summaryrefslogtreecommitdiff
path: root/lib/zstd/compress/zstd_fast.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/zstd/compress/zstd_fast.c')
-rw-r--r--lib/zstd/compress/zstd_fast.c703
1 files changed, 506 insertions, 197 deletions
diff --git a/lib/zstd/compress/zstd_fast.c b/lib/zstd/compress/zstd_fast.c
index a752e6beab52..60e07e839e5f 100644
--- a/lib/zstd/compress/zstd_fast.c
+++ b/lib/zstd/compress/zstd_fast.c
@@ -1,5 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
/*
- * Copyright (c) Yann Collet, Facebook, Inc.
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
@@ -11,8 +12,46 @@
#include "zstd_compress_internal.h" /* ZSTD_hashPtr, ZSTD_count, ZSTD_storeSeq */
#include "zstd_fast.h"
+static
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+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);
+ } } } }
+}
-void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
+static
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+void ZSTD_fillHashTableForCCtx(ZSTD_MatchState_t* ms,
const void* const end,
ZSTD_dictTableLoadMethod_e dtlm)
{
@@ -25,6 +64,10 @@ void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
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.
*/
@@ -42,6 +85,60 @@ void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
} } } }
}
+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);
+ }
+}
+
+
+typedef int (*ZSTD_match4Found) (const BYTE* currentPtr, const BYTE* matchAddress, U32 matchIdx, U32 idxLowLimit);
+
+static int
+ZSTD_match4Found_cmov(const BYTE* currentPtr, const BYTE* matchAddress, U32 matchIdx, U32 idxLowLimit)
+{
+ /* Array of ~random data, should have low probability of matching data.
+ * Load from here if the index is invalid.
+ * Used to avoid unpredictable branches. */
+ static const BYTE dummy[] = {0x12,0x34,0x56,0x78};
+
+ /* currentIdx >= lowLimit is a (somewhat) unpredictable branch.
+ * However expression below compiles into conditional move.
+ */
+ const BYTE* mvalAddr = ZSTD_selectAddr(matchIdx, idxLowLimit, matchAddress, dummy);
+ /* Note: this used to be written as : return test1 && test2;
+ * Unfortunately, once inlined, these tests become branches,
+ * in which case it becomes critical that they are executed in the right order (test1 then test2).
+ * So we have to write these tests in a specific manner to ensure their ordering.
+ */
+ if (MEM_read32(currentPtr) != MEM_read32(mvalAddr)) return 0;
+ /* force ordering of these tests, which matters once the function is inlined, as they become branches */
+ __asm__("");
+ return matchIdx >= idxLowLimit;
+}
+
+static int
+ZSTD_match4Found_branch(const BYTE* currentPtr, const BYTE* matchAddress, U32 matchIdx, U32 idxLowLimit)
+{
+ /* using a branch instead of a cmov,
+ * because it's faster in scenarios where matchIdx >= idxLowLimit is generally true,
+ * aka almost all candidates are within range */
+ U32 mval;
+ if (matchIdx >= idxLowLimit) {
+ mval = MEM_read32(matchAddress);
+ } else {
+ mval = MEM_read32(currentPtr) ^ 1; /* guaranteed to not match. */
+ }
+
+ return (MEM_read32(currentPtr) == mval);
+}
+
/*
* If you squint hard enough (and ignore repcodes), the search operation at any
@@ -89,17 +186,17 @@ void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
