diff --git a/src/matchfinder.c b/src/matchfinder.c
index 2138b5d..224a8aa 100644
--- a/src/matchfinder.c
+++ b/src/matchfinder.c
@@ -90,7 +90,7 @@ int lzsa_build_suffix_array(lzsa_compressor *pCompressor, const unsigned char *p
intervals[0] &= POS_MASK;
int nMinMatchSize = pCompressor->min_match_size;
- if ((pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) && pCompressor->format_version >= 2) {
+ if (pCompressor->format_version >= 2) {
for (i = 1; i < nInWindowSize - 1; i++) {
int nIndex = (int)(intervals[i] & POS_MASK);
int nLen = PLCP[nIndex];
@@ -246,7 +246,7 @@ int lzsa_find_matches_at(lzsa_compressor *pCompressor, const int nOffset, lzsa_m
int nMatchOffset = (int)(nOffset - match_pos);
if (nMatchOffset <= MAX_OFFSET) {
- if ((pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) && pCompressor->format_version >= 2) {
+ if (pCompressor->format_version >= 2) {
matchptr->length = (unsigned short)(ref >> (LCP_SHIFT + TAG_BITS));
}
else {
diff --git a/src/shrink_block_v1.c b/src/shrink_block_v1.c
index 71b2c63..e21b188 100644
--- a/src/shrink_block_v1.c
+++ b/src/shrink_block_v1.c
@@ -156,9 +156,10 @@ static inline int lzsa_get_offset_cost_v1(const unsigned int nMatchOffset) {
* @param nStartOffset current offset in input window (typically the number of previously compressed bytes)
* @param nEndOffset offset to end finding matches at (typically the size of the total input window in bytes
*/
-static void lzsa_optimize_arrivals_v1(lzsa_compressor *pCompressor, const int nStartOffset, const int nEndOffset) {
+static void lzsa_optimize_forward_v1(lzsa_compressor *pCompressor, const int nStartOffset, const int nEndOffset) {
lzsa_arrival *arrival = pCompressor->arrival;
- int nMinMatchSize = pCompressor->min_match_size;
+ const int nMinMatchSize = pCompressor->min_match_size;
+ const int nFavorRatio = (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) ? 1 : 0;
int i, j, n;
memset(arrival + (nStartOffset << MATCHES_PER_OFFSET_SHIFT), 0, sizeof(lzsa_arrival) * ((nEndOffset - nStartOffset) << MATCHES_PER_OFFSET_SHIFT));
@@ -178,6 +179,9 @@ static void lzsa_optimize_arrivals_v1(lzsa_compressor *pCompressor, const int nS
nCodingChoiceCost += 8;
}
+ if (!nFavorRatio && nNumLiterals == 1)
+ nCodingChoiceCost += MODESWITCH_PENALTY * 3;
+
lzsa_arrival *pDestArrival = &arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT)];
if (pDestArrival->from_slot == 0 ||
nCodingChoiceCost <= pDestArrival->cost) {
@@ -216,6 +220,9 @@ static void lzsa_optimize_arrivals_v1(lzsa_compressor *pCompressor, const int nS
int nCodingChoiceCost = nPrevCost + 8 /* token */ /* the actual cost of the literals themselves accumulates up the chain */ + nMatchOffsetCost + nMatchLenCost;
int exists = 0;
+ if (!nFavorRatio && !arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].num_literals)
+ nCodingChoiceCost += MODESWITCH_PENALTY * 3;
+
for (n = 0;
n < 3 && arrival[((i + k) << MATCHES_PER_OFFSET_SHIFT) + n].from_slot && arrival[((i + k) << MATCHES_PER_OFFSET_SHIFT) + n].cost <= nCodingChoiceCost;
n++) {
@@ -261,114 +268,6 @@ static void lzsa_optimize_arrivals_v1(lzsa_compressor *pCompressor, const int nS
}
}
-/**
- * Attempt to pick optimal matches using a backward LZSS style parser, so as to produce the smallest possible output that decompresses to the same input
- *
- * @param pCompressor compression context
- * @param nStartOffset current offset in input window (typically the number of previously compressed bytes)
- * @param nEndOffset offset to end finding matches at (typically the size of the total input window in bytes
- */
-static void lzsa_optimize_matches_v1(lzsa_compressor *pCompressor, const int nStartOffset, const int nEndOffset) {
- int *cost = (int*)pCompressor->pos_data; /* Reuse */
- int nLastLiteralsOffset;
- int nMinMatchSize = pCompressor->min_match_size;
- const int nFavorRatio = (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) ? 1 : 0;
- int i;
-
- cost[nEndOffset - 1] = 8;
- nLastLiteralsOffset = nEndOffset;
-
- for (i = nEndOffset - 2; i != (nStartOffset - 1); i--) {
- int nBestCost, nBestMatchLen, nBestMatchOffset;
-
- int nLiteralsLen = nLastLiteralsOffset - i;
- nBestCost = 8 + cost[i + 1];
- if (nLiteralsLen == LITERALS_RUN_LEN_V1 || nLiteralsLen == 256 || nLiteralsLen == 512) {
- /* Add to the cost of encoding literals as their number crosses a variable length encoding boundary.
