Yann Collet
GitHub
commit
9f6b7b6ef4
11
Makefile
11
Makefile
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@ -27,7 +27,7 @@ endif
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default: lib-release zstd-release
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.PHONY: all
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all: | allmost examples manual
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all: | allmost examples manual contrib
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.PHONY: allmost
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allmost: allzstd
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@ -92,6 +92,12 @@ examples:
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manual:
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$(MAKE) -C contrib/gen_html $@
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.PHONY: contrib
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contrib: lib
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$(MAKE) -C contrib/pzstd all
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$(MAKE) -C contrib/seekable_format/examples all
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$(MAKE) -C contrib/adaptive-compression all
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.PHONY: cleanTabs
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cleanTabs:
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cd contrib; ./cleanTabs
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@ -104,6 +110,9 @@ clean:
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@$(MAKE) -C $(ZWRAPDIR) $@ > $(VOID)
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@$(MAKE) -C examples/ $@ > $(VOID)
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@$(MAKE) -C contrib/gen_html $@ > $(VOID)
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@$(MAKE) -C contrib/pzstd $@ > $(VOID)
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@$(MAKE) -C contrib/seekable_format/examples $@ > $(VOID)
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@$(MAKE) -C contrib/adaptive-compression $@ > $(VOID)
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@$(RM) zstd$(EXT) zstdmt$(EXT) tmp*
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@$(RM) -r lz4
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@echo Cleaning completed
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@ -0,0 +1,3 @@
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# binaries generated
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adapt
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datagen
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@ -40,7 +40,6 @@ static unsigned g_compressionLevel = DEFAULT_COMPRESSION_LEVEL;
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static UTIL_time_t g_startTime;
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static size_t g_streamedSize = 0;
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static unsigned g_useProgressBar = 1;
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static UTIL_freq_t g_ticksPerSecond;
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static unsigned g_forceCompressionLevel = 0;
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static unsigned g_minCLevel = 1;
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static unsigned g_maxCLevel;
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@ -576,13 +575,12 @@ static void* compressionThread(void* arg)
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/* begin compression */
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{
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size_t const useDictSize = MIN(getUseableDictSize(cLevel), job->dictSize);
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size_t const dictModeError = ZSTD_setCCtxParameter(ctx->cctx, ZSTD_p_forceRawDict, 1);
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ZSTD_parameters params = ZSTD_getParams(cLevel, 0, useDictSize);
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params.cParams.windowLog = 23;
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{
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size_t const initError = ZSTD_compressBegin_advanced(ctx->cctx, job->src.start + job->dictSize - useDictSize, useDictSize, params, 0);
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size_t const windowSizeError = ZSTD_setCCtxParameter(ctx->cctx, ZSTD_p_forceWindow, 1);
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if (ZSTD_isError(dictModeError) || ZSTD_isError(initError) || ZSTD_isError(windowSizeError)) {
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size_t const windowSizeError = ZSTD_CCtx_setParameter(ctx->cctx, ZSTD_p_forceMaxWindow, 1);
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if (ZSTD_isError(initError) || ZSTD_isError(windowSizeError)) {
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DISPLAY("Error: something went wrong while starting compression\n");
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signalErrorToThreads(ctx);
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return arg;
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@ -644,21 +642,17 @@ static void* compressionThread(void* arg)
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static void displayProgress(unsigned cLevel, unsigned last)
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{
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UTIL_time_t currTime;
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UTIL_getTime(&currTime);
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UTIL_time_t currTime = UTIL_getTime();
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if (!g_useProgressBar) return;
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{
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double const timeElapsed = (double)(UTIL_getSpanTimeMicro(g_ticksPerSecond, g_startTime, currTime) / 1000.0);
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{ double const timeElapsed = (double)(UTIL_getSpanTimeMicro(g_startTime, currTime) / 1000.0);
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double const sizeMB = (double)g_streamedSize / (1 << 20);
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double const avgCompRate = sizeMB * 1000 / timeElapsed;
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fprintf(stderr, "\r| Comp. Level: %2u | Time Elapsed: %7.2f s | Data Size: %7.1f MB | Avg Comp. Rate: %6.2f MB/s |", cLevel, timeElapsed/1000.0, sizeMB, avgCompRate);
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if (last) {
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fprintf(stderr, "\n");
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}
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else {
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} else {
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fflush(stderr);
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}
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}
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} }
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}
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static void* outputThread(void* arg)
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@ -971,7 +965,6 @@ static int compressFilename(const char* const srcFilename, const char* const dst
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{
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int ret = 0;
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fcResources fcr = createFileCompressionResources(srcFilename, dstFilenameOrNull);
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UTIL_getTime(&g_startTime);
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g_streamedSize = 0;
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ret |= performCompression(fcr.ctx, fcr.srcFile, fcr.otArg);
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ret |= freeFileCompressionResources(&fcr);
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@ -1044,8 +1037,6 @@ int main(int argCount, const char* argv[])
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filenameTable[0] = stdinmark;
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g_maxCLevel = ZSTD_maxCLevel();
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UTIL_initTimer(&g_ticksPerSecond);
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if (filenameTable == NULL) {
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DISPLAY("Error: could not allocate sapce for filename table.\n");
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return 1;
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@ -1,36 +0,0 @@
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# ################################################################
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# Copyright (c) 2017-present, Facebook, Inc.
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# All rights reserved.
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#
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# This source code is licensed under both the BSD-style license (found in the
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# LICENSE file in the root directory of this source tree) and the GPLv2 (found
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# in the COPYING file in the root directory of this source tree).
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# ################################################################
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# This Makefile presumes libzstd is installed, using `sudo make install`
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CPPFLAGS+= -I../../lib/common
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CFLAGS ?= -O3
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DEBUGFLAGS = -Wall -Wextra -Wcast-qual -Wcast-align -Wshadow \
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-Wstrict-aliasing=1 -Wswitch-enum -Wdeclaration-after-statement \
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-Wstrict-prototypes -Wundef -Wpointer-arith -Wformat-security \
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-Wvla -Wformat=2 -Winit-self -Wfloat-equal -Wwrite-strings \
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-Wredundant-decls
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CFLAGS += $(DEBUGFLAGS) $(MOREFLAGS)
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FLAGS = $(CPPFLAGS) $(CFLAGS)
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LDFLAGS += -lzstd
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.PHONY: default all clean
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default: all
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all: ldm
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ldm: ldm_common.c ldm.c main.c
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$(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@
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clean:
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@rm -f core *.o tmp* result* *.ldm *.ldm.dec \
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ldm
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@echo Cleaning completed
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@ -1,102 +0,0 @@
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This is a compression algorithm focused on finding long distance matches.
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It is based upon lz4 and uses nearly the same block format (github.com/lz4/lz4/blob/dev/doc/lz4_Block_format.md). The number of bytes to encode the offset is four instead of two in lz4 to reflect the longer distance matching. The block format is described in `ldm.h`.
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### Build
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Run `make`.
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### Compressing a file
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`ldm <filename>`
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Decompression and verification can be enabled by defining `DECOMPRESS_AND_VERIFY` in `main.c`.
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The output file names are as follows:
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- `<filename>.ldm` : compressed file
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- `<filename>.ldm.dec` : decompressed file
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### Parameters
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There are various parameters that can be tuned. These parameters can be tuned in `ldm.h` or, alternatively if `ldm_params.h` is included, in `ldm_params.h` (for easier configuration).
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The parameters are as follows and must all be defined:
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- `LDM_MEMORY_USAGE` : the memory usage of the underlying hash table in bytes.
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- `HASH_BUCKET_SIZE_LOG` : the log size of each bucket in the hash table (used in collision resolution).
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- `LDM_LAG` : the lag (in bytes) in inserting entries into the hash table.
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- `LDM_WINDOW_SIZE_LOG` : the log maximum window size when searching for matches.
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- `LDM_MIN_MATCH_LENGTH` : the minimum match length.
