X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=lzma%2Flz%2Flz_encoder.c;fp=lzma%2Flz%2Flz_encoder.c;h=5a2be798fd8e9918e3d7c296b98f75871782746f;hb=32b8a6b26ed8843828e03e505d2256960bda0980;hp=0000000000000000000000000000000000000000;hpb=d48fc23a4bcf8ca3c406d6e8c8a6f8c6b0fa2f1e;p=zpackage diff --git a/lzma/lz/lz_encoder.c b/lzma/lz/lz_encoder.c new file mode 100644 index 0000000..5a2be79 --- /dev/null +++ b/lzma/lz/lz_encoder.c @@ -0,0 +1,609 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lz_encoder.c +/// \brief LZ in window +/// +// Authors: Igor Pavlov +// Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "lz_encoder.h" +#include "lz_encoder_hash.h" + +// See lz_encoder_hash.h. This is a bit hackish but avoids making +// endianness a conditional in makefiles. +#if defined(WORDS_BIGENDIAN) && !defined(HAVE_SMALL) +# include "lz_encoder_hash_table.h" +#endif + +#include "memcmplen.h" + + +struct lzma_coder_s { + /// LZ-based encoder e.g. LZMA + lzma_lz_encoder lz; + + /// History buffer and match finder + lzma_mf mf; + + /// Next coder in the chain + lzma_next_coder next; +}; + + +/// \brief Moves the data in the input window to free space for new data +/// +/// mf->buffer is a sliding input window, which keeps mf->keep_size_before +/// bytes of input history available all the time. Now and then we need to +/// "slide" the buffer to make space for the new data to the end of the +/// buffer. At the same time, data older than keep_size_before is dropped. +/// +static void +move_window(lzma_mf *mf) +{ + // Align the move to a multiple of 16 bytes. Some LZ-based encoders + // like LZMA use the lowest bits of mf->read_pos to know the + // alignment of the uncompressed data. We also get better speed + // for memmove() with aligned buffers. + assert(mf->read_pos > mf->keep_size_before); + const uint32_t move_offset + = (mf->read_pos - mf->keep_size_before) & ~UINT32_C(15); + + assert(mf->write_pos > move_offset); + const size_t move_size = mf->write_pos - move_offset; + + assert(move_offset + move_size <= mf->size); + + memmove(mf->buffer, mf->buffer + move_offset, move_size); + + mf->offset += move_offset; + mf->read_pos -= move_offset; + mf->read_limit -= move_offset; + mf->write_pos -= move_offset; + + return; +} + + +/// \brief Tries to fill the input window (mf->buffer) +/// +/// If we are the last encoder in the chain, our input data is in in[]. +/// Otherwise we call the next filter in the chain to process in[] and +/// write its output to mf->buffer. +/// +/// This function must not be called once it has returned LZMA_STREAM_END. +/// +static lzma_ret +fill_window(lzma_coder *coder, const lzma_allocator *allocator, + const uint8_t *in, size_t *in_pos, size_t in_size, + lzma_action action) +{ + assert(coder->mf.read_pos <= coder->mf.write_pos); + + // Move the sliding window if needed. + if (coder->mf.read_pos >= coder->mf.size - coder->mf.keep_size_after) + move_window(&coder->mf); + + // Maybe this is ugly, but lzma_mf uses uint32_t for most things + // (which I find cleanest), but we need size_t here when filling + // the history window. + size_t write_pos = coder->mf.write_pos; + lzma_ret ret; + if (coder->next.code == NULL) { + // Not using a filter, simply memcpy() as much as possible. + lzma_bufcpy(in, in_pos, in_size, coder->mf.buffer, + &write_pos, coder->mf.size); + + ret = action != LZMA_RUN && *in_pos == in_size + ? LZMA_STREAM_END : LZMA_OK; + + } else { + ret = coder->next.code(coder->next.coder, allocator, + in, in_pos, in_size, + coder->mf.buffer, &write_pos, + coder->mf.size, action); + } + + coder->mf.write_pos = write_pos; + + // Silence Valgrind. lzma_memcmplen() can read extra bytes + // and Valgrind will give warnings if those bytes are uninitialized + // because Valgrind cannot see that the values of the uninitialized + // bytes are eventually ignored. + memzero(coder->mf.buffer + write_pos, LZMA_MEMCMPLEN_EXTRA); + + // If end of stream has been reached or flushing completed, we allow + // the encoder to process all the input (that is, read_pos is allowed + // to reach write_pos). Otherwise we keep keep_size_after bytes + // available as prebuffer. + if (ret == LZMA_STREAM_END) { + assert(*in_pos == in_size); + ret = LZMA_OK; + coder->mf.action = action; + coder->mf.read_limit = coder->mf.write_pos; + + } else if (coder->mf.write_pos > coder->mf.keep_size_after) { + // This needs to be done conditionally, because if we got + // only little new input, there may be too little input + // to do any encoding yet. + coder->mf.read_limit = coder->mf.write_pos + - coder->mf.keep_size_after; + } + + // Restart the match finder after finished LZMA_SYNC_FLUSH. + if (coder->mf.pending > 0 + && coder->mf.read_pos < coder->mf.read_limit) { + // Match finder may update coder->pending and expects it to + // start from zero, so use a temporary variable. + const uint32_t pending = coder->mf.pending; + coder->mf.pending = 0; + + // Rewind read_pos so that the match finder can hash + // the pending bytes. + assert(coder->mf.read_pos >= pending); + coder->mf.read_pos -= pending; + + // Call the skip function directly instead of using + // mf_skip(), since we don't want to touch mf->read_ahead. + coder->mf.skip(&coder->mf, pending); + } + + return ret; +} + + +static lzma_ret +lz_encode(lzma_coder *coder, 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) +{ + while (*out_pos < out_size + && (*in_pos < in_size || action != LZMA_RUN)) { + // Read more data to coder->mf.buffer if needed. + if (coder->mf.action == LZMA_RUN && coder->mf.read_pos + >= coder->mf.read_limit) + return_if_error(fill_window(coder, allocator, + in, in_pos, in_size, action)); + + // Encode + const lzma_ret ret = coder->lz.code(coder->lz.coder, + &coder->mf, out, out_pos, out_size); + if (ret != LZMA_OK) { + // Setting this to LZMA_RUN for cases when we are + // flushing. It doesn't matter when finishing or if + // an error occurred. + coder->mf.action = LZMA_RUN; + return ret; + } + } + + return LZMA_OK; +} + + +static bool +lz_encoder_prepare(lzma_mf *mf, const lzma_allocator *allocator, + const lzma_lz_options *lz_options) +{ + // For now, the dictionary size is limited to 1.5 GiB. This may grow + // in the future if needed, but it needs a little more work than just + // changing this check. + if (lz_options->dict_size < LZMA_DICT_SIZE_MIN + || lz_options->dict_size + > (UINT32_C(1) << 30) + (UINT32_C(1) << 29) + || lz_options->nice_len > lz_options->match_len_max) + return true; + + mf->keep_size_before = lz_options->before_size + lz_options->dict_size; + + mf->keep_size_after = lz_options->after_size + + lz_options->match_len_max; + + // To avoid constant memmove()s, allocate some extra space. Since + // memmove()s become more expensive when the size of the buffer + // increases, we reserve more space when a large dictionary is + // used to make the memmove() calls rarer. + // + // This works with dictionaries up to about 3 GiB. If bigger + // dictionary is wanted, some extra work is needed: + // - Several variables in lzma_mf have to be changed from uint32_t + // to