initial implementation of common file source base class

Only the file_signal_source uses it at this time; changing multi-channel
to use it can be done with a little work

src/algorithms/signal_source/adapters/CMakeLists.txt

@@ -93,6 +93,7 @@ endif()
 
 set(SIGNAL_SOURCE_ADAPTER_SOURCES
     signal_source_base.cc
+    file_source_base.cc
     file_signal_source.cc
     multichannel_file_signal_source.cc
     gen_signal_source.cc
@@ -108,6 +109,7 @@ set(SIGNAL_SOURCE_ADAPTER_SOURCES
 
 set(SIGNAL_SOURCE_ADAPTER_HEADERS
     signal_source_base.h
+    file_source_base.h
     file_signal_source.h
     multichannel_file_signal_source.h
     gen_signal_source.h
@@ -170,6 +172,18 @@ if(GNURADIO_USES_STD_POINTERS)
     )
 endif()
 
+# This should really be at a higher level and apply universally to the
+# build system
+if(FILESYSTEM_FOUND)
+    target_compile_definitions(signal_source_adapters PUBLIC -DHAS_STD_FILESYSTEM=1)
+    if(find_experimental)
+        target_compile_definitions(signal_source_adapters PUBLIC -DHAS_STD_FILESYSTEM_EXPERIMENTAL=1)
+    endif()
+    target_link_libraries(signal_source_adapters PUBLIC std::filesystem)
+else()
+    target_link_libraries(signal_source_adapters PUBLIC Boost::filesystem Boost::system)
+endif()
+
 if(ENABLE_RAW_UDP AND PCAP_FOUND)
     target_link_libraries(signal_source_adapters
         PRIVATE

