--- /dev/null
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+#include "zstd_compress_internal.h" /* ZSTD_hashPtr, ZSTD_count, ZSTD_storeSeq */
+#include "zstd_fast.h"
+
+static void ZSTD_fillHashTableForCDict(ZSTD_matchState_t* ms,
+ const void* const end,
+ ZSTD_dictTableLoadMethod_e dtlm)
+{
+ const ZSTD_compressionParameters* const cParams = &ms->cParams;
+ U32* const hashTable = ms->hashTable;
+ U32 const hBits = cParams->hashLog + ZSTD_SHORT_CACHE_TAG_BITS;
+ U32 const mls = cParams->minMatch;
+ const BYTE* const base = ms->window.base;
+ const BYTE* ip = base + ms->nextToUpdate;
+ const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
+ const U32 fastHashFillStep = 3;
+
+ /* Currently, we always use ZSTD_dtlm_full for filling CDict tables.
+ * Feel free to remove this assert if there's a good reason! */
+ assert(dtlm == ZSTD_dtlm_full);
+
+ /* Always insert every fastHashFillStep position into the hash table.
+ * Insert the other positions if their hash entry is empty.
+ */
+ for ( ; ip + fastHashFillStep < iend + 2; ip += fastHashFillStep) {
+ U32 const curr = (U32)(ip - base);
+ { size_t const hashAndTag = ZSTD_hashPtr(ip, hBits, mls);
+ ZSTD_writeTaggedIndex(hashTable, hashAndTag, curr); }
+
+ if (dtlm == ZSTD_dtlm_fast) continue;
+ /* Only load extra positions for ZSTD_dtlm_full */
+ { U32 p;
+ for (p = 1; p < fastHashFillStep; ++p) {
+ size_t const hashAndTag = ZSTD_hashPtr(ip + p, hBits, mls);
+ if (hashTable[hashAndTag >> ZSTD_SHORT_CACHE_TAG_BITS] == 0) { /* not yet filled */
+ ZSTD_writeTaggedIndex(hashTable, hashAndTag, curr + p);
+ } } } }
+}
+
+static void ZSTD_fillHashTableForCCtx(ZSTD_matchState_t* ms,
+ const void* const end,
+ ZSTD_dictTableLoadMethod_e dtlm)
+{
+ const ZSTD_compressionParameters* const cParams = &ms->cParams;
+ U32* const hashTable = ms->hashTable;
+ U32 const hBits = cParams->hashLog;
+ U32 const mls = cParams->minMatch;
+ const BYTE* const base = ms->window.base;
+ const BYTE* ip = base + ms->nextToUpdate;
+ const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
+ const U32 fastHashFillStep = 3;
+
+ /* Currently, we always use ZSTD_dtlm_fast for filling CCtx tables.
+ * Feel free to remove this assert if there's a good reason! */
+ assert(dtlm == ZSTD_dtlm_fast);
+
+ /* Always insert every fastHashFillStep position into the hash table.
+ * Insert the other positions if their hash entry is empty.
+ */
+ for ( ; ip + fastHashFillStep < iend + 2; ip += fastHashFillStep) {
+ U32 const curr = (U32)(ip - base);
+ size_t const hash0 = ZSTD_hashPtr(ip, hBits, mls);
+ hashTable[hash0] = curr;
+ if (dtlm == ZSTD_dtlm_fast) continue;
+ /* Only load extra positions for ZSTD_dtlm_full */
+ { U32 p;
+ for (p = 1; p < fastHashFillStep; ++p) {
+ size_t const hash = ZSTD_hashPtr(ip + p, hBits, mls);
+ if (hashTable[hash] == 0) { /* not yet filled */
+ hashTable[hash] = curr + p;
+ } } } }
+}
+
+void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
+ const void* const end,
+ ZSTD_dictTableLoadMethod_e dtlm,
+ ZSTD_tableFillPurpose_e tfp)
+{
+ if (tfp == ZSTD_tfp_forCDict) {
+ ZSTD_fillHashTableForCDict(ms, end, dtlm);
+ } else {
+ ZSTD_fillHashTableForCCtx(ms, end, dtlm);
+ }
+}
+
+
+/**
+ * If you squint hard enough (and ignore repcodes), the search operation at any
+ * given position is broken into 4 stages:
+ *
+ * 1. Hash (map position to hash value via input read)
+ * 2. Lookup (map hash val to index via hashtable read)
+ * 3. Load (map index to value at that position via input read)
+ * 4. Compare
+ *
+ * Each of these steps involves a memory read at an address which is computed
+ * from the previous step. This means these steps must be sequenced and their
+ * latencies are cumulative.
+ *
+ * Rather than do 1->2->3->4 sequentially for a single position before moving
+ * onto the next, this implementation interleaves these operations across the
+ * next few positions:
+ *
+ * R = Repcode Read & Compare
+ * H = Hash
+ * T = Table Lookup
+ * M = Match Read & Compare
+ *
+ * Pos | Time -->
+ * ----+-------------------
+ * N | ... M
+ * N+1 | ... TM
+ * N+2 | R H T M
+ * N+3 | H TM
+ * N+4 | R H T M
+ * N+5 | H ...
