Skip to content

Commit

Permalink
Compress a little more
Browse files Browse the repository at this point in the history
  • Loading branch information
@emmanuel-marty
emmanuel-marty authored Dec 8, 2021
1 parent b1a5ecb commit b508e9c
Show file tree
Hide file tree
Showing 2 changed files with 22 additions and 27 deletions.
46 changes: 20 additions & 26 deletions src/shrink.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -115,7 +115,7 @@ static int salvador_get_elias_size(const int nValue) {
static int salvador_write_zero_ctrl_bit(unsigned char *pOutData, int nOutOffset, const int nMaxOutDataSize, int *nCurBitsOffset, int *nCurBitShift) {
if (nOutOffset < 0) return -1;

if ((*nCurBitsOffset) == INT_MIN) {
if ((*nCurBitShift) == -1) {
/* Allocate a new byte in the stream to pack bits in */
if (nOutOffset >= nMaxOutDataSize) return -1;
(*nCurBitsOffset) = nOutOffset;
Expand All @@ -141,7 +141,7 @@ static int salvador_write_zero_ctrl_bit(unsigned char *pOutData, int nOutOffset,
static int salvador_write_one_ctrl_bit(unsigned char* pOutData, int nOutOffset, const int nMaxOutDataSize, int* nCurBitsOffset, int* nCurBitShift) {
if (nOutOffset < 0) return -1;

if ((*nCurBitsOffset) == INT_MIN) {
if ((*nCurBitShift) == -1) {
/* Allocate a new byte in the stream to pack bits in */
if (nOutOffset >= nMaxOutDataSize) return -1;
(*nCurBitsOffset) = nOutOffset;
Expand Down Expand Up @@ -169,12 +169,6 @@ static int salvador_write_data_bit(unsigned char* pOutData, int nOutOffset, cons
if (nOutOffset < 0) return -1;

pOutData[(*nCurBitsOffset)] |= nValue << ((*nCurBitShift)--);

if ((*nCurBitShift) == -1) {
/* Current byte is full */
(*nCurBitsOffset) = INT_MIN;
}

return nOutOffset;
}

Expand Down Expand Up @@ -328,12 +322,12 @@ static inline int salvador_get_literals_varlen_size(const int nLength) {
* @param nDepth current insertion depth
*/
static void salvador_insert_forward_match(salvador_compressor *pCompressor, const unsigned char *pInWindow, const int i, const int nMatchOffset, const int nStartOffset, const int nEndOffset, int nDepth) {
const salvador_arrival *arrival = pCompressor->arrival + ((i - nStartOffset) * NARRIVALS_PER_POSITION);
const salvador_arrival *arrival = pCompressor->arrival + ((i - nStartOffset) * NMAX_ARRIVALS_PER_POSITION);
const int *rle_len = (int*)pCompressor->intervals /* reuse */;
salvador_visited* visited = ((salvador_visited*)pCompressor->pos_data) - nStartOffset /* reuse */;
int j;

for (j = 0; j < NARRIVALS_PER_POSITION && arrival[j].from_slot; j++) {
for (j = 0; j < NMAX_ARRIVALS_PER_POSITION && arrival[j].from_slot; j++) {
if (arrival[j].num_literals) {
const int nRepOffset = arrival[j].rep_offset;

Expand Down Expand Up @@ -421,19 +415,19 @@ static void salvador_insert_forward_match(salvador_compressor *pCompressor, cons
* @param nBlockFlags bit 0: 1 for first block, 0 otherwise; bit 1: 1 for last block, 0 otherwise
*/
static void salvador_optimize_forward(salvador_compressor *pCompressor, const unsigned char *pInWindow, const int nStartOffset, const int nEndOffset, const int nInsertForwardReps, const int *nCurRepMatchOffset, const int nArrivalsPerPosition, const int nBlockFlags) {
salvador_arrival *arrival = pCompressor->arrival - (nStartOffset * NARRIVALS_PER_POSITION);
salvador_arrival *arrival = pCompressor->arrival - (nStartOffset * NMAX_ARRIVALS_PER_POSITION);
const int* rle_len = (int*)pCompressor->intervals /* reuse */;
salvador_visited* visited = ((salvador_visited*)pCompressor->pos_data) - nStartOffset /* reuse */;
int i;

