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Another small LZSA2 compression speedup
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@emmanuel-marty
emmanuel-marty authored Dec 17, 2020
1 parent 6bebfb7 commit e553854
Showing 1 changed file with 23 additions and 15 deletions.
38 changes: 23 additions & 15 deletions src/shrink_block_v2.c
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Original file line number Diff line number Diff line change
Expand Up @@ -187,7 +187,7 @@ static inline int lzsa_write_match_varlen_v2(unsigned char *pOutData, int nOutOf
*/
static void lzsa_insert_forward_match_v2(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int i, const int nMatchOffset, const int nStartOffset, const int nEndOffset, int nDepth) {
lzsa_arrival *arrival = pCompressor->arrival + ((i - nStartOffset) << ARRIVALS_PER_POSITION_SHIFT);
const int *rle_end = (int*)pCompressor->intervals /* reuse */;
const int *rle_len = (int*)pCompressor->intervals /* reuse */;
lzsa_match* visited = ((lzsa_match*)pCompressor->pos_data) - nStartOffset /* reuse */;
int j;

Expand All @@ -207,8 +207,8 @@ static void lzsa_insert_forward_match_v2(lzsa_compressor *pCompressor, const uns
visited[nRepPos].length = nRepLen;

if (pInWindow[nRepPos] == pInWindow[nRepPos - nMatchOffset]) {
int nLen0 = rle_end[nRepPos - nMatchOffset] - (nRepPos - nMatchOffset);
int nLen1 = rle_end[nRepPos] - (nRepPos);
int nLen0 = rle_len[nRepPos - nMatchOffset];
int nLen1 = rle_len[nRepPos];
int nMinLen = (nLen0 < nLen1) ? nLen0 : nLen1;

if (nMinLen >= nRepLen || !memcmp(pInWindow + nRepPos + nMinLen, pInWindow + nRepPos + nMinLen - nMatchOffset, nRepLen - nMinLen)) {
Expand Down Expand Up @@ -269,7 +269,7 @@ static void lzsa_insert_forward_match_v2(lzsa_compressor *pCompressor, const uns
*/
static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigned char *pInWindow, lzsa_match *pBestMatch, const int nStartOffset, const int nEndOffset, const int nReduce, const int nInsertForwardReps, const int nArrivalsPerPosition) {
lzsa_arrival *arrival = pCompressor->arrival - (nStartOffset << ARRIVALS_PER_POSITION_SHIFT);
const int *rle_end = (int*)pCompressor->intervals /* reuse */;
const int *rle_len = (int*)pCompressor->intervals /* reuse */;
lzsa_match *visited = ((lzsa_match*)pCompressor->pos_data) - nStartOffset /* reuse */;
char *nRepSlotHandledMask = pCompressor->rep_slot_handled_mask;
char *nRepLenHandledMask = pCompressor->rep_len_handled_mask;
Expand Down Expand Up @@ -387,8 +387,8 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
lzsa_match *match = pCompressor->match + ((i - nStartOffset) << MATCHES_PER_INDEX_SHIFT_V2);
int nNumArrivalsForThisPos = j, nMinOverallRepLen = 0, nMaxOverallRepLen = 0;

int nRepLenForArrival[NARRIVALS_PER_POSITION_V2_BIG];
memset(nRepLenForArrival, 0, nArrivalsPerPosition * sizeof(int));
int nRepMatchArrivalIdxAndLen[(NARRIVALS_PER_POSITION_V2_BIG * 2) + 1];
int nNumRepMatchArrivals = 0;

int nMaxRepLenForPos = nEndOffset - i;
if (nMaxRepLenForPos > LCP_MAX)
Expand All @@ -404,8 +404,8 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
if (pInWindow[i] == pInWindow[i - nRepOffset]) {
const unsigned char* pInWindowAtPos;