- * The cost automatically accumulates down the chain. */
- nBestCost += 8;
- }
- if (pCompressor->match[(i + 1) << MATCHES_PER_OFFSET_SHIFT].length >= MIN_MATCH_SIZE_V1)
- nBestCost += MODESWITCH_PENALTY;
- nBestMatchLen = 0;
- nBestMatchOffset = 0;
-
- lzsa_match *pMatch = pCompressor->match + (i << MATCHES_PER_OFFSET_SHIFT);
- int m;
-
- for (m = 0; m < NMATCHES_PER_OFFSET && pMatch[m].length >= nMinMatchSize; m++) {
- int nMatchOffsetSize = (pMatch[m].offset <= 256) ? 8 : 16;
-
- if (pMatch[m].length >= LEAVE_ALONE_MATCH_SIZE) {
- int nCurCost;
- int nMatchLen = pMatch[m].length;
-
- if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
- nMatchLen = nEndOffset - LAST_LITERALS - i;
-
- nCurCost = 8 + nMatchOffsetSize + lzsa_get_match_varlen_size_v1(nMatchLen - MIN_MATCH_SIZE_V1);
- nCurCost += cost[i + nMatchLen];
- if (pCompressor->match[(i + nMatchLen) << MATCHES_PER_OFFSET_SHIFT].length >= MIN_MATCH_SIZE_V1)
- nCurCost += MODESWITCH_PENALTY;
-
- if (nBestCost > (nCurCost - nFavorRatio)) {
- nBestCost = nCurCost;
- nBestMatchLen = nMatchLen;
- nBestMatchOffset = pMatch[m].offset;
- }
- }
- else {
- int nMatchLen = pMatch[m].length;
- int k, nMatchRunLen;
-
- if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
- nMatchLen = nEndOffset - LAST_LITERALS - i;
-
- nMatchRunLen = nMatchLen;
- if (nMatchRunLen > MATCH_RUN_LEN_V1)
- nMatchRunLen = MATCH_RUN_LEN_V1;
-
- for (k = nMinMatchSize; k < nMatchRunLen; k++) {
- int nCurCost;
-
- nCurCost = 8 + nMatchOffsetSize /* no extra match len bytes */;
- nCurCost += cost[i + k];
- if (pCompressor->match[(i + k) << MATCHES_PER_OFFSET_SHIFT].length >= MIN_MATCH_SIZE_V1)
- nCurCost += MODESWITCH_PENALTY;
-
- if (nBestCost > (nCurCost - nFavorRatio)) {
- nBestCost = nCurCost;
- nBestMatchLen = k;
- nBestMatchOffset = pMatch[m].offset;
- }
- }
-
- for (; k <= nMatchLen; k++) {
- int nCurCost;
-
- nCurCost = 8 + nMatchOffsetSize + lzsa_get_match_varlen_size_v1(k - MIN_MATCH_SIZE_V1);
- nCurCost += cost[i + k];
- if (pCompressor->match[(i + k) << MATCHES_PER_OFFSET_SHIFT].length >= MIN_MATCH_SIZE_V1)
- nCurCost += MODESWITCH_PENALTY;
-
- if (nBestCost > (nCurCost - nFavorRatio)) {
- nBestCost = nCurCost;
- nBestMatchLen = k;
- nBestMatchOffset = pMatch[m].offset;
- }
- }
- }
- }
-
- if (nBestMatchLen >= MIN_MATCH_SIZE_V1)
- nLastLiteralsOffset = i;
-
- cost[i] = nBestCost;
- pMatch->length = nBestMatchLen;
- pMatch->offset = nBestMatchOffset;
- }
-}
-
/**
* Attempt to minimize the number of commands issued in the compressed data block, in order to speed up decompression without
* impacting the compression ratio
@@ -609,10 +508,7 @@ static int lzsa_write_raw_uncompressed_block_v1(lzsa_compressor *pCompressor, co
int lzsa_optimize_and_write_block_v1(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int nPreviousBlockSize, const int nInDataSize, unsigned char *pOutData, const int nMaxOutDataSize) {
int nResult;
- if (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO)
- lzsa_optimize_arrivals_v1(pCompressor, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
- else
- lzsa_optimize_matches_v1(pCompressor, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
+ lzsa_optimize_forward_v1(pCompressor, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
