diff options
Diffstat (limited to 'vendor/github.com/DataDog/zstd/zstd_ldm.c')
| -rw-r--r-- | vendor/github.com/DataDog/zstd/zstd_ldm.c | 597 |
1 files changed, 0 insertions, 597 deletions
diff --git a/vendor/github.com/DataDog/zstd/zstd_ldm.c b/vendor/github.com/DataDog/zstd/zstd_ldm.c deleted file mode 100644 index 784d20f3a..000000000 --- a/vendor/github.com/DataDog/zstd/zstd_ldm.c +++ /dev/null @@ -1,597 +0,0 @@ -/* - * 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). - */ - -#include "zstd_ldm.h" - -#include "debug.h" -#include "zstd_fast.h" /* ZSTD_fillHashTable() */ -#include "zstd_double_fast.h" /* ZSTD_fillDoubleHashTable() */ - -#define LDM_BUCKET_SIZE_LOG 3 -#define LDM_MIN_MATCH_LENGTH 64 -#define LDM_HASH_RLOG 7 -#define LDM_HASH_CHAR_OFFSET 10 - -void ZSTD_ldm_adjustParameters(ldmParams_t* params, - ZSTD_compressionParameters const* cParams) -{ - params->windowLog = cParams->windowLog; - ZSTD_STATIC_ASSERT(LDM_BUCKET_SIZE_LOG <= ZSTD_LDM_BUCKETSIZELOG_MAX); - DEBUGLOG(4, "ZSTD_ldm_adjustParameters"); - if (!params->bucketSizeLog) params->bucketSizeLog = LDM_BUCKET_SIZE_LOG; - if (!params->minMatchLength) params->minMatchLength = LDM_MIN_MATCH_LENGTH; - if (cParams->strategy >= ZSTD_btopt) { - /* Get out of the way of the optimal parser */ - U32 const minMatch = MAX(cParams->targetLength, params->minMatchLength); - assert(minMatch >= ZSTD_LDM_MINMATCH_MIN); - assert(minMatch <= ZSTD_LDM_MINMATCH_MAX); - params->minMatchLength = minMatch; - } - if (params->hashLog == 0) { - params->hashLog = MAX(ZSTD_HASHLOG_MIN, params->windowLog - LDM_HASH_RLOG); - assert(params->hashLog <= ZSTD_HASHLOG_MAX); - } - if (params->hashRateLog == 0) { - params->hashRateLog = params->windowLog < params->hashLog - ? 0 - : params->windowLog - params->hashLog; - } - params->bucketSizeLog = MIN(params->bucketSizeLog, params->hashLog); -} - -size_t ZSTD_ldm_getTableSize(ldmParams_t params) -{ - size_t const ldmHSize = ((size_t)1) << params.hashLog; - size_t const ldmBucketSizeLog = MIN(params.bucketSizeLog, params.hashLog); - size_t const ldmBucketSize = - ((size_t)1) << (params.hashLog - ldmBucketSizeLog); - size_t const totalSize = ldmBucketSize + ldmHSize * sizeof(ldmEntry_t); - return params.enableLdm ? totalSize : 0; -} - -size_t ZSTD_ldm_getMaxNbSeq(ldmParams_t params, size_t maxChunkSize) -{ - return params.enableLdm ? (maxChunkSize / params.minMatchLength) : 0; -} - -/** ZSTD_ldm_getSmallHash() : - * numBits should be <= 32 - * If numBits==0, returns 0. - * @return : the most significant numBits of value. */ -static U32 ZSTD_ldm_getSmallHash(U64 value, U32 numBits) -{ - assert(numBits <= 32); - return numBits == 0 ? 0 : (U32)(value >> (64 - numBits)); -} - -/** ZSTD_ldm_getChecksum() : - * numBitsToDiscard should be <= 32 - * @return : the next most significant 32 bits after numBitsToDiscard */ -static U32 ZSTD_ldm_getChecksum(U64 hash, U32 numBitsToDiscard) -{ - assert(numBitsToDiscard <= 32); - return (hash >> (64 - 32 - numBitsToDiscard)) & 0xFFFFFFFF; -} - -/** ZSTD_ldm_getTag() ; - * Given the hash, returns the most significant numTagBits bits - * after (32 + hbits) bits. - * - * If there are not enough bits remaining, return the last - * numTagBits bits. */ -static U32 ZSTD_ldm_getTag(U64 hash, U32 hbits, U32 numTagBits) -{ - assert(numTagBits < 32 && hbits <= 32); - if (32 - hbits < numTagBits) { - return hash & (((U32)1 << numTagBits) - 1); - } else { - return (hash >> (32 - hbits - numTagBits)) & (((U32)1 << numTagBits) - 1); - } -} - -/** ZSTD_ldm_getBucket() : - * Returns a pointer to the start of the bucket associated with hash. */ -static ldmEntry_t* ZSTD_ldm_getBucket( - ldmState_t* ldmState, size_t hash, ldmParams_t const ldmParams) -{ - return ldmState->hashTable + (hash << ldmParams.bucketSizeLog); -} - -/** ZSTD_ldm_insertEntry() : - * Insert the entry with corresponding hash into the hash table */ -static void ZSTD_ldm_insertEntry(ldmState_t* ldmState, - size_t const hash, const ldmEntry_t entry, - ldmParams_t const ldmParams) -{ - BYTE* const bucketOffsets = ldmState->bucketOffsets; - *(ZSTD_ldm_getBucket(ldmState, hash, ldmParams) + bucketOffsets[hash]) = entry; - bucketOffsets[hash]++; - bucketOffsets[hash] &= ((U32)1 << ldmParams.bucketSizeLog) - 1; -} - -/** ZSTD_ldm_makeEntryAndInsertByTag() : - * - * Gets the small hash, checksum, and tag from the rollingHash. - * - * If the tag matches (1 << ldmParams.hashRateLog)-1, then - * creates an ldmEntry from the offset, and inserts it into the hash table. - * - * hBits is the length of the small hash, which is the most significant hBits - * of rollingHash. The checksum is the next 32 most significant bits, followed - * by ldmParams.hashRateLog bits that make up the tag. */ -static void ZSTD_ldm_makeEntryAndInsertByTag(ldmState_t* ldmState, - U64 const rollingHash, - U32 const hBits, - U32 const offset, - ldmParams_t const ldmParams) -{ - U32 const tag = ZSTD_ldm_getTag(rollingHash, hBits, ldmParams.hashRateLog); - U32 const tagMask = ((U32)1 << ldmParams.hashRateLog) - 1; - if (tag == tagMask) { - U32 const hash = ZSTD_ldm_getSmallHash(rollingHash, hBits); - U32 const checksum = ZSTD_ldm_getChecksum(rollingHash, hBits); - ldmEntry_t entry; - entry.offset = offset; - entry.checksum = checksum; - ZSTD_ldm_insertEntry(ldmState, hash, entry, ldmParams); - } -} - -/** ZSTD_ldm_countBackwardsMatch() : - * Returns the number of bytes that match backwards before pIn and pMatch. - * - * We count only bytes where pMatch >= pBase and pIn >= pAnchor. */ -static size_t ZSTD_ldm_countBackwardsMatch( - const BYTE* pIn, const BYTE* pAnchor, - const BYTE* pMatch, const BYTE* pBase) -{ - size_t matchLength = 0; - while (pIn > pAnchor && pMatch > pBase && pIn[-1] == pMatch[-1]) { - pIn--; - pMatch--; - matchLength++; - } - return matchLength; -} - -/** ZSTD_ldm_fillFastTables() : - * - * Fills the relevant tables for the ZSTD_fast and ZSTD_dfast strategies. - * This is similar to ZSTD_loadDictionaryContent. - * - * The tables for the other strategies are filled within their - * block compressors. */ -static size_t ZSTD_ldm_fillFastTables(ZSTD_matchState_t* ms, - void const* end) -{ - const BYTE* const iend = (const BYTE*)end; - - switch(ms->cParams.strategy) - { - case ZSTD_fast: - ZSTD_fillHashTable(ms, iend, ZSTD_dtlm_fast); - break; - - case ZSTD_dfast: - ZSTD_fillDoubleHashTable(ms, iend, ZSTD_dtlm_fast); - break; - - case ZSTD_greedy: - case ZSTD_lazy: - case ZSTD_lazy2: - case ZSTD_btlazy2: - case ZSTD_btopt: - case ZSTD_btultra: - case ZSTD_btultra2: - break; - default: - assert(0); /* not possible : not a valid strategy id */ - } - - return 0; -} - -/** ZSTD_ldm_fillLdmHashTable() : - * - * Fills hashTable from (lastHashed + 