diff options
Diffstat (limited to 'src/liblzma/lz')
| -rw-r--r-- | src/liblzma/lz/Makefile.inc | 22 | ||||
| -rw-r--r-- | src/liblzma/lz/lz_decoder.c | 304 | ||||
| -rw-r--r-- | src/liblzma/lz/lz_decoder.h | 234 | ||||
| -rw-r--r-- | src/liblzma/lz/lz_encoder.c | 633 | ||||
| -rw-r--r-- | src/liblzma/lz/lz_encoder.h | 341 | ||||
| -rw-r--r-- | src/liblzma/lz/lz_encoder_hash.h | 108 | ||||
| -rw-r--r-- | src/liblzma/lz/lz_encoder_hash_table.h | 68 | ||||
| -rw-r--r-- | src/liblzma/lz/lz_encoder_mf.c | 744 |
8 files changed, 2454 insertions, 0 deletions
diff --git a/src/liblzma/lz/Makefile.inc b/src/liblzma/lz/Makefile.inc new file mode 100644 index 0000000..75742a8 --- /dev/null +++ b/src/liblzma/lz/Makefile.inc @@ -0,0 +1,22 @@ +## +## Author: Lasse Collin +## +## This file has been put into the public domain. +## You can do whatever you want with this file. +## + +if COND_ENCODER_LZ +liblzma_la_SOURCES += \ + lz/lz_encoder.c \ + lz/lz_encoder.h \ + lz/lz_encoder_hash.h \ + lz/lz_encoder_hash_table.h \ + lz/lz_encoder_mf.c +endif + + +if COND_DECODER_LZ +liblzma_la_SOURCES += \ + lz/lz_decoder.c \ + lz/lz_decoder.h +endif diff --git a/src/liblzma/lz/lz_decoder.c b/src/liblzma/lz/lz_decoder.c new file mode 100644 index 0000000..06c95c1 --- /dev/null +++ b/src/liblzma/lz/lz_decoder.c @@ -0,0 +1,304 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lz_decoder.c +/// \brief LZ out window +/// +// Authors: Igor Pavlov +// Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +// liblzma supports multiple LZ77-based filters. The LZ part is shared +// between these filters. The LZ code takes care of dictionary handling +// and passing the data between filters in the chain. The filter-specific +// part decodes from the input buffer to the dictionary. + + +#include "lz_decoder.h" + + +typedef struct { + /// Dictionary (history buffer) + lzma_dict dict; + + /// The actual LZ-based decoder e.g. LZMA + lzma_lz_decoder lz; + + /// Next filter in the chain, if any. Note that LZMA and LZMA2 are + /// only allowed as the last filter, but the long-range filter in + /// future can be in the middle of the chain. + lzma_next_coder next; + + /// True if the next filter in the chain has returned LZMA_STREAM_END. + bool next_finished; + + /// True if the LZ decoder (e.g. LZMA) has detected end of payload + /// marker. This may become true before next_finished becomes true. + bool this_finished; + + /// Temporary buffer needed when the LZ-based filter is not the last + /// filter in the chain. The output of the next filter is first + /// decoded into buffer[], which is then used as input for the actual + /// LZ-based decoder. + struct { + size_t pos; + size_t size; + uint8_t buffer[LZMA_BUFFER_SIZE]; + } temp; +} lzma_coder; + + +static void +lz_decoder_reset(lzma_coder *coder) +{ + coder->dict.pos = 0; + coder->dict.full = 0; + coder->dict.buf[coder->dict.size - 1] = '\0'; + coder->dict.need_reset = false; + return; +} + + +static lzma_ret +decode_buffer(lzma_coder *coder, + 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) +{ + while (true) { + // Wrap the dictionary if needed. + if (coder->dict.pos == coder->dict.size) + coder->dict.pos = 0; + + // Store the current dictionary position. It is needed to know + // where to start copying to the out[] buffer. + const size_t dict_start = coder->dict.pos; + + // Calculate how much we allow coder->lz.code() to decode. + // It must not decode past the end of the dictionary + // buffer, and we don't want it to decode more than is + // actually needed to fill the out[] buffer. + coder->dict.limit = coder->dict.pos + + my_min(out_size - *out_pos, + coder->dict.size - coder->dict.pos); + + // Call the coder->lz.code() to do the actual decoding. + const lzma_ret ret = coder->lz.code( + coder->lz.coder, &coder->dict, + in, in_pos, in_size); + + // Copy the decoded data from the dictionary to the out[] + // buffer. Do it conditionally because out can be NULL + // (in which case copy_size is always 0). Calling memcpy() + // with a null-pointer is undefined even if the third + // argument is 0. + const size_t copy_size = coder->dict.pos - dict_start; + assert(copy_size <= out_size - *out_pos); + + if (copy_size > 0) + memcpy(out + *out_pos, coder->dict.buf + dict_start, + copy_size); + + *out_pos += copy_size; + + // Reset the dictionary if so requested by coder->lz.code(). + if (coder->dict.need_reset) { + lz_decoder_reset(coder); + + // Since we reset dictionary, we don't check if + // dictionary became full. + if (ret != LZMA_OK || *out_pos == out_size) + return ret; + } else { + // Return if everything got decoded or an error + // occurred, or if there's no more data to decode. + // + // Note that detecting if there's something to decode + // is done by looking if dictionary become full + // instead of looking if *in_pos == in_size. This + // is because it is possible that all the input was + // consumed already but some data is pending to be + // written to the dictionary. + if (ret != LZMA_OK || *out_pos == out_size + || coder->dict.pos < coder->dict.size) + return ret; + } + } +} + + +static lzma_ret +lz_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_coder *coder = coder_ptr; + + if (coder->next.code == NULL) + return decode_buffer(coder, in, in_pos, in_size, + out, out_pos, out_size); + + // We aren't the last coder in the chain, we need to decode + // our input to a temporary buffer. + while (*out_pos < out_size) { + // Fill the temporary buffer if it is empty. + if (!coder->next_finished + && coder->temp.pos == coder->temp.size) { + coder->temp.pos = 0; + coder->temp.size = 0; + + const lzma_ret ret = coder->next.code( + coder->next.coder, + allocator, in, in_pos, in_size, + coder->temp.buffer, &coder->temp.size, + LZMA_BUFFER_SIZE, action); + + if (ret == LZMA_STREAM_END) + coder->next_finished = true; + else if (ret != LZMA_OK || coder->temp.size == 0) + return ret; + } + + if (coder->this_finished) { + if (coder->temp.size != 0) + return LZMA_DATA_ERROR; + + if (coder->next_finished) + return LZMA_STREAM_END; + + return LZMA_OK; + } + + const lzma_ret ret = decode_buffer(coder, coder->temp.buffer, + &coder->temp.pos, coder->temp.size, + out, out_pos, out_size); + + if (ret == LZMA_STREAM_END) + coder->this_finished = true; + else if (ret != LZMA_OK) + return ret; + else if (coder->next_finished && *out_pos < out_size) + return LZMA_DATA_ERROR; + } + + return LZMA_OK; +} + + +static void +lz_decoder_end(void *coder_ptr, const lzma_allocator *allocator) +{ + lzma_coder *coder = coder_ptr; + + lzma_next_end(&coder->next, allocator); + lzma_free(coder->dict.buf, 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; +} + + +extern lzma_ret +lzma_lz_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator, + const lzma_filter_info *filters, + lzma_ret (*lz_init)(lzma_lz_decoder *lz, + const lzma_allocator *allocator, + lzma_vli id, const void *options, + lzma_lz_options *lz_options)) +{ + // Allocate the base structure if it isn't already allocated. + lzma_coder *coder = next->coder; + if (coder == NULL) { + coder = lzma_alloc(sizeof(lzma_coder), allocator); + if (coder == NULL) + return LZMA_MEM_ERROR; + + next->coder = coder; + next->code = &lz_decode; + next->end = &lz_decoder_end; + + coder->dict.buf = NULL; + coder->dict.size = 0; + coder->lz = LZMA_LZ_DECODER_INIT; + coder->next = LZMA_NEXT_CODER_INIT; + } + + // Allocate and initialize the LZ-based decoder. It will also give + // us the dictionary size. + lzma_lz_options lz_options; + return_if_error(lz_init(&coder->lz, allocator, + filters[0].id, filters[0].options, &lz_options)); + + // If the dictionary size is very small, increase it to 4096 bytes. + // This is to prevent constant wrapping of the dictionary, which + // would slow things down. The downside is that since we don't check + // separately for the real dictionary size, we may happily accept + // corrupt files. + if (lz_options.dict_size < 4096) + lz_options.dict_size = 4096; + + // Make dictionary size a multiple of 16. Some LZ-based decoders like + // LZMA use the lowest bits lzma_dict.pos to know the alignment of the + // data. Aligned buffer is also good when memcpying from the + // dictionary to the output buffer, since applications are + // recommended to give aligned buffers to liblzma. + // + // Avoid integer overflow. + if (lz_options.dict_size > SIZE_MAX - 15) + return LZMA_MEM_ERROR; + + lz_options.dict_size = (lz_options.dict_size + 15) & ~((size_t)(15)); + + // Allocate and initialize the dictionary. + if (coder->dict.size != lz_options.dict_size) { + lzma_free(coder->dict.buf, allocator); + coder->dict.buf + = lzma_alloc(lz_options.dict_size, allocator); + if (coder->dict.buf == NULL) + return LZMA_MEM_ERROR; + + coder->dict.size = lz_options.dict_size; + } + + lz_decoder_reset(next->coder); + + // Use the preset dictionary if it was given to us. + if (lz_options.preset_dict != NULL + && lz_options.preset_dict_size > 0) { + // If the preset dictionary is bigger than the actual + // dictionary, copy only the tail. + const size_t copy_size = my_min(lz_options.preset_dict_size, + lz_options.dict_size); + const size_t offset = lz_options.preset_dict_size - copy_size; + memcpy(coder->dict.buf, lz_options.preset_dict + offset, + copy_size); + coder->dict.pos = copy_size; + coder->dict.full = copy_size; + } + + // Miscellaneous initializations + coder->next_finished = false; + coder->this_finished = false; + coder->temp.pos = 0; + coder->temp.size = 0; + + // Initialize the next filter in the chain, if any. + return lzma_next_filter_init(&coder->next, allocator, filters + 1); +} + + +extern uint64_t +lzma_lz_decoder_memusage(size_t dictionary_size) +{ + return sizeof(lzma_coder) + (uint64_t)(dictionary_size); +} diff --git a/src/liblzma/lz/lz_decoder.h b/src/liblzma/lz/lz_decoder.h new file mode 100644 index 0000000..ad80d4d --- /dev/null +++ b/src/liblzma/lz/lz_decoder.h @@ -0,0 +1,234 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lz_decoder.h +/// \brief LZ out window +/// +// Authors: Igor Pavlov +// Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#ifndef LZMA_LZ_DECODER_H +#define LZMA_LZ_DECODER_H + +#include "common.h" + + +typedef struct { + /// Pointer to the dictionary buffer. It can be an allocated buffer + /// internal to liblzma, or it can a be a buffer given by the + /// application when in single-call mode (not implemented yet). + uint8_t *buf; + + /// Write position in dictionary. The next byte will be written to + /// buf[pos]. + size_t pos; + + /// Indicates how full the dictionary is. This is used by + /// dict_is_distance_valid() to detect corrupt files that would + /// read beyond the beginning of the dictionary. + size_t full; + + /// Write limit + size_t limit; + + /// Size of the dictionary + size_t size; + + /// True when dictionary should be reset before decoding more data. + bool need_reset; + +} lzma_dict; + + +typedef struct { + size_t dict_size; + const uint8_t *preset_dict; + size_t preset_dict_size; +} lzma_lz_options; + + +typedef struct { + /// Data specific to the LZ-based decoder + void *coder; + + /// Function to decode from in[] to *dict + lzma_ret (*code)(void *coder, + lzma_dict *restrict dict, const uint8_t *restrict in, + size_t *restrict in_pos, size_t in_size); + + void (*reset)(void *coder, const void *options); + + /// Set the uncompressed size. If uncompressed_size == LZMA_VLI_UNKNOWN + /// then allow_eopm will always be true. + void (*set_uncompressed)(void *coder, lzma_vli uncompressed_size, + bool allow_eopm); + + /// Free allocated resources + void (*end)(void *coder, const lzma_allocator *allocator); + +} lzma_lz_decoder; + + +#define LZMA_LZ_DECODER_INIT \ + (lzma_lz_decoder){ \ + .coder = NULL, \ + .code = NULL, \ + .reset = NULL, \ + .set_uncompressed = NULL, \ + .end = NULL, \ + } + + +extern lzma_ret lzma_lz_decoder_init(lzma_next_coder *next, + const lzma_allocator *allocator, + const lzma_filter_info *filters, + lzma_ret (*lz_init)(lzma_lz_decoder *lz, + const lzma_allocator *allocator, + lzma_vli id, const void *options, + lzma_lz_options *lz_options)); + +extern uint64_t lzma_lz_decoder_memusage(size_t dictionary_size); + + +////////////////////// +// Inline functions // +////////////////////// + +/// Get a byte from the history buffer. +static inline uint8_t +dict_get(const lzma_dict *const dict, const uint32_t distance) +{ + return dict->buf[dict->pos - distance - 1 + + (distance < dict->pos ? 0 : dict->size)]; +} + + +/// Test if dictionary is empty. +static inline bool +dict_is_empty(const lzma_dict *const dict) +{ + return dict->full == 0; +} + + +/// Validate the match distance +static inline bool +dict_is_distance_valid(const lzma_dict *const dict, const size_t distance) +{ + return dict->full > distance; +} + + +/// Repeat *len bytes at distance. +static inline bool +dict_repeat(lzma_dict *dict, uint32_t distance, uint32_t *len) +{ + // Don't write past the end of the dictionary. + const size_t dict_avail = dict->limit - dict->pos; + uint32_t left = my_min(dict_avail, *len); + *len -= left; + + // Repeat a block of data from the history. Because memcpy() is faster + // than copying byte by byte in a loop, the copying process gets split + // into three cases. + if (distance < left) { + // Source and target areas overlap, thus we can't use + // memcpy() nor even memmove() safely. + do { + dict->buf[dict->pos] = dict_get(dict, distance); + ++dict->pos; + } while (--left > 0); + + } else if (distance < dict->pos) { + // The easiest and fastest case + memcpy(dict->buf + dict->pos, + dict->buf + dict->pos - distance - 1, + left); + dict->pos += left; + + } else { + // The bigger the dictionary, the more rare this + // case occurs. We need to "wrap" the dict, thus + // we might need two memcpy() to copy all the data. + assert(dict->full == dict->size); + const uint32_t copy_pos + = dict->pos - distance - 1 + dict->size; + uint32_t copy_size = dict->size - copy_pos; + + if (copy_size < left) { + memmove(dict->buf + dict->pos, dict->buf + copy_pos, + copy_size); + dict->pos += copy_size; + copy_size = left - copy_size; + memcpy(dict->buf + dict->pos, dict->buf, copy_size); + dict->pos += copy_size; + } else { + memmove(dict->buf + dict->pos, dict->buf + copy_pos, + left); + dict->pos += left; + } + } + + // Update how full the dictionary is. + if (dict->full < dict->pos) + dict->full = dict->pos; + + return unlikely(*len != 0); +} + + +/// Puts one byte into the dictionary. Returns true if the dictionary was +/// already full and the byte couldn't be added. +static inline bool +dict_put(lzma_dict *dict, uint8_t byte) +{ + if (unlikely(dict->pos == dict->limit)) + return true; + + dict->buf[dict->pos++] = byte; + + if (dict->pos > dict->full) + dict->full = dict->pos; + + return false; +} + + +/// Copies arbitrary amount of data into the dictionary. +static inline void +dict_write(lzma_dict *restrict dict, const uint8_t *restrict in, + size_t *restrict in_pos, size_t in_size, + size_t *restrict left) +{ + // NOTE: If we are being given more data than the size of the + // dictionary, it could be possible to optimize the LZ decoder + // so that not everything needs to go through the dictionary. + // This shouldn't be very common thing in practice though, and + // the slowdown of one extra memcpy() isn't bad compared to how + // much time it would have taken if the data were compressed. + + if (in_size - *in_pos > *left) + in_size = *in_pos + *left; + + *left -= lzma_bufcpy(in, in_pos, in_size, + dict->buf, &dict->pos, dict->limit); + + if (dict->pos > dict->full) + dict->full = dict->pos; + + return; +} + + +static inline void +dict_reset(lzma_dict *dict) +{ + dict->need_reset = true; + return; +} + +#endif diff --git a/src/liblzma/lz/lz_encoder.c b/src/liblzma/lz/lz_encoder.c new file mode 100644 index 0000000..5489085 --- /dev/null +++ b/src/liblzma/lz/lz_encoder.c @@ -0,0 +1,633 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \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" + + +typedef struct { + /// 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; +} lzma_coder; + + +/// \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(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_coder *coder = coder_ptr; + + 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. + // + // NOTE: Since 5.3.5beta the LZMA encoder ensures that nice_len + // is big enough for the selected match finder. This makes it + // easier for applications as nice_len = 2 will always be accepted + // even though the effective value can be slightly bigger. + const uint32_t hash_bytes + = mf_get_hash_bytes(lz_options->match_finder); + assert(hash_bytes <= mf->nice_len); + + 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(void *coder_ptr, const lzma_allocator *allocator) +{ + lzma_coder *coder = coder_ptr; + + 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(void *coder_ptr, const lzma_allocator *allocator, + const lzma_filter *filters_null lzma_attribute((__unused__)), + const lzma_filter *reversed_filters) +{ + lzma_coder *coder = coder_ptr; + + 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); +} + + +static lzma_ret +lz_encoder_set_out_limit(void *coder_ptr, uint64_t *uncomp_size, + uint64_t out_limit) +{ + lzma_coder *coder = coder_ptr; + + // This is supported only if there are no other filters chained. + if (coder->next.code == NULL && coder->lz.set_out_limit != NULL) + return coder->lz.set_out_limit( + coder->lz.coder, uncomp_size, out_limit); + + return LZMA_OPTIONS_ERROR; +} + + +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, + lzma_vli id, const void *options, + lzma_lz_options *lz_options)) +{ +#if defined(HAVE_SMALL) && !defined(HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR) + // We need that the CRC32 table has been initialized. + lzma_crc32_init(); +#endif + + // Allocate and initialize the base data structure. + lzma_coder *coder = next->coder; + if (coder == NULL) { + coder = lzma_alloc(sizeof(lzma_coder), allocator); + if (coder == NULL) + return LZMA_MEM_ERROR; + + next->coder = coder; + next->code = &lz_encode; + next->end = &lz_encoder_end; + next->update = &lz_encoder_update; + next->set_out_limit = &lz_encoder_set_out_limit; + + coder->lz.coder = NULL; + coder->lz.code = NULL; + 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). + coder->mf.buffer = NULL; + coder->mf.size = 0; + coder->mf.hash = NULL; + coder->mf.son = NULL; + coder->mf.hash_count = 0; + coder->mf.sons_count = 0; + + coder->next = LZMA_NEXT_CODER_INIT; + } + + // Initialize the LZ-based encoder. + lzma_lz_options lz_options; + return_if_error(lz_init(&coder->lz, allocator, + filters[0].id, filters[0].options, &lz_options)); + + // Setup the size information into coder->mf and deallocate + // old buffers if they have wrong size. + if (lz_encoder_prepare(&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(&coder->mf, allocator, &lz_options)) + return LZMA_MEM_ERROR; + + // Initialize the next filter in the chain, if any. + return lzma_next_filter_init(&coder->next, allocator, filters + 1); +} + + +extern LZMA_API(lzma_bool) +lzma_mf_is_supported(lzma_match_finder mf) +{ + switch (mf) { +#ifdef HAVE_MF_HC3 + case LZMA_MF_HC3: + return true; +#endif +#ifdef HAVE_MF_HC4 + case LZMA_MF_HC4: + return true; +#endif +#ifdef HAVE_MF_BT2 + case LZMA_MF_BT2: + return true; +#endif +#ifdef HAVE_MF_BT3 + case LZMA_MF_BT3: + return true; +#endif +#ifdef HAVE_MF_BT4 + case LZMA_MF_BT4: + return true; +#endif + default: + return false; + } +} diff --git a/src/liblzma/lz/lz_encoder.h b/src/liblzma/lz/lz_encoder.h new file mode 100644 index 0000000..7950a2f --- /dev/null +++ b/src/liblzma/lz/lz_encoder.h @@ -0,0 +1,341 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lz_encoder.h +/// \brief LZ in window and match finder API +/// +// Authors: Igor Pavlov +// Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#ifndef LZMA_LZ_ENCODER_H +#define LZMA_LZ_ENCODER_H + +#include "common.h" + + +/// A table of these is used by the LZ-based encoder to hold +/// the length-distance pairs found by the match finder. +typedef struct { + uint32_t len; + uint32_t dist; +} lzma_match; + + +typedef struct lzma_mf_s lzma_mf; +struct lzma_mf_s { + /////////////// + // In Window // + /////////////// + + /// Pointer to buffer with data to be compressed + uint8_t *buffer; + + /// Total size of the allocated buffer (that is, including all + /// the extra space) + uint32_t size; + + /// Number of bytes that must be kept available in our input history. + /// That is, once keep_size_before bytes have been processed, + /// buffer[read_pos - keep_size_before] is the oldest byte that + /// must be available for reading. + uint32_t keep_size_before; + + /// Number of bytes that must be kept in buffer after read_pos. + /// That is, read_pos <= write_pos - keep_size_after as long as + /// action is LZMA_RUN; when action != LZMA_RUN, read_pos is allowed + /// to reach write_pos so that the last bytes get encoded too. + uint32_t keep_size_after; + + /// Match finders store locations of matches using 32-bit integers. + /// To avoid adjusting several megabytes of integers every time the + /// input window is moved with move_window, we only adjust the + /// offset of the buffer. Thus, buffer[value_in_hash_table - offset] + /// is the byte pointed by value_in_hash_table. + uint32_t offset; + + /// buffer[read_pos] is the next byte to run through the match + /// finder. This is incremented in the match finder once the byte + /// has been processed. + uint32_t read_pos; + + /// Number of bytes that have been ran through the match finder, but + /// which haven't been encoded by the LZ-based encoder yet. + uint32_t read_ahead; + + /// As long as read_pos is less than read_limit, there is enough + /// input available in buffer for at least one encoding loop. + /// + /// Because of the stateful API, read_limit may and will get greater + /// than read_pos quite often. This is taken into account when + /// calculating the value for keep_size_after. + uint32_t read_limit; + + /// buffer[write_pos] is the first byte that doesn't contain valid + /// uncompressed data; that is, the next input byte will be copied + /// to buffer[write_pos]. + uint32_t write_pos; + + /// Number of bytes not hashed before read_pos. This is needed to + /// restart the match finder after LZMA_SYNC_FLUSH. + uint32_t pending; + + ////////////////// + // Match Finder // + ////////////////// + + /// Find matches. Returns the number of distance-length pairs written + /// to the matches array. This is called only via lzma_mf_find(). + uint32_t (*find)(lzma_mf *mf, lzma_match *matches); + + /// Skips num bytes. This is like find() but doesn't make the + /// distance-length pairs available, thus being a little faster. + /// This is called only via mf_skip(). + void (*skip)(lzma_mf *mf, uint32_t num); + + uint32_t *hash; + uint32_t *son; + uint32_t cyclic_pos; + uint32_t cyclic_size; // Must be dictionary size + 1. + uint32_t hash_mask; + + /// Maximum number of loops in the match finder + uint32_t depth; + + /// Maximum length of a match that the match finder will try to find. + uint32_t nice_len; + + /// Maximum length of a match supported by the LZ-based encoder. + /// If the longest match found by the match finder is nice_len, + /// mf_find() tries to expand it up to match_len_max bytes. + uint32_t match_len_max; + + /// When running out of input, binary tree match finders need to know + /// if it is due to flushing or finishing. The action is used also + /// by the LZ-based encoders themselves. + lzma_action action; + + /// Number of elements in hash[] + uint32_t hash_count; + + /// Number of elements in son[] + uint32_t sons_count; +}; + + +typedef struct { + /// Extra amount of data to keep available before the "actual" + /// dictionary. + size_t before_size; + + /// Size of the history buffer + size_t dict_size; + + /// Extra amount of data to keep available after the "actual" + /// dictionary. + size_t after_size; + + /// Maximum length of a match that the LZ-based encoder can accept. + /// This is used to extend matches of length nice_len to the + /// maximum possible length. + size_t match_len_max; + + /// Match finder will search matches up to this length. + /// This must be less than or equal to match_len_max. + size_t nice_len; + + /// Type of the match finder to use + lzma_match_finder match_finder; + + /// Maximum search depth + uint32_t depth; + + /// TODO: Comment + const uint8_t *preset_dict; + + uint32_t preset_dict_size; + +} lzma_lz_options; + + +// The total usable buffer space at any moment outside the match finder: +// before_size + dict_size + after_size + match_len_max +// +// In reality, there's some extra space allocated to prevent the number of +// memmove() calls reasonable. The bigger the dict_size is, the bigger +// this extra buffer will be since with bigger dictionaries memmove() would +// also take longer. +// +// A single encoder loop in the LZ-based encoder may call the match finder +// (mf_find() or mf_skip()) at most after_size times. In other words, +// a single encoder loop may increment lzma_mf.read_pos at most after_size +// times. Since matches are looked up to +// lzma_mf.buffer[lzma_mf.read_pos + match_len_max - 1], the total +// amount of extra buffer needed after dict_size becomes +// after_size + match_len_max. +// +// before_size has two uses. The first one is to keep literals available +// in cases when the LZ-based encoder has made some read ahead. +// TODO: Maybe this could be changed by making the LZ-based encoders to +// store the actual literals as they do with length-distance pairs. +// +// Algorithms such as LZMA2 first try to compress a chunk, and then check +// if the encoded result is smaller than the uncompressed one. If the chunk +// was uncompressible, it is better to store it in uncompressed form in +// the output stream. To do this, the whole uncompressed chunk has to be +// still available in the history buffer. before_size achieves that. + + +typedef struct { + /// Data specific to the LZ-based encoder + void *coder; + + /// Function to encode from *dict to out[] + lzma_ret (*code)(void *coder, + lzma_mf *restrict mf, uint8_t *restrict out, + size_t *restrict out_pos, size_t out_size); + + /// Free allocated resources + void (*end)(void *coder, const lzma_allocator *allocator); + + /// Update the options in the middle of the encoding. + lzma_ret (*options_update)(void *coder, const lzma_filter *filter); + + /// Set maximum allowed output size + lzma_ret (*set_out_limit)(void *coder, uint64_t *uncomp_size, + uint64_t out_limit); + +} lzma_lz_encoder; + + +// Basic steps: +// 1. Input gets copied into the dictionary. +// 2. Data in dictionary gets run through the match finder byte by byte. +// 3. The literals and matches are encoded using e.g. LZMA. +// +// The bytes that have been ran through the match finder, but not encoded yet, +// are called `read ahead'. + + +/// Get how many bytes the match finder hashes in its initial step. +/// This is also the minimum nice_len value with the match finder. +static inline uint32_t +mf_get_hash_bytes(lzma_match_finder match_finder) +{ + return (uint32_t)match_finder & 0x0F; +} + + +/// Get pointer to the first byte not ran through the match finder +static inline const uint8_t * +mf_ptr(const lzma_mf *mf) +{ + return mf->buffer + mf->read_pos; +} + + +/// Get the number of bytes that haven't been ran through the match finder yet. +static inline uint32_t +mf_avail(const lzma_mf *mf) +{ + return mf->write_pos - mf->read_pos; +} + + +/// Get the number of bytes that haven't been encoded yet (some of these +/// bytes may have been ran through the match finder though). +static inline uint32_t +mf_unencoded(const