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- `INSERT_BY_TAG` : insert entries into the hash table as a function of the hash. This increases speed by reducing the number of hash table lookups and match comparisons. Certain hashes will never be inserted.
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- `USE_CHECKSUM` : store a checksum with the hash table entries for faster comparison. This halves the number of entries the hash table can contain.
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The optional parameter `HASH_ONLY_EVERY_LOG` is the log inverse frequency of insertion into the hash table. That is, an entry is inserted approximately every `1 << HASH_ONLY_EVERY_LOG` times. If this parameter is not defined, the value is computed as a function of the window size and memory usage to approximate an even coverage of the window.
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### Benchmark
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Below is a comparison of various compression methods on a tar of four versions of llvm (versions `3.9.0`, `3.9.1`, `4.0.0`, `4.0.1`) with a total size of `727900160` B.
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| Method | Size | Ratio |
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|:---|---:|---:|
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|lrzip -p 32 -n -w 1 | `369968714` | `1.97`|
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|ldm | `209391361` | `3.48`|
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|lz4 | `189954338` | `3.83`|
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|lrzip -p 32 -l -w 1 | `163940343` | `4.44`|
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|zstd -1 | `126080293` | `5.77`|
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|lrzip -p 32 -n | `124821009` | `5.83`|
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|lrzip -p 32 -n -w 1 & zstd -1 | `120317909` | `6.05`|
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|zstd -3 -o | `115290952` | `6.31`|
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|lrzip -p 32 -g -L 9 -w 1 | `107168979` | `6.79`|
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|zstd -6 -o | `102772098` | `7.08`|
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|zstd -T16 -9 | `98040470` | `7.42`|
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|lrzip -p 32 -n -w 1 & zstd -T32 -19 | `88050289` | `8.27`|
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|zstd -T32 -19 | `83626098` | `8.70`|
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|lrzip -p 32 -n & zstd -1 | `36335117` | `20.03`|
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|ldm & zstd -6 | `32856232` | `22.15`|
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|lrzip -p 32 -g -L 9 | `32243594` | `22.58`|
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|lrzip -p 32 -n & zstd -6 | `30954572` | `23.52`|
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|lrzip -p 32 -n & zstd -T32 -19 | `26472064` | `27.50`|
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The method marked `ldm` was run with the following parameters:
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| Parameter | Value |
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|:---|---:|
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| `LDM_MEMORY_USAGE` | `23`|
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|`HASH_BUCKET_SIZE_LOG` | `3`|
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|`LDM_LAG` | `0`|
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|`LDM_WINDOW_SIZE_LOG` | `28`|
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|`LDM_MIN_MATCH_LENGTH`| `64`|
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|`INSERT_BY_TAG` | `1`|
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|`USE_CHECKSUM` | `1`|
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The compression speed was `220.5 MB/s`.
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### Parameter selection
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Below is a brief discussion of the effects of the parameters on the speed and compression ratio.
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#### Speed
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A large bottleneck in terms of speed is finding the matches and comparing to see if they are greater than the minimum match length. Generally:
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- The fewer matches found (or the lower the percentage of the literals matched), the slower the algorithm will behave.
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- Increasing `HASH_ONLY_EVERY_LOG` results in fewer inserts and, if `INSERT_BY_TAG` is set, fewer lookups in the table. This has a large effect on speed, as well as compression ratio.
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- If `HASH_ONLY_EVERY_LOG` is not set, its value is calculated based on `LDM_WINDOW_SIZE_LOG` and `LDM_MEMORY_USAGE`. Increasing `LDM_WINDOW_SIZE_LOG` has the effect of increasing `HASH_ONLY_EVERY_LOG` and increasing `LDM_MEMORY_USAGE` decreases `HASH_ONLY_EVERY_LOG`.
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- `USE_CHECKSUM` generally improves speed with hash table lookups.
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#### Compression ratio
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The compression ratio is highly correlated with the coverage of matches. As a long distance matcher, the algorithm was designed to "optimize" for long distance matches outside the zstd compression window. The compression ratio after recompressing the output of the long-distance matcher with zstd was a more important signal in development than the raw compression ratio itself.
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Generally, increasing `LDM_MEMORY_USAGE` will improve the compression ratio. However when using the default computed value of `HASH_ONLY_EVERY_LOG`, this increases the frequency of insertion and lookup in the table and thus may result in a decrease in speed.
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Below is a table showing the speed and compression ratio when compressing the llvm tar (as described above) using different settings for `LDM_MEMORY_USAGE`. The other parameters were the same as used in the benchmark above.
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| `LDM_MEMORY_USAGE` | Ratio | Speed (MB/s) | Ratio after zstd -6 |
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|---:| ---: | ---: | ---: |
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| `18` | `1.85` | `232.4` | `10.92` |
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| `21` | `2.79` | `233.9` | `15.92` |
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| `23` | `3.48` | `220.5` | `18.29` |
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| `25` | `4.56` | `140.8` | `19.21` |
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### Compression statistics
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Compression statistics (and the configuration) can be enabled/disabled via `COMPUTE_STATS` and `OUTPUT_CONFIGURATION` in `ldm.h`.
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@ -1,856 +0,0 @@
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#include <limits.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "ldm.h"
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#define LDM_HASHTABLESIZE (1 << (LDM_MEMORY_USAGE))
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#define LDM_HASHTABLESIZE_U32 ((LDM_HASHTABLESIZE) >> 2)
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#define LDM_HASHTABLESIZE_U64 ((LDM_HASHTABLESIZE) >> 3)
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#if USE_CHECKSUM
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#define LDM_HASH_ENTRY_SIZE_LOG 3
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#else
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#define LDM_HASH_ENTRY_SIZE_LOG 2
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#endif
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// Entries are inserted into the table HASH_ONLY_EVERY + 1 times "on average".
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#ifndef HASH_ONLY_EVERY_LOG
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#define HASH_ONLY_EVERY_LOG (LDM_WINDOW_SIZE_LOG-((LDM_MEMORY_USAGE)-(LDM_HASH_ENTRY_SIZE_LOG)))
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#endif
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#define HASH_ONLY_EVERY ((1 << (HASH_ONLY_EVERY_LOG)) - 1)
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#define HASH_BUCKET_SIZE (1 << (HASH_BUCKET_SIZE_LOG))
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#define NUM_HASH_BUCKETS_LOG ((LDM_MEMORY_USAGE)-(LDM_HASH_ENTRY_SIZE_LOG)-(HASH_BUCKET_SIZE_LOG))
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#define HASH_CHAR_OFFSET 10
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// Take the first match in the hash bucket only.
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//#define ZSTD_SKIP
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static const U64 prime8bytes = 11400714785074694791ULL;
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// Type of the small hash used to index into the hash table.
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typedef U32 hash_t;
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#if USE_CHECKSUM
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typedef struct LDM_hashEntry {
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U32 offset;
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U32 checksum;
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} LDM_hashEntry;
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#else
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typedef struct LDM_hashEntry {
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U32 offset;
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} LDM_hashEntry;
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#endif
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struct LDM_compressStats {
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U32 windowSizeLog, hashTableSizeLog;
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U32 numMatches;
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U64 totalMatchLength;
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U64 totalLiteralLength;
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U64 totalOffset;
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U32 matchLengthHistogram[32];
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U32 minOffset, maxOffset;
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U32 offsetHistogram[32];
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};
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typedef struct LDM_hashTable LDM_hashTable;
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struct LDM_CCtx {
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size_t isize; /* Input size */
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size_t maxOSize; /* Maximum output size */
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const BYTE *ibase; /* Base of input */
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const BYTE *ip; /* Current input position */
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const BYTE *iend; /* End of input */
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// Maximum input position such that hashing at the position does not exceed
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// end of input.
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const BYTE *ihashLimit;
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// Maximum input position such that finding a match of at least the minimum
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// match length does not exceed end of input.
