X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=lzma%2Flzma%2Flzma2_decoder.c;fp=lzma%2Flzma%2Flzma2_decoder.c;h=84982d2c4286146bda1b757b8dedec1893000309;hb=32b8a6b26ed8843828e03e505d2256960bda0980;hp=0000000000000000000000000000000000000000;hpb=d48fc23a4bcf8ca3c406d6e8c8a6f8c6b0fa2f1e;p=zpackage diff --git a/lzma/lzma/lzma2_decoder.c b/lzma/lzma/lzma2_decoder.c new file mode 100644 index 0000000..84982d2 --- /dev/null +++ b/lzma/lzma/lzma2_decoder.c @@ -0,0 +1,304 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lzma2_decoder.c +/// \brief LZMA2 decoder +/// +// Authors: Igor Pavlov +// Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "lzma2_decoder.h" +#include "lz_decoder.h" +#include "lzma_decoder.h" + + +struct lzma_coder_s { + enum sequence { + SEQ_CONTROL, + SEQ_UNCOMPRESSED_1, + SEQ_UNCOMPRESSED_2, + SEQ_COMPRESSED_0, + SEQ_COMPRESSED_1, + SEQ_PROPERTIES, + SEQ_LZMA, + SEQ_COPY, + } sequence; + + /// Sequence after the size fields have been decoded. + enum sequence next_sequence; + + /// LZMA decoder + lzma_lz_decoder lzma; + + /// Uncompressed size of LZMA chunk + size_t uncompressed_size; + + /// Compressed size of the chunk (naturally equals to uncompressed + /// size of uncompressed chunk) + size_t compressed_size; + + /// True if properties are needed. This is false before the + /// first LZMA chunk. + bool need_properties; + + /// True if dictionary reset is needed. This is false before the + /// first chunk (LZMA or uncompressed). + bool need_dictionary_reset; + + lzma_options_lzma options; +}; + + +static lzma_ret +lzma2_decode(lzma_coder *restrict coder, lzma_dict *restrict dict, + const uint8_t *restrict in, size_t *restrict in_pos, + size_t in_size) +{ + // With SEQ_LZMA it is possible that no new input is needed to do + // some progress. The rest of the sequences assume that there is + // at least one byte of input. + while (*in_pos < in_size || coder->sequence == SEQ_LZMA) + switch (coder->sequence) { + case SEQ_CONTROL: { + const uint32_t control = in[*in_pos]; + ++*in_pos; + + // End marker + if (control == 0x00) + return LZMA_STREAM_END; + + if (control >= 0xE0 || control == 1) { + // Dictionary reset implies that next LZMA chunk has + // to set new properties. + coder->need_properties = true; + coder->need_dictionary_reset = true; + } else if (coder->need_dictionary_reset) { + return LZMA_DATA_ERROR; + } + + if (control >= 0x80) { + // LZMA chunk. The highest five bits of the + // uncompressed size are taken from the control byte. + coder->uncompressed_size = (control & 0x1F) << 16; + coder->sequence = SEQ_UNCOMPRESSED_1; + + // See if there are new properties or if we need to + // reset the state. + if (control >= 0xC0) { + // When there are new properties, state reset + // is done at SEQ_PROPERTIES. + coder->need_properties = false; + coder->next_sequence = SEQ_PROPERTIES; + + } else if (coder->need_properties) { + return LZMA_DATA_ERROR; + + } else { + coder->next_sequence = SEQ_LZMA; + + // If only state reset is wanted with old + // properties, do the resetting here for + // simplicity. + if (control >= 0xA0) + coder->lzma.reset(coder->lzma.coder, + &coder->options); + } + } else { + // Invalid control values + if (control > 2) + return LZMA_DATA_ERROR; + + // It's uncompressed chunk + coder->sequence = SEQ_COMPRESSED_0; + coder->next_sequence = SEQ_COPY; + } + + if (coder->need_dictionary_reset) { + // Finish the dictionary reset and let the caller + // flush the dictionary to the actual output buffer. + coder->need_dictionary_reset = false; + dict_reset(dict); + return LZMA_OK; + } + + break; + } + + case SEQ_UNCOMPRESSED_1: + coder->uncompressed_size += (uint32_t)(in[(*in_pos)++]) << 8; + coder->sequence = SEQ_UNCOMPRESSED_2; + break; + + case SEQ_UNCOMPRESSED_2: + coder->uncompressed_size += in[(*in_pos)++] + 1; + coder->sequence = SEQ_COMPRESSED_0; + coder->lzma.set_uncompressed(coder->lzma.coder, + coder->uncompressed_size); + break; + + case SEQ_COMPRESSED_0: + coder->compressed_size = (uint32_t)(in[(*in_pos)++]) << 8; + coder->sequence = SEQ_COMPRESSED_1; + break; + + case SEQ_COMPRESSED_1: + coder->compressed_size += in[(*in_pos)++] + 1; + coder->sequence = coder->next_sequence; + break; + + case SEQ_PROPERTIES: + if (lzma_lzma_lclppb_decode(&coder->options, in[(*in_pos)++])) + return LZMA_DATA_ERROR; + + coder->lzma.reset(coder->lzma.coder, &coder->options); + + coder->sequence = SEQ_LZMA; + break; + + case SEQ_LZMA: { + // Store the start offset so that we can update + // coder->compressed_size later. + const size_t in_start = *in_pos; + + // Decode from in[] to *dict. + const lzma_ret ret = coder->lzma.code(coder->lzma.coder, + dict, in, in_pos, in_size); + + // Validate and update coder->compressed_size. + const size_t in_used = *in_pos - in_start; + if (in_used > coder->compressed_size) + return LZMA_DATA_ERROR; + + coder->compressed_size -= in_used; + + // Return if we didn't finish the chunk, or an error occurred. + if (ret != LZMA_STREAM_END) + return ret; + + // The LZMA decoder must have consumed the whole chunk now. + // We don't need to worry about uncompressed size since it + // is checked by the LZMA decoder. + if (coder->compressed_size != 0) + return LZMA_DATA_ERROR; + + coder->sequence = SEQ_CONTROL; + break; + } + + case SEQ_COPY: { + // Copy from input to the dictionary as is. + dict_write(dict, in, in_pos, in_size, &coder->compressed_size); + if (coder->compressed_size != 0) + return LZMA_OK; + + coder->sequence = SEQ_CONTROL; + break; + } + + default: + assert(0); + return LZMA_PROG_ERROR; + } + + return LZMA_OK; +} + + +static void +lzma2_decoder_end(lzma_coder *coder, const lzma_allocator *allocator) +{ + assert(coder->lzma.end == NULL); + lzma_free(coder->lzma.coder, allocator); + + lzma_free(coder, allocator); + + return; +} + + +static lzma_ret +lzma2_decoder_init(lzma_lz_decoder *lz, const lzma_allocator *allocator, + const void *opt, lzma_lz_options *lz_options) +{ + if (lz->coder == NULL) { + lz->coder = lzma_alloc(sizeof(lzma_coder), allocator); + if (lz->coder == NULL) + return LZMA_MEM_ERROR; + + lz->code = &lzma2_decode; + lz->end = &lzma2_decoder_end; + + lz->coder->lzma = LZMA_LZ_DECODER_INIT; + } + + const lzma_options_lzma *options = opt; + + lz->coder->sequence = SEQ_CONTROL; + lz->coder->need_properties = true; + lz->coder->need_dictionary_reset = options->preset_dict == NULL + || options->preset_dict_size == 0; + + return lzma_lzma_decoder_create(&lz->coder->lzma, + allocator, options, lz_options); +} + + +extern lzma_ret +lzma_lzma2_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator, + const lzma_filter_info *filters) +{ + // LZMA2 can only be the last filter in the chain. This is enforced + // by the raw_decoder initialization. + assert(filters[1].init == NULL); + + return lzma_lz_decoder_init(next, allocator, filters, + &lzma2_decoder_init); +} + + +extern uint64_t +lzma_lzma2_decoder_memusage(const void *options) +{ + return sizeof(lzma_coder) + + lzma_lzma_decoder_memusage_nocheck(options); +} + + +extern lzma_ret +lzma_lzma2_props_decode(void **options, const lzma_allocator *allocator, + const uint8_t *props, size_t props_size) +{ + if (props_size != 1) + return LZMA_OPTIONS_ERROR; + + // Check that reserved bits are unset. + if (props[0] & 0xC0) + return LZMA_OPTIONS_ERROR; + + // Decode the dictionary size. + if (props[0] > 40) + return LZMA_OPTIONS_ERROR; + + lzma_options_lzma *opt = lzma_alloc( + sizeof(lzma_options_lzma), allocator); + if (opt == NULL) + return LZMA_MEM_ERROR; + + if (props[0] == 40) { + opt->dict_size = UINT32_MAX; + } else { + opt->dict_size = 2 | (props[0] & 1); + opt->dict_size <<= props[0] / 2 + 11; + } + + opt->preset_dict = NULL; + opt->preset_dict_size = 0; + + *options = opt; + + return LZMA_OK; +}