+ * N+6 | R ...
+ *
+ * This is very much analogous to the pipelining of execution in a CPU. And just
+ * like a CPU, we have to dump the pipeline when we find a match (i.e., take a
+ * branch).
+ *
+ * When this happens, we throw away our current state, and do the following prep
+ * to re-enter the loop:
+ *
+ * Pos | Time -->
+ * ----+-------------------
+ * N | H T
+ * N+1 | H
+ *
+ * This is also the work we do at the beginning to enter the loop initially.
+ */
+FORCE_INLINE_TEMPLATE size_t
+ZSTD_compressBlock_fast_noDict_generic(
+ ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
+ void const* src, size_t srcSize,
+ U32 const mls, U32 const hasStep)
+{
+ const ZSTD_compressionParameters* const cParams = &ms->cParams;
+ U32* const hashTable = ms->hashTable;
+ U32 const hlog = cParams->hashLog;
+ /* support stepSize of 0 */
+ size_t const stepSize = hasStep ? (cParams->targetLength + !(cParams->targetLength) + 1) : 2;
+ const BYTE* const base = ms->window.base;
+ const BYTE* const istart = (const BYTE*)src;
+ const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
+ const U32 prefixStartIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog);
+ const BYTE* const prefixStart = base + prefixStartIndex;
+ const BYTE* const iend = istart + srcSize;
+ const BYTE* const ilimit = iend - HASH_READ_SIZE;
+
+ const BYTE* anchor = istart;
+ const BYTE* ip0 = istart;
+ const BYTE* ip1;
+ const BYTE* ip2;
+ const BYTE* ip3;
+ U32 current0;
+
+ U32 rep_offset1 = rep[0];
+ U32 rep_offset2 = rep[1];
+ U32 offsetSaved1 = 0, offsetSaved2 = 0;
+
+ size_t hash0; /* hash for ip0 */
+ size_t hash1; /* hash for ip1 */
+ U32 idx; /* match idx for ip0 */
+ U32 mval; /* src value at match idx */
+
+ U32 offcode;
+ const BYTE* match0;
+ size_t mLength;
+
+ /* ip0 and ip1 are always adjacent. The targetLength skipping and
+ * uncompressibility acceleration is applied to every other position,
+ * matching the behavior of #1562. step therefore represents the gap
+ * between pairs of positions, from ip0 to ip2 or ip1 to ip3. */
+ size_t step;
+ const BYTE* nextStep;
+ const size_t kStepIncr = (1 << (kSearchStrength - 1));
+
+ DEBUGLOG(5, "ZSTD_compressBlock_fast_generic");
+ ip0 += (ip0 == prefixStart);
+ { U32 const curr = (U32)(ip0 - base);
+ U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, cParams->windowLog);
+ U32 const maxRep = curr - windowLow;
+ if (rep_offset2 > maxRep) offsetSaved2 = rep_offset2, rep_offset2 = 0;
+ if (rep_offset1 > maxRep) offsetSaved1 = rep_offset1, rep_offset1 = 0;
+ }
+
+ /* start each op */
+_start: /* Requires: ip0 */
+
+ step = stepSize;
+ nextStep = ip0 + kStepIncr;
+
+ /* calculate positions, ip0 - anchor == 0, so we skip step calc */
+ ip1 = ip0 + 1;
+ ip2 = ip0 + step;
+ ip3 = ip2 + 1;
+
+ if (ip3 >= ilimit) {
+ goto _cleanup;
+ }
+
+ hash0 = ZSTD_hashPtr(ip0, hlog, mls);
+ hash1 = ZSTD_hashPtr(ip1, hlog, mls);
+
+ idx = hashTable[hash0];
+
+ do {
+ /* load repcode match for ip[2]*/
+ const U32 rval = MEM_read32(ip2 - rep_offset1);
+
+ /* write back hash table entry */
+ current0 = (U32)(ip0 - base);
+ hashTable[hash0] = current0;
+
+ /* check repcode at ip[2] */
+ if ((MEM_read32(ip2) == rval) & (rep_offset1 > 0)) {
+ ip0 = ip2;
+ match0 = ip0 - rep_offset1;
+ mLength = ip0[-1] == match0[-1];
+ ip0 -= mLength;
+ match0 -= mLength;
+ offcode = REPCODE1_TO_OFFBASE;
+ mLength += 4;
+
+ /* First write next hash table entry; we've already calculated it.
+ * This write is known to be safe because the ip1 is before the
+ * repcode (ip2). */
+ hashTable[hash1] = (U32)(ip1 - base);
+
+ goto _match;
+ }
+
+ /* load match for ip[0] */
+ if (idx >= prefixStartIndex) {
+ mval = MEM_read32(base + idx);
+ } else {
+ mval = MEM_read32(ip0) ^ 1; /* guaranteed to not match. */
+ }
+
+ /* check match at ip[0] */
+ if (MEM_read32(ip0) == mval) {
+ /* found a match! */
+
+ /* First write next hash table entry; we've already calculated it.