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const BYTE *imatchLimit;
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const BYTE *obase; /* Base of output */
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BYTE *op; /* Output */
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const BYTE *anchor; /* Anchor to start of current (match) block */
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LDM_compressStats stats; /* Compression statistics */
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LDM_hashTable *hashTable;
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const BYTE *lastPosHashed; /* Last position hashed */
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U64 lastHash;
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const BYTE *nextIp; // TODO: this is redundant (ip + step)
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const BYTE *nextPosHashed;
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U64 nextHash;
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unsigned step; // ip step, should be 1.
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const BYTE *lagIp;
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U64 lagHash;
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};
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struct LDM_hashTable {
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U32 numBuckets; // The number of buckets.
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U32 numEntries; // numBuckets * HASH_BUCKET_SIZE.
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LDM_hashEntry *entries;
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BYTE *bucketOffsets; // A pointer (per bucket) to the next insert position.
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};
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static void HASH_destroyTable(LDM_hashTable *table) {
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free(table->entries);
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free(table->bucketOffsets);
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free(table);
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}
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/**
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* Create a hash table that can contain size elements.
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* The number of buckets is determined by size >> HASH_BUCKET_SIZE_LOG.
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*
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* Returns NULL if table creation failed.
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*/
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static LDM_hashTable *HASH_createTable(U32 size) {
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LDM_hashTable *table = malloc(sizeof(LDM_hashTable));
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if (!table) return NULL;
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table->numBuckets = size >> HASH_BUCKET_SIZE_LOG;
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table->numEntries = size;
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table->entries = calloc(size, sizeof(LDM_hashEntry));
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table->bucketOffsets = calloc(size >> HASH_BUCKET_SIZE_LOG, sizeof(BYTE));
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if (!table->entries || !table->bucketOffsets) {
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HASH_destroyTable(table);
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return NULL;
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}
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return table;
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}
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static LDM_hashEntry *getBucket(const LDM_hashTable *table, const hash_t hash) {
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return table->entries + (hash << HASH_BUCKET_SIZE_LOG);
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}
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static unsigned ZSTD_NbCommonBytes (size_t val) {
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if (MEM_isLittleEndian()) {
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if (MEM_64bits()) {
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# if defined(_MSC_VER) && defined(_WIN64)
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unsigned long r = 0;
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_BitScanForward64( &r, (U64)val );
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return (unsigned)(r>>3);
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# elif defined(__GNUC__) && (__GNUC__ >= 3)
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return (__builtin_ctzll((U64)val) >> 3);
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# else
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static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2,
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0, 3, 1, 3, 1, 4, 2, 7,
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0, 2, 3, 6, 1, 5, 3, 5,
|
||||
1, 3, 4, 4, 2, 5, 6, 7,
|
||||
7, 0, 1, 2, 3, 3, 4, 6,
|
||||
2, 6, 5, 5, 3, 4, 5, 6,
|
||||
7, 1, 2, 4, 6, 4, 4, 5,
|
||||
7, 2, 6, 5, 7, 6, 7, 7 };
|
||||
return DeBruijnBytePos[
|
||||
((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];
|
||||
# endif
|
||||
} else { /* 32 bits */
|
||||
# if defined(_MSC_VER)
|
||||
unsigned long r=0;
|
||||
_BitScanForward( &r, (U32)val );
|
||||
return (unsigned)(r>>3);
|
||||
# elif defined(__GNUC__) && (__GNUC__ >= 3)
|
||||
return (__builtin_ctz((U32)val) >> 3);
|
||||
# else
|
||||
static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0,
|
||||
3, 2, 2, 1, 3, 2, 0, 1,
|
||||
3, 3, 1, 2, 2, 2, 2, 0,
|
||||
3, 1, 2, 0, 1, 0, 1, 1 };
|
||||
return DeBruijnBytePos[
|
||||
((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
|
||||
# endif
|
||||
}
|
||||
} else { /* Big Endian CPU */
|
||||
if (MEM_64bits()) {
|
||||
# if defined(_MSC_VER) && defined(_WIN64)
|
||||
unsigned long r = 0;
|
||||
_BitScanReverse64( &r, val );
|
||||
return (unsigned)(r>>3);
|
||||
# elif defined(__GNUC__) && (__GNUC__ >= 3)
|
||||
return (__builtin_clzll(val) >> 3);
|
||||
# else
|
||||
unsigned r;
|
||||
/* calculate this way due to compiler complaining in 32-bits mode */
|
||||
const unsigned n32 = sizeof(size_t)*4;
|
||||
if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; }
|
||||
if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
|
||||
r += (!val);
|
||||
return r;
|
||||
# endif
|
||||
} else { /* 32 bits */
|
||||
# if defined(_MSC_VER)
|
||||
unsigned long r = 0;
|
||||
_BitScanReverse( &r, (unsigned long)val );
|
||||
return (unsigned)(r>>3);
|
||||
# elif defined(__GNUC__) && (__GNUC__ >= 3)
|
||||
return (__builtin_clz((U32)val) >> 3);
|
||||
# else
|
||||
unsigned r;
|
||||
if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
|
||||
r += (!val);
|
||||
return r;
|
||||
# endif
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// From lib/compress/zstd_compress.c
|
||||
static size_t ZSTD_count(const BYTE *pIn, const BYTE *pMatch,
|
||||
const BYTE *const pInLimit) {
|
||||
const BYTE * const pStart = pIn;
|
||||
const BYTE * const pInLoopLimit = pInLimit - (sizeof(size_t)-1);
|
||||
|
||||
while (pIn < pInLoopLimit) {
|
||||
size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);
|
||||
if (!diff) {
|
||||
pIn += sizeof(size_t);
|
||||
pMatch += sizeof(size_t);
|
||||
continue;
|
||||
}
|
||||
pIn += ZSTD_NbCommonBytes(diff);
|
||||
return (size_t)(pIn - pStart);
|
||||
}
|
||||
|
||||
if (MEM_64bits()) {
|
||||
if ((pIn < (pInLimit - 3)) && (MEM_read32(pMatch) == MEM_read32(pIn))) {
|
||||
pIn += 4;
|
||||
pMatch += 4;
|
||||
}
|
||||
}
|
||||
if ((pIn < (pInLimit - 1)) && (MEM_read16(pMatch) == MEM_read16(pIn))) {
|
||||
pIn += 2;
|
||||
pMatch += 2;
|
||||
}
|
||||
if ((pIn < pInLimit) && (*pMatch == *pIn)) {
|
||||
pIn++;
|
||||
}
|
||||
return (size_t)(pIn - pStart);
|
||||
}
|
||||
|
||||
/**
|
||||
* Count number of bytes that match backwards before pIn and pMatch.
|
||||
*
|
||||
* We count only bytes where pMatch > pBase and pIn > pAnchor.
|
||||
*/
|
||||
static size_t countBackwardsMatch(const BYTE *pIn, const BYTE *pAnchor,
|
||||
const BYTE *pMatch, const BYTE *pBase) {
|
||||
size_t matchLength = 0;
|
||||
while (pIn > pAnchor && pMatch > pBase && pIn[-1] == pMatch[-1]) {
|
||||
pIn--;
|
||||
pMatch--;
|
||||
matchLength++;
|
||||
}
|
||||
return matchLength;
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns a pointer to the entry in the hash table matching the hash and
|
||||
* checksum with the "longest match length" as defined below. The forward and
|
||||
* backward match lengths are written to *pForwardMatchLength and
|
||||
* *pBackwardMatchLength.
|
||||
*
|
||||
* The match length is defined based on cctx->ip and the entry's offset.
|
||||
* The forward match is computed from cctx->ip and entry->offset + cctx->ibase.
|
||||
* The backward match is computed backwards from cctx->ip and
|
||||
* cctx->ibase only if the forward match is longer than LDM_MIN_MATCH_LENGTH.
