diff options
Diffstat (limited to '')
| -rw-r--r-- | src/liblzma/common/stream_flags_encoder.c | 56 |
1 files changed, 35 insertions, 21 deletions
diff --git a/src/liblzma/common/stream_flags_encoder.c b/src/liblzma/common/stream_flags_encoder.c index 55468580..4efbb6f4 100644 --- a/src/liblzma/common/stream_flags_encoder.c +++ b/src/liblzma/common/stream_flags_encoder.c @@ -1,7 +1,7 @@ /////////////////////////////////////////////////////////////////////////////// // /// \file stream_flags_encoder.c -/// \brief Encodes Stream Header and Footer for .lzma files +/// \brief Encodes Stream Header and Stream Footer for .lzma files // // Copyright (C) 2007 Lasse Collin // @@ -21,55 +21,69 @@ static bool -stream_flags_encode(uint8_t *flags_byte, const lzma_stream_flags *options) +stream_flags_encode(const lzma_stream_flags *options, uint8_t *out) { - // 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; + out[0] = 0x00; + out[1] = options->check; return false; } extern LZMA_API lzma_ret -lzma_stream_header_encode(uint8_t *out, const lzma_stream_flags *options) +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(out + sizeof(lzma_header_magic), options)) - return LZMA_PROG_ERROR;; + 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), 1, 0); + const uint32_t crc = lzma_crc32(out + sizeof(lzma_header_magic), + LZMA_STREAM_FLAGS_SIZE, 0); - for (size_t i = 0; i < 4; ++i) - out[sizeof(lzma_header_magic) + 1 + i] = crc >> (i * 8); + integer_write_32(out + sizeof(lzma_header_magic) + + LZMA_STREAM_FLAGS_SIZE, crc); return LZMA_OK; } extern LZMA_API lzma_ret -lzma_stream_tail_encode(uint8_t *out, const lzma_stream_flags *options) +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(out, options)) + 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 + 1, lzma_footer_magic, sizeof(lzma_footer_magic)); + memcpy(out + 2 * 4 + LZMA_STREAM_FLAGS_SIZE, + lzma_footer_magic, sizeof(lzma_footer_magic)); return LZMA_OK; } |