src/algorithms/signal_source/adapters/file_signal_source.cc

@@ -19,7 +19,6 @@
 #include "file_signal_source.h"
 #include "configuration_interface.h"
 #include "gnss_sdr_flags.h"
-#include "gnss_sdr_valve.h"
 #include <glog/logging.h>
 #include <exception>
 #include <fstream>
@@ -32,324 +31,16 @@ using namespace std::string_literals;
 FileSignalSource::FileSignalSource(ConfigurationInterface const* configuration,
     std::string const& role, unsigned int in_streams, unsigned int out_streams,
     Concurrent_Queue<pmt::pmt_t>* queue)
-  : SignalSourceBase(configuration, role, "File_Signal_Source"s)
+  : FileSourceBase(configuration, role, "File_Signal_Source"s, queue)
-, in_streams_(in_streams), out_streams_(out_streams)
 {
-    const std::string default_filename("./example_capture.dat");
+    if (in_streams > 0)
-    const std::string default_item_type("short");
-    const std::string default_dump_filename("./my_capture.dat");
-
-    const double default_seconds_to_skip = 0.0;
-
-    samples_ = configuration->property(role + ".samples", static_cast<uint64_t>(0));
-    sampling_frequency_ = configuration->property(role + ".sampling_frequency", static_cast<int64_t>(0));
-    filename_ = configuration->property(role + ".filename", default_filename);
-
-    // override value with commandline flag, if present
-    if (FLAGS_signal_source != "-")
-        {
-            filename_ = FLAGS_signal_source;
-        }
-    if (FLAGS_s != "-")
-        {
-            filename_ = FLAGS_s;
-        }
-
-    item_type_ = configuration->property(role + ".item_type", default_item_type);
-    repeat_ = configuration->property(role + ".repeat", false);
-    dump_ = configuration->property(role + ".dump", false);
-    dump_filename_ = configuration->property(role + ".dump_filename", default_dump_filename);
-    enable_throttle_control_ = configuration->property(role + ".enable_throttle_control", false);
-
-    const double seconds_to_skip = configuration->property(role + ".seconds_to_skip", default_seconds_to_skip);
-    const size_t header_size = configuration->property(role + ".header_size", 0);
-    int64_t samples_to_skip = 0;
-
-    bool is_complex = false;
-
-    if (item_type_ == "gr_complex")
-        {
-            item_size_ = sizeof(gr_complex);
-        }
-    else if (item_type_ == "float")
-        {
-            item_size_ = sizeof(float);
-        }
-    else if (item_type_ == "short")
-        {
-            item_size_ = sizeof(int16_t);
-        }
-    else if (item_type_ == "ishort")
-        {
-            item_size_ = sizeof(int16_t);
-            is_complex = true;
-        }
-    else if (item_type_ == "byte")
-        {
-            item_size_ = sizeof(int8_t);
-        }
-    else if (item_type_ == "ibyte")
-        {
-            item_size_ = sizeof(int8_t);
-            is_complex = true;
-        }
-    else
-        {
-            LOG(WARNING) << item_type_
-                         << " unrecognized item type. Using gr_complex.";
-            item_size_ = sizeof(gr_complex);
-        }
-    try
-        {
-            file_source_ = gr::blocks::file_source::make(item_size_, filename_.c_str(), repeat_);
-
-            if (seconds_to_skip > 0)
-                {
-                    samples_to_skip = static_cast<int64_t>(seconds_to_skip * sampling_frequency_);
-
-                    if (is_complex)
-                        {
-                            samples_to_skip *= 2;
-                        }
-                }
-            if (header_size > 0)
-                {
-                    samples_to_skip += header_size;
-                }
-
-            if (samples_to_skip > 0)
-                {
-                    LOG(INFO) << "Skipping " << samples_to_skip << " samples of the input file";
-                    if (not file_source_->seek(samples_to_skip, SEEK_SET))
-                        {
-                            LOG(INFO) << "Error skipping bytes!";
-                        }
-                }
-        }
-    catch (const std::exception& e)
-        {
-            if (filename_ == default_filename)
-                {
-                    std::cerr
-                        << "The configuration file has not been found.\n"
-                        << "Please create a configuration file based on the examples at the 'conf/' folder\n"
-                        << "and then generate your own GNSS Software Defined Receiver by doing:\n"
-                        << "$ gnss-sdr --config_file=/path/to/my_GNSS_SDR_configuration.conf\n";
