Merge pull request #480 from inikep/dev11

advanced mode where each parameter can be selected on the command line

programs/bench.c

@@ -125,7 +125,8 @@ typedef struct {
 static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
                         const char* displayName, int cLevel,
                         const size_t* fileSizes, U32 nbFiles,
-                        const void* dictBuffer, size_t dictBufferSize)
+                        const void* dictBuffer, size_t dictBufferSize,
+                        ZSTD_compressionParameters *comprParams)
 {
     size_t const blockSize = ((g_blockSize>=32 && !g_decodeOnly) ? g_blockSize : srcSize) + (!srcSize) /* avoid div by 0 */ ;
     size_t const avgSize = MIN(g_blockSize, (srcSize / nbFiles));
@@ -231,12 +232,19 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
                 UTIL_getTime(&clockStart);
 
                 if (!cCompleted) {   /* still some time to do compression tests */
-                    ZSTD_parameters const zparams = ZSTD_getParams(cLevel, avgSize, dictBufferSize);
+                    ZSTD_parameters zparams = ZSTD_getParams(cLevel, avgSize, dictBufferSize);
                     ZSTD_customMem const cmem = { NULL, NULL, NULL };
                     U64 clockLoop = g_nbSeconds ? TIMELOOP_MICROSEC : 1;
                     U32 nbLoops = 0;
                     ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(dictBuffer, dictBufferSize, zparams, cmem);
                     if (cdict==NULL) EXM_THROW(1, "ZSTD_createCDict_advanced() allocation failure");
+                    if (comprParams->windowLog) zparams.cParams.windowLog = comprParams->windowLog;
+                    if (comprParams->chainLog) zparams.cParams.chainLog = comprParams->chainLog;
+                    if (comprParams->hashLog) zparams.cParams.hashLog = comprParams->hashLog;
+                    if (comprParams->searchLog) zparams.cParams.searchLog = comprParams->searchLog;
+                    if (comprParams->searchLength) zparams.cParams.searchLength = comprParams->searchLength;
+                    if (comprParams->targetLength) zparams.cParams.targetLength = comprParams->targetLength;
+                    if (comprParams->strategy) zparams.cParams.strategy = (ZSTD_strategy)(comprParams->strategy - 1);
                     do {
                         U32 blockNb;
                         size_t rSize;
@@ -247,9 +255,9 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
                                                 blockTable[blockNb].srcPtr,blockTable[blockNb].srcSize,
                                                 cdict);
                             } else {
-                                rSize = ZSTD_compressCCtx (ctx,
+                                rSize = ZSTD_compress_advanced (ctx,
                                                 blockTable[blockNb].cPtr,  blockTable[blockNb].cRoom,
-                                                blockTable[blockNb].srcPtr,blockTable[blockNb].srcSize, cLevel);
+                                                blockTable[blockNb].srcPtr,blockTable[blockNb].srcSize, NULL, 0, zparams);
                             }
                             if (ZSTD_isError(rSize)) EXM_THROW(1, "ZSTD_compress_usingCDict() failed : %s", ZSTD_getErrorName(rSize));
                             blockTable[blockNb].cSize = rSize;
@@ -387,7 +395,8 @@ static size_t BMK_findMaxMem(U64 requiredMem)
 static void BMK_benchCLevel(void* srcBuffer, size_t benchedSize,
                             const char* displayName, int cLevel, int cLevelLast,
                             const size_t* fileSizes, unsigned nbFiles,
-                            const void* dictBuffer, size_t dictBufferSize)
+                            const void* dictBuffer, size_t dictBufferSize,
+                            ZSTD_compressionParameters *compressionParams)
 {
     int l;
 
@@ -406,7 +415,7 @@ static void BMK_benchCLevel(void* srcBuffer, size_t benchedSize,
         BMK_benchMem(srcBuffer, benchedSize,
                      displayName, l,
                      fileSizes, nbFiles,
-                     dictBuffer, dictBufferSize);
+                     dictBuffer, dictBufferSize, compressionParams);
     }
 }
 
@@ -443,8 +452,8 @@ static void BMK_loadFiles(void* buffer, size_t bufferSize,
     if (totalSize == 0) EXM_THROW(12, "no data to bench");
 }
 
