mirror of https://git.tukaani.org/xz.git
76 lines
2.0 KiB
C
76 lines
2.0 KiB
C
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///////////////////////////////////////////////////////////////////////////////
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//
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/// \file stream_flags_encoder.c
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/// \brief Encodes Stream Header and Footer for .lzma files
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//
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// Copyright (C) 2007 Lasse Collin
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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///////////////////////////////////////////////////////////////////////////////
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#include "stream_common.h"
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static bool
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stream_flags_encode(uint8_t *flags_byte, const lzma_stream_flags *options)
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{
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// Check type
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if ((unsigned int)(options->check) > LZMA_CHECK_ID_MAX)
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return true;
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*flags_byte = options->check;
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// Usage of CRC32 in Block Headers
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if (options->has_crc32)
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*flags_byte |= 0x08;
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// Single- or Multi-Block
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if (options->is_multi)
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*flags_byte |= 0x10;
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return false;
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}
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extern LZMA_API lzma_ret
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lzma_stream_header_encode(uint8_t *out, const lzma_stream_flags *options)
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{
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// Magic
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memcpy(out, lzma_header_magic, sizeof(lzma_header_magic));
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// Stream Flags
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if (stream_flags_encode(out + sizeof(lzma_header_magic), options))
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return LZMA_PROG_ERROR;;
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// CRC32 of the Stream Header
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const uint32_t crc = lzma_crc32(out + sizeof(lzma_header_magic), 1, 0);
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for (size_t i = 0; i < 4; ++i)
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out[sizeof(lzma_header_magic) + 1 + i] = crc >> (i * 8);
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return LZMA_OK;
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}
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extern LZMA_API lzma_ret
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lzma_stream_tail_encode(uint8_t *out, const lzma_stream_flags *options)
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{
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// Stream Flags
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if (stream_flags_encode(out, options))
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return LZMA_PROG_ERROR;
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// Magic
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memcpy(out + 1, lzma_footer_magic, sizeof(lzma_footer_magic));
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return LZMA_OK;
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}
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