| /////////////////////////////////////////////////////////////////////////////// |
| // |
| /// \file block_decoder.c |
| /// \brief Decodes .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_decoder.h" |
| #include "block_private.h" |
| #include "raw_decoder.h" |
| #include "check.h" |
| |
| |
| struct lzma_coder_s { |
| enum { |
| SEQ_CODE, |
| SEQ_CHECK, |
| SEQ_UNCOMPRESSED_SIZE, |
| SEQ_BACKWARD_SIZE, |
| SEQ_PADDING, |
| SEQ_END, |
| } sequence; |
| |
| /// The filters in the chain; initialized with lzma_raw_decoder_init(). |
| lzma_next_coder next; |
| |
| /// Decoding options; we also write Total Size, Compressed Size, and |
| /// Uncompressed Size back to this structure when the encoding has |
| /// been finished. |
| lzma_options_block *options; |
| |
| /// Position in variable-length integers (and in some other places). |
| size_t pos; |
| |
| /// Check of the uncompressed data |
| lzma_check check; |
| |
| /// Total Size calculated while encoding |
| lzma_vli total_size; |
| |
| /// Compressed Size calculated while encoding |
| lzma_vli compressed_size; |
| |
| /// Uncompressed Size calculated while encoding |
| lzma_vli uncompressed_size; |
| |
| /// Maximum allowed total_size |
| lzma_vli total_limit; |
| |
| /// Maximum allowed uncompressed_size |
| lzma_vli uncompressed_limit; |
| |
| /// Temporary location for the Uncompressed Size and Backward Size |
| /// fields in Block Footer. |
| lzma_vli tmp; |
| |
| /// Size of the Backward Size field - This is needed so that we |
| /// can verify the Backward Size and still keep updating total_size. |
| size_t size_of_backward_size; |
| }; |
| |
| |
| static lzma_ret |
| update_sequence(lzma_coder *coder) |
| { |
| switch (coder->sequence) { |
| case SEQ_CODE: |
| if (coder->options->check != LZMA_CHECK_NONE) { |
| lzma_check_finish(&coder->check, |
| coder->options->check); |
| coder->sequence = SEQ_CHECK; |
| break; |
| } |
| |
| // Fall through |
| |
| case SEQ_CHECK: |
| if (coder->options->has_uncompressed_size_in_footer) { |
| coder->sequence = SEQ_UNCOMPRESSED_SIZE; |
| break; |
| } |
| |
| // Fall through |
| |
| case SEQ_UNCOMPRESSED_SIZE: |
| if (coder->options->has_backward_size) { |
| coder->sequence = SEQ_BACKWARD_SIZE; |
| break; |
| } |
| |
| // Fall through |
| |
| case SEQ_BACKWARD_SIZE: |
| if (coder->options->handle_padding) { |
| coder->sequence = SEQ_PADDING; |
| break; |
| } |
| |
| case SEQ_PADDING: |
| if (!is_size_valid(coder->total_size, |
| coder->options->total_size) |
| || !is_size_valid(coder->compressed_size, |
| coder->options->compressed_size) |
| || !is_size_valid(coder->uncompressed_size, |
| coder->options->uncompressed_size)) |
| return LZMA_DATA_ERROR; |
| |
| // Copy the values into coder->options. The caller |
| // may use this information to construct Index. |
| coder->options->total_size = coder->total_size; |
| coder->options->compressed_size = coder->compressed_size; |
| coder->options->uncompressed_size = coder->uncompressed_size; |
| |
| return LZMA_STREAM_END; |
| |
| default: |
| assert(0); |
| return LZMA_PROG_ERROR; |
| } |
| |
| return LZMA_OK; |
| } |
| |
| |
| static lzma_ret |
| block_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, |
| size_t *restrict out_pos, size_t out_size, lzma_action action) |
| { |