size_t. + // - Memory usage calculation needs something too, e.g. use uint64_t + // for mf->size. + uint32_t reserve = lz_options->dict_size / 2; + if (reserve > (UINT32_C(1) << 30)) + reserve /= 2; + + reserve += (lz_options->before_size + lz_options->match_len_max + + lz_options->after_size) / 2 + (UINT32_C(1) << 19); + + const uint32_t old_size = mf->size; + mf->size = mf->keep_size_before + reserve + mf->keep_size_after; + + // Deallocate the old history buffer if it exists but has different + // size than what is needed now. + if (mf->buffer != NULL && old_size != mf->size) { + lzma_free(mf->buffer, allocator); + mf->buffer = NULL; + } + + // Match finder options + mf->match_len_max = lz_options->match_len_max; + mf->nice_len = lz_options->nice_len; + + // cyclic_size has to stay smaller than 2 Gi. Note that this doesn't + // mean limiting dictionary size to less than 2 GiB. With a match + // finder that uses multibyte resolution (hashes start at e.g. every + // fourth byte), cyclic_size would stay below 2 Gi even when + // dictionary size is greater than 2 GiB. + // + // It would be possible to allow cyclic_size >= 2 Gi, but then we + // would need to be careful to use 64-bit types in various places + // (size_t could do since we would need bigger than 32-bit address + // space anyway). It would also require either zeroing a multigigabyte + // buffer at initialization (waste of time and RAM) or allow + // normalization in lz_encoder_mf.c to access uninitialized + // memory to keep the code simpler. The current way is simple and + // still allows pretty big dictionaries, so I don't expect these + // limits to change. + mf->cyclic_size = lz_options->dict_size + 1; + + // Validate the match finder ID and setup the function pointers. + switch (lz_options->match_finder) { +#ifdef HAVE_MF_HC3 + case LZMA_MF_HC3: + mf->find = &lzma_mf_hc3_find; + mf->skip = &lzma_mf_hc3_skip; + break; +#endif +#ifdef HAVE_MF_HC4 + case LZMA_MF_HC4: + mf->find = &lzma_mf_hc4_find; + mf->skip = &lzma_mf_hc4_skip; + break; +#endif +#ifdef HAVE_MF_BT2 + case LZMA_MF_BT2: + mf->find = &lzma_mf_bt2_find; + mf->skip = &lzma_mf_bt2_skip; + break; +#endif +#ifdef HAVE_MF_BT3 + case LZMA_MF_BT3: + mf->find = &lzma_mf_bt3_find; + mf->skip = &lzma_mf_bt3_skip; + break; +#endif +#ifdef HAVE_MF_BT4 + case LZMA_MF_BT4: + mf->find = &lzma_mf_bt4_find; + mf->skip = &lzma_mf_bt4_skip; + break; +#endif + + default: + return true; + } + + // Calculate the sizes of mf->hash and mf->son and check that + // nice_len is big enough for the selected match finder. + const uint32_t hash_bytes = lz_options->match_finder & 0x0F; + if (hash_bytes > mf->nice_len) + return true; + + const bool is_bt = (lz_options->match_finder & 0x10) != 0; + uint32_t hs; + + if (hash_bytes == 2) { + hs = 0xFFFF; + } else { + // Round dictionary size up to the next 2^n - 1 so it can + // be used as a hash mask. + hs = lz_options->dict_size - 1; + hs |= hs >> 1; + hs |= hs >> 2; + hs |= hs >> 4; + hs |= hs >> 8; + hs >>= 1; + hs |= 0xFFFF; + + if (hs > (UINT32_C(1) << 24)) { + if (hash_bytes == 3) + hs = (UINT32_C(1) << 24) - 1; + else + hs >>= 1; + } + } + + mf->hash_mask = hs; + + ++hs; + if (hash_bytes > 2) + hs += HASH_2_SIZE; + if (hash_bytes > 3) + hs += HASH_3_SIZE; +/* + No match finder uses this at the moment. + if (mf->hash_bytes > 4) + hs += HASH_4_SIZE; +*/ + + const uint32_t old_hash_count = mf->hash_count; + const uint32_t old_sons_count = mf->sons_count; + mf->hash_count = hs; + mf->sons_count = mf->cyclic_size; + if (is_bt) + mf->sons_count *= 2; + + // Deallocate the old hash array if it exists and has different size + // than what is needed now. + if (old_hash_count != mf->hash_count + || old_sons_count != mf->sons_count) { + lzma_free(mf->hash, allocator); + mf->hash = NULL; + + lzma_free(mf->son, allocator); + mf->son = NULL; + } + + // Maximum number of match finder cycles + mf->depth = lz_options->depth; + if (mf->depth == 0) { + if (is_bt) + mf->depth = 16 + mf->nice_len / 2; + else + mf->depth = 4 + mf->nice_len / 4; + } + + return false; +} + + +static bool +lz_encoder_init(lzma_mf *mf, const lzma_allocator *allocator, + const lzma_lz_options *lz_options) +{ + // Allocate the history buffer. + if (mf->buffer == NULL) { + // lzma_memcmplen() is used for the dictionary buffer + // so we need to allocate a few extra bytes to prevent + // it from reading past the end of the buffer. + mf->buffer = lzma_alloc(mf->size + LZMA_MEMCMPLEN_EXTRA, + allocator); + if (mf->buffer == NULL) + return true; + + // Keep Valgrind happy with lzma_memcmplen() and initialize + // the extra bytes whose value may get read but which will + // effectively get ignored. + memzero(mf->buffer + mf->size, LZMA_MEMCMPLEN_EXTRA); + } + + // Use cyclic_size as initial mf->offset. This allows + // avoiding a few branches in the match finders. The downside is + // that match finder needs to be normalized more often, which may + // hurt performance with huge dictionaries. + mf->offset = mf->cyclic_size; + mf->read_pos = 0; + mf->read_ahead = 0; + mf->read_limit = 0; + mf->write_pos = 0; + mf->pending = 0; + +#if UINT32_MAX >= SIZE_MAX / 4 + // Check for integer overflow. (Huge dictionaries are not + // possible on 32-bit CPU.) + if (mf->hash_count > SIZE_MAX / sizeof(uint32_t) + || mf->sons_count > SIZE_MAX / sizeof(uint32_t)) + return true; +#endif + + // Allocate and initialize the hash table. Since EMPTY_HASH_VALUE + // is zero, we can use lzma_alloc_zero() or memzero() for mf->hash. + // + // We don't need to initialize mf->son, but not doing that may + // make Valgrind complain in normalization (see normalize() in + // lz_encoder_mf.c). Skipping the initialization is *very* good + // when big dictionary is used but only small amount of data gets + // actually compressed: most of the mf->son won't get actually + // allocated by the kernel, so we avoid wasting RAM and improve + // initialization speed a lot. + if (mf->hash == NULL) { + mf->hash = lzma_alloc_zero(mf->hash_count * sizeof(uint32_t), + allocator); + mf->son = lzma_alloc(mf->sons_count * sizeof(uint32_t), + allocator); + + if (mf->hash == NULL || mf->son == NULL) { + lzma_free(mf->hash, allocator); + mf->hash = NULL; + + lzma_free(mf->son, allocator); + mf->son = NULL; + + return true; + } + } else { +/* + for (uint32_t i = 0; i < mf->hash_count; ++i) + mf->hash[i] = EMPTY_HASH_VALUE; +*/ + memzero(mf->hash, mf->hash_count * sizeof(uint32_t)); + } + + mf->cyclic_pos = 0; + + // Handle preset dictionary. + if (lz_options->preset_dict != NULL + && lz_options->preset_dict_size > 0) { + // If the preset dictionary is bigger than the actual + // dictionary, use only the tail. + mf->write_pos = my_min(lz_options->preset_dict_size, mf->size); + memcpy(mf->buffer, lz_options->preset_dict + + lz_options->preset_dict_size - mf->write_pos, + mf->write_pos); + mf->action = LZMA_SYNC_FLUSH; + mf->skip(mf, mf->write_pos); + } + + mf->action = LZMA_RUN; + + return false; +} + + +extern uint64_t +lzma_lz_encoder_memusage(const lzma_lz_options *lz_options) +{ + // Old buffers must not exist