+ * This write is known to be safe because the ip1 == ip0 + 1, so
+ * we know we will resume searching after ip1 */
+ hashTable[hash1] = (U32)(ip1 - base);
+
+ goto _offset;
+ }
+
+ /* lookup ip[1] */
+ idx = hashTable[hash1];
+
+ /* hash ip[2] */
+ hash0 = hash1;
+ hash1 = ZSTD_hashPtr(ip2, hlog, mls);
+
+ /* advance to next positions */
+ ip0 = ip1;
+ ip1 = ip2;
+ ip2 = ip3;
+
+ /* write back hash table entry */
+ current0 = (U32)(ip0 - base);
+ hashTable[hash0] = current0;
+
+ /* load match for ip[0] */
+ if (idx >= prefixStartIndex) {
+ mval = MEM_read32(base + idx);
+ } else {
+ mval = MEM_read32(ip0) ^ 1; /* guaranteed to not match. */
+ }
+
+ /* check match at ip[0] */
+ if (MEM_read32(ip0) == mval) {
+ /* found a match! */
+
+ /* first write next hash table entry; we've already calculated it */
+ if (step <= 4) {
+ /* We need to avoid writing an index into the hash table >= the
+ * position at which we will pick up our searching after we've
+ * taken this match.
+ *
+ * The minimum possible match has length 4, so the earliest ip0
+ * can be after we take this match will be the current ip0 + 4.
+ * ip1 is ip0 + step - 1. If ip1 is >= ip0 + 4, we can't safely
+ * write this position.
+ */
+ hashTable[hash1] = (U32)(ip1 - base);
+ }
+
+ goto _offset;
+ }
+
+ /* lookup ip[1] */
+ idx = hashTable[hash1];
+
+ /* hash ip[2] */
+ hash0 = hash1;
+ hash1 = ZSTD_hashPtr(ip2, hlog, mls);
+
+ /* advance to next positions */
+ ip0 = ip1;
+ ip1 = ip2;
+ ip2 = ip0 + step;
+ ip3 = ip1 + step;
+
+ /* calculate step */
+ if (ip2 >= nextStep) {
+ step++;
+ PREFETCH_L1(ip1 + 64);
+ PREFETCH_L1(ip1 + 128);
+ nextStep += kStepIncr;
+ }
+ } while (ip3 < ilimit);
+
+_cleanup:
+ /* Note that there are probably still a couple positions we could search.
+ * However, it seems to be a meaningful performance hit to try to search
+ * them. So let's not. */
+
+ /* When the repcodes are outside of the prefix, we set them to zero before the loop.
+ * When the offsets are still zero, we need to restore them after the block to have a correct
+ * repcode history. If only one offset was invalid, it is easy. The tricky case is when both
+ * offsets were invalid. We need to figure out which offset to refill with.
+ * - If both offsets are zero they are in the same order.
+ * - If both offsets are non-zero, we won't restore the offsets from `offsetSaved[12]`.
+ * - If only one is zero, we need to decide which offset to restore.
+ * - If rep_offset1 is non-zero, then rep_offset2 must be offsetSaved1.
+ * - It is impossible for rep_offset2 to be non-zero.
+ *
+ * So if rep_offset1 started invalid (offsetSaved1 != 0) and became valid (rep_offset1 != 0), then
+ * set rep[0] = rep_offset1 and rep[1] = offsetSaved1.
+ */
+ offsetSaved2 = ((offsetSaved1 != 0) && (rep_offset1 != 0)) ? offsetSaved1 : offsetSaved2;
+
+ /* save reps for next block */
+ rep[0] = rep_offset1 ? rep_offset1 : offsetSaved1;
+ rep[1] = rep_offset2 ? rep_offset2 : offsetSaved2;
+
+ /* Return the last literals size */
+ return (size_t)(iend - anchor);
+
+_offset: /* Requires: ip0, idx */
+
+ /* Compute the offset code. */
+ match0 = base + idx;
+ rep_offset2 = rep_offset1;
+ rep_offset1 = (U32)(ip0-match0);
+ offcode = OFFSET_TO_OFFBASE(rep_offset1);
+ mLength = 4;
+
+ /* Count the backwards match length. */
+ while (((ip0>anchor) & (match0>prefixStart)) && (ip0[-1] == match0[-1])) {
+ ip0--;
+ match0--;
+ mLength++;
+ }
+
+_match: /* Requires: ip0, match0, offcode */
+
+ /* Count the forward length. */
+ mLength += ZSTD_count(ip0 + mLength, match0 + mLength, iend);
+
+ ZSTD_storeSeq(seqStore, (size_t)(ip0 - anchor), anchor, iend, offcode, mLength);
+
+ ip0 += mLength;
+ anchor = ip0;
+
+ /* Fill table and check for immediate repcode. */
+ if (ip0 <= ilimit) {
+ /* Fill Table */