|
||||
*/
|
||||
static LDM_hashEntry *HASH_getBestEntry(const LDM_CCtx *cctx,
|
||||
const hash_t hash,
|
||||
const U32 checksum,
|
||||
U64 *pForwardMatchLength,
|
||||
U64 *pBackwardMatchLength) {
|
||||
LDM_hashTable *table = cctx->hashTable;
|
||||
LDM_hashEntry *bucket = getBucket(table, hash);
|
||||
LDM_hashEntry *cur;
|
||||
LDM_hashEntry *bestEntry = NULL;
|
||||
U64 bestMatchLength = 0;
|
||||
#if !(USE_CHECKSUM)
|
||||
(void)checksum;
|
||||
#endif
|
||||
for (cur = bucket; cur < bucket + HASH_BUCKET_SIZE; ++cur) {
|
||||
const BYTE *pMatch = cur->offset + cctx->ibase;
|
||||
|
||||
// Check checksum for faster check.
|
||||
#if USE_CHECKSUM
|
||||
if (cur->checksum == checksum &&
|
||||
cctx->ip - pMatch <= LDM_WINDOW_SIZE) {
|
||||
#else
|
||||
if (cctx->ip - pMatch <= LDM_WINDOW_SIZE) {
|
||||
#endif
|
||||
U64 forwardMatchLength = ZSTD_count(cctx->ip, pMatch, cctx->iend);
|
||||
U64 backwardMatchLength, totalMatchLength;
|
||||
|
||||
// Only take matches where the forward match length is large enough
|
||||
// for speed.
|
||||
if (forwardMatchLength < LDM_MIN_MATCH_LENGTH) {
|
||||
continue;
|
||||
}
|
||||
|
||||
backwardMatchLength =
|
||||
countBackwardsMatch(cctx->ip, cctx->anchor,
|
||||
cur->offset + cctx->ibase,
|
||||
cctx->ibase);
|
||||
|
||||
totalMatchLength = forwardMatchLength + backwardMatchLength;
|
||||
|
||||
if (totalMatchLength >= bestMatchLength) {
|
||||
bestMatchLength = totalMatchLength;
|
||||
*pForwardMatchLength = forwardMatchLength;
|
||||
*pBackwardMatchLength = backwardMatchLength;
|
||||
|
||||
bestEntry = cur;
|
||||
#ifdef ZSTD_SKIP
|
||||
return cur;
|
||||
#endif
|
||||
}
|
||||
}
|
||||
}
|
||||
if (bestEntry != NULL) {
|
||||
return bestEntry;
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* Insert an entry into the hash table. The table uses a "circular buffer",
|
||||
* with the oldest entry overwritten.
|
||||
*/
|
||||
static 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;
|
||||
}
|
||||
|
||||
static void HASH_outputTableOccupancy(const LDM_hashTable *table) {
|
||||
U32 ctr = 0;
|
||||
LDM_hashEntry *cur = table->entries;
|
||||
LDM_hashEntry *end = table->entries + (table->numBuckets * HASH_BUCKET_SIZE);
|
||||
for (; cur < end; ++cur) {
|
||||
if (cur->offset == 0) {
|
||||
ctr++;
|
||||
}
|
||||
}
|
||||
|
||||
// The number of buckets is repeated as a check for now.
|
||||
printf("Num buckets, bucket size: %d (2^%d), %d\n",
|
||||
table->numBuckets, NUM_HASH_BUCKETS_LOG, HASH_BUCKET_SIZE);
|
||||
printf("Hash table size, empty slots, %% empty: %u, %u, %.3f\n",
|
||||
table->numEntries, ctr,
|
||||
100.0 * (double)(ctr) / table->numEntries);
|
||||
}
|
||||
|
||||
// TODO: This can be done more efficiently, for example by using builtin
|
||||
// functions (but it is not that important as it is only used for computing
|
||||
// stats).
|
||||
static int intLog2(U64 x) {
|
||||
int ret = 0;
|
||||
while (x >>= 1) {
|
||||
ret++;
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
void LDM_printCompressStats(const LDM_compressStats *stats) {
|
||||
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 | match length histogram\n");
|
||||
printf("offset/ML, num matches, %% of matches | num matches, %% of matches\n");
|
||||
|
||||
{
|
||||
int i;
|
||||
int logMaxOffset = intLog2(stats->maxOffset);
|
||||
for (i = 0; i <= logMaxOffset; i++) {
|
||||
printf("2^%*d: %10u %6.3f%% |2^%*d: %10u %6.3f \n",
|
||||
2, i,
|
||||
stats->offsetHistogram[i],
|
||||
100.0 * (double) stats->offsetHistogram[i] /
|
||||
(double) stats->numMatches,
|
||||
2, i,
|
||||
stats->matchLengthHistogram[i],
|
||||
100.0 * (double) stats->matchLengthHistogram[i] /
|
||||
(double) stats->numMatches);
|
||||
}
|
||||
}
|
||||
printf("\n");
|
||||
printf("=====================\n");
|
||||
}
|
||||
|
||||
/**
|
||||
* Return the upper (most significant) NUM_HASH_BUCKETS_LOG bits.
|
||||
*/
|
||||
static hash_t getSmallHash(U64 hash) {
|
||||
return hash >> (64 - NUM_HASH_BUCKETS_LOG);
|
||||
}
|
||||
|
||||
/**
|
||||
* Return the 32 bits after the upper NUM_HASH_BUCKETS_LOG bits.
|
||||
*/
|
||||
static U32 getChecksum(U64 hash) {
|
||||
return (hash >> (64 - 32 - NUM_HASH_BUCKETS_LOG)) & 0xFFFFFFFF;
|
||||
}
|
||||
|
||||
#if INSERT_BY_TAG
|
||||
static U32 lowerBitsFromHfHash(U64 hash) {
|
||||
// The number of bits used so far is NUM_HASH_BUCKETS_LOG + 32.
|
||||
// So there are 32 - NUM_HASH_BUCKETS_LOG bits left.
|
||||
// Occasional hashing requires HASH_ONLY_EVERY_LOG bits.
|
||||
// So if 32 - LDMHASHLOG < HASH_ONLY_EVERY_LOG, just return lower bits
|
||||
// allowing for reuse of bits.
|
||||
if (32 - NUM_HASH_BUCKETS_LOG < HASH_ONLY_EVERY_LOG) {
|
||||
return hash & HASH_ONLY_EVERY;
|
||||
} else {
|
||||
// Otherwise shift by
|
||||
// (32 - NUM_HASH_BUCKETS_LOG - HASH_ONLY_EVERY_LOG) bits first.
|
||||
return (hash >> (32 - NUM_HASH_BUCKETS_LOG - HASH_ONLY_EVERY_LOG)) &
|
||||
HASH_ONLY_EVERY;
|
||||
}
|
||||
}
|
||||
#endif
|
||||
|
||||
/**
|
||||
* Get a 64-bit hash using the first len bytes from buf.
|
||||
*
|
||||
* Giving bytes s = s_1, s_2, ... s_k, the hash is defined to be
|
||||
* H(s) = s_1*(a^(k-1)) + s_2*(a^(k-2)) + ... + s_k*(a^0)
|
||||
*
|
||||
* where the constant a is defined to be prime8bytes.
|
||||
*
|
||||
* The implementation adds an offset to each byte, so
|
||||
* H(s) = (s_1 + HASH_CHAR_OFFSET)*(a^(k-1)) + ...
|
||||
*/
|
||||
static U64 getHash(const BYTE *buf, U32 len) {
|
||||
U64 ret = 0;
|
||||
U32 i;
|
||||
for (i = 0; i < len; i++) {
|
||||
ret *= prime8bytes;
|
||||
ret += buf[i] + HASH_CHAR_OFFSET;
|
||||
}
|
||||
return ret;
|
||||
|
||||
}
|
||||
|
||||
static U64 ipow(U64 base, U64 exp) {
|
||||
U64 ret = 1;
|
||||
while (exp) {
|
||||
if (exp & 1) {
|
||||
ret *= base;
|
||||
}
|
||||
exp >>= 1;
|
||||
base *= base;
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
static U64 updateHash(U64 hash, U32 len,
|
||||
BYTE toRemove, BYTE toAdd) {
|
||||
// TODO: this relies on compiler optimization.
