| /////////////////////////////////////////////////////////////////////////////// |
| // |
| /// \file alone_decoder.c |
| /// \brief Decoder for LZMA_Alone files |
| // |
| // 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 "alone_decoder.h" |
| #include "lzma_decoder.h" |
| |
| |
| struct lzma_coder_s { |
| lzma_next_coder next; |
| |
| enum { |
| SEQ_PROPERTIES, |
| SEQ_DICTIONARY_SIZE, |
| SEQ_UNCOMPRESSED_SIZE, |
| SEQ_CODER_INIT, |
| SEQ_CODE, |
| } sequence; |
| |
| size_t pos; |
| |
| lzma_options_alone options; |
| }; |
| |
| |
| static lzma_ret |
| alone_decode(lzma_coder *coder, |
| lzma_allocator *allocator lzma_attribute((unused)), |
| 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) |
| { |
| while (*out_pos < out_size |
| && (coder->sequence == SEQ_CODE || *in_pos < in_size)) |
| switch (coder->sequence) { |
| case SEQ_PROPERTIES: |
| if (lzma_lzma_decode_properties( |
| &coder->options.lzma, in[*in_pos])) |
| return LZMA_DATA_ERROR; |
| |
| coder->sequence = SEQ_DICTIONARY_SIZE; |
| ++*in_pos; |
| break; |
| |
| case SEQ_DICTIONARY_SIZE: |
| coder->options.lzma.dictionary_size |
| |= (size_t)(in[*in_pos]) << (coder->pos * 8); |
| |
| if (++coder->pos == 4) { |
| // A hack to ditch tons of false positives: We allow |
| // only dictionary sizes that are a power of two. |
| // LZMA_Alone didn't create other kinds of files, |
| // although it's not impossible that files with |
| // other dictionary sizes exist. Well, if someone |
| // complains, this will be reconsidered. |
| size_t count = 0; |
| for (size_t i = 0; i < 32; ++i) |
| if (coder->options.lzma.dictionary_size |
| & (UINT32_C(1) << i)) |
| ++count; |
| |
| if (count > 1) |
| return LZMA_DATA_ERROR; |
| |
| coder->pos = 0; |
| coder->sequence = SEQ_UNCOMPRESSED_SIZE; |
| } |
| |
| ++*in_pos; |
| break; |
| |
| case SEQ_UNCOMPRESSED_SIZE: |
| coder->options.uncompressed_size |
| |= (lzma_vli)(in[*in_pos]) << (coder->pos * 8); |
| |
| if (++coder->pos == 8) { |
| // Another hack to ditch false positives: Assume that |
| // if the uncompressed size is known, it must be less |
| // than 256 GiB. Again, if someone complains, this |
| // will be reconsidered. |
| if (coder->options.uncompressed_size |
| != LZMA_VLI_VALUE_UNKNOWN |
| && coder->options.uncompressed_size |
| >= (LZMA_VLI_C(1) << 38)) |
| return LZMA_DATA_ERROR; |
| |
| coder->pos = 0; |
| coder->sequence = SEQ_CODER_INIT; |
| } |
| |
| ++*in_pos; |
| break; |
| |
| case SEQ_CODER_INIT: { |
| // Two is enough because there won't be implicit filters. |
| lzma_filter_info filters[2] = { |
| { |
| .init = &lzma_lzma_decoder_init, |
| .options = &coder->options.lzma, |
| .uncompressed_size = coder->options |
| .uncompressed_size, |
| }, { |
| .init = NULL, |
| } |
| }; |
| |
| const lzma_ret ret = lzma_next_filter_init(&coder->next, |
| allocator, filters); |
| if (ret != LZMA_OK) |
| return ret; |
| |
| coder->sequence = SEQ_CODE; |
| } |
| |
| // Fall through |
| |
| case SEQ_CODE: { |
| return coder->next.code(coder->next.coder, |
| allocator, in, in_pos, in_size, |
| out, out_pos, out_size, action); |
| } |
| |
| default: |
| return LZMA_PROG_ERROR; |
| } |
| |
| return LZMA_OK; |
| } |
| |
| |
| static void |
| alone_decoder_end(lzma_coder *coder, lzma_allocator *allocator) |
| { |
| lzma_next_coder_end(&coder->next, allocator); |
| lzma_free(coder, allocator); |
| return; |
| } |
| |
| |
| static lzma_ret |
| alone_decoder_init(lzma_next_coder *next, lzma_allocator *allocator) |
| { |
| if (next->coder == NULL) { |
| next->coder = lzma_alloc(sizeof(lzma_coder), allocator); |
| if (next->coder == NULL) |
| return LZMA_MEM_ERROR; |
| |
| next->code = &alone_decode; |
| next->end = &alone_decoder_end; |
| next->coder->next = LZMA_NEXT_CODER_INIT; |
| } |
| |
| next->coder->sequence = SEQ_PROPERTIES; |
| next->coder->pos = 0; |
| next->coder->options.lzma.dictionary_size = 0; |
| next->coder->options.uncompressed_size = 0; |
| |
| return LZMA_OK; |
| } |
| |
| |
| extern lzma_ret |
| lzma_alone_decoder_init(lzma_next_coder *next, lzma_allocator *allocator) |
| { |
| // We need to use _init2 because we don't pass any varadic args. |
| lzma_next_coder_init2(next, allocator, alone_decoder_init, |
| alone_decoder_init, allocator); |
| } |
| |
| |
| extern LZMA_API lzma_ret |
| lzma_alone_decoder(lzma_stream *strm) |
| { |
| lzma_next_strm_init2(strm, alone_decoder_init, |
| alone_decoder_init, strm->allocator); |
| |
| strm->internal->supported_actions[LZMA_RUN] = true; |
| strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true; |
| |
| return LZMA_OK; |
| } |