1) to iend (non-inclusive). - * lastHash is the rolling hash that corresponds to lastHashed. - * - * Returns the rolling hash corresponding to position iend-1. */ -static U64 ZSTD_ldm_fillLdmHashTable(ldmState_t* state, - U64 lastHash, const BYTE* lastHashed, - const BYTE* iend, const BYTE* base, - U32 hBits, ldmParams_t const ldmParams) -{ - U64 rollingHash = lastHash; - const BYTE* cur = lastHashed + 1; - - while (cur < iend) { - rollingHash = ZSTD_rollingHash_rotate(rollingHash, cur[-1], - cur[ldmParams.minMatchLength-1], - state->hashPower); - ZSTD_ldm_makeEntryAndInsertByTag(state, - rollingHash, hBits, - (U32)(cur - base), ldmParams); - ++cur; - } - return rollingHash; -} - - -/** ZSTD_ldm_limitTableUpdate() : - * - * Sets cctx->nextToUpdate to a position corresponding closer to anchor - * if it is far way - * (after a long match, only update tables a limited amount). */ -static void ZSTD_ldm_limitTableUpdate(ZSTD_matchState_t* ms, const BYTE* anchor) -{ - U32 const current = (U32)(anchor - ms->window.base); - if (current > ms->nextToUpdate + 1024) { - ms->nextToUpdate = - current - MIN(512, current - ms->nextToUpdate - 1024); - } -} - -static size_t ZSTD_ldm_generateSequences_internal( - ldmState_t* ldmState, rawSeqStore_t* rawSeqStore, - ldmParams_t const* params, void const* src, size_t srcSize) -{ - /* LDM parameters */ - int const extDict = ZSTD_window_hasExtDict(ldmState->window); - U32 const minMatchLength = params->minMatchLength; - U64 const hashPower = ldmState->hashPower; - U32 const hBits = params->hashLog - params->bucketSizeLog; - U32 const ldmBucketSize = 1U << params->bucketSizeLog; - U32 const hashRateLog = params->hashRateLog; - U32 const ldmTagMask = (1U << params->hashRateLog) - 1; - /* Prefix and extDict parameters */ - U32 const dictLimit = ldmState->window.dictLimit; - U32 const lowestIndex = extDict ? ldmState->window.lowLimit : dictLimit; - BYTE const* const base = ldmState->window.base; - BYTE const* const dictBase = extDict ? ldmState->window.dictBase : NULL; - BYTE const* const dictStart = extDict ? dictBase + lowestIndex : NULL; - BYTE const* const dictEnd = extDict ? dictBase + dictLimit : NULL; - BYTE const* const lowPrefixPtr = base + dictLimit; - /* Input bounds */ - BYTE const* const istart = (BYTE const*)src; - BYTE const* const iend = istart + srcSize; - BYTE const* const ilimit = iend - MAX(minMatchLength, HASH_READ_SIZE); - /* Input positions */ - BYTE const* anchor = istart; - BYTE const* ip = istart; - /* Rolling hash */ - BYTE const* lastHashed = NULL; - U64 rollingHash = 0; - - while (ip <= ilimit) { - size_t mLength; - U32 const current = (U32)(ip - base); - size_t forwardMatchLength = 0, backwardMatchLength = 0; - ldmEntry_t* bestEntry = NULL; - if (ip != istart) { - rollingHash = ZSTD_rollingHash_rotate(rollingHash, lastHashed[0], - lastHashed[minMatchLength], - hashPower); - } else { - rollingHash = ZSTD_rollingHash_compute(ip, minMatchLength); - } - lastHashed = ip; - - /* Do not insert and do not look for a match */ - if (ZSTD_ldm_getTag(rollingHash, hBits, hashRateLog) != ldmTagMask) { - ip++; - continue; - } - - /* Get the best entry and compute the match lengths */ - { - ldmEntry_t* const bucket = - ZSTD_ldm_getBucket(ldmState, - ZSTD_ldm_getSmallHash(rollingHash, hBits), - *params); - ldmEntry_t* cur; - size_t bestMatchLength = 0; - U32 const