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Allow parameters to be modified from a separate file

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This commit is contained in:
Stella Lau 2017-07-25 18:13:27 -07:00
parent 629c300118
commit e9161637b2
8 changed files with 47 additions and 729 deletions
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8
contrib/long_distance_matching/Makefile
View File

@ -25,16 +25,16 @@ LDFLAGS += -lzstd
default: all
all: main-hash32 main-hash64
all: main-64 main-integrated
main-hash64: ldm_common.c ldm_hash64.c main.c
main-64: ldm_common.c ldm_hash64.c main.c
$(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@
main-hash32: ldm_common.c ldm_hash32.c main.c
main-integrated: ldm_common.c ldm_hash32.c main.c
$(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@
clean:
@rm -f core *.o tmp* result* *.ldm *.ldm.dec \
main-hash64 main-hash32
main-hash64 main-hash32 main-64 main-integrated
@echo Cleaning completed

539
contrib/long_distance_matching/ldm.c
View File

@ -1,539 +0,0 @@
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ldm.h"
#include "ldm_hashtable.h"
#define LDM_HASHTABLESIZE (1 << (LDM_MEMORY_USAGE))
#define LDM_HASHTABLESIZE_U64 ((LDM_HASHTABLESIZE) >> 3)
#define LDM_HASH_ENTRY_SIZE_LOG 3
//#define HASH_ONLY_EVERY_LOG 7
#define HASH_ONLY_EVERY_LOG (LDM_WINDOW_SIZE_LOG-((LDM_MEMORY_USAGE)-(LDM_HASH_ENTRY_SIZE_LOG)))
#define HASH_ONLY_EVERY ((1 << HASH_ONLY_EVERY_LOG) - 1)
#define COMPUTE_STATS
#define OUTPUT_CONFIGURATION
#define CHECKSUM_CHAR_OFFSET 10
//#define RUN_CHECKS
typedef U32 checksum_t;
struct LDM_compressStats {
U32 windowSizeLog, hashTableSizeLog;
U32 numMatches;
U64 totalMatchLength;
U64 totalLiteralLength;
U64 totalOffset;
U32 minOffset, maxOffset;
U32 offsetHistogram[32];
};
struct LDM_CCtx {
U64 isize; /* Input size */
U64 maxOSize; /* Maximum output size */
const BYTE *ibase; /* Base of input */
const BYTE *ip; /* Current input position */
const BYTE *iend; /* End of input */
// Maximum input position such that hashing at the position does not exceed
// end of input.
const BYTE *ihashLimit;
// Maximum input position such that finding a match of at least the minimum
// match length does not exceed end of input.
const BYTE *imatchLimit;
const BYTE *obase; /* Base of output */
BYTE *op; /* Output */
const BYTE *anchor; /* Anchor to start of current (match) block */
LDM_compressStats stats; /* Compression statistics */
LDM_hashTable *hashTable;
const BYTE *lastPosHashed; /* Last position hashed */
hash_t lastHash; /* Hash corresponding to lastPosHashed */
checksum_t lastSum;
const BYTE *nextIp; // TODO: this is redundant (ip + step)
const BYTE *nextPosHashed;
hash_t nextHash; /* Hash corresponding to nextPosHashed */
checksum_t nextSum;
unsigned step; // ip step, should be 1.
const BYTE *lagIp;
hash_t lagHash;
checksum_t lagSum;
// DEBUG
const BYTE *DEBUG_setNextHash;
};
// TODO: This can be done more efficiently (but it is not that important as it
// is only used for computing stats).
static int intLog2(U32 x) {
int ret = 0;
while (x >>= 1) {
ret++;
}
return ret;
}
void LDM_printCompressStats(const LDM_compressStats *stats) {
int i = 0;
printf("=====================\n");
printf("Compression statistics\n");
printf("Window size, hash table size (bytes): 2^%u, 2^%u\n",
stats->windowSizeLog, stats->hashTableSizeLog);
printf("num matches, total match length, %% matched: %u, %llu, %.3f\n",
stats->numMatches,
stats->totalMatchLength,
100.0 * (double)stats->totalMatchLength /
(double)(stats->totalMatchLength + stats->totalLiteralLength));
printf("avg match length: %.1f\n", ((double)stats->totalMatchLength) /
(double)stats->numMatches);
printf("avg literal length, total literalLength: %.1f, %llu\n",
