//These should be multiples of four.
#define LDM_HASH_LENGTH 8
-#define MINMATCH 8
#define ML_BITS 4
#define ML_MASK ((1U<<ML_BITS)-1)
const BYTE *DEBUG_setNextHash;
};
-/**
- * Outputs compression statistics.
- */
-static void printCompressStats(const LDM_CCtx *cctx) {
- const LDM_compressStats *stats = &(cctx->stats);
-#ifdef COMPUTE_STATS
+void LDM_printCompressStats(const LDM_compressStats *stats,
+ const LDM_hashEntry *hashTable,
+ U32 hashTableSize) {
printf("=====================\n");
printf("Compression statistics\n");
printf("Total number of matches: %u\n", stats->numMatches);
{
U32 i = 0;
U32 ctr = 0;
- for (; i < LDM_HASHTABLESIZE_U32; i++) {
- if ((cctx->hashTable)[i].offset == 0) {
+ for (; i < hashTableSize; i++) {
+ if (hashTable[i].offset == 0) {
ctr++;
}
}
printf("Hash table size, empty slots, %% empty: %u %u %.3f\n",
- LDM_HASHTABLESIZE_U32, ctr,
- 100.0 * (double)(ctr) / (double)LDM_HASHTABLESIZE_U32);
+ hashTableSize, ctr,
+ 100.0 * (double)(ctr) / (double)hashTableSize);
}
printf("=====================\n");
-#endif
}
-/**
- * Checks whether the MINMATCH bytes from p are the same as the MINMATCH
- * bytes from match.
- *
- * This assumes MINMATCH is a multiple of four.
- *
- * Return 1 if valid, 0 otherwise.
- */
-static int LDM_isValidMatch(const BYTE *p, const BYTE *match) {
+int LDM_isValidMatch(const BYTE *pIn, const BYTE *pMatch) {
/*
- if (memcmp(p, match, MINMATCH) == 0) {
+ if (memcmp(pIn, pMatch, LDM_MIN_MATCH_LENGTH) == 0) {
return 1;
}
return 0;
*/
//TODO: This seems to be faster for some reason?
- U16 lengthLeft = MINMATCH;
- const BYTE *curP = p;
- const BYTE *curMatch = match;
+ U32 lengthLeft = LDM_MIN_MATCH_LENGTH;
+ const BYTE *curIn = pIn;
+ const BYTE *curMatch = pMatch;
for (; lengthLeft >= 8; lengthLeft -= 8) {
- if (MEM_read64(curP) != MEM_read64(curMatch)) {
+ if (MEM_read64(curIn) != MEM_read64(curMatch)) {
return 0;
}
- curP += 8;
+ curIn += 8;
curMatch += 8;
}
if (lengthLeft > 0) {
- return (MEM_read32(curP) == MEM_read32(curMatch));
+ return (MEM_read32(curIn) == MEM_read32(curMatch));
}
return 1;
}
return cctx->hashTable[hash].offset + cctx->ibase;
}
-/**
- * Counts the number of bytes that match from pIn and pMatch,
- * up to pInLimit.
- *
- * TODO: make more efficient.
- */
-static unsigned countMatchLength(const BYTE *pIn, const BYTE *pMatch,
- const BYTE *pInLimit) {
+U32 LDM_countMatchLength(const BYTE *pIn, const BYTE *pMatch,
+ const BYTE *pInLimit) {
const BYTE * const pStart = pIn;
while (pIn < pInLimit - 1) {
BYTE const diff = (*pMatch) ^ *(pIn);
pMatch++;
continue;
}
- return (unsigned)(pIn - pStart);
+ return (U32)(pIn - pStart);
}
- return (unsigned)(pIn - pStart);
+ return (U32)(pIn - pStart);
}
-void LDM_readHeader(const void *src, U64 *compressSize,
- U64 *decompressSize) {
- const U64 *ip = (const U64 *)src;
- *compressSize = *ip++;
- *decompressSize = *ip;
+void LDM_readHeader(const void *src, U64 *compressedSize,
+ U64 *decompressedSize) {
+ const BYTE *ip = (const BYTE *)src;
+ *compressedSize = MEM_readLE64(ip);
+ ip += sizeof(U64);
+ *decompressedSize = MEM_readLE64(ip);
+ // ip += sizeof(U64);
}
-/**
- * Initialize a compression context.