int nDidReduce;
int nPasses = 0;
diff --git a/src/shrink_block_v2.c b/src/shrink_block_v2.c
index ebdf735..a1e2a59 100644
--- a/src/shrink_block_v2.c
+++ b/src/shrink_block_v2.c
@@ -185,7 +185,8 @@ static inline int lzsa_write_match_varlen_v2(unsigned char *pOutData, int nOutOf
*/
static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int nStartOffset, const int nEndOffset) {
lzsa_arrival *arrival = pCompressor->arrival;
- int nMinMatchSize = pCompressor->min_match_size;
+ const int nFavorRatio = (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) ? 1 : 0;
+ const int nMinMatchSize = pCompressor->min_match_size;
int i, j, n;
lzsa_match match[32];
@@ -211,6 +212,9 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
nCodingChoiceCost += 16;
}
+ if (!nFavorRatio && nNumLiterals == 1)
+ nCodingChoiceCost += MODESWITCH_PENALTY * 3;
+
int exists = 0;
for (n = 0;
n < NMATCHES_PER_OFFSET && arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n].from_slot && arrival[((i + 1) << MATCHES_PER_OFFSET_SHIFT) + n].cost <= nCodingChoiceCost;
@@ -279,6 +283,9 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
int nCodingChoiceCost = nPrevCost + 8 /* token */ /* the actual cost of the literals themselves accumulates up the chain */ + nMatchOffsetCost + nMatchLenCost;
int exists = 0;
+ if (!nFavorRatio && !arrival[(i << MATCHES_PER_OFFSET_SHIFT) + j].num_literals)
+ nCodingChoiceCost += MODESWITCH_PENALTY*3;
+
for (n = 0;
n < NMATCHES_PER_OFFSET && pDestSlots[n].from_slot && pDestSlots[n].cost <= nCodingChoiceCost;
n++) {
@@ -369,268 +376,6 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const unsigne
}
}
-/**
- * Attempt to pick optimal matches using a backward LZSS style parser, so as to produce the smallest possible output that decompresses to the same input
- *
- * @param pCompressor compression context
- * @param nStartOffset current offset in input window (typically the number of previously compressed bytes)
- * @param nEndOffset offset to end finding matches at (typically the size of the total input window in bytes
- */
-static void lzsa_optimize_backward_v2(lzsa_compressor *pCompressor, const int nStartOffset, const int nEndOffset) {
- int *cost = (int*)pCompressor->pos_data; /* Reuse */
- int *prev_match = (int*)pCompressor->intervals; /* Reuse */
- lzsa_repmatch_opt *repmatch_opt = pCompressor->repmatch_opt;
- int nLastLiteralsOffset;
- int nMinMatchSize = pCompressor->min_match_size;
- const int nFavorRatio = (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) ? 1 : 0;
- int i;
-
- cost[nEndOffset - 1] = 8;
- prev_match[nEndOffset - 1] = nEndOffset;
- nLastLiteralsOffset = nEndOffset;
-
- pCompressor->best_match[nEndOffset - 1].length = 0;
- pCompressor->best_match[nEndOffset - 1].offset = 0;
-
- repmatch_opt[nEndOffset - 1].best_slot_for_incoming = -1;
- repmatch_opt[nEndOffset - 1].incoming_offset = -1;
- repmatch_opt[nEndOffset - 1].expected_repmatch = 0;
-
- for (i = nEndOffset - 2; i != (nStartOffset - 1); i--) {
- int nLiteralsCost;
-
- int nLiteralsLen = nLastLiteralsOffset - i;
- nLiteralsCost = 8 + cost[i + 1];
-
- /* Add to the cost of encoding literals as their number crosses a variable length encoding boundary.