*
* 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],
+FORCE_INLINE_TEMPLATE
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+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)
+ U32 const mls, int useCmov)
{
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;
+ size_t const stepSize = cParams->targetLength + !(cParams->targetLength) + 1; /* min 2 */
const BYTE* const base = ms->window.base;
const BYTE* const istart = (const BYTE*)src;
const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
@@ -117,12 +214,11 @@ ZSTD_compressBlock_fast_noDict_generic(
U32 rep_offset1 = rep[0];
U32 rep_offset2 = rep[1];
- U32 offsetSaved = 0;
+ 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 matchIdx; /* match idx for ip0 */
U32 offcode;
const BYTE* match0;
@@ -135,14 +231,15 @@ ZSTD_compressBlock_fast_noDict_generic(
size_t step;
const BYTE* nextStep;
const size_t kStepIncr = (1 << (kSearchStrength - 1));
+ const ZSTD_match4Found matchFound = useCmov ? ZSTD_match4Found_cmov : ZSTD_match4Found_branch;
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) offsetSaved = rep_offset2, rep_offset2 = 0;
- if (rep_offset1 > maxRep) offsetSaved = rep_offset1, rep_offset1 = 0;
+ if (rep_offset2 > maxRep) offsetSaved2 = rep_offset2, rep_offset2 = 0;
+ if (rep_offset1 > maxRep) offsetSaved1 = rep_offset1, rep_offset1 = 0;
}
/* start each op */
@@ -163,7 +260,7 @@ _start: /* Requires: ip0 */
hash0 = ZSTD_hashPtr(ip0, hlog, mls);
hash1 = ZSTD_hashPtr(ip1, hlog, mls);
- idx = hashTable[hash0];
+ matchIdx = hashTable[hash0];
do {
/* load repcode match for ip[2]*/
@@ -180,26 +277,28 @@ _start: /* Requires: ip0 */
mLength = ip0[-1] == match0[-1];
ip0 -= mLength;
match0 -= mLength;
- offcode = STORE_REPCODE_1;
+ offcode = REPCODE1_TO_OFFBASE;
mLength += 4;
+
+ /* Write next hash table entry: it's already calculated.
+ * This write is known to be safe because 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. */
- }
+ if (matchFound(ip0, base + matchIdx, matchIdx, prefixStartIndex)) {
+ /* Write next hash table entry (it's already calculated).
+ * This write is known to be safe because the ip1 == ip0 + 1,
+ * so searching will resume after ip1 */
+ hashTable[hash1] = (U32)(ip1 - base);
- /* check match at ip[0] */
- if (MEM_read32(ip0) == mval) {
- /* found a match! */
goto _offset;
}
/* lookup ip[1] */
- idx = hashTable[hash1];
+ matchIdx = hashTable[hash1];
/* hash ip[2] */
hash0 = hash1;
@@ -214,21 +313,19 @@ _start: /* Requires: ip0 */
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! */
+ if (matchFound(ip0, base + matchIdx, matchIdx, prefixStartIndex)) {
+ /* Write next hash table entry, since it's already calculated */
+ if (step <= 4) {
+ /* Avoid writing an index if it's >= position where search will resume.
+ * The minimum possible match has length 4, so search can resume at ip0 + 4.
+ */
+ hashTable[hash1] = (U32)(ip1 - base);
+ }
goto _offset;
}
/* lookup ip[1] */
- idx = hashTable[hash1];
+ matchIdx = hashTable[hash1];
/* hash ip[2] */
hash0 = hash1;
@@ -250,13 +347,28 @@ _start: /* Requires: ip0 */
} while (ip3 < ilimit);
_cleanup:
- /* Note that there are probably still a couple positions we could search.