- */
-static void initializeCCtx(LDM_CCtx *cctx,
- const void *src, size_t srcSize,
- void *dst, size_t maxDstSize) {
+void LDM_initializeCCtx(LDM_CCtx *cctx,
+ const void *src, size_t srcSize,
+ void *dst, size_t maxDstSize) {
cctx->isize = srcSize;
cctx->maxOSize = maxDstSize;
cctx->iend = cctx->ibase + srcSize;
cctx->ihashLimit = cctx->iend - LDM_HASH_LENGTH;
- cctx->imatchLimit = cctx->iend - MINMATCH;
+ cctx->imatchLimit = cctx->iend - LDM_MIN_MATCH_LENGTH;
cctx->obase = (BYTE *)dst;
cctx->op = (BYTE *)dst;
return 0;
}
-/**
- * Write current block (literals, literal length, match offset,
- * match length).
- *
- * Update input pointer, inserting hashes into hash table along the way.
- */
-static void outputBlock(LDM_CCtx *cctx,
- const unsigned literalLength,
- const unsigned offset,
- const unsigned matchLength) {
- BYTE *token = cctx->op++;
-
+void LDM_encodeLiteralLengthAndLiterals(
+ LDM_CCtx *cctx, BYTE *pToken, const U32 literalLength) {
/* Encode the literal length. */
if (literalLength >= RUN_MASK) {
int len = (int)literalLength - RUN_MASK;
- *token = (RUN_MASK << ML_BITS);
+ *pToken = (RUN_MASK << ML_BITS);
for (; len >= 255; len -= 255) {
*(cctx->op)++ = 255;
}
*(cctx->op)++ = (BYTE)len;
} else {
- *token = (BYTE)(literalLength << ML_BITS);
+ *pToken = (BYTE)(literalLength << ML_BITS);
}
/* Encode the literals. */
memcpy(cctx->op, cctx->anchor, literalLength);
cctx->op += literalLength;
+}
+
+void LDM_outputBlock(LDM_CCtx *cctx,
+ const U32 literalLength,
+ const U32 offset,
+ const U32 matchLength) {
+ BYTE *pToken = cctx->op++;
+
+ /* Encode the literal length and literals. */
+ LDM_encodeLiteralLengthAndLiterals(cctx, pToken, literalLength);
/* Encode the offset. */
MEM_write32(cctx->op, offset);
/* Encode the match length. */
if (matchLength >= ML_MASK) {
unsigned matchLengthRemaining = matchLength;
- *token += ML_MASK;
+ *pToken += ML_MASK;
matchLengthRemaining -= ML_MASK;
MEM_write32(cctx->op, 0xFFFFFFFF);
while (matchLengthRemaining >= 4*0xFF) {
cctx->op += matchLengthRemaining / 255;
*(cctx->op)++ = (BYTE)(matchLengthRemaining % 255);
} else {
- *token += (BYTE)(matchLength);
+ *pToken += (BYTE)(matchLength);
}
}
size_t LDM_compress(const void *src, size_t srcSize,
void *dst, size_t maxDstSize) {
LDM_CCtx cctx;
- initializeCCtx(&cctx, src, srcSize, dst, maxDstSize);
+ LDM_initializeCCtx(&cctx, src, srcSize, dst, maxDstSize);
/* Hash the first position and put it into the hash table. */
LDM_putHashOfCurrentPosition(&cctx);
* length) and update pointers and hashes.