|
||||
// The exponential can be calculated explicitly as len is constant.
|
||||
hash -= ((toRemove + HASH_CHAR_OFFSET) *
|
||||
ipow(prime8bytes, len - 1));
|
||||
hash *= prime8bytes;
|
||||
hash += toAdd + HASH_CHAR_OFFSET;
|
||||
return hash;
|
||||
}
|
||||
|
||||
/**
|
||||
* Update cctx->nextHash and cctx->nextPosHashed
|
||||
* based on cctx->lastHash 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) {
|
||||
cctx->nextHash = updateHash(
|
||||
cctx->lastHash, LDM_HASH_LENGTH,
|
||||
cctx->lastPosHashed[0],
|
||||
cctx->lastPosHashed[LDM_HASH_LENGTH]);
|
||||
cctx->nextPosHashed = cctx->nextIp;
|
||||
|
||||
#if LDM_LAG
|
||||
if (cctx->ip - cctx->ibase > LDM_LAG) {
|
||||
cctx->lagHash = updateHash(
|
||||
cctx->lagHash, LDM_HASH_LENGTH,
|
||||
cctx->lagIp[0], cctx->lagIp[LDM_HASH_LENGTH]);
|
||||
cctx->lagIp++;
|
||||
}
|
||||
#endif
|
||||
}
|
||||
|
||||
static void putHashOfCurrentPositionFromHash(LDM_CCtx *cctx, U64 hash) {
|
||||
// Hash only every HASH_ONLY_EVERY times, based on cctx->ip.
|
||||
// Note: this works only when cctx->step is 1.
|
||||
#if LDM_LAG
|
||||
if (cctx -> lagIp - cctx->ibase > 0) {
|
||||
#if INSERT_BY_TAG
|
||||
U32 hashEveryMask = lowerBitsFromHfHash(cctx->lagHash);
|
||||
if (hashEveryMask == HASH_ONLY_EVERY) {
|
||||
#else
|
||||
if (((cctx->ip - cctx->ibase) & HASH_ONLY_EVERY) == HASH_ONLY_EVERY) {
|
||||
#endif
|
||||
U32 smallHash = getSmallHash(cctx->lagHash);
|
||||
|
||||
# if USE_CHECKSUM
|
||||
U32 checksum = getChecksum(cctx->lagHash);
|
||||
const LDM_hashEntry entry = { cctx->lagIp - cctx->ibase, checksum };
|
||||
# else
|
||||
const LDM_hashEntry entry = { cctx->lagIp - cctx->ibase };
|
||||
# endif
|
||||
|
||||
HASH_insert(cctx->hashTable, smallHash, entry);
|
||||
}
|
||||
} else {
|
||||
#endif // LDM_LAG
|
||||
#if 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
|
||||
HASH_insert(cctx->hashTable, smallHash, entry);
|
||||
}
|
||||
#if LDM_LAG
|
||||
}
|
||||
#endif
|
||||
|
||||
cctx->lastPosHashed = cctx->ip;
|
||||
cctx->lastHash = hash;
|
||||
}
|
||||
|
||||
/**
|
||||
* Copy over the cctx->lastHash, and cctx->lastPosHashed
|
||||
* fields from the "next" fields.
|
||||
*
|
||||
* This requires that cctx->ip == cctx->nextPosHashed.
|
||||
*/
|
||||
static void LDM_updateLastHashFromNextHash(LDM_CCtx *cctx) {
|
||||
putHashOfCurrentPositionFromHash(cctx, cctx->nextHash);
|
||||
}
|
||||
|
||||
/**
|
||||
* Insert hash of the current position into the hash table.
|
||||
*/
|
||||
static void LDM_putHashOfCurrentPosition(LDM_CCtx *cctx) {
|
||||
U64 hash = getHash(cctx->ip, LDM_HASH_LENGTH);
|
||||
|
||||
putHashOfCurrentPositionFromHash(cctx, hash);
|
||||
}
|
||||
|
||||
size_t 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));
|
||||
#if USE_CHECKSUM
|
||||
cctx->hashTable = HASH_createTable(LDM_HASHTABLESIZE_U64);
|
||||
#else
|
||||
cctx->hashTable = HASH_createTable(LDM_HASHTABLESIZE_U32);
|
||||
#endif
|
||||
|
||||
if (!cctx->hashTable) return 1;
|
||||
|
||||
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;
|
||||
|
||||
return 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).
|
||||
*
|
||||
* forwardMatchLength contains the forward length of the match.
|
||||
*/
|
||||
static int LDM_findBestMatch(LDM_CCtx *cctx, const BYTE **match,
|
||||
U64 *forwardMatchLength, U64 *backwardMatchLength) {
|
||||
|
||||
LDM_hashEntry *entry = NULL;
|
||||
cctx->nextIp = cctx->ip + cctx->step;
|
||||
|
||||
while (entry == NULL) {
|
||||
U64 hash;
|
||||
hash_t smallHash;
|
||||
U32 checksum;
|
||||
#if INSERT_BY_TAG
|
||||
U32 hashEveryMask;
|
||||
#endif
|
||||
setNextHash(cctx);
|
||||
|
||||
hash = cctx->nextHash;
|
||||
smallHash = getSmallHash(hash);
|
||||
checksum = getChecksum(hash);
|
||||
#if INSERT_BY_TAG
|
||||
hashEveryMask = lowerBitsFromHfHash(hash);
|
||||
#endif
|
||||
|
||||
cctx->ip = cctx->nextIp;
|
||||
cctx->nextIp += cctx->step;
|
||||
|
||||
if (cctx->ip > cctx->imatchLimit) {
|
||||
return 1;
|
||||
}
|
||||
#if INSERT_BY_TAG
|
||||
if (hashEveryMask == HASH_ONLY_EVERY) {
|
||||
|
||||
entry = HASH_getBestEntry(cctx, smallHash, checksum,
|
||||
forwardMatchLength, backwardMatchLength);
|
||||
}
|
||||
#else
|
||||
entry = HASH_getBestEntry(cctx, smallHash, checksum,
|
||||
forwardMatchLength, backwardMatchLength);
|
||||
#endif
|
||||
|
||||
if (entry != NULL) {
|
||||
*match = entry->offset + cctx->ibase;
|
||||
}
|
||||
|
||||
putHashOfCurrentPositionFromHash(cctx, hash);
|
||||
|
||||
}
|
||||
setNextHash(cctx);
|
||||
return 0;
|
||||
}
|
||||
|
||||
void LDM_encodeLiteralLengthAndLiterals(
|
||||
LDM_CCtx *cctx, BYTE *pToken, const U64 literalLength) {
|
||||
/* Encode the literal length. */
|
||||
if (literalLength >= RUN_MASK) {
|
||||
U64 len = (U64)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;
|
||||
|
||||
if (LDM_initializeCCtx(&cctx, src, srcSize, dst, maxDstSize)) {
|
||||
// Initialization failed.
