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///////////////////////////////////////////////////////////////////////////////
//
/// \file stream_flags_encoder.c
/// \brief Encodes Stream Header and 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(uint8_t *flags_byte, const lzma_stream_flags *options)
{
// Check type
if ((unsigned int)(options->check) > LZMA_CHECK_ID_MAX)
return true;
*flags_byte = options->check;
// Usage of CRC32 in Block Headers
if (options->has_crc32)
*flags_byte |= 0x08;
// Single- or Multi-Block
if (options->is_multi)
*flags_byte |= 0x10;
return false;
}
extern LZMA_API lzma_ret
lzma_stream_header_encode(uint8_t *out, const lzma_stream_flags *options)
{
// Magic
memcpy(out, lzma_header_magic, sizeof(lzma_header_magic));
// Stream Flags
if (stream_flags_encode(out + sizeof(lzma_header_magic), options))
return LZMA_PROG_ERROR;;
// CRC32 of the Stream Header
const uint32_t crc = lzma_crc32(out + sizeof(lzma_header_magic), 1, 0);
for (size_t i = 0; i < 4; ++i)
out[sizeof(lzma_header_magic) + 1 + i] = crc >> (i * 8);
return LZMA_OK;
}
extern LZMA_API lzma_ret
lzma_stream_tail_encode(uint8_t *out, const lzma_stream_flags *options)
{
// Stream Flags
if (stream_flags_encode(out, options))
return LZMA_PROG_ERROR;
// Magic
memcpy(out + 1, lzma_footer_magic, sizeof(lzma_footer_magic));
return LZMA_OK;
}
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