std::chrono::system_clock> start, end;
     start = std::chrono::system_clock::now();
 
-    complex_exp_gen(output, _f, _fs, static_cast<unsigned int>(FLAGS_size_carrier_test));
+    complex_exp_gen(gsl::span<std::complex<float>>(output, static_cast<unsigned int>(FLAGS_size_carrier_test)), _f, _fs);
 
     end = std::chrono::system_clock::now();
     std::chrono::duration<double> elapsed_seconds = end - start;

src/tests/unit-tests/signal-processing-blocks/observables/hybrid_observables_test_fpga.cc

@@ -259,6 +259,7 @@ public:
     Gnss_Synchro gnss_synchro_master;
     std::vector<Gnss_Synchro> gnss_synchro_vec;
     size_t item_size;
+    pthread_mutex_t mutex_obs_test = PTHREAD_MUTEX_INITIALIZER;
 };
 
 int HybridObservablesTestFpga::configure_generator()
@@ -305,11 +306,10 @@ int HybridObservablesTestFpga::generate_signal()
 }
 
 
-const size_t TEST_OBS_PAGE_SIZE = 0x10000;
-const unsigned int TEST_OBS_TEST_REGISTER_TRACK_WRITEVAL = 0x55AA;
-
 void setup_fpga_switch_obs_test(void)
 {
+    const size_t TEST_OBS_PAGE_SIZE = 0x10000;
+    const unsigned int TEST_OBS_TEST_REGISTER_TRACK_WRITEVAL = 0x55AA;
     int switch_device_descriptor;        // driver descriptor
     volatile unsigned* switch_map_base;  // driver memory map
 
@@ -348,7 +348,7 @@ void setup_fpga_switch_obs_test(void)
 }
 
 
-static pthread_mutex_t mutex_obs_test = PTHREAD_MUTEX_INITIALIZER;
+//static pthread_mutex_t mutex_obs_test = PTHREAD_MUTEX_INITIALIZER;
 
 volatile unsigned int send_samples_start_obs_test = 0;
 
@@ -642,9 +642,9 @@ bool HybridObservablesTestFpga::acquire_signal()
                         {
                             std::cout << "ERROR cannot create DMA Process" << std::endl;
                         }
-                    pthread_mutex_lock(&mutex);
+                    pthread_mutex_lock(&mutex_obs_test);
                     send_samples_start_obs_test = 1;
-                    pthread_mutex_unlock(&mutex);
+                    pthread_mutex_unlock(&mutex_obs_test);
                     pthread_join(thread_DMA, nullptr);
                     send_samples_start_obs_test = 0;
 
@@ -669,9 +669,9 @@ bool HybridObservablesTestFpga::acquire_signal()
             msg_rx->rx_message = 0;
             top_block->start();
 
-            pthread_mutex_lock(&mutex);
+            pthread_mutex_lock(&mutex_obs_test);
             send_samples_start_obs_test = 1;
-            pthread_mutex_unlock(&mutex);
+            pthread_mutex_unlock(&mutex_obs_test);
 
             acquisition->reset();  // set active
 
@@ -686,9 +686,9 @@ bool HybridObservablesTestFpga::acquire_signal()
             // wait for the child DMA process to finish
             pthread_join(thread_DMA, nullptr);
 
-            pthread_mutex_lock(&mutex);
+            pthread_mutex_lock(&mutex_obs_test);
             send_samples_start_obs_test = 0;
-            pthread_mutex_unlock(&mutex);
+            pthread_mutex_unlock(&mutex_obs_test);
 
             // the DMA sends the exact number of samples needed for the acquisition.
             // however because of the LPF in the GPS L1/Gal E1 acquisition, this calculation is approximate

src/tests/unit-tests/signal-processing-blocks/tracking/cpu_multicorrelator_real_codes_test.cc

@@ -106,7 +106,7 @@ TEST(CpuMulticorrelatorRealCodesTest, MeasureExecutionTime)
 
     //local code resampler on GPU
     // generate local reference (1 sample per chip)
-    gps_l1_ca_code_gen_float(d_ca_code, 1, 0);
+    gps_l1_ca_code_gen_float(gsl::span<float>(d_ca_code, static_cast<int>(GPS_L1_CA_CODE_LENGTH_CHIPS) * sizeof(float)), 1, 0);
     // generate inut signal
     std::random_device r;
     std::default_random_engine e1(r());

src/tests/unit-tests/signal-processing-blocks/tracking/cpu_multicorrelator_test.cc

@@ -104,7 +104,7 @@ TEST(CpuMulticorrelatorTest, MeasureExecutionTime)
 