+ /* Note that there are probably still a couple positions one 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 : offsetSaved;
- rep[1] = rep_offset2 ? rep_offset2 : offsetSaved;
+ rep[0] = rep_offset1 ? rep_offset1 : offsetSaved1;
+ rep[1] = rep_offset2 ? rep_offset2 : offsetSaved2;
/* Return the last literals size */
return (size_t)(iend - anchor);
@@ -264,10 +376,10 @@ _cleanup:
_offset: /* Requires: ip0, idx */
/* Compute the offset code. */
- match0 = base + idx;
+ match0 = base + matchIdx;
rep_offset2 = rep_offset1;
rep_offset1 = (U32)(ip0-match0);
- offcode = STORE_OFFSET(rep_offset1);
+ offcode = OFFSET_TO_OFFBASE(rep_offset1);
mLength = 4;
/* Count the backwards match length. */
@@ -287,11 +399,6 @@ _match: /* Requires: ip0, match0, offcode */
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 */
@@ -306,7 +413,7 @@ _match: /* Requires: ip0, match0, offcode */
{ 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, STORE_REPCODE_1, rLength);
+ ZSTD_storeSeq(seqStore, 0 /*litLen*/, anchor, iend, REPCODE1_TO_OFFBASE, rLength);
anchor = ip0;
continue; /* faster when present (confirmed on gcc-8) ... (?) */
} } }
@@ -314,12 +421,12 @@ _match: /* Requires: ip0, match0, offcode */
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], \
+#define ZSTD_GEN_FAST_FN(dictMode, mml, cmov) \
+ static size_t ZSTD_compressBlock_fast_##dictMode##_##mml##_##cmov( \
+ 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); \
+ return ZSTD_compressBlock_fast_##dictMode##_generic(ms, seqStore, rep, src, srcSize, mml, cmov); \
}
ZSTD_GEN_FAST_FN(noDict, 4, 1)
@@ -333,13 +440,15 @@ 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],
+ ZSTD_MatchState_t* ms, SeqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
void const* src, size_t srcSize)
{
- U32 const mls = ms->cParams.minMatch;
+ U32 const mml = ms->cParams.minMatch;
+ /* use cmov when "candidate in range" branch is likely unpredictable */
+ int const useCmov = ms->cParams.windowLog < 19;
assert(ms->dictMatchState == NULL);
- if (ms->cParams.targetLength > 1) {
- switch(mls)
+ if (useCmov) {
+ switch(mml)
{
default: /* includes case 3 */
case 4 :
@@ -352,7 +461,8 @@ size_t ZSTD_compressBlock_fast(
return ZSTD_compressBlock_fast_noDict_7_1(ms, seqStore, rep, src, srcSize);
}
} else {
- switch(mls)
+ /* use a branch instead */
+ switch(mml)
{
default: /* includes case 3 */
case 4 :
@@ -364,13 +474,13 @@ size_t ZSTD_compressBlock_fast(
case 7 :
return ZSTD_compressBlock_fast_noDict_7_0(ms, seqStore, rep, src, srcSize);
}
-
}
}
FORCE_INLINE_TEMPLATE
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
size_t ZSTD_compressBlock_fast_dictMatchState_generic(
- ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
+ 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;
@@ -380,16 +490,16 @@ size_t ZSTD_compressBlock_fast_dictMatchState_generic(
U32 const stepSize = cParams->targetLength + !(cParams->targetLength);
const BYTE* const base = ms->window.base;
const BYTE* const istart = (const BYTE*)src;
- const BYTE* ip = istart;
+ 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];
- U32 offsetSaved = 0;
- const ZSTD_matchState_t* const dms = ms->dictMatchState;
+ 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;
@@ -397,13 +507,13 @@ size_t ZSTD_compressBlock_fast_dictMatchState_generic(
const BYTE* const dictStart = dictBase + dictStartIndex;
const BYTE* const dictEnd = dms->window.nextSrc;
const U32 dictIndexDelta = prefixStartIndex - (U32)(dictEnd - dictBase);
- const U32 dictAndPrefixLength = (U32)(ip - prefixStart + dictEnd - dictStart);
- const U32 dictHLog = dictCParams->hashLog;
+ 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)(ip - base) + srcSize);
+ 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 */
@@ -413,106 +523,154 @@ size_t ZSTD_compressBlock_fast_dictMatchState_generic(
* 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");
- ip += (dictAndPrefixLength == 0);
+ ip0 += (dictAndPrefixLength == 0);
/* dictMatchState repCode checks don't currently handle repCode == 0
* disabling. */
assert(offset_1 <= dictAndPrefixLength);
assert(offset_2 <= dictAndPrefixLength);
- /* Main Search Loop */
- while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
+ /* Outer search loop */
+ assert(stepSize >= 1);
+ while (ip1 <= ilimit) { /* repcode check at (ip0 + 1) is safe because ip0 < ip1 */
size_t mLength;
- size_t const h = ZSTD_hashPtr(ip, hlog, mls);
- U32 const curr = (U32)(ip-base);
- U32 const matchIndex = hashTable[h];
- const BYTE* match = base + matchIndex;
- const U32 repIndex = curr + 1 - offset_1;
- const BYTE* repMatch = (repIndex < prefixStartIndex) ?