-                }
-            else
-                {
-                    std::cerr
-                        << "The receiver was configured to work with a file signal source\n"
-                        << "but the specified file is unreachable by GNSS-SDR.\n"
-                        << "Please modify your configuration file\n"
-                        << "and point SignalSource.filename to a valid raw data file. Then:\n"
-                        << "$ gnss-sdr --config_file=/path/to/my_GNSS_SDR_configuration.conf\n"
-                        << "Examples of configuration files available at:\n"
-                        << GNSSSDR_INSTALL_DIR "/share/gnss-sdr/conf/\n";
-                }
-
-            LOG(INFO) << "file_signal_source: Unable to open the samples file "
-                      << filename_.c_str() << ", exiting the program.";
-            throw(e);
-        }
-
-    DLOG(INFO) << "file_source(" << file_source_->unique_id() << ")";
-
-    if (samples_ == 0)  // read all file
-        {
-            /*!
-             * BUG workaround: The GNU Radio file source does not stop the receiver after reaching the End of File.
-             * A possible solution is to compute the file length in samples using file size, excluding the last 100 milliseconds, and enable always the
-             * valve block
-             */
-            std::ifstream file(filename_.c_str(), std::ios::in | std::ios::binary | std::ios::ate);
-            std::ifstream::pos_type size;
-
-            if (file.is_open())
-                {
-                    size = file.tellg();
-                    DLOG(INFO) << "Total samples in the file= " << floor(static_cast<double>(size) / static_cast<double>(item_size_));
-                }
-            else
-                {
-                    std::cout << "file_signal_source: Unable to open the samples file " << filename_.c_str() << '\n';
-                    LOG(ERROR) << "file_signal_source: Unable to open the samples file " << filename_.c_str();
-                }
-            std::streamsize ss = std::cout.precision();
-            std::cout << std::setprecision(16);
-            std::cout << "Processing file " << filename_ << ", which contains " << static_cast<double>(size) << " [bytes]\n";
-            std::cout.precision(ss);
-
-            if (size > 0)
-                {
-                    const int64_t bytes_to_skip = samples_to_skip * item_size_;
-                    const int64_t bytes_to_process = static_cast<int64_t>(size) - bytes_to_skip;
-                    samples_ = floor(static_cast<double>(bytes_to_process) / static_cast<double>(item_size_) - ceil(0.002 * static_cast<double>(sampling_frequency_)));  // process all the samples available in the file excluding at least the last 1 ms
-                }
-        }
-
-    CHECK(samples_ > 0) << "File does not contain enough samples to process.";
-    double signal_duration_s = static_cast<double>(samples_) * (1 / static_cast<double>(sampling_frequency_));
-
-    if (is_complex)
-        {
-            signal_duration_s /= 2.0;
-        }
-
-    DLOG(INFO) << "Total number samples to be processed= " << samples_ << " GNSS signal duration= " << signal_duration_s << " [s]";
-    std::cout << "GNSS signal recorded time to be processed: " << signal_duration_s << " [s]\n";
-
-    valve_ = gnss_sdr_make_valve(item_size_, samples_, queue);
-    DLOG(INFO) << "valve(" << valve_->unique_id() << ")";
-
-    if (dump_)
-        {
-            sink_ = gr::blocks::file_sink::make(item_size_, dump_filename_.c_str());
-            DLOG(INFO) << "file_sink(" << sink_->unique_id() << ")";
-        }
-
-    if (enable_throttle_control_)
-        {
-            throttle_ = gr::blocks::throttle::make(item_size_, sampling_frequency_);
-        }
-
-    DLOG(INFO) << "File source filename " << filename_;
-    DLOG(INFO) << "Samples " << samples_;
-    DLOG(INFO) << "Sampling frequency " << sampling_frequency_;
-    DLOG(INFO) << "Item type " << item_type_;
-    DLOG(INFO) << "Item size " << item_size_;
-    DLOG(INFO) << "Repeat " << repeat_;
-    DLOG(INFO) << "Dump " << dump_;
-    DLOG(INFO) << "Dump filename " << dump_filename_;
-    if (in_streams_ > 0)
         {
             LOG(ERROR) << "A signal source does not have an input stream";
         }
-    if (out_streams_ > 1)
+    if (out_streams > 1)
         {
             LOG(ERROR) << "This implementation only supports one output stream";
         }
 }
 