-static void BMK_benchFileTable(const char** fileNamesTable, unsigned nbFiles,
+static void BMK_benchFileTable(const char** fileNamesTable, unsigned nbFiles, const char* dictFileName, 
-                               const char* dictFileName, int cLevel, int cLevelLast)
+                               int cLevel, int cLevelLast, ZSTD_compressionParameters *compressionParams)
 {
     void* srcBuffer;
     size_t benchedSize;
@@ -483,7 +492,7 @@ static void BMK_benchFileTable(const char** fileNamesTable, unsigned nbFiles,
         BMK_benchCLevel(srcBuffer, benchedSize,
                         displayName, cLevel, cLevelLast,
                         fileSizes, nbFiles,
-                        dictBuffer, dictBufferSize);
+                        dictBuffer, dictBufferSize, compressionParams);
     }
 
     /* clean up */
@@ -493,7 +502,7 @@ static void BMK_benchFileTable(const char** fileNamesTable, unsigned nbFiles,
 }
 
 
-static void BMK_syntheticTest(int cLevel, int cLevelLast, double compressibility)
+static void BMK_syntheticTest(int cLevel, int cLevelLast, double compressibility, ZSTD_compressionParameters* compressionParams)
 {
     char name[20] = {0};
     size_t benchedSize = 10000000;
@@ -507,15 +516,15 @@ static void BMK_syntheticTest(int cLevel, int cLevelLast, double compressibility
 
     /* Bench */
     snprintf (name, sizeof(name), "Synthetic %2u%%", (unsigned)(compressibility*100));
-    BMK_benchCLevel(srcBuffer, benchedSize, name, cLevel, cLevelLast, &benchedSize, 1, NULL, 0);
+    BMK_benchCLevel(srcBuffer, benchedSize, name, cLevel, cLevelLast, &benchedSize, 1, NULL, 0, compressionParams);
 
     /* clean up */
     free(srcBuffer);
 }
 
 
-int BMK_benchFiles(const char** fileNamesTable, unsigned nbFiles,
+int BMK_benchFiles(const char** fileNamesTable, unsigned nbFiles, const char* dictFileName, 
-                   const char* dictFileName, int cLevel, int cLevelLast)
+                   int cLevel, int cLevelLast, ZSTD_compressionParameters* compressionParams)
 {
     double const compressibility = (double)g_compressibilityDefault / 100;
 
@@ -525,8 +534,8 @@ int BMK_benchFiles(const char** fileNamesTable, unsigned nbFiles,
     if (cLevelLast > cLevel) DISPLAYLEVEL(2, "Benchmarking levels from %d to %d\n", cLevel, cLevelLast);
 
     if (nbFiles == 0)
-        BMK_syntheticTest(cLevel, cLevelLast, compressibility);
+        BMK_syntheticTest(cLevel, cLevelLast, compressibility, compressionParams);
     else
-        BMK_benchFileTable(fileNamesTable, nbFiles, dictFileName, cLevel, cLevelLast);
+        BMK_benchFileTable(fileNamesTable, nbFiles, dictFileName, cLevel, cLevelLast, compressionParams);
     return 0;
 }

programs/bench.h

@@ -12,9 +12,11 @@
 #define BENCH_H_121279284357
 
 #include <stddef.h>   /* size_t */
+#define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_compressionParameters */
+#include "zstd.h"     /* ZSTD_compressionParameters */
 
-int BMK_benchFiles(const char** fileNamesTable, unsigned nbFiles,
+int BMK_benchFiles(const char** fileNamesTable, unsigned nbFiles,const char* dictFileName, 
-                   const char* dictFileName, int cLevel, int cLevelLast);
+                   int cLevel, int cLevelLast, ZSTD_compressionParameters* compressionParams);
 
 /* Set Parameters */
 void BMK_SetNbSeconds(unsigned nbLoops);

programs/fileio.c

@@ -247,7 +247,8 @@ typedef struct {
     FILE* srcFile;
 } cRess_t;
 