((double)stats->totalLiteralLength) / (double)stats->numMatches,
stats->totalLiteralLength);
printf("avg offset length: %.1f\n",
((double)stats->totalOffset) / (double)stats->numMatches);
printf("min offset, max offset: %u, %u\n",
stats->minOffset, stats->maxOffset);
printf("\n");
printf("offset histogram: offset, num matches, %% of matches\n");
for (; i <= intLog2(stats->maxOffset); i++) {
printf("2^%*d: %10u %6.3f%%\n", 2, i,
stats->offsetHistogram[i],
100.0 * (double) stats->offsetHistogram[i] /
(double) stats->numMatches);
}
printf("\n");
printf("=====================\n");
}
/**
* Convert a sum computed from getChecksum to a hash value in the range
* of the hash table.
*/
static hash_t checksumToHash(U32 sum) {
return HASH_hashU32(sum);
}
/**
* Computes a 32-bit checksum based on rsync's checksum.
*
* a(k,l) = \sum_{i = k}^l x_i (mod M)
* b(k,l) = \sum_{i = k}^l ((l - i + 1) * x_i) (mod M)
* checksum(k,l) = a(k,l) + 2^{16} * b(k,l)
*/
static checksum_t getChecksum(const BYTE *buf, U32 len) {
U32 i;
checksum_t s1, s2;
s1 = s2 = 0;
for (i = 0; i < (len - 4); i += 4) {
s2 += (4 * (s1 + buf[i])) + (3 * buf[i + 1]) +
(2 * buf[i + 2]) + (buf[i + 3]) +
(10 * CHECKSUM_CHAR_OFFSET);
s1 += buf[i] + buf[i + 1] + buf[i + 2] + buf[i + 3] +
+ (4 * CHECKSUM_CHAR_OFFSET);
}
for(; i < len; i++) {
s1 += buf[i] + CHECKSUM_CHAR_OFFSET;
s2 += s1;
}
return (s1 & 0xffff) + (s2 << 16);
}
/**
* Update a checksum computed from getChecksum(data, len).
*
* The checksum can be updated along its ends as follows:
* a(k+1, l+1) = (a(k,l) - x_k + x_{l+1}) (mod M)
* b(k+1, l+1) = (b(k,l) - (l-k+1)*x_k + (a(k+1,l+1)) (mod M)
*
* Thus toRemove should correspond to data[0].
*/
static checksum_t updateChecksum(checksum_t sum, U32 len,
BYTE toRemove, BYTE toAdd) {
U32 s1 = (sum & 0xffff) - toRemove + toAdd;
U32 s2 = (sum >> 16) - ((toRemove + CHECKSUM_CHAR_OFFSET) * len) + s1;
return (s1 & 0xffff) + (s2 << 16);
}
/**
* Update cctx->nextSum, cctx->nextHash, and cctx->nextPosHashed
* based on cctx->lastSum and cctx->lastPosHashed.
*
* This uses a rolling hash and requires that the last position hashed
* corresponds to cctx->nextIp - step.
*/
static void setNextHash(LDM_CCtx *cctx) {
#ifdef RUN_CHECKS
U32 check;
if ((cctx->nextIp - cctx->ibase != 1) &&
(cctx->nextIp - cctx->DEBUG_setNextHash != 1)) {
printf("CHECK debug fail: %zu %zu\n", cctx->nextIp - cctx->ibase,
cctx->DEBUG_setNextHash - cctx->ibase);
}
cctx->DEBUG_setNextHash = cctx->nextIp;
#endif
cctx->nextSum = updateChecksum(
cctx->lastSum, LDM_HASH_LENGTH,
cctx->lastPosHashed[0],
cctx->lastPosHashed[LDM_HASH_LENGTH]);
cctx->nextPosHashed = cctx->nextIp;
cctx->nextHash = checksumToHash(cctx->nextSum);
#if LDM_LAG
if (cctx->ip - cctx->ibase > LDM_LAG) {
cctx->lagSum = updateChecksum(
cctx->lagSum, LDM_HASH_LENGTH,
cctx->lagIp[0], cctx->lagIp[LDM_HASH_LENGTH]);
cctx->lagIp++;
cctx->lagHash = checksumToHash(cctx->lagSum);
}
#endif
#ifdef RUN_CHECKS
check = getChecksum(cctx->nextIp, LDM_HASH_LENGTH);
if (check != cctx->nextSum) {
printf("CHECK: setNextHash failed %u %u\n", check, cctx->nextSum);
}
if ((cctx->nextIp - cctx->lastPosHashed) != 1) {
printf("setNextHash: nextIp != lastPosHashed + 1. %zu %zu %zu\n",
cctx->nextIp - cctx->ibase, cctx->lastPosHashed - cctx->ibase,
cctx->ip - cctx->ibase);
}
#endif
}
static void putHashOfCurrentPositionFromHash(
LDM_CCtx *cctx, hash_t hash, U32 checksum) {
// Hash only every HASH_ONLY_EVERY times, based on cctx->ip.
// Note: this works only when cctx->step is 1.
if (((cctx->ip - cctx->ibase) & HASH_ONLY_EVERY) == HASH_ONLY_EVERY) {
#if LDM_LAG
// Off by 1, but whatever
if (cctx->lagIp - cctx->ibase > 0) {
const LDM_hashEntry entry = { cctx->lagIp - cctx->ibase, cctx->lagSum };
HASH_insert(cctx->hashTable, cctx->lagHash, entry);
} else {