*/
{
- const unsigned literalLength = (unsigned)(cctx.ip - cctx.anchor);
- const unsigned offset = cctx.ip - match;
- const unsigned matchLength = countMatchLength(
- cctx.ip + MINMATCH, match + MINMATCH, cctx.ihashLimit);
+ const U32 literalLength = cctx.ip - cctx.anchor;
+ const U32 offset = cctx.ip - match;
+ const U32 matchLength = LDM_countMatchLength(
+ cctx.ip + LDM_MIN_MATCH_LENGTH, match + LDM_MIN_MATCH_LENGTH,
+ cctx.ihashLimit);
#ifdef COMPUTE_STATS
cctx.stats.totalLiteralLength += literalLength;
cctx.stats.totalOffset += offset;
- cctx.stats.totalMatchLength += matchLength + MINMATCH;
+ cctx.stats.totalMatchLength += matchLength + LDM_MIN_MATCH_LENGTH;
#endif
- outputBlock(&cctx, literalLength, offset, matchLength);
+ LDM_outputBlock(&cctx, literalLength, offset, matchLength);
// Move ip to end of block, inserting hashes at each position.
cctx.nextIp = cctx.ip + cctx.step;
- while (cctx.ip < cctx.anchor + MINMATCH + matchLength + literalLength) {
+ while (cctx.ip < cctx.anchor + LDM_MIN_MATCH_LENGTH +
+ matchLength + literalLength) {
if (cctx.ip > cctx.lastPosHashed) {
// TODO: Simplify.
LDM_updateLastHashFromNextHash(&cctx);
_last_literals:
/* Encode the last literals (no more matches). */
{
- size_t const lastRun = (size_t)(cctx.iend - cctx.anchor);
- if (lastRun >= RUN_MASK) {
- size_t accumulator = lastRun - RUN_MASK;
- *(cctx.op)++ = RUN_MASK << ML_BITS;
- for(; accumulator >= 255; accumulator -= 255) {
- *(cctx.op)++ = 255;
- }
- *(cctx.op)++ = (BYTE)accumulator;
- } else {
- *(cctx.op)++ = (BYTE)(lastRun << ML_BITS);
- }
- memcpy(cctx.op, cctx.anchor, lastRun);
- cctx.op += lastRun;
+ const size_t lastRun = (size_t)(cctx.iend - cctx.anchor);
+ BYTE *pToken = cctx.op++;
+ LDM_encodeLiteralLengthAndLiterals(&cctx, pToken, lastRun);
}
#ifdef COMPUTE_STATS
- printCompressStats(&cctx);
+ LDM_printCompressStats(&cctx.stats, cctx.hashTable, LDM_HASHTABLESIZE_U32);
#endif
return (cctx.op - (const BYTE *)cctx.obase);
}
-typedef struct LDM_DCtx {
- size_t compressSize;
- size_t maxDecompressSize;
+struct LDM_DCtx {
+ size_t compressedSize;
+ size_t maxDecompressedSize;
const BYTE *ibase; /* Base of input */
const BYTE *ip; /* Current input position */
const BYTE *obase; /* Base of output */
BYTE *op; /* Current output position */
const BYTE *oend; /* End of output */
-} LDM_DCtx;
+};
-static void LDM_initializeDCtx(LDM_DCtx *dctx,
- const void *src, size_t compressSize,
- void *dst, size_t maxDecompressSize) {
- dctx->compressSize = compressSize;
- dctx->maxDecompressSize = maxDecompressSize;
+void LDM_initializeDCtx(LDM_DCtx *dctx,
+ const void *src, size_t compressedSize,
+ void *dst, size_t maxDecompressedSize) {
+ dctx->compressedSize = compressedSize;
+ dctx->maxDecompressedSize = maxDecompressedSize;
dctx->ibase = src;
dctx->ip = (const BYTE *)src;
- dctx->iend = dctx->ip + dctx->compressSize;
+ dctx->iend = dctx->ip + dctx->compressedSize;
dctx->op = dst;
- dctx->oend = dctx->op + dctx->maxDecompressSize;
+ dctx->oend = dctx->op + dctx->maxDecompressedSize;
}
-size_t LDM_decompress(const void *src, size_t compressSize,
- void *dst, size_t maxDecompressSize) {
+size_t LDM_decompress(const void *src, size_t compressedSize,
+ void *dst, size_t maxDecompressedSize) {
LDM_DCtx dctx;
- LDM_initializeDCtx(&dctx, src, compressSize, dst, maxDecompressSize);
+ LDM_initializeDCtx(&dctx, src, compressedSize, dst, maxDecompressedSize);
while (dctx.ip < dctx.iend) {
BYTE *cpy;
length += s;
} while (s == 255);
}
- length += MINMATCH;
+ length += LDM_MIN_MATCH_LENGTH;
/* Copy match. */
cpy = dctx.op + length;
#define LDM_DECOMPRESS_SIZE 8
#define LDM_HEADER_SIZE ((LDM_COMPRESS_SIZE)+(LDM_DECOMPRESS_SIZE))
+// This should be a multiple of four.