-static cRess_t FIO_createCResources(const char* dictFileName, int cLevel, U64 srcSize)
+static cRess_t FIO_createCResources(const char* dictFileName, int cLevel, 
+                                    U64 srcSize, ZSTD_compressionParameters* comprParams)
 {
     cRess_t ress;
     memset(&ress, 0, sizeof(ress));
@@ -268,6 +269,13 @@ static cRess_t FIO_createCResources(const char* dictFileName, int cLevel, U64 sr
             params.fParams.contentSizeFlag = 1;
             params.fParams.checksumFlag = g_checksumFlag;
             params.fParams.noDictIDFlag = !g_dictIDFlag;
+            if (comprParams->windowLog) params.cParams.windowLog = comprParams->windowLog;
+            if (comprParams->chainLog) params.cParams.chainLog = comprParams->chainLog;
+            if (comprParams->hashLog) params.cParams.hashLog = comprParams->hashLog;
+            if (comprParams->searchLog) params.cParams.searchLog = comprParams->searchLog;
+            if (comprParams->searchLength) params.cParams.searchLength = comprParams->searchLength;
+            if (comprParams->targetLength) params.cParams.targetLength = comprParams->targetLength;
+            if (comprParams->strategy) params.cParams.strategy = (ZSTD_strategy)(comprParams->strategy - 1);
             {   size_t const errorCode = ZSTD_initCStream_advanced(ress.cctx, dictBuffer, dictBuffSize, params, srcSize);
                 if (ZSTD_isError(errorCode)) EXM_THROW(33, "Error initializing CStream : %s", ZSTD_getErrorName(errorCode));
         }   }
@@ -401,12 +409,12 @@ static int FIO_compressFilename_dstFile(cRess_t ress,
 
 
 int FIO_compressFilename(const char* dstFileName, const char* srcFileName,
-                         const char* dictFileName, int compressionLevel)
+                         const char* dictFileName, int compressionLevel, ZSTD_compressionParameters* comprParams)
 {
     clock_t const start = clock();
     U64 const srcSize = UTIL_getFileSize(srcFileName);
 
-    cRess_t const ress = FIO_createCResources(dictFileName, compressionLevel, srcSize);
+    cRess_t const ress = FIO_createCResources(dictFileName, compressionLevel, srcSize, comprParams);
     int const result = FIO_compressFilename_dstFile(ress, dstFileName, srcFileName);
 
     double const seconds = (double)(clock() - start) / CLOCKS_PER_SEC;
@@ -419,14 +427,15 @@ int FIO_compressFilename(const char* dstFileName, const char* srcFileName,
 
 int FIO_compressMultipleFilenames(const char** inFileNamesTable, unsigned nbFiles,
                                   const char* suffix,
-                                  const char* dictFileName, int compressionLevel)
+                                  const char* dictFileName, int compressionLevel,
+                                  ZSTD_compressionParameters* comprParams)
 {
     int missed_files = 0;
     size_t dfnSize = FNSPACE;
     char*  dstFileName = (char*)malloc(FNSPACE);
     size_t const suffixSize = suffix ? strlen(suffix) : 0;
     U64 const srcSize = (nbFiles != 1) ? 0 : UTIL_getFileSize(inFileNamesTable[0]) ;
-    cRess_t ress = FIO_createCResources(dictFileName, compressionLevel, srcSize);
+    cRess_t ress = FIO_createCResources(dictFileName, compressionLevel, srcSize, comprParams);
 
     /* init */
     if (dstFileName==NULL) EXM_THROW(27, "FIO_compressMultipleFilenames : allocation error for dstFileName");

programs/fileio.h

@@ -11,6 +11,9 @@
 #ifndef FILEIO_H_23981798732
 #define FILEIO_H_23981798732
 
+#define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_compressionParameters */
+#include "zstd.h"     /* ZSTD_compressionParameters */
+
 #if defined (__cplusplus)
 extern "C" {
 #endif
@@ -44,7 +47,8 @@ void FIO_setMemLimit(unsigned memLimit);
 ***************************************/
 /** FIO_compressFilename() :
     @return : 0 == ok;  1 == pb with src file. */
-int FIO_compressFilename (const char* outfilename, const char* infilename, const char* dictFileName, int compressionLevel);
+int FIO_compressFilename (const char* outfilename, const char* infilename, const char* dictFileName,
+                          int compressionLevel, ZSTD_compressionParameters* comprParams);
 
