diff options
author | mm <mm@FreeBSD.org> | 2010-05-10 06:59:50 +0000 |
---|---|---|
committer | mm <mm@FreeBSD.org> | 2010-05-10 06:59:50 +0000 |
commit | 5c358d45429b654efa9c8177ecd370a7965ec1a7 (patch) | |
tree | d2d916954c6a66a3168ee356b5f24da01c2017d6 /contrib/xz/src/liblzma/common/index_decoder.c | |
parent | 3e09decd1986826f54af1a47be97bb87c1220783 (diff) | |
parent | 1008b7c6744a190c5b15aaf8cab1054671e4c7c3 (diff) | |
download | FreeBSD-src-5c358d45429b654efa9c8177ecd370a7965ec1a7.zip FreeBSD-src-5c358d45429b654efa9c8177ecd370a7965ec1a7.tar.gz |
Import of liblzma, xz, xzdec, lzmainfo from vendor branch
Add support for xz and lzma to lesspipe.sh (xzless, lzless)
Bump __FreeBSD_version
Approved by: delphij (mentor)
MFC after: 2 weeks
Diffstat (limited to 'contrib/xz/src/liblzma/common/index_decoder.c')
-rw-r--r-- | contrib/xz/src/liblzma/common/index_decoder.c | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/contrib/xz/src/liblzma/common/index_decoder.c b/contrib/xz/src/liblzma/common/index_decoder.c new file mode 100644 index 0000000..86a2297 --- /dev/null +++ b/contrib/xz/src/liblzma/common/index_decoder.c @@ -0,0 +1,343 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file index_decoder.c +/// \brief Decodes the Index field +// +// Author: Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "index.h" +#include "check.h" + + +struct lzma_coder_s { + enum { + SEQ_INDICATOR, + SEQ_COUNT, + SEQ_MEMUSAGE, + SEQ_UNPADDED, + SEQ_UNCOMPRESSED, + SEQ_PADDING_INIT, + SEQ_PADDING, + SEQ_CRC32, + } sequence; + + /// Memory usage limit + uint64_t memlimit; + + /// Target Index + lzma_index *index; + + /// Pointer give by the application, which is set after + /// successful decoding. + lzma_index **index_ptr; + + /// Number of Records left to decode. + lzma_vli count; + + /// The most recent Unpadded Size field + lzma_vli unpadded_size; + + /// The most recent Uncompressed Size field + lzma_vli uncompressed_size; + + /// Position in integers + size_t pos; + + /// CRC32 of the List of Records field + uint32_t crc32; +}; + + +static lzma_ret +index_decode(lzma_coder *coder, lzma_allocator *allocator, + const uint8_t *restrict in, size_t *restrict in_pos, + size_t in_size, uint8_t *restrict out lzma_attribute((unused)), + size_t *restrict out_pos lzma_attribute((unused)), + size_t out_size lzma_attribute((unused)), + lzma_action action lzma_attribute((unused))) +{ + // Similar optimization as in index_encoder.c + const size_t in_start = *in_pos; + lzma_ret ret = LZMA_OK; + + while (*in_pos < in_size) + switch (coder->sequence) { + case SEQ_INDICATOR: + // Return LZMA_DATA_ERROR instead of e.g. LZMA_PROG_ERROR or + // LZMA_FORMAT_ERROR, because a typical usage case for Index + // decoder is when parsing the Stream backwards. If seeking + // backward from the Stream Footer gives us something that + // doesn't begin with Index Indicator, the file is considered + // corrupt, not "programming error" or "unrecognized file + // format". One could argue that the application should + // verify the Index Indicator before trying to decode the + // Index, but well, I suppose it is simpler this way. + if (in[(*in_pos)++] != 0x00) + return LZMA_DATA_ERROR; + + coder->sequence = SEQ_COUNT; + break; + + case SEQ_COUNT: + ret = lzma_vli_decode(&coder->count, &coder->pos, + in, in_pos, in_size); + if (ret != LZMA_STREAM_END) + goto out; + + coder->pos = 0; + coder->sequence = SEQ_MEMUSAGE; + + // Fall through + + case SEQ_MEMUSAGE: + if (lzma_index_memusage(1, coder->count) > coder->memlimit) { + ret = LZMA_MEMLIMIT_ERROR; + goto out; + } + + // Tell the Index handling code how many Records this + // Index has to allow it to allocate memory more efficiently. + lzma_index_prealloc(coder->index, coder->count); + + ret = LZMA_OK; + coder->sequence = coder->count == 0 + ? SEQ_PADDING_INIT : SEQ_UNPADDED; + break; + + case SEQ_UNPADDED: + case SEQ_UNCOMPRESSED: { + lzma_vli *size = coder->sequence == SEQ_UNPADDED + ? &coder->unpadded_size + : &coder->uncompressed_size; + + ret = lzma_vli_decode(size, &coder->pos, + in, in_pos, in_size); + if (ret != LZMA_STREAM_END) + goto out; + + ret = LZMA_OK; + coder->pos = 0; + + if (coder->sequence == SEQ_UNPADDED) { + // Validate that encoded Unpadded Size isn't too small + // or too big. + if (coder->unpadded_size < UNPADDED_SIZE_MIN + || coder->unpadded_size + > UNPADDED_SIZE_MAX) + return LZMA_DATA_ERROR; + + coder->sequence = SEQ_UNCOMPRESSED; + } else { + // Add the decoded Record to the Index. + return_if_error(lzma_index_append( + coder->index, allocator, + coder->unpadded_size, + coder->uncompressed_size)); + + // Check if this was the last Record. + coder->sequence = --coder->count == 0 + ? SEQ_PADDING_INIT + : SEQ_UNPADDED; + } + + break; + } + + case SEQ_PADDING_INIT: + coder->pos = lzma_index_padding_size(coder->index); + coder->sequence = SEQ_PADDING; + + // Fall through + + case SEQ_PADDING: + if (coder->pos > 0) { + --coder->pos; + if (in[(*in_pos)++] != 0x00) + return LZMA_DATA_ERROR; + + break; + } + + // Finish the CRC32 calculation. + coder->crc32 = lzma_crc32(in + in_start, + *in_pos - in_start, coder->crc32); + + coder->sequence = SEQ_CRC32; + + // Fall through + + case SEQ_CRC32: + do { + if (*in_pos == in_size) + return LZMA_OK; + + if (((coder->crc32 >> (coder->pos * 8)) & 0xFF) + != in[(*in_pos)++]) + return LZMA_DATA_ERROR; + + } while (++coder->pos < 4); + + // Decoding was successful, now we can let the application + // see the decoded Index. + *coder->index_ptr = coder->index; + + // Make index NULL so we don't free it unintentionally. + coder->index = NULL; + + return LZMA_STREAM_END; + + default: + assert(0); + return LZMA_PROG_ERROR; + } + +out: + // Update the CRC32, + coder->crc32 = lzma_crc32(in + in_start, + *in_pos - in_start, coder->crc32); + + return ret; +} + + +static void +index_decoder_end(lzma_coder *coder, lzma_allocator *allocator) +{ + lzma_index_end(coder->index, allocator); + lzma_free(coder, allocator); + return; +} + + +static lzma_ret +index_decoder_memconfig(lzma_coder *coder, uint64_t *memusage, + uint64_t *old_memlimit, uint64_t new_memlimit) +{ + *memusage = lzma_index_memusage(1, coder->count); + *old_memlimit = coder->memlimit; + + if (new_memlimit != 0) { + if (new_memlimit < *memusage) + return LZMA_MEMLIMIT_ERROR; + + coder->memlimit = new_memlimit; + } + + return LZMA_OK; +} + + +static lzma_ret +index_decoder_reset(lzma_coder *coder, lzma_allocator *allocator, + lzma_index **i, uint64_t memlimit) +{ + // Remember the pointer given by the application. We will set it + // to point to the decoded Index only if decoding is successful. + // Before that, keep it NULL so that applications can always safely + // pass it to lzma_index_end() no matter did decoding succeed or not. + coder->index_ptr = i; + *i = NULL; + + // We always allocate a new lzma_index. + coder->index = lzma_index_init(allocator); + if (coder->index == NULL) + return LZMA_MEM_ERROR; + + // Initialize the rest. + coder->sequence = SEQ_INDICATOR; + coder->memlimit = memlimit; + coder->count = 0; // Needs to be initialized due to _memconfig(). + coder->pos = 0; + coder->crc32 = 0; + + return LZMA_OK; +} + + +static lzma_ret +index_decoder_init(lzma_next_coder *next, lzma_allocator *allocator, + lzma_index **i, uint64_t memlimit) +{ + lzma_next_coder_init(&index_decoder_init, next, allocator); + + if (i == NULL || memlimit == 0) + return LZMA_PROG_ERROR; + + if (next->coder == NULL) { + next->coder = lzma_alloc(sizeof(lzma_coder), allocator); + if (next->coder == NULL) + return LZMA_MEM_ERROR; + + next->code = &index_decode; + next->end = &index_decoder_end; + next->memconfig = &index_decoder_memconfig; + next->coder->index = NULL; + } else { + lzma_index_end(next->coder->index, allocator); + } + + return index_decoder_reset(next->coder, allocator, i, memlimit); +} + + +extern LZMA_API(lzma_ret) +lzma_index_decoder(lzma_stream *strm, lzma_index **i, uint64_t memlimit) +{ + lzma_next_strm_init(index_decoder_init, strm, i, memlimit); + + strm->internal->supported_actions[LZMA_RUN] = true; + + return LZMA_OK; +} + + +extern LZMA_API(lzma_ret) +lzma_index_buffer_decode( + lzma_index **i, uint64_t *memlimit, lzma_allocator *allocator, + const uint8_t *in, size_t *in_pos, size_t in_size) +{ + // Sanity checks + if (i == NULL || memlimit == NULL + || in == NULL || in_pos == NULL || *in_pos > in_size) + return LZMA_PROG_ERROR; + + // Initialize the decoder. + lzma_coder coder; + return_if_error(index_decoder_reset(&coder, allocator, i, *memlimit)); + + // Store the input start position so that we can restore it in case + // of an error. + const size_t in_start = *in_pos; + + // Do the actual decoding. + lzma_ret ret = index_decode(&coder, allocator, in, in_pos, in_size, + NULL, NULL, 0, LZMA_RUN); + + if (ret == LZMA_STREAM_END) { + ret = LZMA_OK; + } else { + // Something went wrong, free the Index structure and restore + // the input position. + lzma_index_end(coder.index, allocator); + *in_pos = in_start; + + if (ret == LZMA_OK) { + // The input is truncated or otherwise corrupt. + // Use LZMA_DATA_ERROR instead of LZMA_BUF_ERROR + // like lzma_vli_decode() does in single-call mode. + ret = LZMA_DATA_ERROR; + + } else if (ret == LZMA_MEMLIMIT_ERROR) { + // Tell the caller how much memory would have + // been needed. + *memlimit = lzma_index_memusage(1, coder.count); + } + } + + return ret; +} |