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-rw-r--r--src/zstd/lib/compress/zstd_fast.c242
1 files changed, 242 insertions, 0 deletions
diff --git a/src/zstd/lib/compress/zstd_fast.c b/src/zstd/lib/compress/zstd_fast.c
new file mode 100644
index 00000000..2e057017
--- /dev/null
+++ b/src/zstd/lib/compress/zstd_fast.c
@@ -0,0 +1,242 @@
+/*
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * 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_fast.h"
+
+
+void ZSTD_fillHashTable (ZSTD_CCtx* zc, const void* end, const U32 mls)
+{
+ U32* const hashTable = zc->hashTable;
+ U32 const hBits = zc->appliedParams.cParams.hashLog;
+ const BYTE* const base = zc->base;
+ const BYTE* ip = base + zc->nextToUpdate;
+ const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
+ const size_t fastHashFillStep = 3;
+
+ while(ip <= iend) {
+ hashTable[ZSTD_hashPtr(ip, hBits, mls)] = (U32)(ip - base);
+ ip += fastHashFillStep;
+ }
+}
+
+
+FORCE_INLINE_TEMPLATE
+size_t ZSTD_compressBlock_fast_generic(ZSTD_CCtx* cctx,
+ const void* src, size_t srcSize,
+ const U32 mls)
+{
+ U32* const hashTable = cctx->hashTable;
+ U32 const hBits = cctx->appliedParams.cParams.hashLog;
+ seqStore_t* seqStorePtr = &(cctx->seqStore);
+ const BYTE* const base = cctx->base;
+ const BYTE* const istart = (const BYTE*)src;
+ const BYTE* ip = istart;
+ const BYTE* anchor = istart;
+ const U32 lowestIndex = cctx->dictLimit;
+ const BYTE* const lowest = base + lowestIndex;
+ const BYTE* const iend = istart + srcSize;
+ const BYTE* const ilimit = iend - HASH_READ_SIZE;
+ U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1];
+ U32 offsetSaved = 0;
+
+ /* init */
+ ip += (ip==lowest);
+ { U32 const maxRep = (U32)(ip-lowest);
+ if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
+ if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
+ }
+
+ /* Main Search Loop */
+ while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
+ size_t mLength;
+ size_t const h = ZSTD_hashPtr(ip, hBits, mls);
+ U32 const current = (U32)(ip-base);
+ U32 const matchIndex = hashTable[h];
+ const BYTE* match = base + matchIndex;
+ hashTable[h] = current; /* update hash table */
+
+ if ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) {
+ mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
+ ip++;
+ ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH);
+ } else {
+ U32 offset;
+ if ( (matchIndex <= lowestIndex) || (MEM_read32(match) != MEM_read32(ip)) ) {
+ ip += ((ip-anchor) >> g_searchStrength) + 1;
+ continue;
+ }
+ mLength = ZSTD_count(ip+4, match+4, iend) + 4;
+ offset = (U32)(ip-match);
+ while (((ip>anchor) & (match>lowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
+ offset_2 = offset_1;
+ offset_1 = offset;
+
+ ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
+ }
+
+ /* match found */
+ ip += mLength;
+ anchor = ip;
+
+ if (ip <= ilimit) {
+ /* Fill Table */
+ hashTable[ZSTD_hashPtr(base+current+2, hBits, mls)] = current+2; /* here because current+2 could be > iend-8 */
+ hashTable[ZSTD_hashPtr(ip-2, hBits, mls)] = (U32)(ip-2-base);
+ /* check immediate repcode */
+ while ( (ip <= ilimit)
+ && ( (offset_2>0)
+ & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
+ /* store sequence */
+ size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
+ { U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; } /* swap offset_2 <=> offset_1 */
+ hashTable[ZSTD_hashPtr(ip, hBits, mls)] = (U32)(ip-base);
+ ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength-MINMATCH);
+ ip += rLength;
+ anchor = ip;
+ continue; /* faster when present ... (?) */
+ } } }
+
+ /* save reps for next block */
+ seqStorePtr->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
+ seqStorePtr->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;
+
+ /* Return the last literals size */
+ return iend - anchor;
+}
+
+
+size_t ZSTD_compressBlock_fast(ZSTD_CCtx* ctx,
+ const void* src, size_t srcSize)
+{
+ const U32 mls = ctx->appliedParams.cParams.searchLength;
+ switch(mls)
+ {
+ default: /* includes case 3 */
+ case 4 :
+ return ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 4);
+ case 5 :
+ return ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 5);
