stream_flags_encoder.c

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//
//
//  Author:     Lasse Collin
//
//  This file has been put into the public domain.
//  You can do whatever you want with this file.
//
 
#include "stream_flags_common.h"
 
 
static bool
stream_flags_encode(const lzma_stream_flags *options, uint8_t *out)
{
    if ((unsigned int)(options->check) > LZMA_CHECK_ID_MAX)
        return true;
 
    out[0] = 0x00;
    out[1] = options->check;
 
    return false;
}
 
 
extern LZMA_API(lzma_ret)
lzma_stream_header_encode(const lzma_stream_flags *options, uint8_t *out)
{
    assert(sizeof(lzma_header_magic) + LZMA_STREAM_FLAGS_SIZE
            + 4 == LZMA_STREAM_HEADER_SIZE);
 
    if (options->version != 0)
        return LZMA_OPTIONS_ERROR;
 
    // Magic
    memcpy(out, lzma_header_magic, sizeof(lzma_header_magic));
 
    // Stream Flags
    if (stream_flags_encode(options, out + sizeof(lzma_header_magic)))
        return LZMA_PROG_ERROR;
 
    // CRC32 of the Stream Header
    const uint32_t crc = lzma_crc32(out + sizeof(lzma_header_magic),
            LZMA_STREAM_FLAGS_SIZE, 0);
 
    write32le(out + sizeof(lzma_header_magic) + LZMA_STREAM_FLAGS_SIZE,
            crc);
 
    return LZMA_OK;
}
 
 
extern LZMA_API(lzma_ret)
lzma_stream_footer_encode(const lzma_stream_flags *options, uint8_t *out)
{
    assert(2 * 4 + LZMA_STREAM_FLAGS_SIZE + sizeof(lzma_footer_magic)
            == LZMA_STREAM_HEADER_SIZE);
 
    if (options->version != 0)
        return LZMA_OPTIONS_ERROR;
 
    // Backward Size
    if (!is_backward_size_valid(options))
        return LZMA_PROG_ERROR;
 
    write32le(out + 4, options->backward_size / 4 - 1);
 
    // Stream Flags
    if (stream_flags_encode(options, out + 2 * 4))
        return LZMA_PROG_ERROR;
 
    // CRC32
    const uint32_t crc = lzma_crc32(
            out + 4, 4 + LZMA_STREAM_FLAGS_SIZE, 0);
 
    write32le(out, crc);
 
    // Magic
    memcpy(out + 2 * 4 + LZMA_STREAM_FLAGS_SIZE,
            lzma_footer_magic, sizeof(lzma_footer_magic));
 
    return LZMA_OK;
}