const LDM_hashEntry entry = { cctx->ip - cctx->ibase, checksum };
HASH_insert(cctx->hashTable, hash, entry);
}
#else
const LDM_hashEntry entry = { cctx->ip - cctx->ibase, checksum };
HASH_insert(cctx->hashTable, hash, entry);
#endif
}
cctx->lastPosHashed = cctx->ip;
cctx->lastHash = hash;
cctx->lastSum = checksum;
}
/**
* Copy over the cctx->lastHash, cctx->lastSum, and cctx->lastPosHashed
* fields from the "next" fields.
*
* This requires that cctx->ip == cctx->nextPosHashed.
*/
static void LDM_updateLastHashFromNextHash(LDM_CCtx *cctx) {
#ifdef RUN_CHECKS
if (cctx->ip != cctx->nextPosHashed) {
printf("CHECK failed: updateLastHashFromNextHash %zu\n",
cctx->ip - cctx->ibase);
}
#endif
putHashOfCurrentPositionFromHash(cctx, cctx->nextHash, cctx->nextSum);
}
/**
* Insert hash of the current position into the hash table.
*/
static void LDM_putHashOfCurrentPosition(LDM_CCtx *cctx) {
checksum_t sum = getChecksum(cctx->ip, LDM_HASH_LENGTH);
hash_t hash = checksumToHash(sum);
#ifdef RUN_CHECKS
if (cctx->nextPosHashed != cctx->ip && (cctx->ip != cctx->ibase)) {
printf("CHECK failed: putHashOfCurrentPosition %zu\n",
cctx->ip - cctx->ibase);
}
#endif
putHashOfCurrentPositionFromHash(cctx, hash, sum);
}
void LDM_initializeCCtx(LDM_CCtx *cctx,
const void *src, size_t srcSize,
void *dst, size_t maxDstSize) {
cctx->isize = srcSize;
cctx->maxOSize = maxDstSize;
cctx->ibase = (const BYTE *)src;
cctx->ip = cctx->ibase;
cctx->iend = cctx->ibase + srcSize;
cctx->ihashLimit = cctx->iend - LDM_HASH_LENGTH;
cctx->imatchLimit = cctx->iend - LDM_MIN_MATCH_LENGTH;
cctx->obase = (BYTE *)dst;
cctx->op = (BYTE *)dst;
cctx->anchor = cctx->ibase;
memset(&(cctx->stats), 0, sizeof(cctx->stats));
cctx->hashTable = HASH_createTable(LDM_HASHTABLESIZE_U64, cctx->ibase,
LDM_MIN_MATCH_LENGTH, LDM_WINDOW_SIZE);
cctx->stats.minOffset = UINT_MAX;
cctx->stats.windowSizeLog = LDM_WINDOW_SIZE_LOG;
cctx->stats.hashTableSizeLog = LDM_MEMORY_USAGE;
cctx->lastPosHashed = NULL;
cctx->step = 1; // Fixed to be 1 for now. Changing may break things.
cctx->nextIp = cctx->ip + cctx->step;
cctx->nextPosHashed = 0;
cctx->DEBUG_setNextHash = 0;
}
void LDM_destroyCCtx(LDM_CCtx *cctx) {
HASH_destroyTable(cctx->hashTable);
}
/**
* Finds the "best" match.
*
* Returns 0 if successful and 1 otherwise (i.e. no match can be found
* in the remaining input that is long enough).
*
* matchLength contains the forward length of the match.
*/
static int LDM_findBestMatch(LDM_CCtx *cctx, const BYTE **match,
U64 *matchLength, U64 *backwardMatchLength) {
LDM_hashEntry *entry = NULL;
cctx->nextIp = cctx->ip + cctx->step;
while (entry == NULL) {
hash_t h;
checksum_t sum;
setNextHash(cctx);
h = cctx->nextHash;
sum = cctx->nextSum;
cctx->ip = cctx->nextIp;
cctx->nextIp += cctx->step;
if (cctx->ip > cctx->imatchLimit) {
return 1;
}
entry = HASH_getBestEntry(cctx->hashTable, h, sum,
cctx->ip, cctx->iend,
cctx->anchor,
matchLength, backwardMatchLength);
if (entry != NULL) {
*match = entry->offset + cctx->ibase;
}
putHashOfCurrentPositionFromHash(cctx, h, sum);
}
setNextHash(cctx);
return 0;
}
void LDM_encodeLiteralLengthAndLiterals(
LDM_CCtx *cctx, BYTE *pToken, const U64 literalLength) {
/* Encode the literal length. */
if (literalLength >= RUN_MASK) {
int len = (int)literalLength - RUN_MASK;
*pToken = (RUN_MASK << ML_BITS);
for (; len >= 255; len -= 255) {
*(cctx->op)++ = 255;
}
*(cctx->op)++ = (BYTE)len;
} else {
*pToken = (BYTE)(literalLength << ML_BITS);
}
/* Encode the literals. */
memcpy(cctx->op, cctx->anchor, literalLength);
cctx->op += literalLength;
}
void LDM_outputBlock(LDM_CCtx *cctx,
const U64 literalLength,
const U32 offset,
const U64 matchLength) {
BYTE *pToken = cctx->op++;
/* Encode the literal length and literals. */
LDM_encodeLiteralLengthAndLiterals(cctx, pToken, literalLength);