- dictBase + (repIndex - dictIndexDelta) :
- base + repIndex;
- hashTable[h] = curr; /* update hash table */
-
- if ( ((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex isn't overlapping dict + prefix */
- && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
- const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
- mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4;
- ip++;
- ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, STORE_REPCODE_1, mLength);
- } else if ( (matchIndex <= prefixStartIndex) ) {
- size_t const dictHash = ZSTD_hashPtr(ip, dictHLog, mls);
- U32 const dictMatchIndex = dictHashTable[dictHash];
- const BYTE* dictMatch = dictBase + dictMatchIndex;
- if (dictMatchIndex <= dictStartIndex ||
- MEM_read32(dictMatch) != MEM_read32(ip)) {
- assert(stepSize >= 1);
- ip += ((ip-anchor) >> kSearchStrength) + stepSize;
- continue;
- } else {
- /* found a dict match */
- U32 const offset = (U32)(curr-dictMatchIndex-dictIndexDelta);
- mLength = ZSTD_count_2segments(ip+4, dictMatch+4, iend, dictEnd, prefixStart) + 4;
- while (((ip>anchor) & (dictMatch>dictStart))
- && (ip[-1] == dictMatch[-1])) {
- ip--; dictMatch--; 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 ((ZSTD_index_overlap_check(prefixStartIndex, repIndex))
+ && (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 (ZSTD_match4Found_cmov(ip0, match, matchIndex, prefixStartIndex)) {
+ /* found a regular match of size >= 4 */
+ 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)(ip-anchor), anchor, iend, STORE_OFFSET(offset), mLength);
+ ZSTD_storeSeq(seqStore, (size_t) (ip0 - anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength);
+ break;
}
- } else if (MEM_read32(match) != MEM_read32(ip)) {
- /* it's not a match, and we're not going to check the dictionary */
- assert(stepSize >= 1);
- ip += ((ip-anchor) >> kSearchStrength) + stepSize;
- continue;
- } else {
- /* found a regular match */
- U32 const offset = (U32)(ip-match);
- mLength = ZSTD_count(ip+4, match+4, iend) + 4;
- while (((ip>anchor) & (match>prefixStart))
- && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
- offset_2 = offset_1;
- offset_1 = offset;
- ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, STORE_OFFSET(offset), mLength);
- }
+
+ /* 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 */
- ip += mLength;
- anchor = ip;
+ assert(mLength);
+ ip0 += mLength;
+ anchor = ip0;
- if (ip <= ilimit) {
+ 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(ip-2, hlog, mls)] = (U32)(ip-2-base);
+ hashTable[ZSTD_hashPtr(ip0-2, hlog, mls)] = (U32)(ip0-2-base);
/* check immediate repcode */
- while (ip <= ilimit) {
- U32 const current2 = (U32)(ip-base);
+ 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(ip)) ) {
+ if ( (ZSTD_index_overlap_check(prefixStartIndex, repIndex2))
+ && (MEM_read32(repMatch2) == MEM_read32(ip0))) {
const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
- size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
+ 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, STORE_REPCODE_1, repLength2);
- hashTable[ZSTD_hashPtr(ip, hlog, mls)] = current2;
- ip += repLength2;
- anchor = ip;
+ 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 ? offset_1 : offsetSaved;
- rep[1] = offset_2 ? offset_2 : offsetSaved;
+ rep[0] = offset_1;
+ rep[1] = offset_2;
/* Return the last literals size */
return (size_t)(iend - anchor);
@@ -525,7 +683,7 @@ 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],
+ ZSTD_MatchState_t* ms, SeqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
void const* src, size_t srcSize)
{
U32 const mls = ms->cParams.minMatch;
@@ -545,19 +703,20 @@ size_t ZSTD_compressBlock_fast_dictMatchState(
}
-static size_t ZSTD_compressBlock_fast_extDict_generic(
- ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
+static
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+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 */