int nLen0 = rle_end[i - nRepOffset] - (i - nRepOffset);
int nLen1 = rle_end[i] - (i);
int nLen0 = rle_len[i - nRepOffset];
int nLen1 = rle_len[i];
int nMinLen = (nLen0 < nLen1) ? nLen0 : nLen1;

if (nMinLen > nMaxRepLenForPos)
Expand All @@ -418,14 +418,19 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
pInWindowAtPos += 4;
while (pInWindowAtPos < pInWindowMax && pInWindowAtPos[-nRepOffset] == pInWindowAtPos[0])
pInWindowAtPos++;
nRepLenForArrival[j] = (int)(pInWindowAtPos - pInWindowStart);
int nCurRepLen = (int)(pInWindowAtPos - pInWindowStart);

if (nMaxOverallRepLen < nRepLenForArrival[j])
nMaxOverallRepLen = nRepLenForArrival[j];
if (nCurRepLen >= MIN_MATCH_SIZE_V2) {
if (nMaxOverallRepLen < nCurRepLen)
nMaxOverallRepLen = nCurRepLen;
nRepMatchArrivalIdxAndLen[nNumRepMatchArrivals++] = j;
nRepMatchArrivalIdxAndLen[nNumRepMatchArrivals++] = nCurRepLen;
}
}
}
}
}
nRepMatchArrivalIdxAndLen[nNumRepMatchArrivals] = -1;

if (!nReduce) {
memset(nRepSlotHandledMask, 0, nArrivalsPerPosition * ((LCP_MAX + 1) / 8) * sizeof(char));
Expand Down Expand Up @@ -564,11 +569,13 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
/* Insert repmatch candidates */

if (k > nMinOverallRepLen && k <= nMaxOverallRepLen && (nRepLenHandledMask[k >> 3] & (1 << (k & 7))) == 0) {
int nCurRepMatchArrival;

nRepLenHandledMask[k >> 3] |= 1 << (k & 7);

for (j = 0; j < nNumArrivalsForThisPos; j++) {
for (nCurRepMatchArrival = 0; (j = nRepMatchArrivalIdxAndLen[nCurRepMatchArrival]) >= 0; nCurRepMatchArrival += 2) {
int nMaskOffset = (j << 7) + (k >> 3);
if (nRepLenForArrival[j] >= k && (nReduce || !(nRepSlotHandledMask[nMaskOffset] & (1 << (k & 7))))) {
if (nRepMatchArrivalIdxAndLen[nCurRepMatchArrival + 1] >= k && (nReduce || !(nRepSlotHandledMask[nMaskOffset] & (1 << (k & 7))))) {
const int nPrevCost = cur_arrival[j].cost & 0x3fffffff;
int nRepCodingChoiceCost = nPrevCost /* the actual cost of the literals themselves accumulates up the chain */ + nMatchLenCost;
int nScore = cur_arrival[j].score + 2;
Expand Down Expand Up @@ -1249,7 +1256,7 @@ static int lzsa_write_raw_uncompressed_block_v2(lzsa_compressor *pCompressor, co
int lzsa_optimize_and_write_block_v2(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int nPreviousBlockSize, const int nInDataSize, unsigned char *pOutData, const int nMaxOutDataSize) {
int nResult, nBaseCompressedSize;
int nArrivalsPerPosition = (nInDataSize < 65536) ? NARRIVALS_PER_POSITION_V2_BIG : NARRIVALS_PER_POSITION_V2_SMALL;
int *rle_end = (int*)pCompressor->intervals /* reuse */;
int *rle_len = (int*)pCompressor->intervals /* reuse */;
int i;

i = 0;
Expand All @@ -1260,7 +1267,8 @@ int lzsa_optimize_and_write_block_v2(lzsa_compressor *pCompressor, const unsigne
i++;
} while (i < (nPreviousBlockSize + nInDataSize) && pInWindow[i] == c);
while (nRangeStartIdx < i) {
rle_end[nRangeStartIdx++] = i;
rle_len[nRangeStartIdx] = i - nRangeStartIdx;
nRangeStartIdx++;
}
}

Expand Down

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