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Add LZMA compression support for sector subchannel blocks

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Natalia Portillo
2025-10-07 20:38:09 +01:00
parent a60ebf8822
commit cd12ef3504
1 changed files with 91 additions and 10 deletions
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101
src/close.c
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@@ -1523,9 +1523,14 @@ static void write_sector_suffix_ddt(aaruformatContext *ctx)
* - Only positive sectors (0 through Sectors-1) and overflow are included; no negative range.
*
* The block size is computed as (applicable_sector_count) × (bytes_per_sector_for_media_type).
* No compression is applied; the raw buffer is written verbatim after a DataBlock header with
* CRC64 integrity protection. The write position is aligned to the DDT block boundary
* (2^blockAlignmentShift) before serialization begins.
* Compression is conditionally applied based on media type and compression settings:
* - **Optical Disc:** When compression is enabled, applies Claunia Subchannel Transform (CST)
* followed by LZMA compression (LzmaClauniaSubchannelTransform). If the compressed size is
* not smaller than the original, falls back to uncompressed storage.
* - **Block Media:** Always attempts LZMA compression for tag data. If the compressed size is
* not smaller than the original, falls back to uncompressed storage.
* The data is written after a DataBlock header with CRC64 integrity protection. The write position
* is aligned to the DDT block boundary (2^blockAlignmentShift) before serialization begins.
*
* **Media type validation:**
* The function only proceeds if XmlMediaType is OpticalDisc or BlockMedia and (for block media)
@@ -1573,13 +1578,59 @@ static void write_sector_subchannel(const aaruformatContext *ctx)
subchannel_block.identifier = DataBlock;
subchannel_block.compression = None;
uint8_t *buffer = ctx->sector_subchannel;
uint8_t lzma_properties[LZMA_PROPERTIES_LENGTH] = {0};
if(ctx->imageInfo.XmlMediaType == OpticalDisc)
{
subchannel_block.type = CdSectorSubchannel;
subchannel_block.length =
(uint32_t)(ctx->userDataDdtHeader.negative + ctx->imageInfo.Sectors + ctx->userDataDdtHeader.overflow) * 96;
if(ctx->compression_enabled)
{
subchannel_block.compression = LzmaClauniaSubchannelTransform;
uint8_t *cst_buffer = malloc(subchannel_block.length);
if(cst_buffer == NULL)
{
TRACE("Failed to allocate memory for Claunia Subchannel Transform output");
return;
}
uint8_t *dst_buffer = malloc(subchannel_block.length);
if(dst_buffer == NULL)
{
TRACE("Failed to allocate memory for LZMA output");
free(cst_buffer);
return;
}
aaruf_cst_transform(ctx->sector_subchannel, cst_buffer, subchannel_block.length);
size_t dst_size = subchannel_block.length;
size_t props_size = LZMA_PROPERTIES_LENGTH;
aaruf_lzma_encode_buffer(buffer, &dst_size, cst_buffer, subchannel_block.length, lzma_properties,
&props_size, 9, ctx->lzma_dict_size, 4, 0, 2, 273, 8);
subchannel_block.cmpLength = (uint32_t)dst_size;
free(cst_buffer);
buffer = dst_buffer;
subchannel_block.crc64 = aaruf_crc64_data(buffer, subchannel_block.cmpLength);
if(subchannel_block.cmpLength >= subchannel_block.length)
{
subchannel_block.compression = None;
subchannel_block.cmpLength = subchannel_block.length;
subchannel_block.cmpCrc64 = subchannel_block.crc64;
free(dst_buffer);
buffer = ctx->sector_subchannel;
}
}
}
else if(ctx->imageInfo.XmlMediaType == BlockMedia)
{
switch(ctx->imageInfo.MediaType)
{
case AppleProfile:
@@ -1600,26 +1651,54 @@ static void write_sector_subchannel(const aaruformatContext *ctx)
TRACE("Incorrect media type, not writing sector subchannel block");
return; // Incorrect media type
}
subchannel_block.compression = Lzma;
uint8_t *dst_buffer = malloc(subchannel_block.length);
if(dst_buffer == NULL)
{
TRACE("Failed to allocate memory for LZMA output");
return;
}
size_t dst_size = subchannel_block.length;
size_t props_size = LZMA_PROPERTIES_LENGTH;
aaruf_lzma_encode_buffer(buffer, &dst_size, ctx->sector_subchannel, subchannel_block.length, lzma_properties,
&props_size, 9, ctx->lzma_dict_size, 4, 0, 2, 273, 8);
subchannel_block.cmpLength = (uint32_t)dst_size;
buffer = dst_buffer;
subchannel_block.crc64 = aaruf_crc64_data(buffer, subchannel_block.cmpLength);
if(subchannel_block.cmpLength >= subchannel_block.length)
{
subchannel_block.compression = None;
subchannel_block.cmpLength = subchannel_block.length;
subchannel_block.cmpCrc64 = subchannel_block.crc64;
free(dst_buffer);
buffer = ctx->sector_subchannel;
}
}
else
{
TRACE("Incorrect media type, not writing sector subchannel block");
return; // Incorrect media type
}
subchannel_block.cmpLength = subchannel_block.length;
// Calculate CRC64
subchannel_block.crc64 = aaruf_crc64_data(ctx->sector_subchannel, subchannel_block.length);
subchannel_block.cmpCrc64 = subchannel_block.crc64;
subchannel_block.crc64 = aaruf_crc64_data(ctx->sector_subchannel, subchannel_block.length);
// Write header
if(fwrite(&subchannel_block, sizeof(BlockHeader), 1, ctx->imageStream) == 1)
{
if(subchannel_block.compression != None) fwrite(lzma_properties, LZMA_PROPERTIES_LENGTH, 1, ctx->imageStream);
// Write data
const size_t written_bytes = fwrite(ctx->sector_subchannel, subchannel_block.length, 1, ctx->imageStream);
const size_t written_bytes = fwrite(buffer, subchannel_block.cmpLength, 1, ctx->imageStream);
if(written_bytes == 1)
{
TRACE("Successfully wrote sector subchannel block (%" PRIu64 " bytes)", subchannel_block.length);
TRACE("Successfully wrote sector subchannel block (%" PRIu64 " bytes)", subchannel_block.cmpLength);
// Add subchannel block to index
TRACE("Adding sector subchannel block to index");
IndexEntry subchannel_index_entry;
@@ -1630,6 +1709,8 @@ static void write_sector_subchannel(const aaruformatContext *ctx)
TRACE("Added sector subchannel block index entry at offset %" PRIu64, block_position);
}
}
if(subchannel_block.compression != None) free(buffer);
}
/**
@@ -3850,7 +3931,7 @@ static int32_t write_index_block(aaruformatContext *ctx)
if(index_crc64_context != NULL && index_header.entries > 0)
{
size_t index_data_size = index_header.entries * sizeof(IndexEntry);
aaruf_crc64_update(index_crc64_context, (uint8_t *)utarray_front(ctx->indexEntries), index_data_size);
aaruf_crc64_update(index_crc64_context, utarray_front(ctx->indexEntries), index_data_size);
aaruf_crc64_final(index_crc64_context, &index_header.crc64);
TRACE("Calculated index CRC64: 0x%16lX", index_header.crc64);
}