/* Encode the offset. */
MEM_write32(cctx->op, offset);
cctx->op += LDM_OFFSET_SIZE;
/* Encode the match length. */
if (matchLength >= ML_MASK) {
U64 matchLengthRemaining = matchLength;
*pToken += ML_MASK;
matchLengthRemaining -= ML_MASK;
MEM_write32(cctx->op, 0xFFFFFFFF);
while (matchLengthRemaining >= 4*0xFF) {
cctx->op += 4;
MEM_write32(cctx->op, 0xffffffff);
matchLengthRemaining -= 4*0xFF;
}
cctx->op += matchLengthRemaining / 255;
*(cctx->op)++ = (BYTE)(matchLengthRemaining % 255);
} else {
*pToken += (BYTE)(matchLength);
}
}
// TODO: maxDstSize is unused. This function may seg fault when writing
// beyond the size of dst, as it does not check maxDstSize. Writing to
// a buffer and performing checks is a possible solution.
//
// This is based upon lz4.
size_t LDM_compress(const void *src, size_t srcSize,
void *dst, size_t maxDstSize) {
LDM_CCtx cctx;
const BYTE *match = NULL;
U64 forwardMatchLength = 0;
U64 backwardsMatchLength = 0;
LDM_initializeCCtx(&cctx, src, srcSize, dst, maxDstSize);
LDM_outputConfiguration();
/* Hash the first position and put it into the hash table. */
LDM_putHashOfCurrentPosition(&cctx);
#if LDM_LAG
cctx.lagIp = cctx.ip;
cctx.lagHash = cctx.lastHash;
cctx.lagSum = cctx.lastSum;
#endif
/**
* Find a match.
* If no more matches can be found (i.e. the length of the remaining input
* is less than the minimum match length), then stop searching for matches
* and encode the final literals.
*/
while (LDM_findBestMatch(&cctx, &match, &forwardMatchLength,
&backwardsMatchLength) == 0) {
#ifdef COMPUTE_STATS
cctx.stats.numMatches++;
#endif
cctx.ip -= backwardsMatchLength;
match -= backwardsMatchLength;
/**
* Write current block (literals, literal length, match offset, match
* length) and update pointers and hashes.
*/
{
const U32 literalLength = cctx.ip - cctx.anchor;
const U32 offset = cctx.ip - match;
const U32 matchLength = forwardMatchLength +
backwardsMatchLength -
LDM_MIN_MATCH_LENGTH;
LDM_outputBlock(&cctx, literalLength, offset, matchLength);
#ifdef COMPUTE_STATS
cctx.stats.totalLiteralLength += literalLength;
cctx.stats.totalOffset += offset;
cctx.stats.totalMatchLength += matchLength + LDM_MIN_MATCH_LENGTH;
cctx.stats.minOffset =
offset < cctx.stats.minOffset ? offset : cctx.stats.minOffset;
cctx.stats.maxOffset =
offset > cctx.stats.maxOffset ? offset : cctx.stats.maxOffset;
cctx.stats.offsetHistogram[(U32)intLog2(offset)]++;
#endif
// Move ip to end of block, inserting hashes at each position.
cctx.nextIp = cctx.ip + cctx.step;
while (cctx.ip < cctx.anchor + LDM_MIN_MATCH_LENGTH +
matchLength + literalLength) {
if (cctx.ip > cctx.lastPosHashed) {
// TODO: Simplify.
LDM_updateLastHashFromNextHash(&cctx);
setNextHash(&cctx);
}
cctx.ip++;
cctx.nextIp++;
}
}
// Set start of next block to current input pointer.
cctx.anchor = cctx.ip;
LDM_updateLastHashFromNextHash(&cctx);
}
/* Encode the last literals (no more matches). */
{
const U32 lastRun = cctx.iend - cctx.anchor;
BYTE *pToken = cctx.op++;
LDM_encodeLiteralLengthAndLiterals(&cctx, pToken, lastRun);
}
#ifdef COMPUTE_STATS
LDM_printCompressStats(&cctx.stats);
HASH_outputTableOccupancy(cctx.hashTable);
#endif
{
const size_t ret = cctx.op - cctx.obase;
LDM_destroyCCtx(&cctx);
return ret;
}
}
void LDM_outputConfiguration(void) {
printf("=====================\n");
printf("Configuration\n");
printf("LDM_WINDOW_SIZE_LOG: %d\n", LDM_WINDOW_SIZE_LOG);
printf("LDM_MIN_MATCH_LENGTH, LDM_HASH_LENGTH: %d, %d\n",
LDM_MIN_MATCH_LENGTH, LDM_HASH_LENGTH);
printf("LDM_MEMORY_USAGE: %d\n", LDM_MEMORY_USAGE);
printf("HASH_ONLY_EVERY_LOG: %d\n", HASH_ONLY_EVERY_LOG);
printf("HASH_BUCKET_SIZE_LOG: %d\n", HASH_BUCKET_SIZE_LOG);
printf("LDM_LAG %d\n", LDM_LAG);
printf("=====================\n");
}
void LDM_test(const BYTE *src) {
(void)src;
}