+ assert(base+current0+2 > istart); /* check base overflow */
+ hashTable[ZSTD_hashPtr(base+current0+2, hlog, mls)] = current0+2; /* here because current+2 could be > iend-8 */
+ hashTable[ZSTD_hashPtr(ip0-2, hlog, mls)] = (U32)(ip0-2-base);
+
+ if (rep_offset2 > 0) { /* rep_offset2==0 means rep_offset2 is invalidated */
+ while ( (ip0 <= ilimit) && (MEM_read32(ip0) == MEM_read32(ip0 - rep_offset2)) ) {
+ /* store sequence */
+ size_t const rLength = ZSTD_count(ip0+4, ip0+4-rep_offset2, iend) + 4;
+ { U32 const tmpOff = rep_offset2; rep_offset2 = rep_offset1; rep_offset1 = tmpOff; } /* swap rep_offset2 <=> rep_offset1 */
+ hashTable[ZSTD_hashPtr(ip0, hlog, mls)] = (U32)(ip0-base);
+ ip0 += rLength;
+ ZSTD_storeSeq(seqStore, 0 /*litLen*/, anchor, iend, REPCODE1_TO_OFFBASE, rLength);
+ anchor = ip0;
+ continue; /* faster when present (confirmed on gcc-8) ... (?) */
+ } } }
+
+ goto _start;
+}
+
+#define ZSTD_GEN_FAST_FN(dictMode, mls, step) \
+ static size_t ZSTD_compressBlock_fast_##dictMode##_##mls##_##step( \
+ ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], \
+ void const* src, size_t srcSize) \
+ { \
+ return ZSTD_compressBlock_fast_##dictMode##_generic(ms, seqStore, rep, src, srcSize, mls, step); \
+ }
+
+ZSTD_GEN_FAST_FN(noDict, 4, 1)
+ZSTD_GEN_FAST_FN(noDict, 5, 1)
+ZSTD_GEN_FAST_FN(noDict, 6, 1)
+ZSTD_GEN_FAST_FN(noDict, 7, 1)
+
+ZSTD_GEN_FAST_FN(noDict, 4, 0)
+ZSTD_GEN_FAST_FN(noDict, 5, 0)
+ZSTD_GEN_FAST_FN(noDict, 6, 0)
+ZSTD_GEN_FAST_FN(noDict, 7, 0)
+
+size_t ZSTD_compressBlock_fast(
+ ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
+ void const* src, size_t srcSize)
+{
+ U32 const mls = ms->cParams.minMatch;
+ assert(ms->dictMatchState == NULL);
+ if (ms->cParams.targetLength > 1) {
+ switch(mls)
+ {
+ default: /* includes case 3 */
+ case 4 :
+ return ZSTD_compressBlock_fast_noDict_4_1(ms, seqStore, rep, src, srcSize);
+ case 5 :
+ return ZSTD_compressBlock_fast_noDict_5_1(ms, seqStore, rep, src, srcSize);
+ case 6 :
+ return ZSTD_compressBlock_fast_noDict_6_1(ms, seqStore, rep, src, srcSize);
+ case 7 :
+ return ZSTD_compressBlock_fast_noDict_7_1(ms, seqStore, rep, src, srcSize);
+ }
+ } else {
+ switch(mls)
+ {
+ default: /* includes case 3 */
+ case 4 :
+ return ZSTD_compressBlock_fast_noDict_4_0(ms, seqStore, rep, src, srcSize);
+ case 5 :
+ return ZSTD_compressBlock_fast_noDict_5_0(ms, seqStore, rep, src, srcSize);
+ case 6 :
+ return ZSTD_compressBlock_fast_noDict_6_0(ms, seqStore, rep, src, srcSize);
+ case 7 :
+ return ZSTD_compressBlock_fast_noDict_7_0(ms, seqStore, rep, src, srcSize);
+ }
+
+ }
+}
+
+FORCE_INLINE_TEMPLATE
+size_t ZSTD_compressBlock_fast_dictMatchState_generic(
+ ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
+ void const* src, size_t srcSize, U32 const mls, U32 const hasStep)
+{
+ const ZSTD_compressionParameters* const cParams = &ms->cParams;
+ U32* const hashTable = ms->hashTable;
+ U32 const hlog = cParams->hashLog;
+ /* support stepSize of 0 */
+ U32 const stepSize = cParams->targetLength + !(cParams->targetLength);
+ const BYTE* const base = ms->window.base;
+ const BYTE* const istart = (const BYTE*)src;
+ const BYTE* ip0 = istart;
+ const BYTE* ip1 = ip0 + stepSize; /* we assert below that stepSize >= 1 */
+ const BYTE* anchor = istart;
+ const U32 prefixStartIndex = ms->window.dictLimit;
+ const BYTE* const prefixStart = base + prefixStartIndex;
+ const BYTE* const iend = istart + srcSize;
+ const BYTE* const ilimit = iend - HASH_READ_SIZE;
+ U32 offset_1=rep[0], offset_2=rep[1];
+
+ const ZSTD_matchState_t* const dms = ms->dictMatchState;
+ const ZSTD_compressionParameters* const dictCParams = &dms->cParams ;
+ const U32* const dictHashTable = dms->hashTable;
+ const U32 dictStartIndex = dms->window.dictLimit;
+ const BYTE* const dictBase = dms->window.base;
+ const BYTE* const dictStart = dictBase + dictStartIndex;