|
||||
return 0;
|
||||
}
|
||||
|
||||
#ifdef OUTPUT_CONFIGURATION
|
||||
LDM_outputConfiguration();
|
||||
#endif
|
||||
|
||||
/* Hash the first position and put it into the hash table. */
|
||||
LDM_putHashOfCurrentPosition(&cctx);
|
||||
|
||||
cctx.lagIp = cctx.ip;
|
||||
cctx.lagHash = cctx.lastHash;
|
||||
|
||||
/**
|
||||
* 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)) {
|
||||
|
||||
#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 U64 literalLength = cctx.ip - cctx.anchor;
|
||||
const U32 offset = cctx.ip - match;
|
||||
const U64 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)]++;
|
||||
cctx.stats.matchLengthHistogram[
|
||||
(U32)intLog2(matchLength + LDM_MIN_MATCH_LENGTH)]++;
|
||||
#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 U64 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("USE_CHECKSUM: %d\n", USE_CHECKSUM);
|
||||
printf("INSERT_BY_TAG: %d\n", INSERT_BY_TAG);
|
||||
printf("HASH_CHAR_OFFSET: %d\n", HASH_CHAR_OFFSET);
|
||||
printf("=====================\n");
|
||||
}
|
||||
|
|
@ -1,197 +0,0 @@
|
|||
#ifndef LDM_H
|
||||
#define LDM_H
|
||||
|
||||
#include "mem.h" // from /lib/common/mem.h
|
||||
|
||||
//#include "ldm_params.h"
|
||||
|
||||
// =============================================================================
|
||||
// Modify the parameters in ldm_params.h if "ldm_params.h" is included.
|
||||
// Otherwise, modify the parameters here.
|
||||
// =============================================================================
|
||||
|
||||
#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 23
|
||||
|
||||
// The number of entries in a hash bucket.
|
||||
#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
|
||||
|
||||
// The maximum window size when searching for matches.
|
||||
// The maximum value is 30
|
||||
#define LDM_WINDOW_SIZE_LOG 28
|
||||
|
||||
// The minimum match length.
|
||||
// This should be a multiple of four.
|
||||
#define LDM_MIN_MATCH_LENGTH 64
|
||||
|
||||
// If INSERT_BY_TAG, insert entries into the hash table as a function of the
|
||||
// hash. Certain hashes will not be inserted.
|
||||
//
|
||||
// Otherwise, insert as a function of the position.
|
||||
#define INSERT_BY_TAG 1
|
||||
|
||||
// Store a checksum with the hash table entries for faster comparison.
|
||||
// This halves the number of entries the hash table can contain.
|
||||
#define USE_CHECKSUM 1
|
||||
#endif
|
||||
|
||||
// Output compression statistics.
|
||||
#define COMPUTE_STATS
|
||||
|
||||
// Output the configuration.
|
||||
#define OUTPUT_CONFIGURATION
|
||||
|
||||
// If defined, forces the probability of insertion to be approximately
|
||||
// one per (1 << HASH_ONLY_EVERY_LOG). If not defined, the probability will be
|
||||
// calculated based on the memory usage and window size for "even" insertion
|
||||
// throughout the window.
|
||||
|
||||
// #define HASH_ONLY_EVERY_LOG 8
|
||||
|
||||
// =============================================================================
|
||||
|
||||
// The number of bytes storing the compressed and decompressed size
|
||||
// in the header.
|
||||
#define LDM_COMPRESSED_SIZE 8
|
||||
#define LDM_DECOMPRESSED_SIZE 8
|
||||
#define LDM_HEADER_SIZE ((LDM_COMPRESSED_SIZE)+(LDM_DECOMPRESSED_SIZE))
|
||||
|
||||
#define ML_BITS 4
|
||||
#define ML_MASK ((1U<<ML_BITS)-1)
|
||||
#define RUN_BITS (8-ML_BITS)
|
||||
#define RUN_MASK ((1U<<RUN_BITS)-1)
|
||||
|
||||
// The number of bytes storing the offset.
|
||||
#define LDM_OFFSET_SIZE 4
|
||||
|
||||
#define LDM_WINDOW_SIZE (1 << (LDM_WINDOW_SIZE_LOG))
|
||||
|
||||
// TODO: Match lengths that are too small do not use the hash table efficiently.
|
||||
// There should be a minimum hash length given the hash table size.
|
||||
#define LDM_HASH_LENGTH LDM_MIN_MATCH_LENGTH
|
||||
|
||||
typedef struct LDM_compressStats LDM_compressStats;
|
||||
typedef struct LDM_CCtx LDM_CCtx;
|
||||
typedef struct LDM_DCtx LDM_DCtx;
|
||||
|
||||
/**
|
||||
* Compresses src into dst.
|
||||
* Returns the compressed size if successful, 0 otherwise.
|
||||
*
|
||||
* NB: This currently ignores maxDstSize and assumes enough space is available.
|
||||
*
|
||||
* Block format (see lz4 documentation for more information):
|
||||
* github.com/lz4/lz4/blob/dev/doc/lz4_Block_format.md
|
||||
*
|
||||
* A block is composed of sequences. Each sequence begins with a token, which
|
||||
* is a one-byte value separated into two 4-bit fields.
|
||||
*
|
||||
* The first field uses the four high bits of the token and encodes the literal
|
||||
* length. If the field value is 0, there is no literal. If it is 15,
|
||||
* additional bytes are added (each ranging from 0 to 255) to the previous
|
||||
* value to produce a total length.
|
||||
*
|
||||
* Following the token and optional length bytes are the literals.
|
||||
*
|
||||
* Next are the 4 bytes representing the offset of the match (2 in lz4),
|
||||
* representing the position to copy the literals.
|
||||
*
|
||||
* The lower four bits of the token encode the match length. With additional
|
||||
* bytes added similarly to the additional literal length bytes after the offset.
|
||||
*
|
||||
* The last sequence is incomplete and stops right after the literals.
|
||||
*/
|
||||
size_t LDM_compress(const void *src, size_t srcSize,
|
||||
void *dst, size_t maxDstSize);
|
||||
|
||||
/**
|
||||
* Initialize the compression context.
|
||||
*
|
||||
* Allocates memory for the hash table.
|
||||
*
|
||||
* Returns 0 if successful, 1 otherwise.
|
||||
*/
|
||||
size_t LDM_initializeCCtx(LDM_CCtx *cctx,
|
||||
const void *src, size_t srcSize,
|
||||
void *dst, size_t maxDstSize);
|
||||
|
||||
/**
|
||||
* Frees up memory allocated in LDM_initializeCCtx().
|
||||
*/
|
||||
void LDM_destroyCCtx(LDM_CCtx *cctx);
|
||||
|
||||
/**
|
||||
* Prints the distribution of offsets in the hash table.
|
||||
*
|
||||
* The offsets are defined as the distance of the hash table entry from the
|
||||
* current input position of the cctx.
|
||||
*/
|
||||
void LDM_outputHashTableOffsetHistogram(const LDM_CCtx *cctx);
|
||||
|
||||
/**
|
||||
* Outputs compression statistics to stdout.
|
||||
*/
|
||||
void LDM_printCompressStats(const LDM_compressStats *stats);
|
||||
|
||||
/**
|
||||
* 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 U64 literalLength);
|
||||
|
||||
/**
|
||||
* Write current block (literals, literal length, match offset,
|
||||
* match length).
|
||||
*/
|
||||
void LDM_outputBlock(LDM_CCtx *cctx,
|
||||
const U64 literalLength,
|
||||
const U32 offset,
|
||||
const U64 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 compressedSize and decompressedSize respectively.
|
||||
*
|
||||
* NB: LDM_compress and LDM_decompress currently do not add/read headers.
|
||||
*/
|
||||
void LDM_readHeader(const void *src, U64 *compressedSize,
|
||||
U64 *decompressedSize);
|
||||
|
||||
/**
|
||||
* Write the compressed and decompressed size.
|
||||
*/
|
||||
void LDM_writeHeader(void *memPtr, U64 compressedSize,
|
||||
U64 decompressedSize);
|
||||
|
||||
/**
|
||||
* Output the configuration used.
|
||||
*/
|
||||
void LDM_outputConfiguration(void);
|
||||
|
||||
#endif /* LDM_H */
|
||||
|
|
@ -1,109 +0,0 @@
|
|||
#include <stdio.h>
|
||||
|
||||
#include "ldm.h"
|
||||
|
||||
/**
|
||||
* This function reads the header at the beginning of src and writes
|
||||
* the compressed and decompressed size to compressedSize and
|
||||
* decompressedSize.