30
contrib/long_distance_matching/ldm.h
View File

@ -2,6 +2,7 @@
#define LDM_H
#include "mem.h" // from /lib/common/mem.h
#include "ldm_params.h"
// The number of bytes storing the compressed and decompressed size
// in the header.
@ -18,35 +19,38 @@
#define LDM_OFFSET_SIZE 4
// =============================================================================
// User parameters.
// Modify parameters in ldm_params.h if "ldm_params.h" is included.
// =============================================================================
#ifndef LDM_PARAMS_H
// Defines the size of the hash table.
// Note that this is not the number of buckets.
// Currently this should be less than WINDOW_SIZE_LOG + 4?
#define LDM_MEMORY_USAGE 25
#define LDM_MEMORY_USAGE 25
// The number of entries in a hash bucket.
#define HASH_BUCKET_SIZE_LOG 3 // The maximum is 4 for now.
#define HASH_BUCKET_SIZE_LOG 3 // The maximum is 4 for now.
// Defines the lag in inserting elements into the hash table.
#define LDM_LAG 0
#define LDM_LAG 0
// The maximum window size.
#define LDM_WINDOW_SIZE_LOG 28 // Max value is 30
#define LDM_WINDOW_SIZE (1 << (LDM_WINDOW_SIZE_LOG))
#define LDM_WINDOW_SIZE_LOG 28 // Max value is 30
//These should be multiples of four (and perhaps set to the same value?).
#define LDM_MIN_MATCH_LENGTH 64
#define LDM_HASH_LENGTH 64
#define LDM_MIN_MATCH_LENGTH 64
// Experimental.
//#define TMP_EVICTION // Experiment with eviction policies.
#define INSERT_BY_TAG // Insertion policy based on hash.
#define INSERT_BY_TAG 1 // Insertion policy based on hash.
#define USE_CHECKSUM 1
#define USE_CHECKSUM 1
#endif
// =============================================================================
#define COMPUTE_STATS
#define OUTPUT_CONFIGURATION
#define LDM_WINDOW_SIZE (1 << (LDM_WINDOW_SIZE_LOG))
#define LDM_HASH_LENGTH LDM_MIN_MATCH_LENGTH
typedef struct LDM_compressStats LDM_compressStats;
typedef struct LDM_CCtx LDM_CCtx;
@ -164,6 +168,4 @@ void LDM_writeHeader(void *memPtr, U64 compressedSize,
*/
void LDM_outputConfiguration(void);
void LDM_test(const BYTE *src);
#endif /* LDM_H */

5
contrib/long_distance_matching/ldm_common.c
View File

@ -70,7 +70,8 @@ size_t LDM_decompress(const void *src, size_t compressedSize,
dctx.ip += length;
dctx.op = cpy;
//TODO : dynamic offset size
//TODO: dynamic offset size?
/* Encode the offset. */
offset = MEM_read32(dctx.ip);
dctx.ip += LDM_OFFSET_SIZE;
match = dctx.op - offset;
@ -89,7 +90,7 @@ size_t LDM_decompress(const void *src, size_t compressedSize,
/* Copy match. */
cpy = dctx.op + length;
// Inefficient for now.
// TODO: this can be made more efficient.
while (match < cpy - offset && dctx.op < dctx.oend) {
*(dctx.op)++ = *match++;
}