+ const BYTE* const dictEnd = dms->window.nextSrc;
+ const U32 dictIndexDelta = prefixStartIndex - (U32)(dictEnd - dictBase);
+ const U32 dictAndPrefixLength = (U32)(istart - prefixStart + dictEnd - dictStart);
+ const U32 dictHBits = dictCParams->hashLog + ZSTD_SHORT_CACHE_TAG_BITS;
+
+ /* if a dictionary is still attached, it necessarily means that
+ * it is within window size. So we just check it. */
+ const U32 maxDistance = 1U << cParams->windowLog;
+ const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
+ assert(endIndex - prefixStartIndex <= maxDistance);
+ (void)maxDistance; (void)endIndex; /* these variables are not used when assert() is disabled */
+
+ (void)hasStep; /* not currently specialized on whether it's accelerated */
+
+ /* ensure there will be no underflow
+ * when translating a dict index into a local index */
+ assert(prefixStartIndex >= (U32)(dictEnd - dictBase));
+
+ if (ms->prefetchCDictTables) {
+ size_t const hashTableBytes = (((size_t)1) << dictCParams->hashLog) * sizeof(U32);
+ PREFETCH_AREA(dictHashTable, hashTableBytes)
+ }
+
+ /* init */
+ DEBUGLOG(5, "ZSTD_compressBlock_fast_dictMatchState_generic");
+ ip0 += (dictAndPrefixLength == 0);
+ /* dictMatchState repCode checks don't currently handle repCode == 0
+ * disabling. */
+ assert(offset_1 <= dictAndPrefixLength);
+ assert(offset_2 <= dictAndPrefixLength);
+
+ /* Outer search loop */
+ assert(stepSize >= 1);
+ while (ip1 <= ilimit) { /* repcode check at (ip0 + 1) is safe because ip0 < ip1 */
+ size_t mLength;
+ size_t hash0 = ZSTD_hashPtr(ip0, hlog, mls);
+
+ size_t const dictHashAndTag0 = ZSTD_hashPtr(ip0, dictHBits, mls);
+ U32 dictMatchIndexAndTag = dictHashTable[dictHashAndTag0 >> ZSTD_SHORT_CACHE_TAG_BITS];
+ int dictTagsMatch = ZSTD_comparePackedTags(dictMatchIndexAndTag, dictHashAndTag0);
+
+ U32 matchIndex = hashTable[hash0];
+ U32 curr = (U32)(ip0 - base);
+ size_t step = stepSize;
+ const size_t kStepIncr = 1 << kSearchStrength;
+ const BYTE* nextStep = ip0 + kStepIncr;
+
+ /* Inner search loop */
+ while (1) {
+ const BYTE* match = base + matchIndex;
+ const U32 repIndex = curr + 1 - offset_1;
+ const BYTE* repMatch = (repIndex < prefixStartIndex) ?
+ dictBase + (repIndex - dictIndexDelta) :
+ base + repIndex;
+ const size_t hash1 = ZSTD_hashPtr(ip1, hlog, mls);
+ size_t const dictHashAndTag1 = ZSTD_hashPtr(ip1, dictHBits, mls);
+ hashTable[hash0] = curr; /* update hash table */
+
+ if (((U32) ((prefixStartIndex - 1) - repIndex) >=
+ 3) /* intentional underflow : ensure repIndex isn't overlapping dict + prefix */
+ && (MEM_read32(repMatch) == MEM_read32(ip0 + 1))) {
+ const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
+ mLength = ZSTD_count_2segments(ip0 + 1 + 4, repMatch + 4, iend, repMatchEnd, prefixStart) + 4;
+ ip0++;
+ ZSTD_storeSeq(seqStore, (size_t) (ip0 - anchor), anchor, iend, REPCODE1_TO_OFFBASE, mLength);
+ break;
+ }
+
+ if (dictTagsMatch) {
+ /* Found a possible dict match */
+ const U32 dictMatchIndex = dictMatchIndexAndTag >> ZSTD_SHORT_CACHE_TAG_BITS;
+ const BYTE* dictMatch = dictBase + dictMatchIndex;
+ if (dictMatchIndex > dictStartIndex &&
+ MEM_read32(dictMatch) == MEM_read32(ip0)) {
+ /* To replicate extDict parse behavior, we only use dict matches when the normal matchIndex is invalid */
+ if (matchIndex <= prefixStartIndex) {
+ U32 const offset = (U32) (curr - dictMatchIndex - dictIndexDelta);
+ mLength = ZSTD_count_2segments(ip0 + 4, dictMatch + 4, iend, dictEnd, prefixStart) + 4;
+ while (((ip0 > anchor) & (dictMatch > dictStart))
+ && (ip0[-1] == dictMatch[-1])) {
+ ip0--;
+ dictMatch--;
+ mLength++;
+ } /* catch up */
+ offset_2 = offset_1;
+ offset_1 = offset;
+ ZSTD_storeSeq(seqStore, (size_t) (ip0 - anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength);
+ break;