- * The cost automatically accumulates down the chain. */
- if (nLiteralsLen == LITERALS_RUN_LEN_V2) {
- nLiteralsCost += 4;
- }
- else if (nLiteralsLen == (LITERALS_RUN_LEN_V2 + 15)) {
- nLiteralsCost += 8;
- }
- else if (nLiteralsLen == 256) {
- nLiteralsCost += 16;
- }
- if (pCompressor->best_match[i + 1].length >= MIN_MATCH_SIZE_V2)
- nLiteralsCost += MODESWITCH_PENALTY;
-
- const lzsa_match *pMatch = pCompressor->match + (i << MATCHES_PER_OFFSET_SHIFT);
- int *pSlotCost = pCompressor->slot_cost + (i << MATCHES_PER_OFFSET_SHIFT);
- int m;
-
- cost[i] = nLiteralsCost;
- pCompressor->best_match[i].length = 0;
- pCompressor->best_match[i].offset = 0;
-
- repmatch_opt[i].best_slot_for_incoming = -1;
- repmatch_opt[i].incoming_offset = -1;
- repmatch_opt[i].expected_repmatch = 0;
-
- for (m = 0; m < NMATCHES_PER_OFFSET && pMatch[m].length >= nMinMatchSize; m++) {
- int nBestCost, nBestMatchLen, nBestMatchOffset, nBestUpdatedSlot, nBestUpdatedIndex, nBestExpectedRepMatch;
-
- nBestCost = nLiteralsCost;
- nBestMatchLen = 0;
- nBestMatchOffset = 0;
- nBestUpdatedSlot = -1;
- nBestUpdatedIndex = -1;
- nBestExpectedRepMatch = 0;
-
- if (pMatch[m].length >= LEAVE_ALONE_MATCH_SIZE) {
- int nCurCost;
- int nMatchLen = pMatch[m].length;
-
- if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
- nMatchLen = nEndOffset - LAST_LITERALS - i;
-
- int nCurIndex = prev_match[i + nMatchLen];
-
- int nMatchOffsetSize = 0;
- int nCurExpectedRepMatch = 1;
- if (nCurIndex >= nEndOffset || pCompressor->best_match[nCurIndex].length < MIN_MATCH_SIZE_V2 ||
- pCompressor->best_match[nCurIndex].offset != pMatch[m].offset) {
- nMatchOffsetSize = (pMatch[m].offset <= 32) ? 4 : ((pMatch[m].offset <= 512) ? 8 : ((pMatch[m].offset <= (8192 + 512)) ? 12 : 16));
- nCurExpectedRepMatch = 0;
- }
-
- nCurCost = 8 + nMatchOffsetSize + lzsa_get_match_varlen_size_v2(nMatchLen - MIN_MATCH_SIZE_V2);
- nCurCost += cost[i + nMatchLen];
- if (pCompressor->best_match[i + nMatchLen].length >= MIN_MATCH_SIZE_V2)
- nCurCost += MODESWITCH_PENALTY;
-
- if (nBestCost > (nCurCost - nFavorRatio)) {
- nBestCost = nCurCost;
- nBestMatchLen = nMatchLen;
- nBestMatchOffset = pMatch[m].offset;
- nBestUpdatedSlot = -1;
- nBestUpdatedIndex = -1;
- nBestExpectedRepMatch = nCurExpectedRepMatch;
- }
- }
- else {
- int nMatchLen = pMatch[m].length;
- int k, nMatchRunLen;
-
- if ((i + nMatchLen) > (nEndOffset - LAST_LITERALS))
- nMatchLen = nEndOffset - LAST_LITERALS - i;
-
- nMatchRunLen = nMatchLen;
- if (nMatchRunLen > MATCH_RUN_LEN_V2)
- nMatchRunLen = MATCH_RUN_LEN_V2;
-
- for (k = nMinMatchSize; k < nMatchRunLen; k++) {
- int nCurCost;
-
- int nCurIndex = prev_match[i + k];
- int nMatchOffsetSize = 0;
- int nCurExpectedRepMatch = 1;
- if (nCurIndex >= nEndOffset || pCompressor->best_match[nCurIndex].length < MIN_MATCH_SIZE_V2 ||
- pCompressor->best_match[nCurIndex].offset != pMatch[m].offset) {
