| /////////////////////////////////////////////////////////////////////////////// |
| // |
| /// \file block_encoder.c |
| /// \brief Encodes .lzma Blocks |
| // |
| // Copyright (C) 2007 Lasse Collin |
| // |
| // This library is free software; you can redistribute it and/or |
| // modify it under the terms of the GNU Lesser General Public |
| // License as published by the Free Software Foundation; either |
| // version 2.1 of the License, or (at your option) any later version. |
| // |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| // Lesser General Public License for more details. |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #include "block_encoder.h" |
| #include "filter_encoder.h" |
| #include "check.h" |
| |
| |
| /// The maximum size of a single Block is limited by the maximum size of |
| /// a Stream, which is 2^63 - 1 bytes (i.e. LZMA_VLI_VALUE_MAX). We could |
| /// take into account the headers etc. to determine the exact maximum size |
| /// of the Compressed Data field, but the complexity would give us nothing |
| /// useful. Instead, limit the size of Compressed Data so that even with |
| /// biggest possible Block Header and Check fields the total size of the |
| /// Block stays as valid VLI. This way we don't produce incorrect output |
| /// if someone will really try creating a Block of 8 EiB. |
| /// |
| /// ~LZMA_VLI_C(3) is to guarantee that if we need padding at the end of |
| /// the Compressed Data field, it will still stay in the proper limit. |
| #define COMPRESSED_SIZE_MAX ((LZMA_VLI_VALUE_MAX - LZMA_BLOCK_HEADER_SIZE_MAX \ |
| - LZMA_CHECK_SIZE_MAX) & ~LZMA_VLI_C(3)) |
| |
| |
| struct lzma_coder_s { |
| /// The filters in the chain; initialized with lzma_raw_decoder_init(). |
| lzma_next_coder next; |
| |
| /// Encoding options; we also write Total Size, Compressed Size, and |
| /// Uncompressed Size back to this structure when the encoding has |
| /// been finished. |
| lzma_block *options; |
| |
| enum { |
| SEQ_CODE, |
| SEQ_PADDING, |
| SEQ_CHECK, |
| } sequence; |
| |
| /// Compressed Size calculated while encoding |
| lzma_vli compressed_size; |
| |
| /// Uncompressed Size calculated while encoding |
| lzma_vli uncompressed_size; |
| |
| /// Position when writing out the Check field |
| size_t check_pos; |
| |
| /// Check of the uncompressed data |
| lzma_check_state check; |
| }; |
| |
| |
| static lzma_ret |
| block_encode(lzma_coder *coder, lzma_allocator *allocator, |
| const uint8_t *restrict in, size_t *restrict in_pos, |
| size_t in_size, uint8_t *restrict out, |
| size_t *restrict out_pos, size_t out_size, lzma_action action) |
| { |
| // Check that our amount of input stays in proper limits. |
| if (LZMA_VLI_VALUE_MAX - coder->uncompressed_size < in_size - *in_pos) |
| return LZMA_PROG_ERROR; |
| |
| switch (coder->sequence) { |
| case SEQ_CODE: { |
| const size_t in_start = *in_pos; |
| const size_t out_start = *out_pos; |
| |
| const lzma_ret ret = coder->next.code(coder->next.coder, |
| allocator, in, in_pos, in_size, |
| out, out_pos, out_size, action); |
| |
| const size_t in_used = *in_pos - in_start; |
| const size_t out_used = *out_pos - out_start; |
| |
| if (COMPRESSED_SIZE_MAX - coder->compressed_size < out_used) |
| return LZMA_DATA_ERROR; |
| |
| coder->compressed_size += out_used; |
| |
| // No need to check for overflow because we have already |
| // checked it at the beginning of this function. |
| coder->uncompressed_size += in_used; |
| |
| lzma_check_update(&coder->check, coder->options->check, |