+ }
+ }
+ }
+
+ if (matchIndex > prefixStartIndex && MEM_read32(match) == MEM_read32(ip0)) {
+ /* found a regular match */
+ U32 const offset = (U32) (ip0 - match);
+ mLength = ZSTD_count(ip0 + 4, match + 4, iend) + 4;
+ while (((ip0 > anchor) & (match > prefixStart))
+ && (ip0[-1] == match[-1])) {
+ ip0--;
+ match--;
+ mLength++;
+ } /* catch up */
+ offset_2 = offset_1;
+ offset_1 = offset;
+ ZSTD_storeSeq(seqStore, (size_t) (ip0 - anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength);
+ break;
+ }
+
+ /* Prepare for next iteration */
+ dictMatchIndexAndTag = dictHashTable[dictHashAndTag1 >> ZSTD_SHORT_CACHE_TAG_BITS];
+ dictTagsMatch = ZSTD_comparePackedTags(dictMatchIndexAndTag, dictHashAndTag1);
+ matchIndex = hashTable[hash1];
+
+ if (ip1 >= nextStep) {
+ step++;
+ nextStep += kStepIncr;
+ }
+ ip0 = ip1;
+ ip1 = ip1 + step;
+ if (ip1 > ilimit) goto _cleanup;
+
+ curr = (U32)(ip0 - base);
+ hash0 = hash1;
+ } /* end inner search loop */
+
+ /* match found */
+ assert(mLength);
+ ip0 += mLength;
+ anchor = ip0;
+
+ if (ip0 <= ilimit) {
+ /* Fill Table */
+ assert(base+curr+2 > istart); /* check base overflow */
+ hashTable[ZSTD_hashPtr(base+curr+2, hlog, mls)] = curr+2; /* here because curr+2 could be > iend-8 */
+ hashTable[ZSTD_hashPtr(ip0-2, hlog, mls)] = (U32)(ip0-2-base);
+
+ /* check immediate repcode */
+ while (ip0 <= ilimit) {
+ U32 const current2 = (U32)(ip0-base);
+ U32 const repIndex2 = current2 - offset_2;
+ const BYTE* repMatch2 = repIndex2 < prefixStartIndex ?
+ dictBase - dictIndexDelta + repIndex2 :
+ base + repIndex2;
+ if ( ((U32)((prefixStartIndex-1) - (U32)repIndex2) >= 3 /* intentional overflow */)
+ && (MEM_read32(repMatch2) == MEM_read32(ip0))) {
+ const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
+ size_t const repLength2 = ZSTD_count_2segments(ip0+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
+ U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
+ ZSTD_storeSeq(seqStore, 0, anchor, iend, REPCODE1_TO_OFFBASE, repLength2);
+ hashTable[ZSTD_hashPtr(ip0, hlog, mls)] = current2;
+ ip0 += repLength2;
+ anchor = ip0;
+ continue;
+ }
+ break;
+ }
+ }
+
+ /* Prepare for next iteration */
+ assert(ip0 == anchor);
+ ip1 = ip0 + stepSize;
+ }
+
+_cleanup:
+ /* save reps for next block */
+ rep[0] = offset_1;
+ rep[1] = offset_2;
+
+ /* Return the last literals size */
+ return (size_t)(iend - anchor);
+}
+
+
+ZSTD_GEN_FAST_FN(dictMatchState, 4, 0)
+ZSTD_GEN_FAST_FN(dictMatchState, 5, 0)
+ZSTD_GEN_FAST_FN(dictMatchState, 6, 0)
+ZSTD_GEN_FAST_FN(dictMatchState, 7, 0)
+
+size_t ZSTD_compressBlock_fast_dictMatchState(
+ ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
+ void const* src, size_t srcSize)
+{
+ U32 const mls = ms->cParams.minMatch;
+ assert(ms->dictMatchState != NULL);
+ switch(mls)
+ {
+ default: /* includes case 3 */
+ case 4 :
+ return ZSTD_compressBlock_fast_dictMatchState_4_0(ms, seqStore, rep, src, srcSize);
+ case 5 :
+ return ZSTD_compressBlock_fast_dictMatchState_5_0(ms, seqStore, rep, src, srcSize);
+ case 6 :
+ return ZSTD_compressBlock_fast_dictMatchState_6_0(ms, seqStore, rep, src, srcSize);
+ case 7 :
+ return ZSTD_compressBlock_fast_dictMatchState_7_0(ms, seqStore, rep, src, srcSize);
+ }
+}
+
+
+static size_t ZSTD_compressBlock_fast_extDict_generic(
+ ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
+ void const* src, size_t srcSize, U32 const mls, U32 const hasStep)
+{
+ const ZSTD_compressionParameters* const cParams = &ms->cParams;
+ U32* const hashTable = ms->hashTable;
+ U32 const hlog = cParams->hashLog;
+ /* support stepSize of 0 */
+ size_t const stepSize = cParams->targetLength + !(cParams->targetLength) + 1;
+ const BYTE* const base = ms->window.base;
+ const BYTE* const dictBase = ms->window.dictBase;
+ const BYTE* const istart = (const BYTE*)src;
