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0e0f34b8e4
Note that this slightly changes how lzma_block_header_decode() has been documented. Earlier it said that the .version is set to the lowest required value, but now it says that the .version field is kept unchanged if possible. In practice this doesn't affect any old code, because before this commit the only possible .version was 0.
91 lines
2.6 KiB
C
91 lines
2.6 KiB
C
///////////////////////////////////////////////////////////////////////////////
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//
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/// \file block_header.c
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/// \brief Utility functions to handle lzma_block
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//
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// Author: Lasse Collin
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//
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// This file has been put into the public domain.
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// You can do whatever you want with this file.
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//
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///////////////////////////////////////////////////////////////////////////////
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#include "common.h"
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#include "index.h"
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extern LZMA_API(lzma_ret)
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lzma_block_compressed_size(lzma_block *block, lzma_vli unpadded_size)
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{
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// Validate everything but Uncompressed Size and filters.
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if (lzma_block_unpadded_size(block) == 0)
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return LZMA_PROG_ERROR;
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const uint32_t container_size = block->header_size
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+ lzma_check_size(block->check);
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// Validate that Compressed Size will be greater than zero.
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if (unpadded_size <= container_size)
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return LZMA_DATA_ERROR;
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// Calculate what Compressed Size is supposed to be.
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// If Compressed Size was present in Block Header,
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// compare that the new value matches it.
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const lzma_vli compressed_size = unpadded_size - container_size;
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if (block->compressed_size != LZMA_VLI_UNKNOWN
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&& block->compressed_size != compressed_size)
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return LZMA_DATA_ERROR;
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block->compressed_size = compressed_size;
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return LZMA_OK;
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}
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extern LZMA_API(lzma_vli)
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lzma_block_unpadded_size(const lzma_block *block)
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{
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// Validate the values that we are interested in i.e. all but
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// Uncompressed Size and the filters.
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//
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// NOTE: This function is used for validation too, so it is
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// essential that these checks are always done even if
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// Compressed Size is unknown.
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if (block == NULL || block->version > 1
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|| block->header_size < LZMA_BLOCK_HEADER_SIZE_MIN
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|| block->header_size > LZMA_BLOCK_HEADER_SIZE_MAX
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|| (block->header_size & 3)
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|| !lzma_vli_is_valid(block->compressed_size)
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|| block->compressed_size == 0
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|| (unsigned int)(block->check) > LZMA_CHECK_ID_MAX)
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return 0;
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// If Compressed Size is unknown, return that we cannot know
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// size of the Block either.
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if (block->compressed_size == LZMA_VLI_UNKNOWN)
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return LZMA_VLI_UNKNOWN;
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// Calculate Unpadded Size and validate it.
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const lzma_vli unpadded_size = block->compressed_size
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+ block->header_size
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+ lzma_check_size(block->check);
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assert(unpadded_size >= UNPADDED_SIZE_MIN);
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if (unpadded_size > UNPADDED_SIZE_MAX)
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return 0;
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return unpadded_size;
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}
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extern LZMA_API(lzma_vli)
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lzma_block_total_size(const lzma_block *block)
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{
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lzma_vli unpadded_size = lzma_block_unpadded_size(block);
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if (unpadded_size != LZMA_VLI_UNKNOWN)
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unpadded_size = vli_ceil4(unpadded_size);
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return unpadded_size;
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}
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