 
-void FileSignalSource::connect(gr::top_block_sptr top_block)
-{
-    if (samples_ > 0)
-        {
-            if (enable_throttle_control_ == true)
-                {
-                    top_block->connect(file_source_, 0, throttle_, 0);
-                    DLOG(INFO) << "connected file source to throttle";
-                    top_block->connect(throttle_, 0, valve_, 0);
-                    DLOG(INFO) << "connected throttle to valve";
-                    if (dump_)
-                        {
-                            top_block->connect(valve_, 0, sink_, 0);
-                            DLOG(INFO) << "connected valve to file sink";
-                        }
-                }
-            else
-                {
-                    top_block->connect(file_source_, 0, valve_, 0);
-                    DLOG(INFO) << "connected file source to valve";
-                    if (dump_)
-                        {
-                            top_block->connect(valve_, 0, sink_, 0);
-                            DLOG(INFO) << "connected valve to file sink";
-                        }
-                }
-        }
-    else
-        {
-            if (enable_throttle_control_ == true)
-                {
-                    top_block->connect(file_source_, 0, throttle_, 0);
-                    DLOG(INFO) << "connected file source to throttle";
-                    if (dump_)
-                        {
-                            top_block->connect(file_source_, 0, sink_, 0);
-                            DLOG(INFO) << "connected file source to sink";
-                        }
-                }
-            else
-                {
-                    if (dump_)
-                        {
-                            top_block->connect(file_source_, 0, sink_, 0);
-                            DLOG(INFO) << "connected file source to sink";
-                        }
-                }
-        }
-}
-
-
-void FileSignalSource::disconnect(gr::top_block_sptr top_block)
-{
-    if (samples_ > 0)
-        {
-            if (enable_throttle_control_ == true)
-                {
-                    top_block->disconnect(file_source_, 0, throttle_, 0);
-                    DLOG(INFO) << "disconnected file source to throttle";
-                    top_block->disconnect(throttle_, 0, valve_, 0);
-                    DLOG(INFO) << "disconnected throttle to valve";
-                    if (dump_)
-                        {
-                            top_block->disconnect(valve_, 0, sink_, 0);
-                            DLOG(INFO) << "disconnected valve to file sink";
-                        }
-                }
-            else
-                {
-                    top_block->disconnect(file_source_, 0, valve_, 0);
-                    DLOG(INFO) << "disconnected file source to valve";
-                    if (dump_)
-                        {
-                            top_block->disconnect(valve_, 0, sink_, 0);
-                            DLOG(INFO) << "disconnected valve to file sink";
-                        }
-                }
-        }
-    else
-        {
-            if (enable_throttle_control_ == true)
-                {
-                    top_block->disconnect(file_source_, 0, throttle_, 0);
-                    DLOG(INFO) << "disconnected file source to throttle";
-                    if (dump_)
-                        {
-                            top_block->disconnect(file_source_, 0, sink_, 0);
-                            DLOG(INFO) << "disconnected file source to sink";
-                        }
-                }
-            else
-                {
-                    if (dump_)
-                        {
-                            top_block->disconnect(file_source_, 0, sink_, 0);
-                            DLOG(INFO) << "disconnected file source to sink";
-                        }
-                }
-        }
-}
-
-
-gr::basic_block_sptr FileSignalSource::get_left_block()
-{
-    LOG(WARNING) << "Left block of a signal source should not be retrieved";
-    return gr::blocks::file_source::sptr();
-}
-
-
-gr::basic_block_sptr FileSignalSource::get_right_block()
-{
-    if (samples_ > 0)
-        {
-            return valve_;
-        }
-    if (enable_throttle_control_ == true)
-        {
-            return throttle_;
-        }
-    return file_source_;
-}