+ const BYTE* anchor = istart;
+ const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
+ const U32 lowLimit = ZSTD_getLowestMatchIndex(ms, endIndex, cParams->windowLog);
+ const U32 dictStartIndex = lowLimit;
+ const BYTE* const dictStart = dictBase + dictStartIndex;
+ const U32 dictLimit = ms->window.dictLimit;
+ const U32 prefixStartIndex = dictLimit < lowLimit ? lowLimit : dictLimit;
+ const BYTE* const prefixStart = base + prefixStartIndex;
+ const BYTE* const dictEnd = dictBase + prefixStartIndex;
+ const BYTE* const iend = istart + srcSize;
+ const BYTE* const ilimit = iend - 8;
+ U32 offset_1=rep[0], offset_2=rep[1];
+ U32 offsetSaved1 = 0, offsetSaved2 = 0;
+
+ const BYTE* ip0 = istart;
+ const BYTE* ip1;
+ const BYTE* ip2;
+ const BYTE* ip3;
+ U32 current0;
+
+
+ size_t hash0; /* hash for ip0 */
+ size_t hash1; /* hash for ip1 */
+ U32 idx; /* match idx for ip0 */
+ const BYTE* idxBase; /* base pointer for idx */
+
+ U32 offcode;
+ const BYTE* match0;
+ size_t mLength;
+ const BYTE* matchEnd = 0; /* initialize to avoid warning, assert != 0 later */
+
+ size_t step;
+ const BYTE* nextStep;
+ const size_t kStepIncr = (1 << (kSearchStrength - 1));
+
+ (void)hasStep; /* not currently specialized on whether it's accelerated */
+
+ DEBUGLOG(5, "ZSTD_compressBlock_fast_extDict_generic (offset_1=%u)", offset_1);
+
+ /* switch to "regular" variant if extDict is invalidated due to maxDistance */
+ if (prefixStartIndex == dictStartIndex)
+ return ZSTD_compressBlock_fast(ms, seqStore, rep, src, srcSize);
+
+ { U32 const curr = (U32)(ip0 - base);
+ U32 const maxRep = curr - dictStartIndex;
+ if (offset_2 >= maxRep) offsetSaved2 = offset_2, offset_2 = 0;
+ if (offset_1 >= maxRep) offsetSaved1 = offset_1, offset_1 = 0;
+ }
+
+ /* start each op */
+_start: /* Requires: ip0 */
+
+ step = stepSize;
+ nextStep = ip0 + kStepIncr;
+
+ /* calculate positions, ip0 - anchor == 0, so we skip step calc */
+ ip1 = ip0 + 1;
+ ip2 = ip0 + step;
+ ip3 = ip2 + 1;
+
+ if (ip3 >= ilimit) {
+ goto _cleanup;
+ }
+
+ hash0 = ZSTD_hashPtr(ip0, hlog, mls);
+ hash1 = ZSTD_hashPtr(ip1, hlog, mls);
+
+ idx = hashTable[hash0];
+ idxBase = idx < prefixStartIndex ? dictBase : base;
+
+ do {
+ { /* load repcode match for ip[2] */
+ U32 const current2 = (U32)(ip2 - base);
+ U32 const repIndex = current2 - offset_1;
+ const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base;
+ U32 rval;
+ if ( ((U32)(prefixStartIndex - repIndex) >= 4) /* intentional underflow */
+ & (offset_1 > 0) ) {
+ rval = MEM_read32(repBase + repIndex);
+ } else {
+ rval = MEM_read32(ip2) ^ 1; /* guaranteed to not match. */
+ }
+
+ /* write back hash table entry */
+ current0 = (U32)(ip0 - base);
+ hashTable[hash0] = current0;
+
+ /* check repcode at ip[2] */
+ if (MEM_read32(ip2) == rval) {
+ ip0 = ip2;
+ match0 = repBase + repIndex;
+ matchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
+ assert((match0 != prefixStart) & (match0 != dictStart));
+ mLength = ip0[-1] == match0[-1];
+ ip0 -= mLength;
+ match0 -= mLength;
+ offcode = REPCODE1_TO_OFFBASE;
+ mLength += 4;
+ goto _match;
+ } }
+
+ { /* load match for ip[0] */
+ U32 const mval = idx >= dictStartIndex ?
+ MEM_read32(idxBase + idx) :
+ MEM_read32(ip0) ^ 1; /* guaranteed not to match */
+
+ /* check match at ip[0] */
+ if (MEM_read32(ip0) == mval) {
+ /* found a match! */
+ goto _offset;
+ } }
+
+ /* lookup ip[1] */
+ idx = hashTable[hash1];
+ idxBase = idx < prefixStartIndex ? dictBase : base;
+
+ /* hash ip[2] */
+ hash0 = hash1;
+ hash1 = ZSTD_hashPtr(ip2, hlog, mls);
+
+ /* advance to next positions */
+ ip0 = ip1;
+ ip1 = ip2;
+ ip2 = ip3;
+
+ /* write back hash table entry */
+ current0 = (U32)(ip0 - base);
+ hashTable[hash0] = current0;
+
+ { /* load match for ip[0] */
+ U32 const mval = idx >= dictStartIndex ?