 /** FIO_decompressFilename() :
     @return : 0 == ok;  1 == pb with src file. */
@@ -58,7 +62,8 @@ int FIO_decompressFilename (const char* outfilename, const char* infilename, con
     @return : nb of missing files */
 int FIO_compressMultipleFilenames(const char** srcNamesTable, unsigned nbFiles,
                                   const char* suffix,
-                                  const char* dictFileName, int compressionLevel);
+                                  const char* dictFileName, int compressionLevel,
+                                  ZSTD_compressionParameters* comprParams);
 
 /** FIO_decompressMultipleFilenames() :
     @return : nb of missing or skipped files */

programs/zstd.1

@@ -264,6 +264,115 @@ and weight typically 100x the target dictionary size (for example, 10 MB for a 1
  cut file into independent blocks of size # (default: no block)
 
 
+.SH ADVANCED COMPRESSION OPTIONS
+.TP
+.B \--zstd[=\fIoptions\fR]
+.PD
+\fBzstd\fR provides 22 predefined compression levels. The selected or default predefined compression level can be changed with advanced compression options.
+The \fIoptions\fR are provided as a comma-separated list. You may specify only the \fIoptions\fR you want to change and the rest will be taken from the selected or default compression level.
+The list of available \fIoptions\fR:
+.RS
+
+.TP
+.BI strategy= strat
+.PD 0
+.TP
+.BI strat= strat
+.PD
+Specify a strategy used by a match finder.
+.IP ""
+There are 8 strategies numbered from 0 to 7, from faster to stronger:
+0=ZSTD_fast, 1=ZSTD_dfast, 2=ZSTD_greedy, 3=ZSTD_lazy, 4=ZSTD_lazy2, 5=ZSTD_btlazy2, 6=ZSTD_btopt, 7=ZSTD_btopt2.
+.IP ""
+
+.TP
+.BI windowLog= wlog
+.PD 0
+.TP
+.BI wlog= wlog
+.PD
+Specify the maximum number of bits for a match distance.
+.IP ""
+The higher number of bits increases the chance to find a match what usually improves compression ratio. 
+It also increases memory requirements for compressor and decompressor.
+.IP ""
+The minimum \fIwlog\fR is 10 (1 KiB) and the maximum is 25 (32 MiB) for 32-bit compilation and 27 (128 MiB) for 64-bit compilation.
+.IP ""
+
+.TP
+.BI hashLog= hlog
+.PD 0
+.TP
+.BI hlog= hlog
+.PD
+Specify the maximum number of bits for a hash table.
+.IP ""
+The bigger hash table causes less collisions what usually make compression faster but requires more memory during compression.
+.IP ""
+The minimum \fIhlog\fR is 6 (64 B) and the maximum is 25 (32 MiB) for 32-bit compilation and 27 (128 MiB) for 64-bit compilation.
+
+.TP
+.BI chainLog= clog
+.PD 0
+.TP
+.BI clog= clog
+.PD
+Specify the maximum number of bits for a hash chain or a binary tree.
+.IP ""
+The higher number of bits increases the chance to find a match what usually improves compression ratio. 
+It also slows down compression speed and increases memory requirements for compression.
+This option is ignored for the ZSTD_fast strategy.
+.IP ""
+The minimum \fIclog\fR is 6 (64 B) and the maximum is 26 (64 MiB) for 32-bit compilation and 28 (256 MiB) for 64-bit compilation.
+.IP ""
+
+.TP
+.BI searchLog= slog
+.PD 0
+.TP
+.BI slog= slog
+.PD
+Specify the maximum number of searches in a hash chain or a binary tree using logarithmic scale.
+.IP ""
+The bigger number of searches increases the chance to find a match what usually improves compression ratio but decreases compression speed.
+.IP ""
+The minimum \fIslog\fR is 1 and the maximum is 24 for 32-bit compilation and 26 for 64-bit compilation.
+.IP ""
+
+.TP
+.BI searchLength= slen
+.PD 0
+.TP
+.BI slen= slen
+.PD
+Specify the minimum searched length of a match in a hash table.
+.IP ""
+The bigger search length usually decreases compression ratio but improves decompression speed.
+.IP ""
+The minimum \fIslen\fR is 3 and the maximum is 7.
+.IP ""
+
+.TP
+.BI targetLength= tlen
+.PD 0
+.TP
+.BI tlen= tlen
+.PD
+Specify the minimum match length that causes a match finder to interrupt searching of better matches.
+.IP ""
+The bigger minimum match length usually improves compression ratio but decreases compression speed.
+This option is used only with ZSTD_btopt and ZSTD_btopt2 strategies.
+.IP ""
+The minimum \fItlen\fR is 4 and the maximum is 999.
+.IP ""
+
+.PP
+.B An example
+.br
+The following parameters sets advanced compression options to predefined level 19 for files bigger than 256 KB:
+.IP ""
+\fB--zstd=\fRwindowLog=23,chainLog=23,hashLog=22,searchLog=6,searchLength=3,targetLength=48,strategy=6
+
 .SH BUGS
 Report bugs at:- https://github.com/facebook/zstd/issues
 