     //local code resampler on GPU
     // generate local reference (1 sample per chip)
-    gps_l1_ca_code_gen_complex(d_ca_code, 1, 0);
+    gps_l1_ca_code_gen_complex(gsl::span<gr_complex>(d_ca_code, static_cast<int>(GPS_L1_CA_CODE_LENGTH_CHIPS) * sizeof(gr_complex)), 1, 0);
     // generate inut signal
     std::random_device r;
     std::default_random_engine e1(r());

src/tests/unit-tests/signal-processing-blocks/tracking/tracking_pull-in_test_fpga.cc

@@ -248,6 +248,7 @@ public:
     std::shared_ptr<InMemoryConfiguration> config;
     Gnss_Synchro gnss_synchro;
     size_t item_size;
+    pthread_mutex_t the_mutex = PTHREAD_MUTEX_INITIALIZER;
 };
 
 
@@ -386,12 +387,10 @@ void TrackingPullInTestFpga::configure_receiver(
 }
 
 
-const size_t PAGE_SIZE = 0x10000;
-const unsigned int TEST_REGISTER_TRACK_WRITEVAL = 0x55AA;
-
-
 void setup_fpga_switch(void)
 {
+    const size_t PAGE_SIZE_ = 0x10000;
+    const unsigned int TEST_REGISTER_TRACK_WRITEVAL = 0x55AA;
     int switch_device_descriptor;        // driver descriptor
     volatile unsigned* switch_map_base;  // driver memory map
 
@@ -400,7 +399,7 @@ void setup_fpga_switch(void)
             LOG(WARNING) << "Cannot open deviceio"
                          << "/dev/uio1";
         }
-    switch_map_base = reinterpret_cast<volatile unsigned*>(mmap(nullptr, PAGE_SIZE,
+    switch_map_base = reinterpret_cast<volatile unsigned*>(mmap(nullptr, PAGE_SIZE_,
         PROT_READ | PROT_WRITE, MAP_SHARED, switch_device_descriptor, 0));
 
     if (switch_map_base == reinterpret_cast<void*>(-1))
@@ -430,7 +429,7 @@ void setup_fpga_switch(void)
 }
 
 
-static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+//static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
 
 volatile unsigned int send_samples_start = 0;
 
@@ -728,9 +727,9 @@ bool TrackingPullInTestFpga::acquire_signal(int SV_ID)
                         {
                             std::cout << "ERROR cannot create DMA Process" << std::endl;
                         }
-                    pthread_mutex_lock(&mutex);
+                    pthread_mutex_lock(&the_mutex);
                     send_samples_start = 1;
-                    pthread_mutex_unlock(&mutex);
+                    pthread_mutex_unlock(&the_mutex);
                     pthread_join(thread_DMA, nullptr);
                     send_samples_start = 0;
 
@@ -753,9 +752,9 @@ bool TrackingPullInTestFpga::acquire_signal(int SV_ID)
             msg_rx->rx_message = 0;
             top_block->start();
 
-            pthread_mutex_lock(&mutex);
+            pthread_mutex_lock(&the_mutex);
             send_samples_start = 1;
-            pthread_mutex_unlock(&mutex);
+            pthread_mutex_unlock(&the_mutex);
 
             acquisition->reset();  // set active
 
@@ -770,9 +769,9 @@ bool TrackingPullInTestFpga::acquire_signal(int SV_ID)
             // wait for the child DMA process to finish
             pthread_join(thread_DMA, nullptr);
 
-            pthread_mutex_lock(&mutex);
+            pthread_mutex_lock(&the_mutex);
             send_samples_start = 0;
-            pthread_mutex_unlock(&mutex);
+            pthread_mutex_unlock(&the_mutex);
 
             // the DMA sends the exact number of samples needed for the acquisition.
             // however because of the LPF in the GPS L1/Gal E1 acquisition, this calculation is approximate
@@ -1063,9 +1062,9 @@ TEST_F(TrackingPullInTestFpga, ValidationOfResults)
 
                             tracking->start_tracking();
 
-                            pthread_mutex_lock(&mutex);
+                            pthread_mutex_lock(&the_mutex);
                             send_samples_start = 1;
-                            pthread_mutex_unlock(&mutex);
+                            pthread_mutex_unlock(&the_mutex);
 
                             top_block->start();
 
@@ -1077,9 +1076,9 @@ TEST_F(TrackingPullInTestFpga, ValidationOfResults)
                             // reset the HW to launch the pending interrupts
                             acquisition->stop_acquisition();
 
-                            pthread_mutex_lock(&mutex);
+                            pthread_mutex_lock(&the_mutex);
                             send_samples_start = 0;
-                            pthread_mutex_unlock(&mutex);
+                            pthread_mutex_unlock(&the_mutex);
 
                             pull_in_results_v.push_back(msg_rx->rx_message != 3);  //save last asynchronous tracking message in order to detect a loss of lock