lzma_mf *mf) +{ + return mf->write_pos - mf->read_pos + mf->read_ahead; +} + + +/// Calculate the absolute offset from the beginning of the most recent +/// dictionary reset. Only the lowest four bits are important, so there's no +/// problem that we don't know the 64-bit size of the data encoded so far. +/// +/// NOTE: When moving the input window, we need to do it so that the lowest +/// bits of dict->read_pos are not modified to keep this macro working +/// as intended. +static inline uint32_t +mf_position(const lzma_mf *mf) +{ + return mf->read_pos - mf->read_ahead; +} + + +/// Since everything else begins with mf_, use it also for lzma_mf_find(). +#define mf_find lzma_mf_find + + +/// Skip the given number of bytes. This is used when a good match was found. +/// For example, if mf_find() finds a match of 200 bytes long, the first byte +/// of that match was already consumed by mf_find(), and the rest 199 bytes +/// have to be skipped with mf_skip(mf, 199). +static inline void +mf_skip(lzma_mf *mf, uint32_t amount) +{ + if (amount != 0) { + mf->skip(mf, amount); + mf->read_ahead += amount; + } +} + + +/// Copies at most *left number of bytes from the history buffer +/// to out[]. This is needed by LZMA2 to encode uncompressed chunks. +static inline void +mf_read(lzma_mf *mf, uint8_t *out, size_t *out_pos, size_t out_size, + size_t *left) +{ + const size_t out_avail = out_size - *out_pos; + const size_t copy_size = my_min(out_avail, *left); + + assert(mf->read_ahead == 0); + assert(mf->read_pos >= *left); + + memcpy(out + *out_pos, mf->buffer + mf->read_pos - *left, + copy_size); + + *out_pos += copy_size; + *left -= copy_size; + return; +} + + +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, + lzma_vli id, const void *options, + lzma_lz_options *lz_options)); + + +extern uint64_t lzma_lz_encoder_memusage(const lzma_lz_options *lz_options); + + +// These are only for LZ encoder's internal use. +extern uint32_t lzma_mf_find( + lzma_mf *mf, uint32_t *count, lzma_match *matches); + +extern uint32_t lzma_mf_hc3_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_hc3_skip(lzma_mf *dict, uint32_t amount); + +extern uint32_t lzma_mf_hc4_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_hc4_skip(lzma_mf *dict, uint32_t amount); + +extern uint32_t lzma_mf_bt2_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_bt2_skip(lzma_mf *dict, uint32_t amount); + +extern uint32_t lzma_mf_bt3_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_bt3_skip(lzma_mf *dict, uint32_t amount); + +extern uint32_t lzma_mf_bt4_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_bt4_skip(lzma_mf *dict, uint32_t amount); + +#endif diff --git a/src/liblzma/lz/lz_encoder_hash.h b/src/liblzma/lz/lz_encoder_hash.h new file mode 100644 index 0000000..fb15c58 --- /dev/null +++ b/src/liblzma/lz/lz_encoder_hash.h @@ -0,0 +1,108 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lz_encoder_hash.h +/// \brief Hash macros for match finders +// +// Author: Igor Pavlov +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#ifndef LZMA_LZ_ENCODER_HASH_H +#define LZMA_LZ_ENCODER_HASH_H + +#if defined(WORDS_BIGENDIAN) && !defined(HAVE_SMALL) + // This is to make liblzma produce the same output on big endian + // systems that it does on little endian systems. lz_encoder.c + // takes care of including the actual table. + extern const uint32_t lzma_lz_hash_table[256]; +# define hash_table lzma_lz_hash_table +#else +# include "check.h" +# define hash_table lzma_crc32_table[0] +#endif + +#define HASH_2_SIZE (UINT32_C(1) << 10) +#define HASH_3_SIZE (UINT32_C(1) << 16) +#define HASH_4_SIZE (UINT32_C(1) << 20) + +#define HASH_2_MASK (HASH_2_SIZE - 1) +#define HASH_3_MASK (HASH_3_SIZE - 1) +#define HASH_4_MASK (HASH_4_SIZE - 1) + +#define FIX_3_HASH_SIZE (HASH_2_SIZE) +#define FIX_4_HASH_SIZE (HASH_2_SIZE + HASH_3_SIZE) +#define FIX_5_HASH_SIZE (HASH_2_SIZE + HASH_3_SIZE + HASH_4_SIZE) + +// Endianness doesn't matter in hash_2_calc() (no effect on the output). +#ifdef TUKLIB_FAST_UNALIGNED_ACCESS +# define hash_2_calc() \ + const uint32_t hash_value = read16ne(cur) +#else +# define hash_2_calc() \ + const uint32_t hash_value \ + = (uint32_t)(cur[0]) | ((uint32_t)(cur[1]) << 8) +#endif + +#define hash_3_calc() \ + const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \ + const uint32_t hash_2_value = temp & HASH_2_MASK; \ + const uint32_t hash_value \ + = (temp ^ ((uint32_t)(cur[2]) << 8)) & mf->hash_mask + +#define hash_4_calc() \ + const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \ + const uint32_t hash_2_value = temp & HASH_2_MASK; \ + const uint32_t hash_3_value \ + = (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK; \ + const uint32_t hash_value = (temp ^ ((uint32_t)(cur[2]) << 8) \ + ^ (hash_table[cur[3]] << 5)) & mf->hash_mask + + +// The following are not currently used. + +#define hash_5_calc() \ + const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \ + const uint32_t hash_2_value = temp & HASH_2_MASK; \ + const uint32_t hash_3_value \ + = (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK; \ + uint32_t hash_4_value = (temp ^ ((uint32_t)(cur[2]) << 8) ^ \ + ^ hash_table[cur[3]] << 5); \ + const uint32_t hash_value \ + = (hash_4_value ^ (hash_table[cur[4]] << 3)) \ + & mf->hash_mask; \ + hash_4_value &= HASH_4_MASK + +/* +#define hash_zip_calc() \ + const uint32_t hash_value \ + = (((uint32_t)(cur[0]) | ((uint32_t)(cur[1]) << 8)) \ + ^ hash_table[cur[2]]) & 0xFFFF +*/ + +#define hash_zip_calc() \ + const uint32_t hash_value \ + = (((uint32_t)(cur[2]) | ((uint32_t)(cur[0]) << 8)) \ + ^ hash_table[cur[1]]) & 0xFFFF + +#define mt_hash_2_calc() \ + const uint32_t hash_2_value \ + = (hash_table[cur[0]] ^ cur[1]) & HASH_2_MASK + +#define mt_hash_3_calc() \ + const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \ + const uint32_t hash_2_value = temp & HASH_2_MASK; \ + const uint32_t hash_3_value \ + = (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK + +#define mt_hash_4_calc() \ + const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \ + const uint32_t hash_2_value = temp & HASH_2_MASK; \ + const uint32_t hash_3_value \ + = (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK; \ + const uint32_t hash_4_value = (temp ^ ((uint32_t)(cur[2]) << 8) ^ \ + (hash_table[cur[3]] << 5)) & HASH_4_MASK + +#endif diff --git a/src/liblzma/lz/lz_encoder_hash_table.h b/src/liblzma/lz/lz_encoder_hash_table.h new file mode 100644 index 0000000..8c51717 --- /dev/null +++ b/src/liblzma/lz/lz_encoder_hash_table.h @@ -0,0 +1,68 @@ +/* This file has been automatically generated by crc32_tablegen.c. */ + +const uint32_t lzma_lz_hash_table[256] = { + 0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, + 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3, + 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, + 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91, + 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, + 