src/algorithms/signal_source/adapters/file_signal_source.h

@@ -21,7 +21,7 @@
 #ifndef GNSS_SDR_FILE_SIGNAL_SOURCE_H
 #define GNSS_SDR_FILE_SIGNAL_SOURCE_H
 
-#include "signal_source_base.h"
+#include "file_source_base.h"
 
 #include "concurrent_queue.h"
 #include <gnuradio/blocks/file_sink.h>
@@ -46,7 +46,7 @@ class ConfigurationInterface;
  * \brief Class that reads signals samples from a file
  * and adapts it to a SignalSourceInterface
  */
-class FileSignalSource : public SignalSourceBase
+class FileSignalSource : public FileSourceBase
 {
 public:
     FileSignalSource(ConfigurationInterface const* configuration, std::string const& role,
@@ -55,61 +55,7 @@ public:
 
     ~FileSignalSource() = default;
 
-    inline size_t item_size() override
-    {
-        return item_size_;
-    }
-
-    void connect(gr::top_block_sptr top_block) override;
-    void disconnect(gr::top_block_sptr top_block) override;
-    gr::basic_block_sptr get_left_block() override;
-    gr::basic_block_sptr get_right_block() override;
-
-    inline std::string filename() const
-    {
-        return filename_;
-    }
-
-    inline std::string item_type() const
-    {
-        return item_type_;
-    }
-
-    inline bool repeat() const
-    {
-        return repeat_;
-    }
-
-    inline int64_t sampling_frequency() const
-    {
-        return sampling_frequency_;
-    }
-
-    inline uint64_t samples() const
-    {
-        return samples_;
-    }
-
 private:
-    gr::blocks::file_source::sptr file_source_;
-    gnss_shared_ptr<gr::block> valve_;
-    gr::blocks::file_sink::sptr sink_;
-    gr::blocks::throttle::sptr throttle_;
-
-    std::string item_type_;
-    std::string filename_;
-    std::string dump_filename_;
-
-    uint64_t samples_;
-    int64_t sampling_frequency_;
-    size_t item_size_;
-
-    uint32_t in_streams_;
-    uint32_t out_streams_;
-
-    bool enable_throttle_control_;
-    bool repeat_;
-    bool dump_;
 };
 
 

