| /* |
| * 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; |
| } |
| } |