block_header_encoder.c File Reference

Encodes Block Header for .xz files. More...

#include "common.h"
#include "check.h"

Go to the source code of this file.

Functions
	LZMA_API (lzma_ret)

Detailed Description

Encodes Block Header for .xz files.

Definition in file block_header_encoder.c.

Function Documentation

LZMA_API()

LZMA_API

(

lzma_ret

)

Definition at line 17 of file block_header_encoder.c.

{
    if (block->version > 1)
        return LZMA_OPTIONS_ERROR;
 
    // Block Header Size + Block Flags + CRC32.
    uint32_t size = 1 + 1 + 4;
 
    // Compressed Size
    if (block->compressed_size != LZMA_VLI_UNKNOWN) {
        const uint32_t add = lzma_vli_size(block->compressed_size);
        if (add == 0 || block->compressed_size == 0)
            return LZMA_PROG_ERROR;
 
        size += add;
    }
 
    // Uncompressed Size
    if (block->uncompressed_size != LZMA_VLI_UNKNOWN) {
        const uint32_t add = lzma_vli_size(block->uncompressed_size);
        if (add == 0)
            return LZMA_PROG_ERROR;
 
        size += add;
    }
 
    // List of Filter Flags
    if (block->filters == NULL || block->filters[0].id == LZMA_VLI_UNKNOWN)
        return LZMA_PROG_ERROR;
 
    for (size_t i = 0; block->filters[i].id != LZMA_VLI_UNKNOWN; ++i) {
        // Don't allow too many filters.
        if (i == LZMA_FILTERS_MAX)
            return LZMA_PROG_ERROR;
 
        uint32_t add;
        return_if_error(lzma_filter_flags_size(&add,
                block->filters + i));
 
        size += add;
    }
 
    // Pad to a multiple of four bytes.
    block->header_size = (size + 3) & ~UINT32_C(3);
 
    // NOTE: We don't verify that the encoded size of the Block stays
    // within limits. This is because it is possible that we are called
    // with exaggerated Compressed Size (e.g. LZMA_VLI_MAX) to reserve
    // space for Block Header, and later called again with lower,
    // real values.
 
    return LZMA_OK;
}

References add(), lzma_block::compressed_size, lzma_block::filters, lzma_block::header_size, i, lzma_filter::id, LZMA_FILTERS_MAX, LZMA_OK, LZMA_OPTIONS_ERROR, LZMA_PROG_ERROR, LZMA_VLI_UNKNOWN, NULL, return_if_error, UINT32_C, lzma_block::uncompressed_size, and lzma_block::version.