src/algorithms/signal_source/adapters/file_source_base.cc

@@ -0,0 +1,396 @@
+/*!
+ * \file file_source_base.cc
+ * \brief Implementation of the base class for file-oriented signal_source GNSS blocks
+ * \author Jim Melton, 2021. jim.melton(at)sncorp.com
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
+ * This file is part of GNSS-SDR.
+ *
+ * Copyright (C) 2010-2021  (see AUTHORS file for a list of contributors)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * -----------------------------------------------------------------------------
+ */
+
+#include "file_source_base.h"
+
+#include "configuration_interface.h"
+#include "gnss_sdr_flags.h"
+#include "gnss_sdr_filesystem.h"
+#include "gnss_sdr_valve.h"
+#include <glog/logging.h>
+#include <fstream>
+#include <cmath>		// ceil, floor
+
+
+using namespace std::string_literals;
+
+void FileSourceBase::connect(gr::top_block_sptr top_block)
+{
+  init();
+
+    auto source = gr::basic_block_sptr();
+    auto output = gr::basic_block_sptr();
+
+    // THROTTLE
+    if (enable_throttle_control_)
+        {
+            // if we are throttling...
+            throttle_ = gr::blocks::throttle::make(item_size_, sampling_frequency_);
+
+            top_block->connect(file_source_, 0, throttle_, 0);
+            DLOG(INFO) << "connected file source to throttle";
+
+            source = throttle_;
+        }
+    else
+        {
+            // no throttle; let 'er rip
+            source = file_source_;
+        }
+
+    // VALVE
+    if (samples_ > 0)
+        {
+            // if a number of samples is specified, honor it by creating a valve
+            // In practice, this is always true
+            valve_ = gnss_sdr_make_valve(item_size_, samples_, queue_);
+            DLOG(INFO) << "valve(" << valve_->unique_id() << ")";
+
+            top_block->connect(source, 0, valve_, 0);
+            DLOG(INFO) << "connected source to valve";
+
+            output = valve_;
+        }
+    else
+        {
+	  // TODO: dumping a file source is unlikely, but should this be the raw file source or the
+	  // throttle if there is one?  I'm leaning towards "output=source"
+            output = file_source_;
+        }
+
+    // DUMP
+    if (dump_)
+        {
+            sink_ = gr::blocks::file_sink::make(item_size_, dump_filename_.c_str());
+            DLOG(INFO) << "file_sink(" << sink_->unique_id() << ")";
+
+            top_block->connect(output, 0, sink_, 0);
+            DLOG(INFO) << "connected output to file sink";
+        }
+}
+
+
+void FileSourceBase::disconnect(gr::top_block_sptr top_block)
+{
+    if (samples_ > 0)
+        {
+            if (enable_throttle_control_ == true)
+                {
+                    top_block->disconnect(file_source_, 0, throttle_, 0);
+                    DLOG(INFO) << "disconnected file source to throttle";
+                    top_block->disconnect(throttle_, 0, valve_, 0);
+                    DLOG(INFO) << "disconnected throttle to valve";
+                    if (dump_)
+                        {
+                            top_block->disconnect(valve_, 0, sink_, 0);
+                            DLOG(INFO) << "disconnected valve to file sink";
+                        }
+                }
+            else
+                {
+                    top_block->disconnect(file_source_, 0, valve_, 0);
+                    DLOG(INFO) << "disconnected file source to valve";
+                    if (dump_)
+                        {
+                            top_block->disconnect(valve_, 0, sink_, 0);
+                            DLOG(INFO) << "disconnected valve to file sink";
+                        }
+                }
+        }
+    else
+        {
+            if (enable_throttle_control_ == true)
+                {
+                    top_block->disconnect(file_source_, 0, throttle_, 0);
+                    DLOG(INFO) << "disconnected file source to throttle";
+                    if (dump_)
+                        {
+                            top_block->disconnect(file_source_, 0, sink_, 0);
+                            DLOG(INFO) << "disconnected file source to sink";
+                        }
+                }
+            else
+                {
+                    if (dump_)
+                        {
+                            top_block->disconnect(file_source_, 0, sink_, 0);
+                            DLOG(INFO) << "disconnected file source to sink";
+                        }
+                }
+        }
+}
+
+
+gr::basic_block_sptr FileSourceBase::get_left_block()
+{
+  // TODO: is this right? Shouldn't the left block be a nullptr?
+    LOG(WARNING) << "Left block of a signal source should not be retrieved";
+    return gr::blocks::file_source::sptr();
+}
+
+
+gr::basic_block_sptr FileSourceBase::get_right_block()
+{
+    if (samples_ > 0)
+        {
+            return valve_;
+        }
+    if (enable_throttle_control_ == true)
+        {
+            return throttle_;
+        }
+    return file_source_;
+}
+
+
+std::string FileSourceBase::filename() const
+{
+    return filename_;
+}
+
+std::string FileSourceBase::item_type() const
+{
+    return item_type_;
+}
+
+size_t FileSourceBase::item_size()
+{
+    return item_size_;
+}
+size_t FileSourceBase::item_size() const
+{
+    return item_size_;
+}
+
+bool FileSourceBase::repeat() const
+{
+    return repeat_;
+}
+
+int64_t FileSourceBase::sampling_frequency() const
+{
+    return sampling_frequency_;
+}
+
+uint64_t FileSourceBase::samples() const
+{
+    return samples_;
+}
+
+
+void FileSourceBase::init()
+{
+    auto item_tuple = itemTypeToSize();
+    item_size_ = std::get<0>(item_tuple);
+    is_complex_ = std::get<1>(item_tuple);
+
+    try
+        {
+            // TODO: why are we manually seeking, instead of passing the samples_to_skip to the file_source factory?
+            auto samples_to_skip = samplesToSkip();
+
+            file_source_ = gr::blocks::file_source::make(item_size(), filename().data(), repeat());
+
+            if (samples_to_skip > 0)
+                {
+                    LOG(INFO) << "Skipping " << samples_to_skip << " samples of the input file";
+                    if (not file_source_->seek(samples_to_skip, SEEK_SET))
+                        {
+                            LOG(ERROR) << "Error skipping bytes!";
