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Diffstat (limited to 'lib/compress/zstd_ldm.c')
-rw-r--r--lib/compress/zstd_ldm.c85
1 files changed, 18 insertions, 67 deletions
diff --git a/lib/compress/zstd_ldm.c b/lib/compress/zstd_ldm.c
index 6238ddecf24f9..58eb2ffe4db3e 100644
--- a/lib/compress/zstd_ldm.c
+++ b/lib/compress/zstd_ldm.c
@@ -37,8 +37,8 @@ void ZSTD_ldm_adjustParameters(ldmParams_t* params,
params->hashLog = MAX(ZSTD_HASHLOG_MIN, params->windowLog - LDM_HASH_RLOG);
assert(params->hashLog <= ZSTD_HASHLOG_MAX);
}
- if (params->hashEveryLog == 0) {
- params->hashEveryLog = params->windowLog < params->hashLog
+ if (params->hashRateLog == 0) {
+ params->hashRateLog = params->windowLog < params->hashLog
? 0
: params->windowLog - params->hashLog;
}
@@ -119,20 +119,20 @@ static void ZSTD_ldm_insertEntry(ldmState_t* ldmState,
*
* Gets the small hash, checksum, and tag from the rollingHash.
*
- * If the tag matches (1 << ldmParams.hashEveryLog)-1, then
+ * 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.hashEveryLog bits that make up the tag. */
+ * 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.hashEveryLog);
- U32 const tagMask = ((U32)1 << ldmParams.hashEveryLog) - 1;
+ 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);
@@ -143,56 +143,6 @@ static void ZSTD_ldm_makeEntryAndInsertByTag(ldmState_t* ldmState,
}
}
-/** ZSTD_ldm_getRollingHash() :
- * Get a 64-bit hash using the first len bytes from buf.
- *
- * Giving bytes s = s_1, s_2, ... s_k, the hash is defined to be
- * H(s) = s_1*(a^(k-1)) + s_2*(a^(k-2)) + ... + s_k*(a^0)
- *
- * where the constant a is defined to be prime8bytes.
- *
- * The implementation adds an offset to each byte, so
- * H(s) = (s_1 + HASH_CHAR_OFFSET)*(a^(k-1)) + ... */
-static U64 ZSTD_ldm_getRollingHash(const BYTE* buf, U32 len)
-{
- U64 ret = 0;
- U32 i;
- for (i = 0; i < len; i++) {
- ret *= prime8bytes;
- ret += buf[i] + LDM_HASH_CHAR_OFFSET;
- }
- return ret;
-}
-
-/** ZSTD_ldm_ipow() :
- * Return base^exp. */
-static U64 ZSTD_ldm_ipow(U64 base, U64 exp)
-{
- U64 ret = 1;
- while (exp) {
- if (exp & 1) { ret *= base; }
- exp >>= 1;
- base *= base;
- }
- return ret;
-}
-
-U64 ZSTD_ldm_getHashPower(U32 minMatchLength) {
- DEBUGLOG(4, "ZSTD_ldm_getHashPower: mml=%u", minMatchLength);
- assert(minMatchLength >= ZSTD_LDM_MINMATCH_MIN);
- return ZSTD_ldm_ipow(prime8bytes, minMatchLength - 1);
-}
-
-/** ZSTD_ldm_updateHash() :
- * Updates hash by removing toRemove and adding toAdd. */
-static U64 ZSTD_ldm_updateHash(U64 hash, BYTE toRemove, BYTE toAdd, U64 hashPower)
-{
- hash -= ((toRemove + LDM_HASH_CHAR_OFFSET) * hashPower);
- hash *= prime8bytes;
- hash += toAdd + LDM_HASH_CHAR_OFFSET;
- return hash;
-}
-
/** ZSTD_ldm_countBackwardsMatch() :
* Returns the number of bytes that match backwards before pIn and pMatch.
*
@@ -238,6 +188,7 @@ static size_t ZSTD_ldm_fillFastTables(ZSTD_matchState_t* ms,
case ZSTD_btlazy2:
case ZSTD_btopt:
case ZSTD_btultra:
+ case ZSTD_btultra2:
break;
default:
assert(0); /* not possible : not a valid strategy id */
@@ -261,9 +212,9 @@ static U64 ZSTD_ldm_fillLdmHashTable(ldmState_t* state,
const BYTE* cur = lastHashed + 1;
while (cur < iend) {
- rollingHash = ZSTD_ldm_updateHash(rollingHash, cur[-1],
- cur[ldmParams.minMatchLength-1],
- state->hashPower);
+ rollingHash = ZSTD_rollingHash_rotate(rollingHash, cur[-1],
+ cur[ldmParams.minMatchLength-1],
+ state->hashPower);
ZSTD_ldm_makeEntryAndInsertByTag(state,
rollingHash, hBits,
(U32)(cur - base), ldmParams);
@@ -297,8 +248,8 @@ static size_t ZSTD_ldm_generateSequences_internal(
U64 const hashPower = ldmState->hashPower;
U32 const hBits = params->hashLog - params->bucketSizeLog;
U32 const ldmBucketSize = 1U << params->bucketSizeLog;
- U32 const hashEveryLog = params->hashEveryLog;
- U32 const ldmTagMask = (1U << params->hashEveryLog) - 1;
+ 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;
@@ -324,16 +275,16 @@ static size_t ZSTD_ldm_generateSequences_internal(
size_t forwardMatchLength = 0, backwardMatchLength = 0;
ldmEntry_t* bestEntry = NULL;
if (ip != istart) {
- rollingHash = ZSTD_ldm_updateHash(rollingHash, lastHashed[0],
- lastHashed[minMatchLength],
- hashPower);
+ rollingHash = ZSTD_rollingHash_rotate(rollingHash, lastHashed[0],
+ lastHashed[minMatchLength],
+ hashPower);
} else {
- rollingHash = ZSTD_ldm_getRollingHash(ip, minMatchLength);
+ rollingHash = ZSTD_rollingHash_compute(ip, minMatchLength);
}
lastHashed = ip;
/* Do not insert and do not look for a match */
- if (ZSTD_ldm_getTag(rollingHash, hBits, hashEveryLog) != ldmTagMask) {
+ if (ZSTD_ldm_getTag(rollingHash, hBits, hashRateLog) != ldmTagMask) {
ip++;
continue;
}
@@ -593,7 +544,7 @@ size_t ZSTD_ldm_blockCompress(rawSeqStore_t* rawSeqStore,
void const* src, size_t srcSize)
{
const ZSTD_compressionParameters* const cParams = &ms->cParams;
- unsigned const minMatch = cParams->searchLength;
+ unsigned const minMatch = cParams->minMatch;
ZSTD_blockCompressor const blockCompressor =
ZSTD_selectBlockCompressor(cParams->strategy, ZSTD_matchState_dictMode(ms));
/* Input bounds */
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-07 17:42:10 +0000