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author | mm <mm@FreeBSD.org> | 2010-05-10 06:59:50 +0000 |
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committer | mm <mm@FreeBSD.org> | 2010-05-10 06:59:50 +0000 |
commit | 5c358d45429b654efa9c8177ecd370a7965ec1a7 (patch) | |
tree | d2d916954c6a66a3168ee356b5f24da01c2017d6 /contrib/xz/src/liblzma/common/block_buffer_encoder.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/block_buffer_encoder.c')
-rw-r--r-- | contrib/xz/src/liblzma/common/block_buffer_encoder.c | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/contrib/xz/src/liblzma/common/block_buffer_encoder.c b/contrib/xz/src/liblzma/common/block_buffer_encoder.c new file mode 100644 index 0000000..4d90fee --- /dev/null +++ b/contrib/xz/src/liblzma/common/block_buffer_encoder.c @@ -0,0 +1,299 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file block_buffer_encoder.c +/// \brief Single-call .xz Block encoder +// +// Author: Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "block_encoder.h" +#include "filter_encoder.h" +#include "lzma2_encoder.h" +#include "check.h" + + +/// Estimate the maximum size of the Block Header and Check fields for +/// a Block that uses LZMA2 uncompressed chunks. We could use +/// lzma_block_header_size() but this is simpler. +/// +/// Block Header Size + Block Flags + Compressed Size +/// + Uncompressed Size + Filter Flags for LZMA2 + CRC32 + Check +/// and round up to the next multiple of four to take Header Padding +/// into account. +#define HEADERS_BOUND ((1 + 1 + 2 * LZMA_VLI_BYTES_MAX + 3 + 4 \ + + LZMA_CHECK_SIZE_MAX + 3) & ~3) + + +static lzma_vli +lzma2_bound(lzma_vli uncompressed_size) +{ + // Prevent integer overflow in overhead calculation. + if (uncompressed_size > COMPRESSED_SIZE_MAX) + return 0; + + // Calculate the exact overhead of the LZMA2 headers: Round + // uncompressed_size up to the next multiple of LZMA2_CHUNK_MAX, + // multiply by the size of per-chunk header, and add one byte for + // the end marker. + const lzma_vli overhead = ((uncompressed_size + LZMA2_CHUNK_MAX - 1) + / LZMA2_CHUNK_MAX) + * LZMA2_HEADER_UNCOMPRESSED + 1; + + // Catch the possible integer overflow. + if (COMPRESSED_SIZE_MAX - overhead < uncompressed_size) + return 0; + + return uncompressed_size + overhead; +} + + +extern LZMA_API(size_t) +lzma_block_buffer_bound(size_t uncompressed_size) +{ + // For now, if the data doesn't compress, we always use uncompressed + // chunks of LZMA2. In future we may use Subblock filter too, but + // but for simplicity we probably will still use the same bound + // calculation even though Subblock filter would have slightly less + // overhead. + lzma_vli lzma2_size = lzma2_bound(uncompressed_size); + if (lzma2_size == 0) + return 0; + + // Take Block Padding into account. + lzma2_size = (lzma2_size + 3) & ~LZMA_VLI_C(3); + +#if SIZE_MAX < LZMA_VLI_MAX + // Catch the possible integer overflow on 32-bit systems. There's no + // overflow on 64-bit systems, because lzma2_bound() already takes + // into account the size of the headers in the Block. + if (SIZE_MAX - HEADERS_BOUND < lzma2_size) + return 0; +#endif + + return HEADERS_BOUND + lzma2_size; +} + + +static lzma_ret +block_encode_uncompressed(lzma_block *block, const uint8_t *in, size_t in_size, + uint8_t *out, size_t *out_pos, size_t out_size) +{ + // TODO: Figure out if the last filter is LZMA2 or Subblock and use + // that filter to encode the uncompressed chunks. + + // Use LZMA2 uncompressed chunks. We wouldn't need a dictionary at + // all, but LZMA2 always requires a dictionary, so use the minimum + // value to minimize memory usage of the decoder. + lzma_options_lzma lzma2 = { + .dict_size = LZMA_DICT_SIZE_MIN, + }; + + lzma_filter filters[2]; + filters[0].id = LZMA_FILTER_LZMA2; + filters[0].options = &lzma2; + filters[1].id = LZMA_VLI_UNKNOWN; + + // Set the above filter options to *block temporarily so that we can + // encode the Block Header. + lzma_filter *filters_orig = block->filters; + block->filters = filters; + + if (lzma_block_header_size(block) != LZMA_OK) { + block->filters = filters_orig; + return LZMA_PROG_ERROR; + } + + // Check that there's enough output space. The caller has already + // set block->compressed_size to what lzma2_bound() has returned, + // so we can reuse that value. We know that compressed_size is a + // known valid VLI and header_size is a small value so their sum + // will never overflow. + assert(block->compressed_size == lzma2_bound(in_size)); + if (out_size - *out_pos + < block->header_size + block->compressed_size) { + block->filters = filters_orig; + return LZMA_BUF_ERROR; + } + + if (lzma_block_header_encode(block, out + *out_pos) != LZMA_OK) { + block->filters = filters_orig; + return LZMA_PROG_ERROR; + } + + block->filters = filters_orig; + *out_pos += block->header_size; + + // Encode the data using LZMA2 uncompressed chunks. + size_t in_pos = 0; + uint8_t control = 0x01; // Dictionary reset + + while (in_pos < in_size) { + // Control byte: Indicate uncompressed chunk, of which + // the first resets the dictionary. + out[(*out_pos)++] = control; + control = 0x02; // No dictionary reset + + // Size of the uncompressed chunk + const size_t copy_size + = MIN(in_size - in_pos, LZMA2_CHUNK_MAX); + out[(*out_pos)++] = (copy_size - 1) >> 8; + out[(*out_pos)++] = (copy_size - 1) & 0xFF; + + // The actual data + assert(*out_pos + copy_size <= out_size); + memcpy(out + *out_pos, in + in_pos, copy_size); + + in_pos += copy_size; + *out_pos += copy_size; + } + + // End marker + out[(*out_pos)++] = 0x00; + assert(*out_pos <= out_size); + + return LZMA_OK; +} + + +static lzma_ret +block_encode_normal(lzma_block *block, lzma_allocator *allocator, + const uint8_t *in, size_t in_size, + uint8_t *out, size_t *out_pos, size_t out_size) +{ + // Find out the size of the Block Header. + block->compressed_size = lzma2_bound(in_size); + if (block->compressed_size == 0) + return LZMA_DATA_ERROR; + + block->uncompressed_size = in_size; + return_if_error(lzma_block_header_size(block)); + + // Reserve space for the Block Header and skip it for now. + if (out_size - *out_pos <= block->header_size) + return LZMA_BUF_ERROR; + + const size_t out_start = *out_pos; + *out_pos += block->header_size; + + // Limit out_size so that we stop encoding if the output would grow + // bigger than what uncompressed Block would be. + if (out_size - *out_pos > block->compressed_size) + out_size = *out_pos + block->compressed_size; + + // TODO: In many common cases this could be optimized to use + // significantly less memory. + lzma_next_coder raw_encoder = LZMA_NEXT_CODER_INIT; + lzma_ret ret = lzma_raw_encoder_init( + &raw_encoder, allocator, block->filters); + + if (ret == LZMA_OK) { + size_t in_pos = 0; + ret = raw_encoder.code(raw_encoder.coder, allocator, + in, &in_pos, in_size, out, out_pos, out_size, + LZMA_FINISH); + } + + // NOTE: This needs to be run even if lzma_raw_encoder_init() failed. + lzma_next_end(&raw_encoder, allocator); + + if (ret == LZMA_STREAM_END) { + // Compression was successful. Write the Block Header. + block->compressed_size + = *out_pos - (out_start + block->header_size); + ret = lzma_block_header_encode(block, out + out_start); + if (ret != LZMA_OK) + ret = LZMA_PROG_ERROR; + + } else if (ret == LZMA_OK) { + // Output buffer became full. + ret = LZMA_BUF_ERROR; + } + + // Reset *out_pos if something went wrong. + if (ret != LZMA_OK) + *out_pos = out_start; + + return ret; +} + + +extern LZMA_API(lzma_ret) +lzma_block_buffer_encode(lzma_block *block, lzma_allocator *allocator, + const uint8_t *in, size_t in_size, + uint8_t *out, size_t *out_pos, size_t out_size) +{ + // Sanity checks + if (block == NULL || block->filters == NULL + || (in == NULL && in_size != 0) || out == NULL + || out_pos == NULL || *out_pos > out_size) + return LZMA_PROG_ERROR; + + // Check the version field. + if (block->version != 0) + return LZMA_OPTIONS_ERROR; + + // Size of a Block has to be a multiple of four, so limit the size + // here already. This way we don't need to check it again when adding + // Block Padding. + out_size -= (out_size - *out_pos) & 3; + + // Get the size of the Check field. + const size_t check_size = lzma_check_size(block->check); + if (check_size == UINT32_MAX) + return LZMA_PROG_ERROR; + + // Reserve space for the Check field. + if (out_size - *out_pos <= check_size) + return LZMA_BUF_ERROR; + + out_size -= check_size; + + // Do the actual compression. + const lzma_ret ret = block_encode_normal(block, allocator, + in, in_size, out, out_pos, out_size); + if (ret != LZMA_OK) { + // If the error was something else than output buffer + // becoming full, return the error now. + if (ret != LZMA_BUF_ERROR) + return ret; + + // The data was uncompressible (at least with the options + // given to us) or the output buffer was too small. Use the + // uncompressed chunks of LZMA2 to wrap the data into a valid + // Block. If we haven't been given enough output space, even + // this may fail. + return_if_error(block_encode_uncompressed(block, in, in_size, + out, out_pos, out_size)); + } + + assert(*out_pos <= out_size); + + // Block Padding. No buffer overflow here, because we already adjusted + // out_size so that (out_size - out_start) is a multiple of four. + // Thus, if the buffer is full, the loop body can never run. + for (size_t i = (size_t)(block->compressed_size); i & 3; ++i) { + assert(*out_pos < out_size); + out[(*out_pos)++] = 0x00; + } + + // If there's no Check field, we are done now. + if (check_size > 0) { + // Calculate the integrity check. We reserved space for + // the Check field earlier so we don't need to check for + // available output space here. + lzma_check_state check; + lzma_check_init(&check, block->check); + lzma_check_update(&check, block->check, in, in_size); + lzma_check_finish(&check, block->check); + + memcpy(block->raw_check, check.buffer.u8, check_size); + memcpy(out + *out_pos, check.buffer.u8, check_size); + *out_pos += check_size; + } + + return LZMA_OK; +} |