+ case 6 :
+ return ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 6);
+ case 7 :
+ return ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 7);
+ }
+}
+
+
+static size_t ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx* ctx,
+ const void* src, size_t srcSize,
+ const U32 mls)
+{
+ U32* hashTable = ctx->hashTable;
+ const U32 hBits = ctx->appliedParams.cParams.hashLog;
+ seqStore_t* seqStorePtr = &(ctx->seqStore);
+ const BYTE* const base = ctx->base;
+ const BYTE* const dictBase = ctx->dictBase;
+ const BYTE* const istart = (const BYTE*)src;
+ const BYTE* ip = istart;
+ const BYTE* anchor = istart;
+ const U32 lowestIndex = ctx->lowLimit;
+ const BYTE* const dictStart = dictBase + lowestIndex;
+ const U32 dictLimit = ctx->dictLimit;
+ const BYTE* const lowPrefixPtr = base + dictLimit;
+ const BYTE* const dictEnd = dictBase + dictLimit;
+ const BYTE* const iend = istart + srcSize;
+ const BYTE* const ilimit = iend - 8;
+ U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1];
+
+ /* Search Loop */
+ while (ip < ilimit) { /* < instead of <=, because (ip+1) */
+ const size_t h = ZSTD_hashPtr(ip, hBits, mls);
+ const U32 matchIndex = hashTable[h];
+ const BYTE* matchBase = matchIndex < dictLimit ? dictBase : base;
+ const BYTE* match = matchBase + matchIndex;
+ const U32 current = (U32)(ip-base);
+ const U32 repIndex = current + 1 - offset_1; /* offset_1 expected <= current +1 */
+ const BYTE* repBase = repIndex < dictLimit ? dictBase : base;
+ const BYTE* repMatch = repBase + repIndex;
+ size_t mLength;
+ hashTable[h] = current; /* update hash table */
+
+ if ( (((U32)((dictLimit-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex))
+ && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
+ const BYTE* repMatchEnd = repIndex < dictLimit ? dictEnd : iend;
+ mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, lowPrefixPtr) + 4;
+ ip++;
+ ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH);
+ } else {
+ if ( (matchIndex < lowestIndex) ||
+ (MEM_read32(match) != MEM_read32(ip)) ) {
+ ip += ((ip-anchor) >> g_searchStrength) + 1;
+ continue;
+ }
+ { const BYTE* matchEnd = matchIndex < dictLimit ? dictEnd : iend;
+ const BYTE* lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr;
+ U32 offset;
+ mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, lowPrefixPtr) + 4;
+ while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
+ offset = current - matchIndex;
+ offset_2 = offset_1;
+ offset_1 = offset;
+ ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
+ } }
+
+ /* found a match : store it */
+ ip += mLength;
+ anchor = ip;
+
+ if (ip <= ilimit) {
+ /* Fill Table */
+ hashTable[ZSTD_hashPtr(base+current+2, hBits, mls)] = current+2;
+ hashTable[ZSTD_hashPtr(ip-2, hBits, 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* repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2;
+ if ( (((U32)((dictLimit-1) - repIndex2) >= 3) & (repIndex2 > lowestIndex)) /* intentional overflow */
+ && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
+ const BYTE* const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend;
+ size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, lowPrefixPtr) + 4;
+ U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
+ ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2-MINMATCH);
+ hashTable[ZSTD_hashPtr(ip, hBits, mls)] = current2;
+ ip += repLength2;
+ anchor = ip;
+ continue;
+ }
+ break;
+ } } }
+
+ /* save reps for next block */
+ seqStorePtr->repToConfirm[0] = offset_1; seqStorePtr->repToConfirm[1] = offset_2;
+
+ /* Return the last literals size */
+ return iend - anchor;
+}
+
+
+size_t ZSTD_compressBlock_fast_extDict(ZSTD_CCtx* ctx,
+ const void* src, size_t srcSize)
+{
+ U32 const mls = ctx->appliedParams.cParams.searchLength;
+ switch(mls)
+ {
+ default: /* includes case 3 */
+ case 4 :
+ return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 4);
+ case 5 :
+ return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 5);
+ case 6 :
+ return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 6);
+ case 7 :
+ return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 7);
+ }
+}
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