+                        }
+                }
+        }
+    catch (const std::exception& e)
+        {
+            std::cerr
+                << "The receiver was configured to work with a file-based signal source\n"
+                << "but the specified file is unreachable by GNSS-SDR.\n"
+                << "[" << filename() << "]\n"
+                << "\n"
+                << "Please modify your configuration file\n"
+                << "and point SignalSource.filename to a valid raw data file. Then:\n"
+                << "$ gnss-sdr --config_file=/path/to/my_GNSS_SDR_configuration.conf\n"
+                << "Examples of configuration files available at:\n"
+                << GNSSSDR_INSTALL_DIR "/share/gnss-sdr/conf/\n"
+		<< std::endl;
+
+            LOG(ERROR) << "file_signal_source: Unable to open the samples file "
+                       << filename() << ", exiting the program.";
+            throw;
+        }
+
+    DLOG(INFO) << implementation() << "(" << file_source_->unique_id() << ")";
+
+    // At this point, we know that the file exists
+    samples_ = computeSamplesInFile();
+    auto signal_duration_s = 1.0 * samples_ / sampling_frequency_;
+
+    if (is_complex_)
+        {
+            signal_duration_s /= 2.0;
+        }
+
+    DLOG(INFO) << "Total number samples to be processed= " << samples_ << " GNSS signal duration= " << signal_duration_s << " [s]";
+    std::cout << "GNSS signal recorded time to be processed: " << signal_duration_s << " [s]\n";
+
+
+    DLOG(INFO) << "File source filename " << filename_;
+    DLOG(INFO) << "Samples " << samples_;
+    DLOG(INFO) << "Sampling frequency " << sampling_frequency_;
+    DLOG(INFO) << "Item type " << item_type_;
+    DLOG(INFO) << "Item size " << item_size_;
+    DLOG(INFO) << "Repeat " << repeat_;
+    DLOG(INFO) << "Dump " << dump_;
+    DLOG(INFO) << "Dump filename " << dump_filename_;
+}
+
+
+FileSourceBase::FileSourceBase(ConfigurationInterface const* configuration, std::string role, std::string impl,
+        Concurrent_Queue<pmt::pmt_t>* queue)
+    : SignalSourceBase(configuration, role, impl)
+    , filename_(configuration->property(role + ".filename"s, "../data/example_capture.dat"s))
+    , file_source_()
+
+    , item_type_(configuration->property(role + ".item_type"s, "short"s))
+    , item_size_(0)		// invalid
+    , is_complex_(false)
+
+    , header_size_(configuration->property(role + ".header_size"s, 0UL))
+    , seconds_to_skip_(configuration->property(role + ".seconds_to_skip", 0.0))
+    , repeat_(configuration->property(role + ".repeat"s, false))
+
+    , samples_(configuration->property(role + ".samples"s, 0UL))
+    , sampling_frequency_(configuration->property(role + ".sampling_frequency"s, 0UL))
+    , valve_()
+    , queue_(queue)
+      
+    , enable_throttle_control_(configuration->property(role + ".enable_throttle_control"s, false))
+    , throttle_()
+      
+    , dump_(configuration->property(role + ".dump"s, false))
+    , dump_filename_(configuration->property(role + ".dump_filename"s, "../data/my_capture.dat"s))
+    , sink_()
+{
+    // override value with commandline flag, if present
+    if (FLAGS_signal_source != "-")
+        {
+            filename_ = FLAGS_signal_source;
+        }
+    if (FLAGS_s != "-")
+        {
+            filename_ = FLAGS_s;
+        }
+
+}
+
+std::tuple<size_t, bool> FileSourceBase::itemTypeToSize() const
+{
+    auto is_complex = false;
+    auto item_size = size_t(0);
+
+    if (item_type_ == "gr_complex")
+        {
+            item_size = sizeof(gr_complex);
+        }
+    else if (item_type_ == "float")
+        {
+            item_size = sizeof(float);
+        }
+    else if (item_type_ == "short")
+        {
+            item_size = sizeof(int16_t);
+        }
+    else if (item_type_ == "ishort")
+        {
+            item_size = sizeof(int16_t);
+            is_complex = true;
+        }
+    else if (item_type_ == "byte")
+        {
+            item_size = sizeof(int8_t);
+        }
+    else if (item_type_ == "ibyte")
+        {
+            item_size = sizeof(int8_t);
+            is_complex = true;
+        }
+    else
+        {
+            LOG(WARNING) << item_type_
+                         << " unrecognized item type. Using gr_complex.";
+            item_size = sizeof(gr_complex);
+        }
+
+    return std::make_tuple(item_size, is_complex);
+}
+
+size_t FileSourceBase::samplesToSkip() const
+{
+    auto samples_to_skip = size_t(0);
+
+    if (seconds_to_skip_ > 0)
+        {
+            samples_to_skip = static_cast<size_t>(seconds_to_skip_ * sampling_frequency_);
+
+            if (is_complex_)
+                {
+                    samples_to_skip *= 2;
+                }
+        }
+
+    if (header_size_ > 0)
+        {
+            samples_to_skip += header_size_;
+        }
+
+    return samples_to_skip;
+}
+
+size_t FileSourceBase::computeSamplesInFile() const
+{
+    auto n_samples = size_t(samples());
+
+
+    // this could throw, but the existence of the file has been proven before we get here.
+    auto size = fs::file_size(filename());
+    n_samples = std::floor(1.0 * size / item_size());
+
+    auto to_skip = samplesToSkip();
+
+    /*!
+     * BUG workaround: The GNU Radio file source does not stop the receiver after reaching the End of File.
+     * A possible solution is to compute the file length in samples using file size, excluding at least
+     * the last 2 milliseconds, and enable always the valve block
+     */
+    auto tail = static_cast<size_t>(std::ceil(0.002 * sampling_frequency()));
+
+    DLOG(INFO) << "Total samples in the file= " << n_samples;
+    std::cout << "Processing file " << filename() << ", which contains " << n_samples << " samples (" << size << " bytes)\n";
+
+    if (n_samples > (to_skip + tail))
+        {
+            // process all the samples available in the file excluding up to the last 2 ms
+            n_samples -= to_skip + tail;
+        }
+    else
+        {
+	    // this will terminate the program
+            LOG(FATAL) << "Skipping " << to_skip << " samples from the front and truncating 2ms (" << tail << " samples)\n"
+		       << "is greater than the number of samples in the file (" << n_samples << ")";
+        }
+
+    return n_samples;
+}

