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Simpler handling of simpler bit formats

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If a sample is the same size as a word, it is much easier to read.
This commit is contained in:
Victor Castillo 2024-08-17 20:14:31 +02:00
parent 38a24f5250
commit 01bbc39fa6
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GPG Key ID: 8EF1FC8B7182F608
1 changed files with 28 additions and 2 deletions
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30
src/algorithms/signal_source/libs/ion_gsms_chunk_unpacking_ctx.h
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@ -34,7 +34,7 @@ struct IONGSMSChunkUnpackingCtx
static constexpr uint8_t word_bitsize_ = sizeof(WT) * 8; static constexpr uint8_t word_bitsize_ = sizeof(WT) * 8;
const GnssMetadata::Chunk::WordShift word_shift_direction_; const GnssMetadata::Chunk::WordShift word_shift_direction_;
WT* iterator_; // Not owned by this class, must not destroy WT* iterator_; // Not owned by this class, MUST NOT destroy
WT current_word_; WT current_word_;
uint8_t bitshift_ = 0; uint8_t bitshift_ = 0;
@ -71,6 +71,15 @@ struct IONGSMSChunkUnpackingCtx
void shift_current_word(uint8_t n) void shift_current_word(uint8_t n)
{ {
if ((n % word_bitsize_) == 0)
{
for (uint8_t i = 0; i < (n / word_bitsize_); ++i)
{
advance_word();
}
return;
}
if (word_shift_direction_ == GnssMetadata::Chunk::Left) if (word_shift_direction_ == GnssMetadata::Chunk::Left)
{ {
current_word_ <<= n; current_word_ <<= n;
@ -111,7 +120,24 @@ struct IONGSMSChunkUnpackingCtx
template <typename OT> template <typename OT>
void shift_sample(const uint8_t sample_bitsize, OT* output, uint8_t output_bit_offset = 0) void shift_sample(const uint8_t sample_bitsize, OT* output, uint8_t output_bit_offset = 0)
{ {
if ((sample_bitsize + (bitshift_ % word_bitsize_)) > word_bitsize_) if (sample_bitsize % word_bitsize_ == 0)
{
const uint8_t words_per_sample = sample_bitsize / word_bitsize_;
for (uint8_t i = 0; i < words_per_sample; ++i)
{
if (word_shift_direction_ == GnssMetadata::Chunk::Left)
{
*output |= (current_word_ << ((words_per_sample - 1 - i) * word_bitsize_));
}
else if (word_shift_direction_ == GnssMetadata::Chunk::Right)
{
*output |= (current_word_ << (i * word_bitsize_));
// TODO - reverse bit order of sample? maybe?
}
advance_word();
}
}
else if ((sample_bitsize + (bitshift_ % word_bitsize_)) > word_bitsize_)
{ {
const uint8_t bits_shifted = word_bitsize_ - (bitshift_ % word_bitsize_); const uint8_t bits_shifted = word_bitsize_ - (bitshift_ % word_bitsize_);