source: vbox/trunk/src/libs/liblzma-5.4.1/common/block_util.c

///////////////////////////////////////////////////////////////////////////////
//
/// \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;
}