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Diffstat (limited to '3rdparty/zstd/contrib/externalSequenceProducer/sequence_producer.c')
-rw-r--r--3rdparty/zstd/contrib/externalSequenceProducer/sequence_producer.c80
1 files changed, 80 insertions, 0 deletions
diff --git a/3rdparty/zstd/contrib/externalSequenceProducer/sequence_producer.c b/3rdparty/zstd/contrib/externalSequenceProducer/sequence_producer.c
new file mode 100644
index 00000000000..60a2f9572b0
--- /dev/null
+++ b/3rdparty/zstd/contrib/externalSequenceProducer/sequence_producer.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) Yann Collet, Meta Platforms, 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_compress_internal.h"
+#include "sequence_producer.h"
+
+#define HSIZE 1024
+static U32 const HLOG = 10;
+static U32 const MLS = 4;
+static U32 const BADIDX = 0xffffffff;
+
+size_t simpleSequenceProducer(
+ void* sequenceProducerState,
+ ZSTD_Sequence* outSeqs, size_t outSeqsCapacity,
+ const void* src, size_t srcSize,
+ const void* dict, size_t dictSize,
+ int compressionLevel,
+ size_t windowSize
+) {
+ const BYTE* const istart = (const BYTE*)src;
+ const BYTE* const iend = istart + srcSize;
+ const BYTE* ip = istart;
+ const BYTE* anchor = istart;
+ size_t seqCount = 0;
+ U32 hashTable[HSIZE];
+
+ (void)sequenceProducerState;
+ (void)dict;
+ (void)dictSize;
+ (void)outSeqsCapacity;
+ (void)compressionLevel;
+
+ { int i;
+ for (i=0; i < HSIZE; i++) {
+ hashTable[i] = BADIDX;
+ } }
+
+ while (ip + MLS < iend) {
+ size_t const hash = ZSTD_hashPtr(ip, HLOG, MLS);
+ U32 const matchIndex = hashTable[hash];
+ hashTable[hash] = (U32)(ip - istart);
+
+ if (matchIndex != BADIDX) {
+ const BYTE* const match = istart + matchIndex;
+ U32 const matchLen = (U32)ZSTD_count(ip, match, iend);
+ if (matchLen >= ZSTD_MINMATCH_MIN) {
+ U32 const litLen = (U32)(ip - anchor);
+ U32 const offset = (U32)(ip - match);
+ ZSTD_Sequence const seq = {
+ offset, litLen, matchLen, 0
+ };
+
+ /* Note: it's crucial to stay within the window size! */
+ if (offset <= windowSize) {
+ outSeqs[seqCount++] = seq;
+ ip += matchLen;
+ anchor = ip;
+ continue;
+ }
+ }
+ }
+
+ ip++;
+ }
+
+ { ZSTD_Sequence const finalSeq = {
+ 0, (U32)(iend - anchor), 0, 0
+ };
+ outSeqs[seqCount++] = finalSeq;
+ }
+
+ return seqCount;
+}