- U32 const stepSize = cParams->targetLength + !(cParams->targetLength);
+ 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* ip = istart;
const BYTE* anchor = istart;
const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
const U32 lowLimit = ZSTD_getLowestMatchIndex(ms, endIndex, cParams->windowLog);
@@ -570,6 +729,28 @@ static size_t ZSTD_compressBlock_fast_extDict_generic(
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 */
@@ -579,75 +760,202 @@ static size_t ZSTD_compressBlock_fast_extDict_generic(
if (prefixStartIndex == dictStartIndex)
return ZSTD_compressBlock_fast(ms, seqStore, rep, src, srcSize);
- /* Search Loop */
- while (ip < ilimit) { /* < instead of <=, because (ip+1) */
- const size_t h = ZSTD_hashPtr(ip, hlog, mls);
- const U32 matchIndex = hashTable[h];
- const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base;
- const BYTE* match = matchBase + matchIndex;
- const U32 curr = (U32)(ip-base);
- const U32 repIndex = curr + 1 - offset_1;
- const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base;
- const BYTE* const repMatch = repBase + repIndex;
- hashTable[h] = curr; /* update hash table */
- DEBUGLOG(7, "offset_1 = %u , curr = %u", offset_1, curr);
-
- if ( ( ((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow */
- & (offset_1 <= curr+1 - dictStartIndex) ) /* note: we are searching at curr+1 */
- && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
- const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
- size_t const rLength = ZSTD_count_2segments(ip+1 +4, repMatch +4, iend, repMatchEnd, prefixStart) + 4;
- ip++;
- ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, STORE_REPCODE_1, rLength);
- ip += rLength;
- anchor = ip;
- } else {
- if ( (matchIndex < dictStartIndex) ||
- (MEM_read32(match) != MEM_read32(ip)) ) {
- assert(stepSize >= 1);
- ip += ((ip-anchor) >> kSearchStrength) + stepSize;
- continue;
+ { 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. */
}
- { const BYTE* const matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend;
- const BYTE* const lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart;
- U32 const offset = curr - matchIndex;
- size_t mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, prefixStart) + 4;
- while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
- offset_2 = offset_1; offset_1 = offset; /* update offset history */
- ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, STORE_OFFSET(offset), mLength);
- ip += mLength;
- anchor = ip;
+
+ /* 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;
} }
- if (ip <= ilimit) {
- /* Fill Table */
- hashTable[ZSTD_hashPtr(base+curr+2, hlog, mls)] = curr+2;
- hashTable[ZSTD_hashPtr(ip-2, hlog, mls)] = (U32)(ip-2-base);
- /* check immediate repcode */
- while (ip <= ilimit) {
- U32 const current2 = (U32)(ip-base);
- U32 const repIndex2 = current2 - offset_2;
- const BYTE* const repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2;
- if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (offset_2 <= curr - dictStartIndex)) /* intentional overflow */
- && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
- const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
- size_t const repLength2 = ZSTD_count_2segments(ip+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, STORE_REPCODE_1, repLength2);
- hashTable[ZSTD_hashPtr(ip, hlog, mls)] = current2;
- ip += repLength2;
- anchor = ip;
- continue;
- }
- break;
- } } }
+ { /* 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;
- rep[1] = offset_2;
+ 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 ( ((ZSTD_index_overlap_check(prefixStartIndex, repIndex2)) & (offset_2 > 0))
+ && (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)
@@ -656,10 +964,11 @@ 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],
+ 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 */
generated by cgit v1.2.3 (git 2.46.0) at 2025-10-31 08:48:36 +0000