+#define LDM_MIN_MATCH_LENGTH 8
+
typedef U32 offset_t;
typedef U32 hash_t;
typedef struct LDM_hashEntry LDM_hashEntry;
typedef struct LDM_compressStats LDM_compressStats;
typedef struct LDM_CCtx LDM_CCtx;
+typedef struct LDM_DCtx LDM_DCtx;
/**
* Compresses src into dst.
size_t LDM_compress(const void *src, size_t srcSize,
void *dst, size_t maxDstSize);
+/**
+ * Initialize the compression context.
+ */
+void LDM_initializeCCtx(LDM_CCtx *cctx,
+ const void *src, size_t srcSize,
+ void *dst, size_t maxDstSize);
+/**
+ * Outputs compression statistics to stdout.
+ */
+void LDM_printCompressStats(const LDM_compressStats *stats,
+ const LDM_hashEntry *hashTable,
+ U32 hashTableSize);
+/**
+ * Checks whether the LDM_MIN_MATCH_LENGTH bytes from p are the same as the
+ * LDM_MIN_MATCH_LENGTH bytes from match.
+ *
+ * This assumes LDM_MIN_MATCH_LENGTH is a multiple of four.
+ *
+ * Return 1 if valid, 0 otherwise.
+ */
+int LDM_isValidMatch(const BYTE *pIn, const BYTE *pMatch);
+
+/**
+ * Counts the number of bytes that match from pIn and pMatch,
+ * up to pInLimit.
+ */
+U32 LDM_countMatchLength(const BYTE *pIn, const BYTE *pMatch,
+ const BYTE *pInLimit);
+
+/**
+ * Encode the literal length followed by the literals.
+ *
+ * The literal length is written to the upper four bits of pToken, with
+ * additional bytes written to the output as needed (see lz4).
+ *
+ * This is followed by literalLength bytes corresponding to the literals.
+ */
+void LDM_encodeLiteralLengthAndLiterals(
+ LDM_CCtx *cctx, BYTE *pToken, const U32 literalLength);
+
+/**
+ * Write current block (literals, literal length, match offset,
+ * match length).
+ */
+void LDM_outputBlock(LDM_CCtx *cctx,
+ const U32 literalLength,
+ const U32 offset,
+ const U32 matchLength);
+
+/**
+ * Decompresses src into dst.
+ *
+ * Note: assumes src does not have a header.
+ */
size_t LDM_decompress(const void *src, size_t srcSize,
void *dst, size_t maxDstSize);
+/**
+ * Initialize the decompression context.
+ */
+void LDM_initializeDCtx(LDM_DCtx *dctx,
+ const void *src, size_t compressedSize,
+ void *dst, size_t maxDecompressedSize);
+
/**
* Reads the header from src and writes the compressed size and
- * decompressed size into compressSize and decompressSize respectively.
+ * decompressed size into compressedSize and decompressedSize respectively.
*
* NB: LDM_compress and LDM_decompress currently do not add/read headers.