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, + 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, + 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5, + 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, + 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, + 0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, + 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, + 0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, + 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F, + 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, + 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, + 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, + 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433, + 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, + 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01, + 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, + 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, + 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, + 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, + 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, + 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, + 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, + 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, + 0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, + 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F, + 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, + 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, + 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, + 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683, + 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, + 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, + 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, + 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7, + 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, + 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, + 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, + 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B, + 0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, + 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79, + 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, + 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, + 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, + 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D, + 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, + 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713, + 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, + 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, + 0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, + 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777, + 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, + 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, + 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, + 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, + 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, + 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9, + 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, + 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF, + 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, + 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D +}; diff --git a/src/liblzma/lz/lz_encoder_mf.c b/src/liblzma/lz/lz_encoder_mf.c new file mode 100644 index 0000000..d03657a --- /dev/null +++ b/src/liblzma/lz/lz_encoder_mf.c @@ -0,0 +1,744 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lz_encoder_mf.c +/// \brief Match finders +/// +// 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" +#include "memcmplen.h" + + +/// \brief Find matches starting from the current byte +/// +/// \return The length of the longest match found +extern uint32_t +lzma_mf_find(lzma_mf *mf, uint32_t *count_ptr, lzma_match *matches) +{ + // Call the match finder. It returns the number of length-distance + // pairs found. + // FIXME: Minimum count is zero, what _exactly_ is the maximum? + const uint32_t count = mf->find(mf, matches); + + // Length of the longest match; assume that no matches were found + // and thus the maximum length is zero. + uint32_t len_best = 0; + + if (count > 0) { +#ifndef NDEBUG + // Validate the matches. + for (uint32_t i = 0; i < count; ++i) { + assert(matches[i].len <= mf->nice_len); + assert(matches[i].dist < mf->read_pos); + assert(memcmp(mf_ptr(mf) - 1, + mf_ptr(mf) - matches[i].dist - 2, + matches[i].len) == 0); + } +#endif + + // The last used element in the array contains + // the longest match. + len_best = matches[count - 1].len; + + // If a match of maximum search length was found, try to + // extend the match to maximum possible length. + if (len_best == mf->nice_len) { + // The limit for the match length is either the + // maximum match length supported by the LZ-based + // encoder or the number of bytes left in the + // dictionary, whichever is smaller. + uint32_t limit = mf_avail(mf) + 1; + if (limit > mf->match_len_max) + limit = mf->match_len_max; + + // Pointer to the byte we just ran through + // the match finder. + const uint8_t *p1 = mf_ptr(mf) - 1; + + // Pointer to the beginning of the match. We need -1 + // here because the match distances are zero based. + const uint8_t *p2 = p1 - matches[count - 1].dist - 1; + + len_best = lzma_memcmplen(p1, p2, len_best, limit); + } + } + + *count_ptr = count; + + // Finally update the read position to indicate that match finder was + // run for this dictionary offset. + ++mf->read_ahead; + + return len_best; +} + + +/// Hash value to indicate unused element in the hash. Since we start the +/// positions from dict_size + 1, zero is always too far to qualify +/// as usable match position. +#define EMPTY_HASH_VALUE 0 + + +/// Normalization must be done when lzma_mf.offset + lzma_mf.read_pos +/// reaches MUST_NORMALIZE_POS. +#define MUST_NORMALIZE_POS UINT32_MAX + + +/// \brief Normalizes hash values +/// +/// The hash arrays store positions of match candidates. The positions are +/// relative to an arbitrary offset that is not the same as the absolute +/// offset in the input stream. The relative position of the current byte +/// is lzma_mf.offset + lzma_mf.read_pos. The distances of the matches are +/// the differences of the current read position and the position found from +/// the hash. +/// +/// To prevent integer overflows of the offsets stored in the hash arrays, +/// we need to "normalize" the stored values now and then. During the +/// normalization, we drop values that indicate distance greater than the +/// dictionary size, thus making space for new values. +static void +normalize(lzma_mf *mf) +{ + assert(mf->read_pos + mf->offset == MUST_NORMALIZE_POS); + + // In future we may not want to touch the lowest bits, because there + // may be match finders that use