Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party

xz/src/liblzma/lz/lz_encoder.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \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
+
+
+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, 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;
+
+        // 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 size_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, 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, 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;
+*/
+
+        // If the above code calculating hs is modified, make sure that
+        // this assertion stays valid (UINT32_MAX / 5 is not strictly the
+        // exact limit). If it doesn't, you need to calculate that
+        // hash_size_sum + sons_count cannot overflow.
+        assert(hs < UINT32_MAX / 5);
+
+        const uint32_t old_count = mf->hash_size_sum + mf->sons_count;
+        mf->hash_size_sum = hs;
+        mf->sons_count = mf->cyclic_size;
+        if (is_bt)
+                mf->sons_count *= 2;
+
+        const uint32_t new_count = mf->hash_size_sum + mf->sons_count;
+
+        // Deallocate the old hash array if it exists and has different size
+        // than what is needed now.
+        if (old_count != new_count) {
+                lzma_free(mf->hash, allocator);
+                mf->hash = NULL;
+        }
+
+        // Maximum number of match finder cycles
+        mf->depth = lz_options->depth;
+        if (mf->depth == 0) {
+                mf->depth = 16 + (mf->nice_len / 2);
+                if (!is_bt)
+                        mf->depth /= 2;
+        }
+
+        return false;
+}
+
+
+static bool
+lz_encoder_init(lzma_mf *mf, lzma_allocator *allocator,
+                const lzma_lz_options *lz_options)
+{
+        // Allocate the history buffer.
+        if (mf->buffer == NULL) {
+                mf->buffer = lzma_alloc(mf->size, allocator);
+                if (mf->buffer == NULL)
+                        return true;
+        }
+
+        // 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;
+
+        // Allocate match finder's hash array.
+        const size_t alloc_count = mf->hash_size_sum + mf->sons_count;
+
+#if UINT32_MAX >= SIZE_MAX / 4
+        // Check for integer overflow. (Huge dictionaries are not
+        // possible on 32-bit CPU.)
+        if (alloc_count > SIZE_MAX / sizeof(uint32_t))
+                return true;
+#endif
+
+        if (mf->hash == NULL) {
+                mf->hash = lzma_alloc(alloc_count * sizeof(uint32_t),
+                                allocator);
+                if (mf->hash == NULL)
+                        return true;
+        }
+
+        mf->son = mf->hash + mf->hash_size_sum;
+        mf->cyclic_pos = 0;
+
+        // Initialize the hash table. Since EMPTY_HASH_VALUE is zero, we
+        // can use memset().
+/*
+        for (uint32_t i = 0; i < hash_size_sum; ++i)
+                mf->hash[i] = EMPTY_HASH_VALUE;
+*/
+        memzero(mf->hash, (size_t)(mf->hash_size_sum) * sizeof(uint32_t));
+
+        // We don't need to initialize mf->son, but not doing that will
+        // make Valgrind complain in normalization (see normalize() in
+        // lz_encoder_mf.c).
+        //
+        // Skipping this initialization is *very* good when big dictionary is
+        // used but only small amount of data gets actually compressed: most
+        // of the mf->hash won't get actually allocated by the kernel, so
+        // we avoid wasting RAM and improve initialization speed a lot.
+        //memzero(mf->son, (size_t)(mf->sons_count) * sizeof(uint32_t));
+
+        // 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,
+                .hash_size_sum = 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_size_sum + mf.sons_count)
+                                * sizeof(uint32_t)
+                        + (uint64_t)(mf.size) + sizeof(lzma_coder);
+}
+
+
+static void
+lz_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+        lzma_next_end(&coder->next, 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, 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, lzma_allocator *allocator,
+                const lzma_filter_info *filters,
+                lzma_ret (*lz_init)(lzma_lz_encoder *lz,
+                        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;
+
+                next->coder->mf.buffer = NULL;
+                next->coder->mf.hash = NULL;
+                next->coder->mf.hash_size_sum = 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;
+}