| // Special case when the Block has only Block Header. |
| if (coder->sequence == SEQ_END) |
| return LZMA_STREAM_END; |
| |
| // FIXME: Termination condition should work but could be cleaner. |
| while (*out_pos < out_size && (*in_pos < in_size |
| || coder->sequence == SEQ_CODE)) |
| switch (coder->sequence) { |
| case SEQ_CODE: { |
| const size_t in_start = *in_pos; |
| const size_t out_start = *out_pos; |
| |
| 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 (update_size(&coder->total_size, in_used, |
| coder->total_limit) |
| || update_size(&coder->compressed_size, |
| in_used, |
| coder->options->compressed_size) |
| || update_size(&coder->uncompressed_size, |
| out_used, coder->uncompressed_limit)) |
| return LZMA_DATA_ERROR; |
| |
| lzma_check_update(&coder->check, coder->options->check, |
| out + out_start, out_used); |
| |
| if (ret != LZMA_STREAM_END) |
| return ret; |
| |
| ret = update_sequence(coder); |
| if (ret != LZMA_OK) |
| return ret; |
| |
| break; |
| } |
| |
| case SEQ_CHECK: |
| switch (coder->options->check) { |
| case LZMA_CHECK_CRC32: |
| if (((coder->check.crc32 >> (coder->pos * 8)) |
| & 0xFF) != in[*in_pos]) |
| return LZMA_DATA_ERROR; |
| break; |
| |
| case LZMA_CHECK_CRC64: |
| if (((coder->check.crc64 >> (coder->pos * 8)) |
| & 0xFF) != in[*in_pos]) |
| return LZMA_DATA_ERROR; |
| break; |
| |
| case LZMA_CHECK_SHA256: |
| if (coder->check.sha256.buffer[coder->pos] |
| != in[*in_pos]) |
| return LZMA_DATA_ERROR; |
| break; |
| |
| default: |
| assert(coder->options->check != LZMA_CHECK_NONE); |
| assert(coder->options->check <= LZMA_CHECK_ID_MAX); |
| break; |
| } |
| |
| if (update_size(&coder->total_size, 1, coder->total_limit)) |
| return LZMA_DATA_ERROR; |
| |
| ++*in_pos; |
| |
| if (++coder->pos == lzma_check_sizes[coder->options->check]) { |
| const lzma_ret ret = update_sequence(coder); |
| if (ret != LZMA_OK) |
| return ret; |
| |
| coder->pos = 0; |
| } |
| |
| break; |
| |
| case SEQ_UNCOMPRESSED_SIZE: { |
| const size_t in_start = *in_pos; |
| |
| lzma_ret ret = lzma_vli_decode(&coder->tmp, |
| &coder->pos, in, in_pos, in_size); |
| |
| if (update_size(&coder->total_size, *in_pos - in_start, |
| coder->total_limit)) |
| return LZMA_DATA_ERROR; |
| |
| if (ret != LZMA_STREAM_END) |
| return ret; |
| |
| if (coder->tmp != coder->uncompressed_size) |
| return LZMA_DATA_ERROR; |
| |
| coder->pos = 0; |
| coder->tmp = 0; |
| |
| ret = update_sequence(coder); |
| if (ret != LZMA_OK) |
| return ret; |
| |
| break; |
| } |
| |
| case SEQ_BACKWARD_SIZE: { |
| const size_t in_start = *in_pos; |
| |
| lzma_ret ret = lzma_vli_decode(&coder->tmp, |
| &coder->pos, in, in_pos, in_size); |
| |
| const size_t in_used = *in_pos - in_start; |
| |
| if (update_size(&coder->total_size, in_used, |
| coder->total_limit)) |
| return LZMA_DATA_ERROR; |
| |
| coder->size_of_backward_size += in_used; |
| |
| if (ret != LZMA_STREAM_END) |
| return ret; |
| |
| if (coder->tmp != coder->total_size |
| - coder->size_of_backward_size) |
| return LZMA_DATA_ERROR; |
| |
| ret = update_sequence(coder); |
| if (ret != LZMA_OK) |
| return ret; |
| |
| break; |
| } |
| |
| case SEQ_PADDING: |
| if (in[*in_pos] == 0x00) { |
| if (update_size(&coder->total_size, 1, |
| coder->total_limit)) |
| return LZMA_DATA_ERROR; |