| in + in_start, in_used); |
| |
| if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH) |
| return ret; |
| |
| assert(*in_pos == in_size); |
| assert(action == LZMA_FINISH); |
| |
| coder->sequence = SEQ_PADDING; |
| } |
| |
| // Fall through |
| |
| case SEQ_PADDING: |
| // Pad Compressed Data to a multiple of four bytes. |
| while (coder->compressed_size & 3) { |
| if (*out_pos >= out_size) |
| return LZMA_OK; |
| |
| out[*out_pos] = 0x00; |
| ++*out_pos; |
| |
| // No need to use check for overflow here since we |
| // have already checked in SEQ_CODE that Compressed |
| // Size will stay in proper limits. |
| ++coder->compressed_size; |
| } |
| |
| // Copy the values into coder->options. The caller |
| // may use this information to construct Index. |
| coder->options->compressed_size = coder->compressed_size; |
| coder->options->uncompressed_size = coder->uncompressed_size; |
| |
| if (coder->options->check == LZMA_CHECK_NONE) |
| return LZMA_STREAM_END; |
| |
| lzma_check_finish(&coder->check, coder->options->check); |
| coder->sequence = SEQ_CHECK; |
| |
| // Fall through |
| |
| case SEQ_CHECK: { |
| const uint32_t check_size |
| = lzma_check_size(coder->options->check); |
| |
| while (*out_pos < out_size) { |
| out[*out_pos] = coder->check.buffer.u8[ |
| coder->check_pos]; |
| ++*out_pos; |
| |
| if (++coder->check_pos == check_size) |
| return LZMA_STREAM_END; |
| } |
| |
| return LZMA_OK; |
| } |
| } |
| |
| return LZMA_PROG_ERROR; |
| } |
| |
| |
| static void |
| block_encoder_end(lzma_coder *coder, lzma_allocator *allocator) |
| { |
| lzma_next_end(&coder->next, allocator); |
| lzma_free(coder, allocator); |
| return; |
| } |
| |
| |
| extern lzma_ret |
| lzma_block_encoder_init(lzma_next_coder *next, lzma_allocator *allocator, |
| lzma_block *options) |
| { |
| lzma_next_coder_init(lzma_block_encoder_init, next, allocator); |
| |
| // While lzma_block_total_size_get() is meant to calculate the Total |
| // Size, it also validates the options excluding the filters. |
| if (lzma_block_total_size_get(options) == 0) |
| return LZMA_PROG_ERROR; |
| |
| // If the Check ID is not supported, we cannot calculate the check and |
| // thus not create a proper Block. |
| if ((unsigned)(options->check) > LZMA_CHECK_ID_MAX) |
| return LZMA_PROG_ERROR; |
| |
| if (!lzma_check_is_supported(options->check)) |
| return LZMA_UNSUPPORTED_CHECK; |
| |
| // Allocate and initialize *next->coder if needed. |
| if (next->coder == NULL) { |
| next->coder = lzma_alloc(sizeof(lzma_coder), allocator); |
| if (next->coder == NULL) |
| return LZMA_MEM_ERROR; |
| |
| next->code = &block_encode; |
| next->end = &block_encoder_end; |
| next->coder->next = LZMA_NEXT_CODER_INIT; |
| } |
| |
| // Basic initializations |
| next->coder->sequence = SEQ_CODE; |
| next->coder->options = options; |
| next->coder->compressed_size = 0; |
| next->coder->uncompressed_size = 0; |
| |
| // Initialize the check |
| next->coder->check_pos = 0; |
| lzma_check_init(&next->coder->check, options->check); |
| |
| // Initialize the requested filters. |
| return lzma_raw_encoder_init(&next->coder->next, allocator, |
| options->filters); |
| } |
| |
| |
| extern LZMA_API lzma_ret |
| lzma_block_encoder(lzma_stream *strm, lzma_block *options) |
| { |
| lzma_next_strm_init(lzma_block_encoder_init, strm, options); |
| |
| strm->internal->supported_actions[LZMA_RUN] = true; |
| strm->internal->supported_actions[LZMA_FINISH] = true; |
| |
| return LZMA_OK; |
| } |