if ((nEndOffset - nStartOffset) > pCompressor->block_size) return;

memset(arrival + (nStartOffset * NARRIVALS_PER_POSITION), 0, sizeof(salvador_arrival) * ((nEndOffset - nStartOffset + 1) * NARRIVALS_PER_POSITION));
memset(arrival + (nStartOffset * NMAX_ARRIVALS_PER_POSITION), 0, sizeof(salvador_arrival) * ((nEndOffset - nStartOffset + 1) * NMAX_ARRIVALS_PER_POSITION));

arrival[nStartOffset * NARRIVALS_PER_POSITION].from_slot = -1;
arrival[nStartOffset * NARRIVALS_PER_POSITION].rep_offset = *nCurRepMatchOffset;
arrival[nStartOffset * NMAX_ARRIVALS_PER_POSITION].from_slot = -1;
arrival[nStartOffset * NMAX_ARRIVALS_PER_POSITION].rep_offset = *nCurRepMatchOffset;

for (i = (nStartOffset * NARRIVALS_PER_POSITION); i != ((nEndOffset+1) * NARRIVALS_PER_POSITION); i++) {
for (i = (nStartOffset * NMAX_ARRIVALS_PER_POSITION); i != ((nEndOffset+1) * NMAX_ARRIVALS_PER_POSITION); i++) {
arrival[i].cost = 0x40000000;
}

Expand All @@ -442,8 +436,8 @@ static void salvador_optimize_forward(salvador_compressor *pCompressor, const un
}

for (i = nStartOffset; i != nEndOffset; i++) {
salvador_arrival *cur_arrival = &arrival[i * NARRIVALS_PER_POSITION];
salvador_arrival *pDestLiteralSlots = &cur_arrival[NARRIVALS_PER_POSITION];
salvador_arrival *cur_arrival = &arrival[i * NMAX_ARRIVALS_PER_POSITION];
salvador_arrival *pDestLiteralSlots = &cur_arrival[NMAX_ARRIVALS_PER_POSITION];
int j, m;

for (j = 0; j < nArrivalsPerPosition && cur_arrival[j].from_slot; j++) {
Expand Down Expand Up @@ -525,7 +519,7 @@ static void salvador_optimize_forward(salvador_compressor *pCompressor, const un
const int nNumArrivalsForThisPos = j;
int nOverallMinRepLen = 0, nOverallMaxRepLen = 0;

int nRepMatchArrivalIdx[(2 * NARRIVALS_PER_POSITION) + 1];
int nRepMatchArrivalIdx[(2 * NMAX_ARRIVALS_PER_POSITION) + 1];
int nNumRepMatchArrivals = 0;

if (i < nEndOffset) {
Expand Down Expand Up @@ -617,7 +611,7 @@ static void salvador_optimize_forward(salvador_compressor *pCompressor, const un
}

for (k = nStartingMatchLen; k <= nMatchLen; k++) {
salvador_arrival* pDestSlots = &cur_arrival[k * NARRIVALS_PER_POSITION];
salvador_arrival* pDestSlots = &cur_arrival[k * NMAX_ARRIVALS_PER_POSITION];

/* Insert non-repmatch candidate */

Expand Down Expand Up @@ -780,7 +774,7 @@ static void salvador_optimize_forward(salvador_compressor *pCompressor, const un
}

if (!nInsertForwardReps) {
const salvador_arrival* end_arrival = &arrival[(i * NARRIVALS_PER_POSITION) + 0];
const salvador_arrival* end_arrival = &arrival[(i * NMAX_ARRIVALS_PER_POSITION) + 0];
salvador_final_match* pBestMatch = pCompressor->best_match - nStartOffset;

while (end_arrival->from_slot > 0 && end_arrival->from_pos >= 0 && (int)end_arrival->from_pos < nEndOffset) {
Expand All @@ -790,7 +784,7 @@ static void salvador_optimize_forward(salvador_compressor *pCompressor, const un
else
pBestMatch[end_arrival->from_pos].offset = 0;

end_arrival = &arrival[(end_arrival->from_pos * NARRIVALS_PER_POSITION) + (end_arrival->from_slot - 1)];
end_arrival = &arrival[(end_arrival->from_pos * NMAX_ARRIVALS_PER_POSITION) + (end_arrival->from_slot - 1)];
}
}
}
Expand Down Expand Up @@ -1578,7 +1572,7 @@ static int salvador_optimize_and_write_block(salvador_compressor *pCompressor, c
}