src/algorithms/signal_source/adapters/file_source_base.h

@@ -0,0 +1,139 @@
+/*!
+ * \file file_source_base.h
+ * \brief Header file of the base class to file-oriented signal_source GNSS blocks.
+ * \author Jim Melton, 2021. jim.melton(at)sncorp.com
+ *
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
+ * This file is part of GNSS-SDR.
+ *
+ * Copyright (C) 2010-2021  (see AUTHORS file for a list of contributors)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * -----------------------------------------------------------------------------
+ */
+
+#ifndef GNSS_SDR_FILE_SOURCE_BASE_H
+#define GNSS_SDR_FILE_SOURCE_BASE_H
+
+#include "signal_source_base.h"
+
+#include "concurrent_queue.h"
+#include <pmt/pmt.h>
+#include <gnuradio/blocks/file_source.h>
+#include <gnuradio/blocks/throttle.h>
+
+// for dump
+#include <gnuradio/blocks/file_sink.h>
+
+
+#include <cstddef>
+#include <string>
+
+
+class ConfigurationInterface;
+
+// This class supports the following properties:
+//
+//   .filename - the path to the input file
+//             - may be overridden by the -signal_source or -s command-line arguments
+//   .samples  - number of samples to process (default 0)
+//             - if not specified or 0, read the entire file; otherwise stop after that many samples
+//   .sampling_frequency - the frequency of the sampled data (samples/second)
+//   .item_type - data type of the samples (default "short")
+//   .header_size - the size of a prefixed header to skip in "samples" (default 0)
+//   .seconds_to_skip - number of seconds of lead-in data to skip over (default 0)
+//   .enable_throttle_control - whether to stop reading if the upstream buffer is full (default false)
+//   .repeat   - whether to rewind and continue at end of file (default false)
+//
+// (probably abstracted to the base class)
+//   .dump     - whether to archive input data
+//   .dump_filename - if dumping, path to file for output
+
+
+class FileSourceBase : public SignalSourceBase
+{
+public:
+
+  //! virtual overrides
+    void connect(gr::top_block_sptr top_block) override;
+    void disconnect(gr::top_block_sptr top_block) override;
+    gr::basic_block_sptr get_left_block() override;
+    gr::basic_block_sptr get_right_block() override;
+
+  
+    //! the file to read
+    std::string filename() const;
+
+    //! the item type
+    std::string item_type() const;
+
+    //! the configured size of each item
+    size_t item_size() override;
+    virtual size_t item_size() const; // what the interface **should** have declared
+
+    //! Whether to repeat reading after end-of-file
+    bool repeat() const;
+
+    //! the sampling frequency of the source file
+    int64_t sampling_frequency() const;
+
+    //! the number of samples in the file
+    uint64_t samples() const;
+
+    //! perform post-construction initialization
+    void init();
+
+protected:
+    //! Constructor
+    FileSourceBase(ConfigurationInterface const* configuration, std::string role, std::string impl,
+        Concurrent_Queue<pmt::pmt_t>* queue);
+
+    //! compute the item size, from the item_type(). Subclasses may constrain types that don't make
+    //  sense. The return of this method is a tuple of item_size and is_complex
+    virtual std::tuple<size_t,bool> itemTypeToSize() const;
+    
+    //! compute the number of samples to skip
+    virtual size_t samplesToSkip() const;
+
+    //! compute the number of samples in the file
+    size_t computeSamplesInFile() const;
+    
+private:
+    std::string filename_;
+    gr::blocks::file_source::sptr file_source_;
+
+    std::string item_type_;
+    size_t item_size_;
+    bool is_complex_;		// a misnomer; if I/Q are interleaved as integer values
+
+    size_t header_size_;	// length (in samples) of the header (if any)
+    double seconds_to_skip_;
+    bool repeat_;
+
+    // The valve allows only the configured number of samples through, then it closes.
+
+    // The framework passes the queue as a naked pointer, rather than a shared pointer, so this
+    // class has two choices: construct the valve in the ctor, or hold onto the pointer, possibly
+    // beyond its lifetime. Fortunately, the queue is only used to create the valve, so the
+    // likelihood of holding a stale pointer is mitigated
+    uint64_t samples_;
+    int64_t sampling_frequency_;
+    gnss_shared_ptr<gr::block> valve_;
+    Concurrent_Queue<pmt::pmt_t>* queue_;
+
+    bool enable_throttle_control_;
+    gr::blocks::throttle::sptr throttle_;
+
+    bool dump_;
+    std::string dump_filename_;
+    gr::blocks::file_sink::sptr sink_;
+
+
+
+};
+
+
+#endif

src/algorithms/signal_source/adapters/signal_source_base.h

@@ -6,13 +6,10 @@
  *
  * -----------------------------------------------------------------------------
  *
- * Copyright (C) 2010-2020  (see AUTHORS file for a list of contributors)
+ * GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
- *
- * GNSS-SDR is a software defined Global Navigation
- *          Satellite Systems receiver
- *
  * This file is part of GNSS-SDR.
  *
+ * Copyright (C) 2010-2021  (see AUTHORS file for a list of contributors)
  * SPDX-License-Identifier: GPL-3.0-or-later
  *
  * -----------------------------------------------------------------------------