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-rw-r--r--src/liblzma/common/block_util.c90
1 files changed, 90 insertions, 0 deletions
diff --git a/src/liblzma/common/block_util.c b/src/liblzma/common/block_util.c
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+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file block_util.c
+/// \brief Utility functions to handle lzma_block
+//
+// Author: Lasse Collin
+//
+// This file has been put into the public domain.
+// You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "common.h"
+#include "index.h"
+
+
+extern LZMA_API(lzma_ret)
+lzma_block_compressed_size(lzma_block *block, lzma_vli unpadded_size)
+{
+ // Validate everything but Uncompressed Size and filters.
+ if (lzma_block_unpadded_size(block) == 0)
+ return LZMA_PROG_ERROR;
+
+ const uint32_t container_size = block->header_size
+ + lzma_check_size(block->check);
+
+ // Validate that Compressed Size will be greater than zero.
+ if (unpadded_size <= container_size)
+ return LZMA_DATA_ERROR;
+
+ // Calculate what Compressed Size is supposed to be.
+ // If Compressed Size was present in Block Header,
+ // compare that the new value matches it.
+ const lzma_vli compressed_size = unpadded_size - container_size;
+ if (block->compressed_size != LZMA_VLI_UNKNOWN
+ && block->compressed_size != compressed_size)
+ return LZMA_DATA_ERROR;
+
+ block->compressed_size = compressed_size;
+
+ return LZMA_OK;
+}
+
+
+extern LZMA_API(lzma_vli)
+lzma_block_unpadded_size(const lzma_block *block)
+{
+ // Validate the values that we are interested in i.e. all but
+ // Uncompressed Size and the filters.
+ //
+ // NOTE: This function is used for validation too, so it is
+ // essential that these checks are always done even if
+ // Compressed Size is unknown.
+ if (block == NULL || block->version > 1
+ || block->header_size < LZMA_BLOCK_HEADER_SIZE_MIN
+ || block->header_size > LZMA_BLOCK_HEADER_SIZE_MAX
+ || (block->header_size & 3)
+ || !lzma_vli_is_valid(block->compressed_size)
+ || block->compressed_size == 0
+ || (unsigned int)(block->check) > LZMA_CHECK_ID_MAX)
+ return 0;
+
+ // If Compressed Size is unknown, return that we cannot know
+ // size of the Block either.
+ if (block->compressed_size == LZMA_VLI_UNKNOWN)
+ return LZMA_VLI_UNKNOWN;
+
+ // Calculate Unpadded Size and validate it.
+ const lzma_vli unpadded_size = block->compressed_size
+ + block->header_size
+ + lzma_check_size(block->check);
+
+ assert(unpadded_size >= UNPADDED_SIZE_MIN);
+ if (unpadded_size > UNPADDED_SIZE_MAX)
+ return 0;
+
+ return unpadded_size;
+}
+
+
+extern LZMA_API(lzma_vli)
+lzma_block_total_size(const lzma_block *block)
+{
+ lzma_vli unpadded_size = lzma_block_unpadded_size(block);
+
+ if (unpadded_size != LZMA_VLI_UNKNOWN)
+ unpadded_size = vli_ceil4(unpadded_size);
+
+ return unpadded_size;
+}