diff options
Diffstat (limited to 'src/liblzma/common/stream_flags_encoder.c')
-rw-r--r-- | src/liblzma/common/stream_flags_encoder.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/src/liblzma/common/stream_flags_encoder.c b/src/liblzma/common/stream_flags_encoder.c new file mode 100644 index 0000000..b98ab17 --- /dev/null +++ b/src/liblzma/common/stream_flags_encoder.c @@ -0,0 +1,86 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file stream_flags_encoder.c +/// \brief Encodes Stream Header and Stream Footer for .xz files +// +// 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; +} |