First Commit

externals/zstd/tests/external_matchfinder.c

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+/*
+ * 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 "external_matchfinder.h"
+#include <string.h>
+#include "zstd_compress_internal.h"
+
+#define HSIZE 1024
+static U32 const HLOG = 10;
+static U32 const MLS = 4;
+static U32 const BADIDX = 0xffffffff;
+
+static 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;
+}
+
+size_t zstreamSequenceProducer(
+  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
+) {
+    EMF_testCase const testCase = *((EMF_testCase*)sequenceProducerState);
+    memset(outSeqs, 0, outSeqsCapacity);
+
+    switch (testCase) {
+        case EMF_ZERO_SEQS:
+            return 0;
+        case EMF_ONE_BIG_SEQ:
+            outSeqs[0].offset = 0;
+            outSeqs[0].matchLength = 0;
+            outSeqs[0].litLength = (U32)(srcSize);
+            return 1;
+         case EMF_LOTS_OF_SEQS:
+            return simpleSequenceProducer(
+                sequenceProducerState,
+                outSeqs, outSeqsCapacity,
+                src, srcSize,
+                dict, dictSize,
+                compressionLevel,
+                windowSize
+            );
+        case EMF_INVALID_OFFSET:
+            outSeqs[0].offset = 1 << 20;
+            outSeqs[0].matchLength = 4;
+            outSeqs[0].litLength = (U32)(srcSize - 4);
+            return 1;
+        case EMF_INVALID_MATCHLEN:
+            outSeqs[0].offset = 1;
+            outSeqs[0].matchLength = (U32)(srcSize);
+            outSeqs[0].litLength = 1;
+            return 1;
+        case EMF_INVALID_LITLEN:
+            outSeqs[0].offset = 0;
+            outSeqs[0].matchLength = 0;
+            outSeqs[0].litLength = (U32)(srcSize + 1);
+            return 1;
+        case EMF_INVALID_LAST_LITS:
+            outSeqs[0].offset = 1;
+            outSeqs[0].matchLength = 1;
+            outSeqs[0].litLength = 1;
+            outSeqs[1].offset = 0;
+            outSeqs[1].matchLength = 0;
+            outSeqs[1].litLength = (U32)(srcSize - 1);
+            return 2;
+        case EMF_SMALL_ERROR:
+            return outSeqsCapacity + 1;
+        case EMF_BIG_ERROR:
+        default:
+            return ZSTD_SEQUENCE_PRODUCER_ERROR;
+    }
+}