| |
| ++*in_pos; |
| break; |
| } |
| |
| return update_sequence(coder); |
| |
| default: |
| return LZMA_PROG_ERROR; |
| } |
| |
| return LZMA_OK; |
| } |
| |
| |
| static void |
| block_decoder_end(lzma_coder *coder, lzma_allocator *allocator) |
| { |
| lzma_next_coder_end(&coder->next, allocator); |
| lzma_free(coder, allocator); |
| return; |
| } |
| |
| |
| extern lzma_ret |
| lzma_block_decoder_init(lzma_next_coder *next, lzma_allocator *allocator, |
| lzma_options_block *options) |
| { |
| // This is pretty similar to lzma_block_encoder_init(). |
| // See comments there. |
| |
| if (next->coder == NULL) { |
| next->coder = lzma_alloc(sizeof(lzma_coder), allocator); |
| if (next->coder == NULL) |
| return LZMA_MEM_ERROR; |
| |
| next->code = &block_decode; |
| next->end = &block_decoder_end; |
| next->coder->next = LZMA_NEXT_CODER_INIT; |
| } |
| |
| if (!lzma_vli_is_valid(options->total_size) |
| || !lzma_vli_is_valid(options->compressed_size) |
| || !lzma_vli_is_valid(options->uncompressed_size) |
| || !lzma_vli_is_valid(options->total_size) |
| || !lzma_vli_is_valid(options->total_limit) |
| || !lzma_vli_is_valid(options->uncompressed_limit) |
| || (options->uncompressed_size |
| != LZMA_VLI_VALUE_UNKNOWN |
| && options->uncompressed_size |
| > options->uncompressed_limit) |
| || (options->total_size != LZMA_VLI_VALUE_UNKNOWN |
| && options->total_size |
| > options->total_limit) |
| || (!options->has_eopm && options->uncompressed_size |
| == LZMA_VLI_VALUE_UNKNOWN) |
| || options->header_size > options->total_size |
| || (options->handle_padding |
| && (options->has_uncompressed_size_in_footer |
| || options->has_backward_size))) |
| return LZMA_PROG_ERROR; |
| |
| return_if_error(lzma_check_init(&next->coder->check, options->check)); |
| |
| if (!options->has_eopm && options->uncompressed_size == 0) { |
| if (!is_size_valid(0, options->compressed_size)) |
| return LZMA_PROG_ERROR; |
| |
| if (options->check != LZMA_CHECK_NONE) { |
| lzma_check_finish(&next->coder->check, options->check); |
| next->coder->sequence = SEQ_CHECK; |
| } else if (options->handle_padding) { |
| next->coder->sequence = SEQ_PADDING; |
| } else { |
| next->coder->sequence = SEQ_END; |
| } |
| } else { |
| next->coder->sequence = SEQ_CODE; |
| } |
| |
| return_if_error(lzma_raw_decoder_init(&next->coder->next, allocator, |
| options->filters, options->has_eopm |
| ? LZMA_VLI_VALUE_UNKNOWN |
| : options->uncompressed_size, |
| true)); |
| |
| next->coder->options = options; |
| next->coder->pos = 0; |
| next->coder->total_size = options->header_size; |
| next->coder->compressed_size = 0; |
| next->coder->uncompressed_size = 0; |
| next->coder->total_limit |
| = MIN(options->total_size, options->total_limit); |
| next->coder->uncompressed_limit = MIN(options->uncompressed_size, |
| options->uncompressed_limit); |
| next->coder->tmp = 0; |
| next->coder->size_of_backward_size = 0; |
| |
| return LZMA_OK; |
| } |
| |
| |
| extern LZMA_API lzma_ret |
| lzma_block_decoder(lzma_stream *strm, lzma_options_block *options) |
| { |
| lzma_next_strm_init(strm, lzma_block_decoder_init, options); |
| |
| strm->internal->supported_actions[LZMA_RUN] = true; |
| strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true; |
| |
| return LZMA_OK; |
| } |