- nMatchOffsetSize = (pMatch[m].offset <= 32) ? 4 : ((pMatch[m].offset <= 512) ? 8 : ((pMatch[m].offset <= (8192 + 512)) ? 12 : 16));
- nCurExpectedRepMatch = 0;
- }
-
- nCurCost = 8 + nMatchOffsetSize /* no extra match len bytes */;
- nCurCost += cost[i + k];
- if (pCompressor->best_match[i + k].length >= MIN_MATCH_SIZE_V2)
- nCurCost += MODESWITCH_PENALTY;
-
- int nCurUpdatedSlot = -1;
- int nCurUpdatedIndex = -1;
-
- if (nMatchOffsetSize && nCurIndex < nEndOffset && pCompressor->best_match[nCurIndex].length >= MIN_MATCH_SIZE_V2 && !repmatch_opt[nCurIndex].expected_repmatch) {
- int r;
-
- for (r = 0; r < NMATCHES_PER_OFFSET && pCompressor->selected_match[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r].length >= MIN_MATCH_SIZE_V2; r++) {
- if (pCompressor->selected_match[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r].offset == pMatch[m].offset) {
- int nAltCost = nCurCost - nMatchOffsetSize + pCompressor->slot_cost[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r] - cost[nCurIndex];
-
- if (nAltCost <= nCurCost) {
- nCurUpdatedSlot = r;
- nCurUpdatedIndex = nCurIndex;
- nCurCost = nAltCost;
- nCurExpectedRepMatch = 2;
- }
- }
- }
- }
-
- if (nBestCost > (nCurCost - nFavorRatio)) {
- nBestCost = nCurCost;
- nBestMatchLen = k;
- nBestMatchOffset = pMatch[m].offset;
- nBestUpdatedSlot = nCurUpdatedSlot;
- nBestUpdatedIndex = nCurUpdatedIndex;
- nBestExpectedRepMatch = nCurExpectedRepMatch;
- }
- }
-
- for (; k <= nMatchLen; k++) {
- int nCurCost;
-
- int nCurIndex = prev_match[i + k];
- int nMatchOffsetSize = 0;
- int nCurExpectedRepMatch = 1;
- if (nCurIndex >= nEndOffset || pCompressor->best_match[nCurIndex].length < MIN_MATCH_SIZE_V2 ||
- pCompressor->best_match[nCurIndex].offset != pMatch[m].offset) {
- nMatchOffsetSize = (pMatch[m].offset <= 32) ? 4 : ((pMatch[m].offset <= 512) ? 8 : ((pMatch[m].offset <= (8192 + 512)) ? 12 : 16));
- nCurExpectedRepMatch = 0;
- }
-
- nCurCost = 8 + nMatchOffsetSize + lzsa_get_match_varlen_size_v2(k - MIN_MATCH_SIZE_V2);
- nCurCost += cost[i + k];
- if (pCompressor->best_match[i + k].length >= MIN_MATCH_SIZE_V2)
- nCurCost += MODESWITCH_PENALTY;
-
- int nCurUpdatedSlot = -1;
- int nCurUpdatedIndex = -1;
-
- if (nMatchOffsetSize && nCurIndex < nEndOffset && pCompressor->best_match[nCurIndex].length >= MIN_MATCH_SIZE_V2 && !repmatch_opt[nCurIndex].expected_repmatch) {
- int r;
-
- for (r = 0; r < NMATCHES_PER_OFFSET && pCompressor->selected_match[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r].length >= MIN_MATCH_SIZE_V2; r++) {
- if (pCompressor->selected_match[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r].offset == pMatch[m].offset) {
- int nAltCost = nCurCost - nMatchOffsetSize + pCompressor->slot_cost[(nCurIndex << MATCHES_PER_OFFSET_SHIFT) + r] - cost[nCurIndex];
-
- if (nAltCost <= nCurCost) {
- nCurUpdatedSlot = r;
- nCurUpdatedIndex = nCurIndex;