when calling lz_encoder_prepare(). + lzma_mf mf = { + .buffer = NULL, + .hash = NULL, + .son = NULL, + .hash_count = 0, + .sons_count = 0, + }; + + // Setup the size information into mf. + if (lz_encoder_prepare(&mf, NULL, lz_options)) + return UINT64_MAX; + + // Calculate the memory usage. + return ((uint64_t)(mf.hash_count) + mf.sons_count) * sizeof(uint32_t) + + mf.size + sizeof(lzma_coder); +} + + +static void +lz_encoder_end(lzma_coder *coder, const lzma_allocator *allocator) +{ + lzma_next_end(&coder->next, allocator); + + lzma_free(coder->mf.son, allocator); + lzma_free(coder->mf.hash, allocator); + lzma_free(coder->mf.buffer, allocator); + + if (coder->lz.end != NULL) + coder->lz.end(coder->lz.coder, allocator); + else + lzma_free(coder->lz.coder, allocator); + + lzma_free(coder, allocator); + return; +} + + +static lzma_ret +lz_encoder_update(lzma_coder *coder, const lzma_allocator *allocator, + const lzma_filter *filters_null lzma_attribute((__unused__)), + const lzma_filter *reversed_filters) +{ + if (coder->lz.options_update == NULL) + return LZMA_PROG_ERROR; + + return_if_error(coder->lz.options_update( + coder->lz.coder, reversed_filters)); + + return lzma_next_filter_update( + &coder->next, allocator, reversed_filters + 1); +} + + +extern lzma_ret +lzma_lz_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator, + const lzma_filter_info *filters, + lzma_ret (*lz_init)(lzma_lz_encoder *lz, + const lzma_allocator *allocator, const void *options, + lzma_lz_options *lz_options)) +{ +#ifdef HAVE_SMALL + // We need that the CRC32 table has been initialized. + lzma_crc32_init(); +#endif + + // Allocate and initialize the base data structure. + if (next->coder == NULL) { + next->coder = lzma_alloc(sizeof(lzma_coder), allocator); + if (next->coder == NULL) + return LZMA_MEM_ERROR; + + next->code = &lz_encode; + next->end = &lz_encoder_end; + next->update = &lz_encoder_update; + + next->coder->lz.coder = NULL; + next->coder->lz.code = NULL; + next->coder->lz.end = NULL; + + // mf.size is initialized to silence Valgrind + // when used on optimized binaries (GCC may reorder + // code in a way that Valgrind gets unhappy). + next->coder->mf.buffer = NULL; + next->coder->mf.size = 0; + next->coder->mf.hash = NULL; + next->coder->mf.son = NULL; + next->coder->mf.hash_count = 0; + next->coder->mf.sons_count = 0; + + next->coder->next = LZMA_NEXT_CODER_INIT; + } + + // Initialize the LZ-based encoder. + lzma_lz_options lz_options; + return_if_error(lz_init(&next->coder->lz, allocator, + filters[0].options, &lz_options)); + + // Setup the size information into next->coder->mf and deallocate + // old buffers if they have wrong size. + if (lz_encoder_prepare(&next->coder->mf, allocator, &lz_options)) + return LZMA_OPTIONS_ERROR; + + // Allocate new buffers if needed, and do the rest of + // the initialization. + if (lz_encoder_init(&next->coder->mf, allocator, &lz_options)) + return LZMA_MEM_ERROR; + + // Initialize the next filter in the chain, if any. + return lzma_next_filter_init(&next->coder->next, allocator, + filters + 1); +} + + +extern LZMA_API(lzma_bool) +lzma_mf_is_supported(lzma_match_finder mf) +{ + bool ret = false; + +#ifdef HAVE_MF_HC3 + if (mf == LZMA_MF_HC3) + ret = true; +#endif + +#ifdef HAVE_MF_HC4 + if (mf == LZMA_MF_HC4) + ret = true; +#endif + +#ifdef HAVE_MF_BT2 + if (mf == LZMA_MF_BT2) + ret = true; +#endif + +#ifdef HAVE_MF_BT3 + if (mf == LZMA_MF_BT3) + ret = true; +#endif + +#ifdef HAVE_MF_BT4 + if (mf == LZMA_MF_BT4) + ret = true; +#endif + + return ret; +}