/* Compress and insert additional matches */
salvador_optimize_forward(pCompressor, pInWindow, nPreviousBlockSize, nEndOffset, 1 /* nInsertForwardReps */, nCurRepMatchOffset, NARRIVALS_PER_POSITION / 2, nBlockFlags);
salvador_optimize_forward(pCompressor, pInWindow, nPreviousBlockSize, nEndOffset, 1 /* nInsertForwardReps */, nCurRepMatchOffset, NINITIAL_ARRIVALS_PER_POSITION, nBlockFlags);

/* Supplement matches further */

Expand Down Expand Up @@ -1671,7 +1665,7 @@ static int salvador_optimize_and_write_block(salvador_compressor *pCompressor, c
}

/* Pick final matches */
salvador_optimize_forward(pCompressor, pInWindow, nPreviousBlockSize, nEndOffset, 0 /* nInsertForwardReps */, nCurRepMatchOffset, NARRIVALS_PER_POSITION, nBlockFlags);
salvador_optimize_forward(pCompressor, pInWindow, nPreviousBlockSize, nEndOffset, 0 /* nInsertForwardReps */, nCurRepMatchOffset, NMAX_ARRIVALS_PER_POSITION, nBlockFlags);

/* Apply reduction and merge pass */
int nDidReduce;
Expand Down Expand Up @@ -1891,7 +1885,7 @@ size_t salvador_compress(const unsigned char *pInputData, unsigned char *pOutBuf
size_t nOriginalSize = 0;
size_t nCompressedSize = 0L;
int nResult;
int nMaxArrivals = NARRIVALS_PER_POSITION;
int nMaxArrivals = NMAX_ARRIVALS_PER_POSITION;
int nError = 0;
const int nBlockSize = (nInputSize < BLOCK_SIZE) ? ((nInputSize < 1024) ? 1024 : (int)nInputSize) : BLOCK_SIZE;
const int nMaxOutBlockSize = (int)salvador_get_max_compressed_size(nBlockSize);
Expand All @@ -1911,7 +1905,7 @@ size_t salvador_compress(const unsigned char *pInputData, unsigned char *pOutBuf

int nPreviousBlockSize = 0;
int nNumBlocks = 0;
int nCurBitsOffset = INT_MIN, nCurBitShift = 0, nCurFinalLiterals = 0;
int nCurBitsOffset = 0, nCurBitShift = -1, nCurFinalLiterals = 0;
int nBlockFlags = 1;
int nCurRepMatchOffset = 1;

Expand Down Expand Up @@ -1948,7 +1942,7 @@ size_t salvador_compress(const unsigned char *pInputData, unsigned char *pOutBuf
nOriginalSize += nInDataSize;
nCurFinalLiterals = 0;
nCompressedSize += nOutDataSize;
if (nCurBitsOffset != INT_MIN)
if (nCurBitShift != -1)
nCurBitsOffset -= nOutDataSize;
}
}
Expand Down
3 changes: 2 additions & 1 deletion src/shrink.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,8 @@ extern "C" {
#define VISITED_FLAG 0x8000000000000000ULL
#define EXCL_VISITED_MASK 0x7fffffffffffffffULL

#define NARRIVALS_PER_POSITION 80
#define NINITIAL_ARRIVALS_PER_POSITION 40
#define NMAX_ARRIVALS_PER_POSITION 92
#define NMATCHES_PER_INDEX 64
#define MATCHES_PER_INDEX_SHIFT 6

Expand Down

0 comments on commit b508e9c

Please sign in to comment.