checksum = ZSTD_ldm_getChecksum(rollingHash, hBits); - - for (cur = bucket; cur < bucket + ldmBucketSize; ++cur) { - size_t curForwardMatchLength, curBackwardMatchLength, - curTotalMatchLength; - if (cur->checksum != checksum || cur->offset <= lowestIndex) { - continue; - } - if (extDict) { - BYTE const* const curMatchBase = - cur->offset < dictLimit ? dictBase : base; - BYTE const* const pMatch = curMatchBase + cur->offset; - BYTE const* const matchEnd = - cur->offset < dictLimit ? dictEnd : iend; - BYTE const* const lowMatchPtr = - cur->offset < dictLimit ? dictStart : lowPrefixPtr; - - curForwardMatchLength = ZSTD_count_2segments( - ip, pMatch, iend, - matchEnd, lowPrefixPtr); - if (curForwardMatchLength < minMatchLength) { - continue; - } - curBackwardMatchLength = - ZSTD_ldm_countBackwardsMatch(ip, anchor, pMatch, - lowMatchPtr); - curTotalMatchLength = curForwardMatchLength + - curBackwardMatchLength; - } else { /* !extDict */ - BYTE const* const pMatch = base + cur->offset; - curForwardMatchLength = ZSTD_count(ip, pMatch, iend); - if (curForwardMatchLength < minMatchLength) { - continue; - } - curBackwardMatchLength = - ZSTD_ldm_countBackwardsMatch(ip, anchor, pMatch, - lowPrefixPtr); - curTotalMatchLength = curForwardMatchLength + - curBackwardMatchLength; - } - - if (curTotalMatchLength > bestMatchLength) { - bestMatchLength = curTotalMatchLength; - forwardMatchLength = curForwardMatchLength; - backwardMatchLength = curBackwardMatchLength; - bestEntry = cur; - } - } - } - - /* No match found -- continue searching */ - if (bestEntry == NULL) { - ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash, - hBits, current, - *params); - ip++; - continue; - } - - /* Match found */ - mLength = forwardMatchLength + backwardMatchLength; - ip -= backwardMatchLength; - - { - /* Store the sequence: - * ip = current - backwardMatchLength - * The match is at (bestEntry->offset - backwardMatchLength) - */ - U32 const matchIndex = bestEntry->offset; - U32 const offset = current - matchIndex; - rawSeq* const seq = rawSeqStore->seq + rawSeqStore->size; - - /* Out of sequence storage */ - if (rawSeqStore->size == rawSeqStore->capacity) - return ERROR(dstSize_tooSmall); - seq->litLength = (U32)(ip - anchor); - seq->matchLength = (U32)mLength; - seq->offset = offset; - rawSeqStore->size++; - } - - /* Insert the current entry into the hash table */ - ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash, hBits, - (U32)(lastHashed - base), - *params); - - assert(ip + backwardMatchLength == lastHashed); - - /* Fill the hash table from lastHashed+1 to ip+mLength*/ - /* Heuristic: don't need to fill the entire table at end of block */ - if (ip + mLength <= ilimit) { - rollingHash = ZSTD_ldm_fillLdmHashTable( - ldmState, rollingHash, lastHashed, - ip + mLength, base, hBits, *params); - lastHashed = ip + mLength - 1; - } - ip += mLength; - anchor = ip; - } - return iend - anchor; -} - -/*! ZSTD_ldm_reduceTable() : - * reduce table indexes by `reducerValue` */ -static void ZSTD_ldm_reduceTable(ldmEntry_t* const table, U32 const size, - U32 const reducerValue) -{ - U32 u; - for (u = 0; u < size; u++) { - if (table[u].offset < reducerValue) table[u].offset = 0; - else table[u].offset -= reducerValue; - } -} - -size_t ZSTD_ldm_generateSequences( - ldmState_t* ldmState, rawSeqStore_t* sequences, - ldmParams_t