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-rw-r--r--src/lib/util/chdcodec.cpp29
1 files changed, 22 insertions, 7 deletions
diff --git a/src/lib/util/chdcodec.cpp b/src/lib/util/chdcodec.cpp
index be1d2022cd7..ba1840489d6 100644
--- a/src/lib/util/chdcodec.cpp
+++ b/src/lib/util/chdcodec.cpp
@@ -1128,20 +1128,35 @@ chd_lzma_decompressor::chd_lzma_decompressor(chd_file &chd, UINT32 hunkbytes, bo
// construct the decoder
LzmaDec_Construct(&m_decoder);
+ // FIXME: this code is written in a way that makes it impossible to safely upgrade the LZMA SDK
+ // This code assumes that the current version of the encoder imposes the same requirements on the
+ // decoder as the encoder used to produce the file. This is not necessarily true. The format
+ // needs to be changed so the encoder properties are written to the file.
+
// configure the properties like the compressor did
CLzmaEncProps encoder_props;
chd_lzma_compressor::configure_properties(encoder_props, hunkbytes);
// convert to decoder properties
- CLzmaProps decoder_props;
- decoder_props.lc = encoder_props.lc;
- decoder_props.lp = encoder_props.lp;
- decoder_props.pb = encoder_props.pb;
- decoder_props.dicSize = encoder_props.dictSize;
+ CLzmaEncHandle enc = LzmaEnc_Create(&m_allocator);
+ if (!enc)
+ throw CHDERR_DECOMPRESSION_ERROR;
+ if (LzmaEnc_SetProps(enc, &encoder_props) != SZ_OK)
+ {
+ LzmaEnc_Destroy(enc, &m_allocator, &m_allocator);
+ throw CHDERR_DECOMPRESSION_ERROR;
+ }
+ Byte decoder_props[LZMA_PROPS_SIZE];
+ SizeT props_size = sizeof(decoder_props);
+ if (LzmaEnc_WriteProperties(enc, decoder_props, &props_size) != SZ_OK)
+ {
+ LzmaEnc_Destroy(enc, &m_allocator, &m_allocator);
+ throw CHDERR_DECOMPRESSION_ERROR;
+ }
+ LzmaEnc_Destroy(enc, &m_allocator, &m_allocator);
// do memory allocations
- SRes res = LzmaDec_Allocate_MAME(&m_decoder, &decoder_props, &m_allocator);
- if (res != SZ_OK)
+ if (LzmaDec_Allocate(&m_decoder, decoder_props, LZMA_PROPS_SIZE, &m_allocator) != SZ_OK)
throw CHDERR_DECOMPRESSION_ERROR;
}