- nCurCost = nAltCost;
- nCurExpectedRepMatch = 2;
- }
- }
- }
- }
-
- if (nBestCost > (nCurCost - nFavorRatio)) {
- nBestCost = nCurCost;
- nBestMatchLen = k;
- nBestMatchOffset = pMatch[m].offset;
- nBestUpdatedSlot = nCurUpdatedSlot;
- nBestUpdatedIndex = nCurUpdatedIndex;
- nBestExpectedRepMatch = nCurExpectedRepMatch;
- }
- }
- }
-
- pSlotCost[m] = nBestCost;
- pCompressor->selected_match[(i << MATCHES_PER_OFFSET_SHIFT) + m].length = nBestMatchLen;
- pCompressor->selected_match[(i << MATCHES_PER_OFFSET_SHIFT) + m].offset = nBestMatchOffset;
-
- if (m == 0 || (nBestMatchLen && cost[i] >= nBestCost)) {
- cost[i] = nBestCost;
- pCompressor->best_match[i].length = nBestMatchLen;
- pCompressor->best_match[i].offset = nBestMatchOffset;
-
- repmatch_opt[i].expected_repmatch = nBestExpectedRepMatch;
-
- if (nBestUpdatedSlot >= 0 && nBestUpdatedIndex >= 0) {
- repmatch_opt[nBestUpdatedIndex].best_slot_for_incoming = nBestUpdatedSlot;
- repmatch_opt[nBestUpdatedIndex].incoming_offset = i;
- }
- }
- }
- for (; m < NMATCHES_PER_OFFSET; m++) {
- pSlotCost[m] = 0;
- pCompressor->selected_match[(i << MATCHES_PER_OFFSET_SHIFT) + m] = pMatch[m];
- }
-
- if (pCompressor->best_match[i].length >= MIN_MATCH_SIZE_V2)
- nLastLiteralsOffset = i;
-
- prev_match[i] = nLastLiteralsOffset;
- }
-
- int nIncomingOffset = -1;
- for (i = nStartOffset; i < nEndOffset; ) {
- if (pCompressor->best_match[i].length >= MIN_MATCH_SIZE_V2) {
- if (nIncomingOffset >= 0 && repmatch_opt[i].incoming_offset == nIncomingOffset && repmatch_opt[i].best_slot_for_incoming >= 0) {
- lzsa_match *pMatch = pCompressor->selected_match + (i << MATCHES_PER_OFFSET_SHIFT) + repmatch_opt[i].best_slot_for_incoming;
- int *pSlotCost = pCompressor->slot_cost + (i << MATCHES_PER_OFFSET_SHIFT) + repmatch_opt[i].best_slot_for_incoming;
-
- pCompressor->best_match[i].length = pMatch->length;
- pCompressor->best_match[i].offset = pMatch->offset;
- cost[i] = *pSlotCost;
-
- if (repmatch_opt[i].expected_repmatch == 2)
- repmatch_opt[i].expected_repmatch = 1;
- }
- else {
- if (repmatch_opt[i].expected_repmatch == 2)
- repmatch_opt[i].expected_repmatch = 0;
- }
-
- nIncomingOffset = i;
- i += pCompressor->best_match[i].length;
- }
- else {
- i++;
- }
- }
-}
-
/**
* Attempt to minimize the number of commands issued in the compressed data block, in order to speed up decompression without
* impacting the compression ratio
@@ -677,6 +422,41 @@ static int lzsa_optimize_command_count_v2(lzsa_compressor *pCompressor, const un
pMatch->offset = nRepMatchOffset;
}
+ if (pBestMatch[nNextIndex].offset && pMatch->offset != pBestMatch[nNextIndex].offset && nRepMatchOffset != pBestMatch[nNextIndex].offset) {
+ /* Otherwise, try to gain a match forward as well */
+ if (i >= pBestMatch[nNextIndex].offset && (i - pBestMatch[nNextIndex].offset + pMatch->length) <= (nEndOffset - LAST_LITERALS)) {
+ int nMaxLen = 0;