larger resolution than one byte. + const uint32_t subvalue + = (MUST_NORMALIZE_POS - mf->cyclic_size); + // & ~((UINT32_C(1) << 10) - 1); + + for (uint32_t i = 0; i < mf->hash_count; ++i) { + // If the distance is greater than the dictionary size, + // we can simply mark the hash element as empty. + if (mf->hash[i] <= subvalue) + mf->hash[i] = EMPTY_HASH_VALUE; + else + mf->hash[i] -= subvalue; + } + + for (uint32_t i = 0; i < mf->sons_count; ++i) { + // Do the same for mf->son. + // + // NOTE: There may be uninitialized elements in mf->son. + // Valgrind may complain that the "if" below depends on + // an uninitialized value. In this case it is safe to ignore + // the warning. See also the comments in lz_encoder_init() + // in lz_encoder.c. + if (mf->son[i] <= subvalue) + mf->son[i] = EMPTY_HASH_VALUE; + else + mf->son[i] -= subvalue; + } + + // Update offset to match the new locations. + mf->offset -= subvalue; + + return; +} + + +/// Mark the current byte as processed from point of view of the match finder. +static void +move_pos(lzma_mf *mf) +{ + if (++mf->cyclic_pos == mf->cyclic_size) + mf->cyclic_pos = 0; + + ++mf->read_pos; + assert(mf->read_pos <= mf->write_pos); + + if (unlikely(mf->read_pos + mf->offset == UINT32_MAX)) + normalize(mf); +} + + +/// When flushing, we cannot run the match finder unless there is nice_len +/// bytes available in the dictionary. Instead, we skip running the match +/// finder (indicating that no match was found), and count how many bytes we +/// have ignored this way. +/// +/// When new data is given after the flushing was completed, the match finder +/// is restarted by rewinding mf->read_pos backwards by mf->pending. Then +/// the missed bytes are added to the hash using the match finder's skip +/// function (with small amount of input, it may start using mf->pending +/// again if flushing). +/// +/// Due to this rewinding, we don't touch cyclic_pos or test for +/// normalization. It will be done when the match finder's skip function +/// catches up after a flush. +static void +move_pending(lzma_mf *mf) +{ + ++mf->read_pos; + assert(mf->read_pos <= mf->write_pos); + ++mf->pending; +} + + +/// Calculate len_limit and determine if there is enough input to run +/// the actual match finder code. Sets up "cur" and "pos". This macro +/// is used by all find functions and binary tree skip functions. Hash +/// chain skip function doesn't need len_limit so a simpler code is used +/// in them. +#define header(is_bt, len_min, ret_op) \ + uint32_t len_limit = mf_avail(mf); \ + if (mf->nice_len <= len_limit) { \ + len_limit = mf->nice_len; \ + } else if (len_limit < (len_min) \ + || (is_bt && mf->action == LZMA_SYNC_FLUSH)) { \ + assert(mf->action != LZMA_RUN); \ + move_pending(mf); \ + ret_op; \ + } \ + const uint8_t *cur = mf_ptr(mf); \ + const uint32_t pos = mf->read_pos + mf->offset + + +/// Header for find functions. "return 0" indicates that zero matches +/// were found. +#define header_find(is_bt, len_min) \ + header(is_bt, len_min, return 0); \ + uint32_t matches_count = 0 + + +/// Header for a loop in a skip function. "continue" tells to skip the rest +/// of the code in the loop. +#define header_skip(is_bt, len_min) \ + header(is_bt, len_min, continue) + + +/// Calls hc_find_func() or bt_find_func() and calculates the total number +/// of matches found. Updates the dictionary position and returns the number +/// of matches found. +#define call_find(func, len_best) \ +do { \ + matches_count = func(len_limit, pos, cur, cur_match, mf->depth, \ + mf->son, mf->cyclic_pos, mf->cyclic_size, \ + matches + matches_count, len_best) \ + - matches; \ + move_pos(mf); \ + return matches_count; \ +} while (0) + + +//////////////// +// Hash Chain // +//////////////// + +#if defined(HAVE_MF_HC3) || defined(HAVE_MF_HC4) +/// +/// +/// \param len_limit Don't look for matches longer than len_limit. +/// \param pos lzma_mf.read_pos + lzma_mf.offset +/// \param cur Pointer to current byte (mf_ptr(mf)) +/// \param cur_match Start position of the current match candidate +/// \param depth Maximum length of the hash chain +/// \param son lzma_mf.son (contains the hash chain) +/// \param cyclic_pos +/// \param cyclic_size +/// \param matches Array to hold the matches. +/// \param len_best The length of the longest match found so far. +static lzma_match * +hc_find_func( + const uint32_t len_limit, + const uint32_t pos, + const uint8_t *const cur, + uint32_t cur_match, + uint32_t depth, + uint32_t *const son, + const uint32_t cyclic_pos, + const uint32_t cyclic_size, + lzma_match *matches, + uint32_t len_best) +{ + son[cyclic_pos] = cur_match; + + while (true) { + const uint32_t delta = pos - cur_match; + if (depth-- == 0 || delta >= cyclic_size) + return matches; + + const uint8_t *const pb = cur - delta; + cur_match = son[cyclic_pos - delta + + (delta > cyclic_pos ? cyclic_size : 0)]; + + if (pb[len_best] == cur[len_best] && pb[0] == cur[0]) { + uint32_t len = lzma_memcmplen(pb, cur, 1, len_limit); + + if (len_best < len) { + len_best = len; + matches->len = len; + matches->dist = delta - 1; + ++matches; + + if (len == len_limit) + return matches; + } + } + } +} + + +#define hc_find(len_best) \ + call_find(hc_find_func, len_best) + + +#define hc_skip() \ +do { \ + mf->son[mf->cyclic_pos] = cur_match; \ + move_pos(mf); \ +} while (0) + +#endif + + +#ifdef HAVE_MF_HC3 +extern uint32_t +lzma_mf_hc3_find(lzma_mf *mf, lzma_match *matches) +{ + header_find(false, 3); + + hash_3_calc(); + + const uint32_t delta2 = pos - mf->hash[hash_2_value]; + const uint32_t cur_match = mf->hash[FIX_3_HASH_SIZE + hash_value]; + + mf->hash[hash_2_value] = pos; + mf->hash[FIX_3_HASH_SIZE + hash_value] = pos; + + uint32_t len_best = 2; + + if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) { + len_best = lzma_memcmplen(cur - delta2, cur, + len_best, len_limit); + + matches[0].len = len_best; + matches[0].dist = delta2 - 1; + matches_count = 1; + + if (len_best == len_limit) { + hc_skip(); + return 1; // matches_count + } + } + + hc_find(len_best); +} + + +extern void +lzma_mf_hc3_skip(lzma_mf *mf, uint32_t amount) +{ + do { + if (mf_avail(mf) < 3) { + move_pending(mf); + continue; + } + + const uint8_t *cur = mf_ptr(mf); + const uint32_t pos = mf->read_pos + mf->offset; + + hash_3_calc(); + + const uint32_t cur_match + = mf->hash[FIX_3_HASH_SIZE + hash_value]; + + mf->hash[hash_2_value] = pos; + mf->hash[FIX_3_HASH_SIZE + hash_value] = pos; + + hc_skip(); + + } while (--amount != 0); +} +#endif + + +#ifdef HAVE_MF_HC4 +extern uint32_t +lzma_mf_hc4_find(lzma_mf *mf, lzma_match *matches) +{ + header_find(false, 4); + + hash_4_calc(); + + uint32_t delta2 = pos - mf->hash[hash_2_value]; + const uint32_t delta3 + = pos - mf->hash[FIX_3_HASH_SIZE + hash_3_value]; + const uint32_t cur_match = mf->hash[FIX_4_HASH_SIZE + hash_value]; + + mf->hash[hash_2_value ] = pos; + mf->hash[FIX_3_HASH_SIZE + hash_3_value] = pos; + mf->hash[FIX_4_HASH_SIZE + hash_value] = pos; + + uint32_t len_best = 1; + + if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) { + len_best = 2; + matches[0].len = 2; + matches[0].dist = delta2 - 1; + matches_count = 1; + } + + if (delta2 != delta3 && delta3 < mf->cyclic_size + && *(cur - delta3) == *cur) { + len_best = 3; + matches[matches_count++].dist = delta3 - 1; + delta2 = delta3; + } + + if (matches_count != 0) { + len_best = lzma_memcmplen(cur - delta2, cur, + len_best, len_limit); + + matches[matches_count - 1].len = len_best; + + if (len_best == len_limit) { + hc_skip(); + return matches_count; + } + } + + if (len_best < 3) + len_best = 3; + + hc_find(len_best); +} + + +extern void +lzma_mf_hc4_skip(lzma_mf *mf, uint32_t amount) +{ + do { + if (mf_avail(mf) < 4) { + move_pending(mf); + continue; + } + + const uint8_t *cur = mf_ptr(mf); + const uint32_t pos = mf->read_pos + mf->offset; + + hash_4_calc(); + + const uint32_t cur_match + = mf->hash[FIX_4_HASH_SIZE + hash_value]; + + mf->hash[hash_2_value] = pos; + mf->hash[FIX_3_HASH_SIZE + hash_3_value] = pos; + mf->hash[FIX_4_HASH_SIZE + hash_value] = pos; + + hc_skip(); + + } while (--amount != 0); +} +#endif + + +///////////////// +// Binary Tree // +///////////////// + +#if defined(HAVE_MF_BT2) || defined(HAVE_MF_BT3) || defined(HAVE_MF_BT4) +static lzma_match * +bt_find_func( + const uint32_t len_limit, + const uint32_t pos, + const uint8_t *const cur, + uint32_t cur_match, + uint32_t depth, + uint32_t *const son, + const uint32_t cyclic_pos, + const uint32_t cyclic_size, + lzma_match *matches, + uint32_t len_best) +{ + uint32_t *ptr0 = son + (cyclic_pos << 1) + 1; + uint32_t *ptr1 = son + (cyclic_pos << 1); + + uint32_t len0 = 0; + uint32_t len1 = 0; + + while (true) { + const uint32_t delta = pos - cur_match; + if (depth-- == 0 || delta >= cyclic_size) { + *ptr0 = EMPTY_HASH_VALUE; + *ptr1 = EMPTY_HASH_VALUE; + return matches; + } + + uint32_t *const pair = son + ((cyclic_pos - delta + + (delta > cyclic_pos ? cyclic_size : 0)) + << 1); + + const uint8_t *const pb = cur - delta; + uint32_t len = my_min(len0, len1); + + if (pb[len] == cur[len]) { + len = lzma_memcmplen(pb, cur, len + 1, len_limit); + + if (len_best < len) { + len_best = len; + matches->len = len; + matches->dist = delta - 1; + ++matches; + + if (len == len_limit) { + *ptr1 = pair[0]; + *ptr0 = pair[1]; + return matches; + } + } + } + + if (pb[len] < cur[len]) { + *ptr1 = cur_match; + ptr1 = pair + 1; + cur_match = *ptr1; + len1 = len; + } else { + *ptr0 = cur_match; + ptr0 = pair; + cur_match = *ptr0; + len0 = len; + } + } +} + + +static void +bt_skip_func( + const uint32_t len_limit, + const uint32_t pos, + const uint8_t *const cur, + uint32_t cur_match, + uint32_t depth, + uint32_t *const son, + const uint32_t cyclic_pos, + const uint32_t cyclic_size) +{ + uint32_t *ptr0 = son + (cyclic_pos << 1) + 1; + uint32_t *ptr1 = son + (cyclic_pos << 1); + + uint32_t len0 = 0; + uint32_t len1 = 0; + + while (true) { + const uint32_t delta = pos - cur_match; + if (depth-- == 0 || delta >= cyclic_size) { + *ptr0 = EMPTY_HASH_VALUE; + *ptr1 = EMPTY_HASH_VALUE; + return; + } + + uint32_t *pair = son + ((cyclic_pos - delta + + (delta > cyclic_pos ? cyclic_size : 0)) + << 1); + const uint8_t *pb = cur - delta; + uint32_t len = my_min(len0, len1); + + if (pb[len] == cur[len]) { + len = lzma_memcmplen(pb, cur, len + 1, len_limit); + + if (len == len_limit) { + *ptr1 = pair[0]; + *ptr0 = pair[1]; + return; + } + } + + if (pb[len] < cur[len]) { + *ptr1 = cur_match; + ptr1 = pair + 1; + cur_match = *ptr1; + len1 = len; + } else { + *ptr0 = cur_match; + ptr0 = pair; + cur_match = *ptr0; + len0 = len; + } + } +} + + +#define bt_find(len_best) \ + call_find(bt_find_func, len_best) + +#define bt_skip() \ +do { \ + bt_skip_func(len_limit, pos, cur, cur_match, mf->depth, \ + mf->son, mf->cyclic_pos, \ + mf->cyclic_size); \ + move_pos(mf); \ +} while (0) + +#endif + + +#ifdef HAVE_MF_BT2 +extern uint32_t +lzma_mf_bt2_find(lzma_mf *mf, lzma_match *matches) +{ + header_find(true, 2); + + hash_2_calc(); + + const uint32_t cur_match = mf->hash[hash_value]; + mf->hash[hash_value] = pos; + + bt_find(1); +} + + +extern void +lzma_mf_bt2_skip(lzma_mf *mf, uint32_t amount) +{ + do { + header_skip(true, 2); + + hash_2_calc(); + + const uint32_t cur_match = mf->hash[hash_value]; + mf->hash[hash_value] = pos; + + bt_skip(); + + } while (--amount != 0); +} +#endif + + +#ifdef HAVE_MF_BT3 +extern uint32_t +lzma_mf_bt3_find(lzma_mf *mf, lzma_match *matches) +{ + header_find(true, 3); + + hash_3_calc(); + + const uint32_t delta2 = pos - mf->hash[hash_2_value]; + const uint32_t cur_match = mf->hash[FIX_3_HASH_SIZE + hash_value]; + + mf->hash[hash_2_value] = pos; + mf->hash[FIX_3_HASH_SIZE + hash_value] = pos; + + uint32_t len_best = 2; + + if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) { + len_best = lzma_memcmplen( + cur, cur - delta2, len_best, len_limit); + + matches[0].len = len_best; + matches[0].dist = delta2 - 1; + matches_count = 1; + + if (len_best == len_limit) { + bt_skip(); + return 1; // matches_count + } + } + + bt_find(len_best); +} + + +extern void +lzma_mf_bt3_skip(lzma_mf *mf, uint32_t amount) +{ + do { + header_skip(true, 3); + + hash_3_calc(); + + const uint32_t cur_match + = mf->hash[FIX_3_HASH_SIZE + hash_value]; + + mf->hash[hash_2_value] = pos; + mf->hash[FIX_3_HASH_SIZE + hash_value] = pos; + + bt_skip(); + + } while (--amount != 0); +} +#endif + + +#ifdef HAVE_MF_BT4 +extern uint32_t +lzma_mf_bt4_find(lzma_mf *mf, lzma_match *matches) +{ + header_find(true, 4); + + hash_4_calc(); + + uint32_t delta2 = pos - mf->hash[hash_2_value]; + const uint32_t delta3 + = pos - mf->hash[FIX_3_HASH_SIZE + hash_3_value]; + const uint32_t cur_match = mf->hash[FIX_4_HASH_SIZE + hash_value]; + + mf->hash[hash_2_value] = pos; + mf->hash[FIX_3_HASH_SIZE + hash_3_value] = pos; + mf->hash[FIX_4_HASH_SIZE + hash_value] = pos; + + uint32_t len_best = 1; + + if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) { + len_best = 2; + matches[0].len = 2; + matches[0].dist = delta2 - 1; + matches_count = 1; + } + + if (delta2 != delta3 && delta3 < mf->cyclic_size + && *(cur - delta3) == *cur) { + len_best = 3; + matches[matches_count++].dist = delta3 - 1; + delta2 = delta3; + } + + if (matches_count != 0) { + len_best = lzma_memcmplen( + cur, cur - delta2, len_best, len_limit); + + matches[matches_count - 1].len = len_best; + + if (len_best == len_limit) { + bt_skip(); + return matches_count; + } + } + + if (len_best < 3) + len_best = 3; + + bt_find(len_best); +} + + +extern void +lzma_mf_bt4_skip(lzma_mf *mf, uint32_t amount) +{ + do { + header_skip(true, 4); + + hash_4_calc(); + + const uint32_t cur_match + = mf->hash[FIX_4_HASH_SIZE + hash_value]; + + mf->hash[hash_2_value] = pos; + mf->hash[FIX_3_HASH_SIZE + hash_3_value] = pos; + mf->hash[FIX_4_HASH_SIZE + hash_value] = pos; + + bt_skip(); + + } while (--amount != 0); +} +#endif |