*/
-void LDM_readHeader(const void *src, U64 *compressSize,
- U64 *decompressSize);
+void LDM_readHeader(const void *src, U64 *compressedSize,
+ U64 *decompressedSize);
void LDM_test(void);
int fdin, fdout;
struct stat statbuf;
char *src, *dst;
- size_t maxCompressSize, compressSize;
+ size_t maxCompressedSize, compressedSize;
/* Open the input file. */
if ((fdin = open(fname, O_RDONLY)) < 0) {
return 1;
}
- maxCompressSize = statbuf.st_size + LDM_HEADER_SIZE;
+ maxCompressedSize = statbuf.st_size + LDM_HEADER_SIZE;
/* Go to the location corresponding to the last byte. */
/* TODO: fallocate? */
- if (lseek(fdout, maxCompressSize - 1, SEEK_SET) == -1) {
+ if (lseek(fdout, maxCompressedSize - 1, SEEK_SET) == -1) {
perror("lseek error");
return 1;
}
}
/* mmap the output file */
- if ((dst = mmap(0, maxCompressSize, PROT_READ | PROT_WRITE,
+ if ((dst = mmap(0, maxCompressedSize, PROT_READ | PROT_WRITE,
MAP_SHARED, fdout, 0)) == (caddr_t) - 1) {
perror("mmap error for output");
return 1;
}
- compressSize = LDM_HEADER_SIZE +
+ compressedSize = LDM_HEADER_SIZE +
LDM_compress(src, statbuf.st_size,
- dst + LDM_HEADER_SIZE, maxCompressSize);
+ dst + LDM_HEADER_SIZE, maxCompressedSize);
// Write compress and decompress size to header
// TODO: should depend on LDM_DECOMPRESS_SIZE write32
- memcpy(dst, &compressSize, 8);
+ memcpy(dst, &compressedSize, 8);
memcpy(dst + 8, &(statbuf.st_size), 8);
#ifdef DEBUG
- printf("Compressed size: %zu\n", compressSize);
+ printf("Compressed size: %zu\n", compressedSize);
printf("Decompressed size: %zu\n", (size_t)statbuf.st_size);
#endif
- // Truncate file to compressSize.
- ftruncate(fdout, compressSize);
+ // Truncate file to compressedSize.
+ ftruncate(fdout, compressedSize);
printf("%25s : %6u -> %7u - %s (%.1f%%)\n", fname,
- (unsigned)statbuf.st_size, (unsigned)compressSize, oname,
- (double)compressSize / (statbuf.st_size) * 100);
+ (unsigned)statbuf.st_size, (unsigned)compressedSize, oname,
+ (double)compressedSize / (statbuf.st_size) * 100);
// Close files.
close(fdin);
int fdin, fdout;
struct stat statbuf;
char *src, *dst;
- U64 compressSize, decompressSize;
+ U64 compressedSize, decompressedSize;
size_t outSize;
/* Open the input file. */
}
/* Read the header. */
- LDM_readHeader(src, &compressSize, &decompressSize);
+ LDM_readHeader(src, &compressedSize, &decompressedSize);
/* Go to the location corresponding to the last byte. */
- if (lseek(fdout, decompressSize - 1, SEEK_SET) == -1) {
+ if (lseek(fdout, decompressedSize - 1, SEEK_SET) == -1) {
perror("lseek error");
return 1;
}
}
/* mmap the output file */
- if ((dst = mmap(0, decompressSize, PROT_READ | PROT_WRITE,
+ if ((dst = mmap(0, decompressedSize, PROT_READ | PROT_WRITE,
MAP_SHARED, fdout, 0)) == (caddr_t) - 1) {
perror("mmap error for output");
return 1;
outSize = LDM_decompress(
src + LDM_HEADER_SIZE, statbuf.st_size - LDM_HEADER_SIZE,
- dst, decompressSize);
+ dst, decompressedSize);
printf("Ret size out: %zu\n", outSize);
ftruncate(fdout, outSize);
projects / thirdparty / zstd.git / commitdiff
