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///////////////////////////////////////////////////////////////////////////////
//
/// \file stream_flags_encoder.c
/// \brief Encodes Stream Header and Stream Footer for .lzma files
//
// Copyright (C) 2007 Lasse Collin
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
///////////////////////////////////////////////////////////////////////////////
#include "stream_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);
// 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);
integer_write_32(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);
// Backward Size
if (options->backward_size < LZMA_BACKWARD_SIZE_MIN
|| options->backward_size > LZMA_BACKWARD_SIZE_MAX
|| (options->backward_size & 3))
return LZMA_PROG_ERROR;
integer_write_32(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);
integer_write_32(out, crc);
// Magic
memcpy(out + 2 * 4 + LZMA_STREAM_FLAGS_SIZE,
lzma_footer_magic, sizeof(lzma_footer_magic));
return LZMA_OK;
}
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