+ while (nMaxLen < pMatch->length && pInWindow[i - pBestMatch[nNextIndex].offset + nMaxLen] == pInWindow[i - pMatch->offset + nMaxLen])
+ nMaxLen++;
+ if (nMaxLen >= pMatch->length) {
+ /* Replace */
+ pMatch->offset = pBestMatch[nNextIndex].offset;
+ }
+ else if (nMaxLen >= 2 && pMatch->offset != nRepMatchOffset) {
+ int nPartialSizeBefore, nPartialSizeAfter;
+
+ nPartialSizeBefore = lzsa_get_match_varlen_size_v2(pMatch->length - MIN_MATCH_SIZE_V2);
+ nPartialSizeBefore += (pMatch->offset <= 32) ? 4 : ((pMatch->offset <= 512) ? 8 : ((pMatch->offset <= (8192 + 512)) ? 12 : 16));
+ nPartialSizeBefore += lzsa_get_literals_varlen_size_v2(nNextLiterals);
+
+ nPartialSizeAfter = lzsa_get_match_varlen_size_v2(nMaxLen - MIN_MATCH_SIZE_V2);
+ nPartialSizeAfter += lzsa_get_literals_varlen_size_v2(nNextLiterals + (pMatch->length - nMaxLen)) + ((pMatch->length - nMaxLen) << 3);
+
+ if (nPartialSizeAfter < nPartialSizeBefore) {
+ int j;
+
+ /* We gain a repmatch that is shorter than the original match as this is the best we can do, so it is followed by extra literals, but
+ * we have calculated that this is shorter */
+ pMatch->offset = pBestMatch[nNextIndex].offset;
+ for (j = nMaxLen; j < pMatch->length; j++) {
+ pBestMatch[i + j].length = 0;
+ }
+ pMatch->length = nMaxLen;
+ }
+ }
+ }
+ }
+
if (pMatch->length < 9 /* Don't waste time considering large matches, they will always win over literals */) {
/* Calculate this command's current cost (excluding 'nNumLiterals' bytes) */
@@ -977,10 +757,7 @@ 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;
- if (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO)
- lzsa_optimize_forward_v2(pCompressor, pInWindow, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
- else
- lzsa_optimize_backward_v2(pCompressor, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
+ lzsa_optimize_forward_v2(pCompressor, pInWindow, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
int nDidReduce;
int nPasses = 0;
diff --git a/src/shrink_context.c b/src/shrink_context.c
index 1f9b6d7..dc77bdd 100644
--- a/src/shrink_context.c
+++ b/src/shrink_context.c
@@ -59,10 +59,7 @@ int lzsa_compressor_init(lzsa_compressor *pCompressor, const int nMaxWindowSize,
pCompressor->pos_data = NULL;
pCompressor->open_intervals = NULL;
pCompressor->match = NULL;
- pCompressor->selected_match = NULL;
pCompressor->best_match = NULL;
- pCompressor->slot_cost = NULL;
- pCompressor->repmatch_opt = NULL;
pCompressor->arrival = NULL;
pCompressor->min_match_size = nMinMatchSize;
if (pCompressor->min_match_size < nMinMatchSizeForFormat)
@@ -87,31 +84,14 @@ int lzsa_compressor_init(lzsa_compressor *pCompressor, const int nMaxWindowSize,
pCompressor->match = (lzsa_match *)malloc(nMaxWindowSize * NMATCHES_PER_OFFSET * sizeof(lzsa_match));
if (pCompressor->match) {
- if (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO)
