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Diffstat (limited to 'src/liblzma/common/erofs_decoder.c')
-rw-r--r-- | src/liblzma/common/erofs_decoder.c | 219 |
1 files changed, 0 insertions, 219 deletions
diff --git a/src/liblzma/common/erofs_decoder.c b/src/liblzma/common/erofs_decoder.c deleted file mode 100644 index 9264adda..00000000 --- a/src/liblzma/common/erofs_decoder.c +++ /dev/null @@ -1,219 +0,0 @@ -/////////////////////////////////////////////////////////////////////////////// -// -/// \file erofs_decoder.c -/// \brief Decode EROFS LZMA format -// -// Author: Lasse Collin -// -// This file has been put into the public domain. -// You can do whatever you want with this file. -// -/////////////////////////////////////////////////////////////////////////////// - -#include "lzma_decoder.h" -#include "lz_decoder.h" - - -typedef struct { - /// LZMA1 decoder - lzma_next_coder lzma; - - /// Compressed size of the stream as given by the application. - /// This must be exactly correct. - /// - /// This will be decremented when input is read. - uint64_t comp_size; - - /// Uncompressed size of the stream as given by the application. - /// This may be less than the actual uncompressed size if - /// uncomp_size_is_exact is false. - /// - /// This will be decremented when output is produced. - lzma_vli uncomp_size; - - /// LZMA dictionary size as given by the application - uint32_t dict_size; - - /// If true, the exact uncompressed size is known. If false, - /// uncomp_size may be smaller than the real uncompressed size; - /// uncomp_size may never be bigger than the real uncompressed size. - bool uncomp_size_is_exact; - - /// True once the first byte of the EROFS LZMA stream - /// has been processed. - bool props_decoded; -} lzma_erofs_coder; - - -static lzma_ret -erofs_decode(void *coder_ptr, const 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) -{ - lzma_erofs_coder *coder = coder_ptr; - - // Remember the in start position so that we can update comp_size. - const size_t in_start = *in_pos; - - // Remember the out start position so that we can update uncomp_size. - const size_t out_start = *out_pos; - - // Limit the amount of input so that the decoder won't read more than - // comp_size. This is required when uncomp_size isn't exact because - // in that case the LZMA decoder will try to decode more input even - // when it has no output space (it can be looking for EOPM). - if (in_size - *in_pos > coder->comp_size) - in_size = *in_pos + (size_t)(coder->comp_size); - - // When the exact uncompressed size isn't known, we must limit - // the available output space to prevent the LZMA decoder from - // trying to decode too much. - if (!coder->uncomp_size_is_exact - && out_size - *out_pos > coder->uncomp_size) - out_size = *out_pos + (size_t)(coder->uncomp_size); - - if (!coder->props_decoded) { - // There must be at least one byte of input to decode - // the properties byte. - if (*in_pos >= in_size) - return LZMA_OK; - - lzma_options_lzma options = { - .preset_dict = NULL, - .preset_dict_size = 0, - }; - - // The properties are stored as bitwise-negation - // of the typical encoding. - if (lzma_lzma_lclppb_decode(&options, ~in[*in_pos])) - return LZMA_OPTIONS_ERROR; - - ++*in_pos; - - // Initialize the decoder. - options.dict_size = coder->dict_size; - lzma_filter_info filters[2] = { - { - .init = &lzma_lzma_decoder_init, - .options = &options, - }, { - .init = NULL, - } - }; - - return_if_error(lzma_next_filter_init(&coder->lzma, - allocator, filters)); - - // Use a hack to set the uncompressed size. - if (coder->uncomp_size_is_exact) - lzma_lz_decoder_uncompressed(coder->lzma.coder, - coder->uncomp_size); - - // Pass one dummy 0x00 byte to the LZMA decoder since that - // is what it expects the first byte to be. - const uint8_t dummy_in = 0; - size_t dummy_in_pos = 0; - if (coder->lzma.code(coder->lzma.coder, allocator, - &dummy_in, &dummy_in_pos, 1, - out, out_pos, out_size, LZMA_RUN) != LZMA_OK) - return LZMA_PROG_ERROR; - - assert(dummy_in_pos == 1); - coder->props_decoded = true; - } - - // The rest is normal LZMA decoding. - lzma_ret ret = coder->lzma.code(coder->lzma.coder, allocator, - in, in_pos, in_size, - out, out_pos, out_size, action); - - // Update the remaining compressed size. - assert(coder->comp_size >= *in_pos - in_start); - coder->comp_size -= *in_pos - in_start; - - if (coder->uncomp_size_is_exact) { - // After successful decompression of the complete stream - // the compressed size must match. - if (ret == LZMA_STREAM_END && coder->comp_size != 0) - ret = LZMA_DATA_ERROR; - } else { - // Update the amount of output remaining. - assert(coder->uncomp_size >= *out_pos - out_start); - coder->uncomp_size -= *out_pos - out_start; - - // - We must not get LZMA_STREAM_END because the stream - // shouldn't have EOPM. - // - We must use uncomp_size to determine when to - // return LZMA_STREAM_END. - if (ret == LZMA_STREAM_END) - ret = LZMA_DATA_ERROR; - else if (coder->uncomp_size == 0) - ret = LZMA_STREAM_END; - } - - return ret; -} - - -static void -erofs_decoder_end(void *coder_ptr, const lzma_allocator *allocator) -{ - lzma_erofs_coder *coder = coder_ptr; - lzma_next_end(&coder->lzma, allocator); - lzma_free(coder, allocator); - return; -} - - -static lzma_ret -erofs_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator, - uint64_t comp_size, - uint64_t uncomp_size, bool uncomp_size_is_exact, - uint32_t dict_size) -{ - lzma_next_coder_init(&erofs_decoder_init, next, allocator); - - lzma_erofs_coder *coder = next->coder; - - if (coder == NULL) { - coder = lzma_alloc(sizeof(lzma_erofs_coder), allocator); - if (coder == NULL) - return LZMA_MEM_ERROR; - - next->coder = coder; - next->code = &erofs_decode; - next->end = &erofs_decoder_end; - - coder->lzma = LZMA_NEXT_CODER_INIT; - } - - // The public API is uint64_t but the internal LZ decoder API uses - // lzma_vli. - if (uncomp_size > LZMA_VLI_MAX) - return LZMA_OPTIONS_ERROR; - - coder->comp_size = comp_size; - coder->uncomp_size = uncomp_size; - coder->uncomp_size_is_exact = uncomp_size_is_exact; - coder->dict_size = dict_size; - - coder->props_decoded = false; - - return LZMA_OK; -} - - -extern LZMA_API(lzma_ret) -lzma_erofs_decoder(lzma_stream *strm, uint64_t comp_size, - uint64_t uncomp_size, lzma_bool uncomp_size_is_exact, - uint32_t dict_size) -{ - lzma_next_strm_init(erofs_decoder_init, strm, comp_size, - uncomp_size, uncomp_size_is_exact, dict_size); - - strm->internal->supported_actions[LZMA_RUN] = true; - strm->internal->supported_actions[LZMA_FINISH] = true; - - return LZMA_OK; -} |