const* params, void const* src, size_t srcSize) -{ - U32 const maxDist = 1U << params->windowLog; - BYTE const* const istart = (BYTE const*)src; - BYTE const* const iend = istart + srcSize; - size_t const kMaxChunkSize = 1 << 20; - size_t const nbChunks = (srcSize / kMaxChunkSize) + ((srcSize % kMaxChunkSize) != 0); - size_t chunk; - size_t leftoverSize = 0; - - assert(ZSTD_CHUNKSIZE_MAX >= kMaxChunkSize); - /* Check that ZSTD_window_update() has been called for this chunk prior - * to passing it to this function. - */ - assert(ldmState->window.nextSrc >= (BYTE const*)src + srcSize); - /* The input could be very large (in zstdmt), so it must be broken up into - * chunks to enforce the maximum distance and handle overflow correction. - */ - assert(sequences->pos <= sequences->size); - assert(sequences->size <= sequences->capacity); - for (chunk = 0; chunk < nbChunks && sequences->size < sequences->capacity; ++chunk) { - BYTE const* const chunkStart = istart + chunk * kMaxChunkSize; - size_t const remaining = (size_t)(iend - chunkStart); - BYTE const *const chunkEnd = - (remaining < kMaxChunkSize) ? iend : chunkStart + kMaxChunkSize; - size_t const chunkSize = chunkEnd - chunkStart; - size_t newLeftoverSize; - size_t const prevSize = sequences->size; - - assert(chunkStart < iend); - /* 1. Perform overflow correction if necessary. */ - if (ZSTD_window_needOverflowCorrection(ldmState->window, chunkEnd)) { - U32 const ldmHSize = 1U << params->hashLog; - U32 const correction = ZSTD_window_correctOverflow( - &ldmState->window, /* cycleLog */ 0, maxDist, src); - ZSTD_ldm_reduceTable(ldmState->hashTable, ldmHSize, correction); - } - /* 2. We enforce the maximum offset allowed. - * - * kMaxChunkSize should be small enough that we don't lose too much of - * the window through early invalidation. - * TODO: * Test the chunk size. - * * Try invalidation after the sequence generation and test the - * the offset against maxDist directly. - */ - ZSTD_window_enforceMaxDist(&ldmState->window, chunkEnd, maxDist, NULL, NULL); - /* 3. Generate the sequences for the chunk, and get newLeftoverSize. */ - newLeftoverSize = ZSTD_ldm_generateSequences_internal( - ldmState, sequences, params, chunkStart, chunkSize); - if (ZSTD_isError(newLeftoverSize)) - return newLeftoverSize; - /* 4. We add the leftover literals from previous iterations to the first - * newly generated sequence, or add the `newLeftoverSize` if none are - * generated. - */ - /* Prepend the leftover literals from the last call */ - if (prevSize < sequences->size) { - sequences->seq[prevSize].litLength += (U32)leftoverSize; - leftoverSize = newLeftoverSize; - } else { - assert(newLeftoverSize == chunkSize); - leftoverSize += chunkSize; - } - } - return 0; -} - -void ZSTD_ldm_skipSequences(rawSeqStore_t* rawSeqStore, size_t srcSize, U32 const minMatch) { - while (srcSize > 0 && rawSeqStore->pos < rawSeqStore->size) { - rawSeq* seq = rawSeqStore->seq + rawSeqStore->pos; - if (srcSize <= seq->litLength) { - /* Skip past srcSize literals */ - seq->litLength -= (U32)srcSize; - return; - } - srcSize -= seq->litLength; - seq->litLength = 0; - if (srcSize < seq->matchLength) { - /* Skip past the first srcSize of the match */ - seq->matchLength -= (U32)srcSize; - if (seq->matchLength < minMatch) { - /* The match is too short, omit it */ - if (rawSeqStore->pos + 1 < rawSeqStore->size) { - seq[1].litLength += seq[0].matchLength; - } - rawSeqStore->pos++; - } - return; - } - srcSize -= seq->matchLength; - seq->matchLength = 0; - rawSeqStore->pos++; - } -} - -/** - * If the sequence length is longer than remaining then the sequence is split - * between this block and the next. - * - * Returns the current sequence to handle, or if the rest of the block should - * be literals, it returns a sequence with offset == 0. - */ -static rawSeq maybeSplitSequence(rawSeqStore_t* rawSeqStore, - U32 const remaining, U32 const minMatch) -{ - rawSeq sequence = rawSeqStore->seq[rawSeqStore->pos]; - assert(sequence.offset > 0); - /* Likely: No partial sequence */ - if (remaining >= sequence.litLength + sequence.matchLength) { - rawSeqStore->pos++; - return sequence; - } - /* Cut the sequence short (offset == 0 ==> rest is literals). */ - if (remaining <= sequence.litLength) { - sequence.offset = 0; - } else if (remaining < sequence.litLength + sequence.matchLength) { - sequence.matchLength = remaining - sequence.litLength; - if (sequence.matchLength < minMatch) { - sequence.offset = 0; - } - } - /* Skip past `remaining` bytes for the future sequences. */ - ZSTD_ldm_skipSequences(rawSeqStore, remaining, minMatch); - return sequence; -} - -size_t ZSTD_ldm_blockCompress(rawSeqStore_t* rawSeqStore, - ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], - void const* src, size_t srcSize) -{ - const ZSTD_compressionParameters* const cParams = &ms->cParams; - unsigned const minMatch = cParams->minMatch; - ZSTD_blockCompressor const blockCompressor = - ZSTD_selectBlockCompressor(cParams->strategy, ZSTD_matchState_dictMode(ms)); - /* Input bounds */ - BYTE const* const istart = (BYTE const*)src; - BYTE const* const iend = istart + srcSize; - /* Input positions */ - BYTE const* ip = istart; - - DEBUGLOG(5, "ZSTD_ldm_blockCompress: srcSize=%zu", srcSize); - assert(rawSeqStore->pos <= rawSeqStore->size); - assert(rawSeqStore->size <= rawSeqStore->capacity); - /* Loop through each sequence and apply the block compressor to the lits */ - while (rawSeqStore->pos < rawSeqStore->size && ip < iend) { - /* maybeSplitSequence updates rawSeqStore->pos */ - rawSeq const sequence = maybeSplitSequence(rawSeqStore, - (U32)(iend - ip), minMatch); - int i; - /* End signal */ - if (sequence.offset == 0) - break; - - assert(sequence.offset <= (1U << cParams->windowLog)); - assert(ip + sequence.litLength + sequence.matchLength <= iend); - - /* Fill tables for block compressor */ - ZSTD_ldm_limitTableUpdate(ms, ip); - ZSTD_ldm_fillFastTables(ms, ip); - /* Run the block compressor */ - DEBUGLOG(5, "calling block compressor on segment of size %u", sequence.litLength); - { - size_t const newLitLength = - blockCompressor(ms, seqStore, rep, ip, sequence.litLength); - ip += sequence.litLength; - /* Update the repcodes */ - for (i = ZSTD_REP_NUM - 1; i > 0; i--) - rep[i] = rep[i-1]; - rep[0] = sequence.offset; - /* Store the sequence */ - ZSTD_storeSeq(seqStore, newLitLength, ip - newLitLength, - sequence.offset + ZSTD_REP_MOVE, - sequence.matchLength - MINMATCH); - ip += sequence.matchLength; - } - } - /* Fill the tables for the block compressor */ - ZSTD_ldm_limitTableUpdate(ms, ip); - ZSTD_ldm_fillFastTables(ms, ip); - /* Compress the last literals */ - return blockCompressor(ms, seqStore, rep, ip, iend - ip); -} |