12
contrib/long_distance_matching/ldm_hash32.c
View File

@ -21,9 +21,7 @@
#define HASH_BUCKET_SIZE (1 << (HASH_BUCKET_SIZE_LOG))
#define LDM_HASHLOG ((LDM_MEMORY_USAGE)-(LDM_HASH_ENTRY_SIZE_LOG)-(HASH_BUCKET_SIZE_LOG))
#define COMPUTE_STATS
#define OUTPUT_CONFIGURATION
#define CHECKSUM_CHAR_OFFSET 1
#define CHECKSUM_CHAR_OFFSET 10
// Take first match only.
//#define ZSTD_SKIP
@ -779,8 +777,6 @@ size_t LDM_compress(const void *src, size_t srcSize,
LDM_updateLastHashFromNextHash(&cctx);
}
// HASH_outputTableOffsetHistogram(&cctx);
/* Encode the last literals (no more matches). */
{
const U32 lastRun = cctx.iend - cctx.anchor;
@ -815,9 +811,3 @@ void LDM_outputConfiguration(void) {
// TODO: implement and test hash function
void LDM_test(const BYTE *src) {
(void)src;
}

164
contrib/long_distance_matching/ldm_hash64.c
View File

@ -24,8 +24,6 @@
#define HASH_BUCKET_SIZE (1 << (HASH_BUCKET_SIZE_LOG))
#define LDM_HASHLOG ((LDM_MEMORY_USAGE)-(LDM_HASH_ENTRY_SIZE_LOG)-(HASH_BUCKET_SIZE_LOG))
#define COMPUTE_STATS
#define OUTPUT_CONFIGURATION
#define HASH_CHAR_OFFSET 10
// Take first match only.
@ -63,11 +61,6 @@ struct LDM_compressStats {
U64 TMP_hashCount[1 << HASH_ONLY_EVERY_LOG];
U64 TMP_totalHashCount;
U64 TMP_totalInWindow;
U64 TMP_totalInserts;
U64 TMP_matchCount;
};
typedef struct LDM_hashTable LDM_hashTable;
@ -328,91 +321,12 @@ LDM_hashEntry *HASH_getBestEntry(const LDM_CCtx *cctx,
return NULL;
}
#ifdef TMP_EVICTION
void HASH_insert(LDM_hashTable *table,
const hash_t hash, const LDM_hashEntry entry,
LDM_CCtx *cctx) {
// Overwrite based on part of checksum.
/*
LDM_hashEntry *toOverwrite =
getBucket(table, hash) + table->bucketOffsets[hash];
const BYTE *pMatch = toOverwrite->offset + cctx->ibase;
if (toOverwrite->offset != 0 &&
cctx->ip - pMatch <= LDM_WINDOW_SIZE) {
cctx->stats.TMP_totalInWindow++;
}
cctx->stats.TMP_totalInserts++;
*(toOverwrite) = entry;
*/
/*
int i;
LDM_hashEntry *bucket = getBucket(table, hash);
for (i = 0; i < HASH_BUCKET_SIZE; i++) {
if (bucket[i].checksum == entry.checksum) {
bucket[i] = entry;
cctx->stats.TMP_matchCount++;
return;
}
}
*/
// Find entry beyond window size, replace. Else, random.
int i;
LDM_hashEntry *bucket = getBucket(table, hash);
for (i = 0; i < HASH_BUCKET_SIZE; i++) {
if (cctx->ip - cctx->ibase - bucket[i].offset > LDM_WINDOW_SIZE) {
bucket[i] = entry;
return;
}
}
i = rand() & (HASH_BUCKET_SIZE - 1);
*(bucket + i) = entry;
/**
* Sliding buffer style pointer
* Keep old entry as temporary. If the old entry is outside the window,
* overwrite and we are done.
*
* Backwards (insert at x):
* x, a, b b, c c c c, d d d d d d d d
* x, d d d d d d d d, c c c c, b b, a
*
* Else, find something to evict.
* If old entry has more ones, it takes
* the next spot. <-- reversed order?
*
* If window size > LDM_WINDOW_SIZE,
* overwrite,
*
* Insert forwards. If > tag, keep. Else evict.
*
*/
/*
*(getBucket(table, hash) + table->bucketOffsets[hash]) = entry;
table->bucketOffsets[hash]++;
table->bucketOffsets[hash] &= HASH_BUCKET_SIZE - 1;
*/
// U16 mask = entry.checksum & (HASH_BUCKET_SIZE - 1);
// *(getBucket(table, hash) + mask) = entry;
}
#else
void HASH_insert(LDM_hashTable *table,
const hash_t hash, const LDM_hashEntry entry) {
*(getBucket(table, hash) + table->bucketOffsets[hash]) = entry;
table->bucketOffsets[hash]++;
table->bucketOffsets[hash] &= HASH_BUCKET_SIZE - 1;
}
#endif // TMP_EVICTION
U32 HASH_getSize(const LDM_hashTable *table) {
return table->numBuckets;
@ -489,7 +403,7 @@ void LDM_printCompressStats(const LDM_compressStats *stats) {
(double) stats->numMatches);
}
printf("\n");
#ifdef INSERT_BY_TAG
#if INSERT_BY_TAG
/*
printf("Lower bit distribution\n");
for (i = 0; i < (1 << HASH_ONLY_EVERY_LOG); i++) {
@ -500,13 +414,6 @@ void LDM_printCompressStats(const LDM_compressStats *stats) {
*/
#endif
#ifdef TMP_EVICTION
printf("Evicted something in window: %llu %6.3f\n",
stats->TMP_totalInWindow,
100.0 * (double)stats->TMP_totalInWindow /
(double)stats->TMP_totalInserts);
printf("Match count: %llu\n", stats->TMP_matchCount);
#endif
printf("=====================\n");
}
@ -524,7 +431,7 @@ static U32 getChecksum(U64 hash) {