|
||||
*
|
||||
* The header consists of 16 bytes: 8 bytes each in little-endian format
|
||||
* of the compressed size and the decompressed size.
|
||||
*/
|
||||
void LDM_readHeader(const void *src, U64 *compressedSize,
|
||||
U64 *decompressedSize) {
|
||||
const BYTE *ip = (const BYTE *)src;
|
||||
*compressedSize = MEM_readLE64(ip);
|
||||
*decompressedSize = MEM_readLE64(ip + 8);
|
||||
}
|
||||
|
||||
/**
|
||||
* Writes the 16-byte header (8-bytes each of the compressedSize and
|
||||
* decompressedSize in little-endian format) to memPtr.
|
||||
*/
|
||||
void LDM_writeHeader(void *memPtr, U64 compressedSize,
|
||||
U64 decompressedSize) {
|
||||
MEM_writeLE64(memPtr, compressedSize);
|
||||
MEM_writeLE64((BYTE *)memPtr + 8, decompressedSize);
|
||||
}
|
||||
|
||||
struct LDM_DCtx {
|
||||
size_t compressedSize;
|
||||
size_t maxDecompressedSize;
|
||||
|
||||
const BYTE *ibase; /* Base of input */
|
||||
const BYTE *ip; /* Current input position */
|
||||
const BYTE *iend; /* End of source */
|
||||
|
||||
const BYTE *obase; /* Base of output */
|
||||
BYTE *op; /* Current output position */
|
||||
const BYTE *oend; /* End of output */
|
||||
};
|
||||
|
||||
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->compressedSize;
|
||||
dctx->op = dst;
|
||||
dctx->oend = dctx->op + dctx->maxDecompressedSize;
|
||||
}
|
||||
|
||||
size_t LDM_decompress(const void *src, size_t compressedSize,
|
||||
void *dst, size_t maxDecompressedSize) {
|
||||
|
||||
LDM_DCtx dctx;
|
||||
LDM_initializeDCtx(&dctx, src, compressedSize, dst, maxDecompressedSize);
|
||||
|
||||
while (dctx.ip < dctx.iend) {
|
||||
BYTE *cpy;
|
||||
const BYTE *match;
|
||||
size_t length, offset;
|
||||
|
||||
/* Get the literal length. */
|
||||
const unsigned token = *(dctx.ip)++;
|
||||
if ((length = (token >> ML_BITS)) == RUN_MASK) {
|
||||
unsigned s;
|
||||
do {
|
||||
s = *(dctx.ip)++;
|
||||
length += s;
|
||||
} while (s == 255);
|
||||
}
|
||||
|
||||
/* Copy the literals. */
|
||||
cpy = dctx.op + length;
|
||||
memcpy(dctx.op, dctx.ip, length);
|
||||
dctx.ip += length;
|
||||
dctx.op = cpy;
|
||||
|
||||
//TODO: dynamic offset size?
|
||||
/* Encode the offset. */
|
||||
offset = MEM_read32(dctx.ip);
|
||||
dctx.ip += LDM_OFFSET_SIZE;
|
||||
match = dctx.op - offset;
|
||||
|
||||
/* Get the match length. */
|
||||
length = token & ML_MASK;
|
||||
if (length == ML_MASK) {
|
||||
unsigned s;
|
||||
do {
|
||||
s = *(dctx.ip)++;
|
||||
length += s;
|
||||
} while (s == 255);
|
||||
}
|
||||
length += LDM_MIN_MATCH_LENGTH;
|
||||
|
||||
/* Copy match. */
|
||||
cpy = dctx.op + length;
|
||||
|
||||
// TODO: this can be made more efficient.
|
||||
while (match < cpy - offset && dctx.op < dctx.oend) {
|
||||
*(dctx.op)++ = *match++;
|
||||
}
|
||||
}
|
||||
return dctx.op - (BYTE *)dst;
|
||||
}
|
||||
|
|
@ -1,12 +0,0 @@
|
|||
#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 // LDM_PARAMS_H
|
||||
|
|
@ -1,269 +0,0 @@
|
|||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
#include <sys/time.h>
|
||||
#include <sys/types.h>
|
||||
#include <sys/mman.h>
|
||||
#include <sys/stat.h>
|
||||
#include <unistd.h>
|
||||
#include <zstd.h>
|
||||
|
||||
#include <fcntl.h>
|
||||
#include "ldm.h"
|
||||
#include "zstd.h"
|
||||
|
||||
// #define DECOMPRESS_AND_VERIFY
|
||||
|
||||
/* Compress file given by fname and output to oname.
|
||||
* Returns 0 if successful, error code otherwise.
|
||||
*
|
||||
* This adds a header from LDM_writeHeader to the beginning of the output.
|
||||
*
|
||||
* This might seg fault if the compressed size is > the decompress
|
||||
* size due to the mmapping and output file size allocated to be the input size
|
||||
* The compress function should check before writing or buffer writes.
|
||||
*/
|
||||
static int compress(const char *fname, const char *oname) {
|
||||
int fdin, fdout;
|
||||
struct stat statbuf;
|
||||
char *src, *dst;
|
||||
size_t maxCompressedSize, compressedSize;
|
||||
|
||||
struct timeval tv1, tv2;
|
||||
double timeTaken;
|
||||
|
||||
|
||||
/* Open the input file. */
|
||||
if ((fdin = open(fname, O_RDONLY)) < 0) {
|
||||
perror("Error in file opening");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* Open the output file. */
|
||||
if ((fdout = open(oname, O_RDWR | O_CREAT | O_TRUNC, (mode_t)0600)) < 0) {
|
||||
perror("Can't create output file");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* Find the size of the input file. */
|
||||
if (fstat (fdin, &statbuf) < 0) {
|
||||
perror("Fstat error");
|
||||
return 1;
|
||||
}
|
||||
|
||||
maxCompressedSize = (statbuf.st_size + LDM_HEADER_SIZE);
|
||||
|
||||
// Handle case where compressed size is > decompressed size.
|
||||
// TODO: The compress function should check before writing or buffer writes.
|
||||
maxCompressedSize += statbuf.st_size / 255;
|
||||
|
||||
ftruncate(fdout, maxCompressedSize);
|
||||
|
||||
/* mmap the input file. */
|
||||
if ((src = mmap(0, statbuf.st_size, PROT_READ, MAP_SHARED, fdin, 0))
|
||||
== (caddr_t) - 1) {
|
||||
perror("mmap error for input");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* mmap the output file. */
|
||||
if ((dst = mmap(0, maxCompressedSize, PROT_READ | PROT_WRITE,
|
||||
MAP_SHARED, fdout, 0)) == (caddr_t) - 1) {
|
||||
perror("mmap error for output");
|
||||
return 1;
|
||||
}
|
||||
|
||||
gettimeofday(&tv1, NULL);
|
||||
|
||||
compressedSize = LDM_HEADER_SIZE +
|
||||
LDM_compress(src, statbuf.st_size,
|
||||
dst + LDM_HEADER_SIZE, maxCompressedSize);
|
||||
|
||||
gettimeofday(&tv2, NULL);
|
||||
|
||||
// Write the header.
|
||||
LDM_writeHeader(dst, compressedSize, statbuf.st_size);
|
||||
|
||||
// Truncate file to compressedSize.
|
||||
ftruncate(fdout, compressedSize);
|
||||
|
||||
printf("%25s : %10lu -> %10lu - %s \n", fname,
|
||||
(size_t)statbuf.st_size, (size_t)compressedSize, oname);
|
||||
printf("Compression ratio: %.2fx --- %.1f%%\n",
|
||||
(double)statbuf.st_size / (double)compressedSize,
|
||||
(double)compressedSize / (double)(statbuf.st_size) * 100.0);
|
||||
|
||||
timeTaken = (double) (tv2.tv_usec - tv1.tv_usec) / 1000000 +
|
||||
(double) (tv2.tv_sec - tv1.tv_sec),
|
||||
|
||||
printf("Total compress time = %.3f seconds, Average scanning speed: %.3f MB/s\n",
|
||||
timeTaken,
|
||||
((double)statbuf.st_size / (double) (1 << 20)) / timeTaken);
|
||||
|
||||
// Close files.