+ MEM_read32(idxBase + idx) :
+ MEM_read32(ip0) ^ 1; /* guaranteed not to match */
+
+ /* check match at ip[0] */
+ if (MEM_read32(ip0) == mval) {
+ /* found a match! */
+ goto _offset;
+ } }
+
+ /* lookup ip[1] */
+ idx = hashTable[hash1];
+ idxBase = idx < prefixStartIndex ? dictBase : base;
+
+ /* hash ip[2] */
+ hash0 = hash1;
+ hash1 = ZSTD_hashPtr(ip2, hlog, mls);
+
+ /* advance to next positions */
+ ip0 = ip1;
+ ip1 = ip2;
+ ip2 = ip0 + step;
+ ip3 = ip1 + step;
+
+ /* calculate step */
+ if (ip2 >= nextStep) {
+ step++;
+ PREFETCH_L1(ip1 + 64);
+ PREFETCH_L1(ip1 + 128);
+ nextStep += kStepIncr;
+ }
+ } while (ip3 < ilimit);
+
+_cleanup:
+ /* Note that there are probably still a couple positions we could search.
+ * However, it seems to be a meaningful performance hit to try to search
+ * them. So let's not. */
+
+ /* If offset_1 started invalid (offsetSaved1 != 0) and became valid (offset_1 != 0),
+ * rotate saved offsets. See comment in ZSTD_compressBlock_fast_noDict for more context. */
+ offsetSaved2 = ((offsetSaved1 != 0) && (offset_1 != 0)) ? offsetSaved1 : offsetSaved2;
+
+ /* save reps for next block */
+ rep[0] = offset_1 ? offset_1 : offsetSaved1;
+ rep[1] = offset_2 ? offset_2 : offsetSaved2;
+
+ /* Return the last literals size */
+ return (size_t)(iend - anchor);
+
+_offset: /* Requires: ip0, idx, idxBase */
+
+ /* Compute the offset code. */
+ { U32 const offset = current0 - idx;
+ const BYTE* const lowMatchPtr = idx < prefixStartIndex ? dictStart : prefixStart;
+ matchEnd = idx < prefixStartIndex ? dictEnd : iend;
+ match0 = idxBase + idx;
+ offset_2 = offset_1;
+ offset_1 = offset;
+ offcode = OFFSET_TO_OFFBASE(offset);
+ mLength = 4;
+
+ /* Count the backwards match length. */
+ while (((ip0>anchor) & (match0>lowMatchPtr)) && (ip0[-1] == match0[-1])) {
+ ip0--;
+ match0--;
+ mLength++;
+ } }
+
+_match: /* Requires: ip0, match0, offcode, matchEnd */
+
+ /* Count the forward length. */
+ assert(matchEnd != 0);
+ mLength += ZSTD_count_2segments(ip0 + mLength, match0 + mLength, iend, matchEnd, prefixStart);
+
+ ZSTD_storeSeq(seqStore, (size_t)(ip0 - anchor), anchor, iend, offcode, mLength);
+
+ ip0 += mLength;
+ anchor = ip0;
+
+ /* write next hash table entry */
+ if (ip1 < ip0) {
+ hashTable[hash1] = (U32)(ip1 - base);
+ }
+
+ /* Fill table and check for immediate repcode. */
+ if (ip0 <= ilimit) {
+ /* Fill Table */
+ assert(base+current0+2 > istart); /* check base overflow */
+ hashTable[ZSTD_hashPtr(base+current0+2, hlog, mls)] = current0+2; /* here because current+2 could be > iend-8 */
+ hashTable[ZSTD_hashPtr(ip0-2, hlog, mls)] = (U32)(ip0-2-base);
+
+ while (ip0 <= ilimit) {
+ U32 const repIndex2 = (U32)(ip0-base) - offset_2;
+ const BYTE* const repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2;
+ if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (offset_2 > 0)) /* intentional underflow */
+ && (MEM_read32(repMatch2) == MEM_read32(ip0)) ) {
+ const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
+ size_t const repLength2 = ZSTD_count_2segments(ip0+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
+ { U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; } /* swap offset_2 <=> offset_1 */
+ ZSTD_storeSeq(seqStore, 0 /*litlen*/, anchor, iend, REPCODE1_TO_OFFBASE, repLength2);
+ hashTable[ZSTD_hashPtr(ip0, hlog, mls)] = (U32)(ip0-base);
+ ip0 += repLength2;
+ anchor = ip0;
+ continue;
+ }
+ break;
+ } }
+
+ goto _start;
+}
+
+ZSTD_GEN_FAST_FN(extDict, 4, 0)
+ZSTD_GEN_FAST_FN(extDict, 5, 0)
+ZSTD_GEN_FAST_FN(extDict, 6, 0)
+ZSTD_GEN_FAST_FN(extDict, 7, 0)
+
+size_t ZSTD_compressBlock_fast_extDict(
+ ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
+ void const* src, size_t srcSize)
+{
+ U32 const mls = ms->cParams.minMatch;
+ assert(ms->dictMatchState == NULL);
+ switch(mls)
+ {
+ default: /* includes case 3 */
+ case 4 :
+ return ZSTD_compressBlock_fast_extDict_4_0(ms, seqStore, rep, src, srcSize);
+ case 5 :
+ return ZSTD_compressBlock_fast_extDict_5_0(ms, seqStore, rep, src, srcSize);
+ case 6 :
+ return ZSTD_compressBlock_fast_extDict_6_0(ms, seqStore, rep, src, srcSize);
+ case 7 :
+ return ZSTD_compressBlock_fast_extDict_7_0(ms, seqStore, rep, src, srcSize);
+ }
+}
notaz.gp2x.de / pcsx_rearmed.git / blobdiff