return (hash >> (64 - 32 - LDM_HASHLOG)) & 0xFFFFFFFF;
}
#ifdef INSERT_BY_TAG
#if INSERT_BY_TAG
static U32 lowerBitsFromHfHash(U64 hash) {
// The number of bits used so far is LDM_HASHLOG + 32.
// So there are 32 - LDM_HASHLOG bits left.
@ -611,7 +518,7 @@ static void setNextHash(LDM_CCtx *cctx) {
cctx->lastPosHashed[LDM_HASH_LENGTH]);
cctx->nextPosHashed = cctx->nextIp;
#ifdef INSERT_BY_TAG
#if INSERT_BY_TAG
{
U32 hashEveryMask = lowerBitsFromHfHash(cctx->nextHash);
cctx->stats.TMP_totalHashCount++;
@ -648,7 +555,7 @@ static void putHashOfCurrentPositionFromHash(LDM_CCtx *cctx, U64 hash) {
// Note: this works only when cctx->step is 1.
#if LDM_LAG
if (cctx -> lagIp - cctx->ibase > 0) {
#ifdef INSERT_BY_TAG
#if INSERT_BY_TAG
U32 hashEveryMask = lowerBitsFromHfHash(cctx->lagHash);
if (hashEveryMask == HASH_ONLY_EVERY) {
#else
@ -663,14 +570,11 @@ static void putHashOfCurrentPositionFromHash(LDM_CCtx *cctx, U64 hash) {
const LDM_hashEntry entry = { cctx->lagIp - cctx->ibase };
# endif
# ifdef TMP_EVICTION
HASH_insert(cctx->hashTable, smallHash, entry, cctx);
# else
HASH_insert(cctx->hashTable, smallHash, entry);
# endif
}
} else {
#ifdef INSERT_BY_TAG
#endif // LDM_LAG
#if INSERT_BY_TAG
U32 hashEveryMask = lowerBitsFromHfHash(hash);
if (hashEveryMask == HASH_ONLY_EVERY) {
#else
@ -684,33 +588,9 @@ static void putHashOfCurrentPositionFromHash(LDM_CCtx *cctx, U64 hash) {
#else
const LDM_hashEntry entry = { cctx->ip - cctx->ibase };
#endif
#ifdef TMP_EVICTION
HASH_insert(cctx->hashTable, smallHash, entry, cctx);
#else
HASH_insert(cctx->hashTable, smallHash, entry);
#endif
}
}
#else
#ifdef INSERT_BY_TAG
U32 hashEveryMask = lowerBitsFromHfHash(hash);
if (hashEveryMask == HASH_ONLY_EVERY) {
#else
if (((cctx->ip - cctx->ibase) & HASH_ONLY_EVERY) == HASH_ONLY_EVERY) {
#endif
U32 smallHash = getSmallHash(hash);
#if USE_CHECKSUM
U32 checksum = getChecksum(hash);
const LDM_hashEntry entry = { cctx->ip - cctx->ibase, checksum };
#else
const LDM_hashEntry entry = { cctx->ip - cctx->ibase };
#endif
#ifdef TMP_EVICTION
HASH_insert(cctx->hashTable, smallHash, entry, cctx);
#else
HASH_insert(cctx->hashTable, smallHash, entry);
#endif
#if LDM_LAG
}
#endif
@ -812,7 +692,7 @@ static int LDM_findBestMatch(LDM_CCtx *cctx, const BYTE **match,
U64 hash;
hash_t smallHash;
U32 checksum;
#ifdef INSERT_BY_TAG
#if INSERT_BY_TAG
U32 hashEveryMask;
#endif
setNextHash(cctx);
@ -820,7 +700,7 @@ static int LDM_findBestMatch(LDM_CCtx *cctx, const BYTE **match,
hash = cctx->nextHash;
smallHash = getSmallHash(hash);
checksum = getChecksum(hash);
#ifdef INSERT_BY_TAG
#if INSERT_BY_TAG
hashEveryMask = lowerBitsFromHfHash(hash);
#endif
@ -830,7 +710,7 @@ static int LDM_findBestMatch(LDM_CCtx *cctx, const BYTE **match,
if (cctx->ip > cctx->imatchLimit) {
return 1;
}
#ifdef INSERT_BY_TAG
#if INSERT_BY_TAG
if (hashEveryMask == HASH_ONLY_EVERY) {
entry = HASH_getBestEntry(cctx, smallHash, checksum,
@ -923,10 +803,8 @@ size_t LDM_compress(const void *src, size_t srcSize,
/* Hash the first position and put it into the hash table. */
LDM_putHashOfCurrentPosition(&cctx);
#if LDM_LAG
cctx.lagIp = cctx.ip;
cctx.lagHash = cctx.lastHash;
#endif
/**
* Find a match.
* If no more matches can be found (i.e. the length of the remaining input
@ -1018,28 +896,8 @@ void LDM_outputConfiguration(void) {
printf("HASH_BUCKET_SIZE_LOG: %d\n", HASH_BUCKET_SIZE_LOG);
printf("LDM_LAG: %d\n", LDM_LAG);
printf("USE_CHECKSUM: %d\n", USE_CHECKSUM);
#ifdef INSERT_BY_TAG
printf("INSERT_BY_TAG: %d\n", 1);
#else
printf("INSERT_BY_TAG: %d\n", 0);
#endif
printf("INSERT_BY_TAG: %d\n", INSERT_BY_TAG);
printf("HASH_CHAR_OFFSET: %d\n", HASH_CHAR_OFFSET);
printf("=====================\n");
}
// TODO: implement and test hash function
void LDM_test(const BYTE *src) {
const U32 diff = 100;
const BYTE *pCur = src + diff;
U64 hash = getHash(pCur, LDM_HASH_LENGTH);
for (; pCur < src + diff + 60; ++pCur) {
U64 nextHash = getHash(pCur + 1, LDM_HASH_LENGTH);
U64 updatedHash = updateHash(hash, LDM_HASH_LENGTH,
pCur[0], pCur[LDM_HASH_LENGTH]);
hash = nextHash;
printf("%llu %llu\n", nextHash, updatedHash);
}
}