|
||||
close(fdin);
|
||||
close(fdout);
|
||||
return 0;
|
||||
}
|
||||
|
||||
#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.
|
||||
*/
|
||||
static int decompress(const char *fname, const char *oname) {
|
||||
int fdin, fdout;
|
||||
struct stat statbuf;
|
||||
char *src, *dst;
|
||||
U64 compressedSize, decompressedSize;
|
||||
size_t outSize;
|
||||
|
||||
/* Open the input file. */
|
||||
if ((fdin = open(fname, O_RDONLY)) < 0) {
|
||||
perror("Error in file opening");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* Open the output file. */
|
||||
if ((fdout = open(oname, O_RDWR | O_CREAT | O_TRUNC, (mode_t)0600)) < 0) {
|
||||
perror("Can't create output file");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* Find the size of the input file. */
|
||||
if (fstat (fdin, &statbuf) < 0) {
|
||||
perror("Fstat error");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* mmap the input file. */
|
||||
if ((src = mmap(0, statbuf.st_size, PROT_READ, MAP_SHARED, fdin, 0))
|
||||
== (caddr_t) - 1) {
|
||||
perror("mmap error for input");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* Read the header. */
|
||||
LDM_readHeader(src, &compressedSize, &decompressedSize);
|
||||
|
||||
ftruncate(fdout, decompressedSize);
|
||||
|
||||
/* mmap the output file */
|
||||
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, decompressedSize);
|
||||
printf("Ret size out: %zu\n", outSize);
|
||||
|
||||
close(fdin);
|
||||
close(fdout);
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Compare two files.
|
||||
* Returns 0 iff they are the same.
|
||||
*/
|
||||
static int compare(FILE *fp0, FILE *fp1) {
|
||||
int result = 0;
|
||||
while (result == 0) {
|
||||
char b0[1024];
|
||||
char b1[1024];
|
||||
const size_t r0 = fread(b0, 1, sizeof(b0), fp0);
|
||||
const size_t r1 = fread(b1, 1, sizeof(b1), fp1);
|
||||
|
||||
result = (int)r0 - (int)r1;
|
||||
|
||||
if (0 == r0 || 0 == r1) break;
|
||||
|
||||
if (0 == result) result = memcmp(b0, b1, r0);
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
/* Verify the input file is the same as the decompressed file. */
|
||||
static int verify(const char *inpFilename, const char *decFilename) {
|
||||
FILE *inpFp, *decFp;
|
||||
|
||||
if ((inpFp = fopen(inpFilename, "rb")) == NULL) {
|
||||
perror("Could not open input file\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
if ((decFp = fopen(decFilename, "rb")) == NULL) {
|
||||
perror("Could not open decompressed file\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
printf("verify : %s <-> %s\n", inpFilename, decFilename);
|
||||
{
|
||||
const int cmp = compare(inpFp, decFp);
|
||||
if(0 == cmp) {
|
||||
printf("verify : OK\n");
|
||||
} else {
|
||||
printf("verify : NG\n");
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
fclose(decFp);
|
||||
fclose(inpFp);
|
||||
return 0;
|
||||
}
|
||||
#endif
|
||||
|
||||
int main(int argc, const char *argv[]) {
|
||||
const char * const exeName = argv[0];
|
||||
char inpFilename[256] = { 0 };
|
||||
char ldmFilename[256] = { 0 };
|
||||
char decFilename[256] = { 0 };
|
||||
|
||||
if (argc < 2) {
|
||||
printf("Wrong arguments\n");
|
||||
printf("Usage:\n");
|
||||
printf("%s FILE\n", exeName);
|
||||
return 1;
|
||||
}
|
||||
|
||||
snprintf(inpFilename, 256, "%s", argv[1]);
|
||||
snprintf(ldmFilename, 256, "%s.ldm", argv[1]);
|
||||
snprintf(decFilename, 256, "%s.ldm.dec", argv[1]);
|
||||
|
||||
printf("inp = [%s]\n", inpFilename);
|
||||
printf("ldm = [%s]\n", ldmFilename);
|
||||
printf("dec = [%s]\n", decFilename);
|
||||
|
||||
/* Compress */
|
||||
{
|
||||
if (compress(inpFilename, ldmFilename)) {
|
||||
printf("Compress error\n");
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
#ifdef DECOMPRESS_AND_VERIFY
|
||||
/* Decompress */
|
||||
{
|
||||
struct timeval tv1, tv2;
|
||||
gettimeofday(&tv1, NULL);
|
||||
if (decompress(ldmFilename, decFilename)) {
|
||||
printf("Decompress error\n");
|
||||
return 1;
|
||||
}
|
||||
gettimeofday(&tv2, NULL);
|
||||
printf("Total decompress time = %f seconds\n",
|
||||
(double) (tv2.tv_usec - tv1.tv_usec) / 1000000 +
|
||||
(double) (tv2.tv_sec - tv1.tv_sec));
|
||||
}
|
||||
/* verify */
|
||||
if (verify(inpFilename, decFilename)) {
|
||||
printf("Verification error\n");
|
||||
return 1;
|
||||
}
|
||||
#endif
|
||||
return 0;
|
||||
}
|
||||
|
|
@ -147,7 +147,7 @@ size_t ZSTD_seekable_initCStream(ZSTD_seekable_CStream* zcs,
|
|||
|
||||
/* make sure maxFrameSize has a reasonable value */
|
||||
if (maxFrameSize > ZSTD_SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE) {
|
||||
return ERROR(compressionParameter_unsupported);
|
||||
return ERROR(frameParameter_unsupported);
|
||||
}
|
||||
|
||||
zcs->maxFrameSize = maxFrameSize
|
||||
|
|
|
|||
|
|
@ -125,7 +125,7 @@ static int ZSTD_seekable_seek_buff(void* opaque, S64 offset, int origin)
|
|||
newOffset = (unsigned long long)buff->size - offset;
|
||||
break;
|
||||
}
|
||||
if (newOffset < 0 || newOffset > buff->size) {
|
||||
if (newOffset > buff->size) {
|
||||
return -1;
|
||||
}
|
||||
buff->pos = newOffset;
|
||||
|
|
@ -145,7 +145,7 @@ typedef struct {
|
|||
int checksumFlag;
|
||||
} seekTable_t;
|
||||
|
||||
#define SEEKABLE_BUFF_SIZE ZSTD_BLOCKSIZE_ABSOLUTEMAX
|
||||
#define SEEKABLE_BUFF_SIZE ZSTD_BLOCKSIZE_MAX
|
||||
|
||||
struct ZSTD_seekable_s {
|
||||
ZSTD_DStream* dstream;
|
||||
|
|
|
|||
|
|
@ -825,9 +825,9 @@ size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long
|
|||
|
||||
ZSTD_p_compressLiterals=1000, </b>/* control huffman compression of literals (enabled) by default.<b>
|
||||
* disabling it improves speed and decreases compression ratio by a large amount.
|
||||
* note : this setting is updated when changing compression level.
|
||||
* positive compression levels set literalCompression to 1.
|
||||
* negative compression levels set literalCompression to 0. */
|
||||
* note : this setting is automatically updated when changing compression level.
|
||||
* positive compression levels set ZSTD_p_compressLiterals to 1.
|
||||
* negative compression levels set ZSTD_p_compressLiterals to 0. */
|
||||
|
||||
ZSTD_p_forceMaxWindow=1100, </b>/* Force back-reference distances to remain < windowSize,<b>
|
||||
* even when referencing into Dictionary content (default:0) */
|
||||
|
|
|
|||
Loading…
Reference in New Issue