block_decoder.h File Reference

Decodes .xz Blocks. More...

#include "common.h"

Go to the source code of this file.

Functions
lzma_ret	lzma_block_decoder_init (lzma_next_coder *next, const lzma_allocator *allocator, lzma_block *block)

Detailed Description

Decodes .xz Blocks.

Definition in file block_decoder.h.

Function Documentation

lzma_block_decoder_init()

lzma_ret lzma_block_decoder_init	(	lzma_next_coder *	next,
		const lzma_allocator *	allocator,
		lzma_block *	block
	)

Definition at line 192 of file block_decoder.c.

{
    lzma_next_coder_init(&lzma_block_decoder_init, next, allocator);
 
    // Validate the options. lzma_block_unpadded_size() does that for us
    // except for Uncompressed Size and filters. Filters are validated
    // by the raw decoder.
    if (lzma_block_unpadded_size(block) == 0
            || !lzma_vli_is_valid(block->uncompressed_size))
        return LZMA_PROG_ERROR;
 
    // Allocate *next->coder if needed.
    lzma_block_coder *coder = next->coder;
    if (coder == NULL) {
        coder = lzma_alloc(sizeof(lzma_block_coder), allocator);
        if (coder == NULL)
            return LZMA_MEM_ERROR;
 
        next->coder = coder;
        next->code = &block_decode;
        next->end = &block_decoder_end;
        coder->next = LZMA_NEXT_CODER_INIT;
    }
 
    // Basic initializations
    coder->sequence = SEQ_CODE;
    coder->block = block;
    coder->compressed_size = 0;
    coder->uncompressed_size = 0;
 
    // If Compressed Size is not known, we calculate the maximum allowed
    // value so that encoded size of the Block (including Block Padding)
    // is still a valid VLI and a multiple of four.
    coder->compressed_limit
            = block->compressed_size == LZMA_VLI_UNKNOWN
                ? (LZMA_VLI_MAX & ~LZMA_VLI_C(3))
                    - block->header_size
                    - lzma_check_size(block->check)
                : block->compressed_size;
 
    // Initialize the check. It's caller's problem if the Check ID is not
    // supported, and the Block decoder cannot verify the Check field.
    // Caller can test lzma_check_is_supported(block->check).
    coder->check_pos = 0;
    lzma_check_init(&coder->check, block->check);
 
    coder->ignore_check = block->version >= 1
            ? block->ignore_check : false;
 
    // Initialize the filter chain.
    return lzma_raw_decoder_init(&coder->next, allocator,
            block->filters);
}

References allocator, lzma_block_coder::block, block_decode(), block_decoder_end(), lzma_block::check, lzma_block_coder::check, lzma_block_coder::check_pos, lzma_next_coder_s::code, lzma_next_coder_s::coder, lzma_block_coder::compressed_limit, lzma_block::compressed_size, lzma_block_coder::compressed_size, lzma_next_coder_s::end, lzma_block::filters, lzma_block::header_size, lzma_block::ignore_check, lzma_block_coder::ignore_check, lzma_alloc(), lzma_check_init(), LZMA_MEM_ERROR, LZMA_NEXT_CODER_INIT, lzma_next_coder_init, LZMA_PROG_ERROR, lzma_raw_decoder_init(), LZMA_VLI_C, lzma_vli_is_valid, LZMA_VLI_MAX, LZMA_VLI_UNKNOWN, lzma_block_coder::next, NULL, lzma_block_coder::sequence, lzma_block::uncompressed_size, lzma_block_coder::uncompressed_size, and lzma_block::version.

Referenced by LZMA_API(), and stream_decode().