10
contrib/long_distance_matching/ldm_params.h Normal file
View File

@ -0,0 +1,10 @@
#ifndef LDM_PARAMS_H
#define LDM_PARAMS_H
#define LDM_MEMORY_USAGE 23
#define HASH_BUCKET_SIZE_LOG 3
#define LDM_LAG 0
#define LDM_WINDOW_SIZE_LOG 28
#define LDM_MIN_MATCH_LENGTH 64
#define INSERT_BY_TAG 1
#define USE_CHECKSUM 1
#endif

8
contrib/long_distance_matching/main.c
View File

@ -12,7 +12,7 @@
#include "ldm.h"
#include "zstd.h"
//#define DECOMPRESS_AND_VERIFY
#define DECOMPRESS_AND_VERIFY
/* Compress file given by fname and output to oname.
* Returns 0 if successful, error code otherwise.
@ -71,10 +71,6 @@ static int compress(const char *fname, const char *oname) {
return 1;
}
#ifdef TEST
LDM_test((const BYTE *)src);
#endif
gettimeofday(&tv1, NULL);
compressedSize = LDM_HEADER_SIZE +
@ -111,7 +107,7 @@ static int compress(const char *fname, const char *oname) {
return 0;
}
#ifdef DECOMPRESS
#ifdef DECOMPRESS_AND_VERIFY
/* Decompress file compressed using LDM_compress.
* The input file should have the LDM_HEADER followed by payload.
* Returns 0 if succesful, and an error code otherwise.