- pCompressor->arrival = (lzsa_arrival *)malloc(nMaxWindowSize * NMATCHES_PER_OFFSET * sizeof(lzsa_arrival));
+ pCompressor->arrival = (lzsa_arrival *)malloc(nMaxWindowSize * NMATCHES_PER_OFFSET * sizeof(lzsa_arrival));
- if (pCompressor->arrival || (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) == 0) {
+ if (pCompressor->arrival) {
if (pCompressor->format_version == 2) {
pCompressor->best_match = (lzsa_match *)malloc(nMaxWindowSize * sizeof(lzsa_match));
if (pCompressor->best_match) {
- if ((pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) == 0) {
- pCompressor->selected_match = (lzsa_match *)malloc(nMaxWindowSize * NMATCHES_PER_OFFSET * sizeof(lzsa_match));
-
- if (pCompressor->selected_match) {
- pCompressor->slot_cost = (int *)malloc(nMaxWindowSize * NMATCHES_PER_OFFSET * sizeof(int));
-
- if (pCompressor->slot_cost) {
- pCompressor->repmatch_opt = (lzsa_repmatch_opt *)malloc(nMaxWindowSize * sizeof(lzsa_repmatch_opt));
-
- if (pCompressor->repmatch_opt)
- return 0;
- }
- }
- }
- else {
- return 0;
- }
+ return 0;
}
}
else {
@@ -141,26 +121,11 @@ void lzsa_compressor_destroy(lzsa_compressor *pCompressor) {
pCompressor->arrival = NULL;
}
- if (pCompressor->repmatch_opt) {
- free(pCompressor->repmatch_opt);
- pCompressor->repmatch_opt = NULL;
- }
-
- if (pCompressor->slot_cost) {
- free(pCompressor->slot_cost);
- pCompressor->slot_cost = NULL;
- }
-
if (pCompressor->best_match) {
free(pCompressor->best_match);
pCompressor->best_match = NULL;
}
- if (pCompressor->selected_match) {
- free(pCompressor->selected_match);
- pCompressor->selected_match = NULL;
- }
-
if (pCompressor->match) {
free(pCompressor->match);
pCompressor->match = NULL;
@@ -207,7 +172,7 @@ int lzsa_compressor_shrink_block(lzsa_compressor *pCompressor, unsigned char *pI
if (nPreviousBlockSize) {
lzsa_skip_matches(pCompressor, 0, nPreviousBlockSize);
}
- if ((pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) == 0 || pCompressor->format_version < 2)
+ if (pCompressor->format_version < 2)
lzsa_find_all_matches(pCompressor, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
if (pCompressor->format_version == 1) {
diff --git a/src/shrink_context.h b/src/shrink_context.h
index 9f99815..6fdfb78 100644
--- a/src/shrink_context.h
+++ b/src/shrink_context.h
@@ -66,13 +66,6 @@ typedef struct _lzsa_match {
unsigned short offset;
} lzsa_match;
-/** One rep-match slot (for LZSA2) */
-typedef struct _lzsa_repmatch_opt {
- int incoming_offset;
- short best_slot_for_incoming;
- short expected_repmatch;
-} lzsa_repmatch_opt;
-
/** Forward arrival slot */
typedef struct {
int cost;
@@ -93,10 +86,7 @@ typedef struct _lzsa_compressor {
unsigned int *pos_data;
unsigned int *open_intervals;
lzsa_match *match;
- lzsa_match *selected_match;
lzsa_match *best_match;
- int *slot_cost;
- lzsa_repmatch_opt *repmatch_opt;
lzsa_arrival *arrival;
int min_match_size;
int format_version;