programs/zstdcli.c

@@ -205,6 +205,32 @@ static unsigned longCommandWArg(const char** stringPtr, const char* longCommand)
     return result;
 }
 
+
+/** parseCompressionParameters() :
+ *  reads compression parameters from *stringPtr (e.g. "--zstd=wlog=23,clog=23,hlog=22,slog=6,slen=3,tlen=48,strat=6") into *params
+ *  @return 1 means that compression parameters were correct
+ *  @return 0 in case of malformed parameters
+ */
+static unsigned parseCompressionParameters(const char* stringPtr, ZSTD_compressionParameters* params)
+{
+    for ( ; ;) {
+        if (longCommandWArg(&stringPtr, "windowLog=") || longCommandWArg(&stringPtr, "wlog=")) { params->windowLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "chainLog=") || longCommandWArg(&stringPtr, "clog=")) { params->chainLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "hashLog=") || longCommandWArg(&stringPtr, "hlog=")) { params->hashLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "searchLog=") || longCommandWArg(&stringPtr, "slog=")) { params->searchLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "searchLength=") || longCommandWArg(&stringPtr, "slen=")) { params->searchLength = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "targetLength=") || longCommandWArg(&stringPtr, "tlen=")) { params->targetLength = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "strategy=") || longCommandWArg(&stringPtr, "strat=")) { params->strategy = (ZSTD_strategy)(1 + readU32FromChar(&stringPtr)); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        return 0;
+    }
+
+    if (stringPtr[0] != 0) return 0; /* check the end of string */
+    DISPLAYLEVEL(4, "windowLog=%d\nchainLog=%d\nhashLog=%d\nsearchLog=%d\n", params->windowLog, params->chainLog, params->hashLog, params->searchLog);
+    DISPLAYLEVEL(4, "searchLength=%d\ntargetLength=%d\nstrategy=%d\n", params->searchLength, params->targetLength, params->strategy);
+    return 1;
+}
+
+
 typedef enum { zom_compress, zom_decompress, zom_test, zom_bench, zom_train } zstd_operation_mode;
 
 #define CLEAN_RETURN(i) { operationResult = (i); goto _end; }
@@ -223,6 +249,7 @@ int main(int argCount, const char* argv[])
         ultra=0,
         lastCommand = 0;
     zstd_operation_mode operation = zom_compress;
+    ZSTD_compressionParameters compressionParams;
     int cLevel = ZSTDCLI_CLEVEL_DEFAULT;
     int cLevelLast = 1;
     unsigned recursive = 0;
@@ -259,6 +286,7 @@ int main(int argCount, const char* argv[])
     /* preset behaviors */
     if (!strcmp(programName, ZSTD_UNZSTD)) operation=zom_decompress;
     if (!strcmp(programName, ZSTD_CAT)) { operation=zom_decompress; forceStdout=1; FIO_overwriteMode(); outFileName=stdoutmark; displayLevel=1; }
+    memset(&compressionParams, 0, sizeof(compressionParams));
 
     /* command switches */
     for (argNb=1; argNb<argCount; argNb++) {
@@ -307,6 +335,7 @@ int main(int argCount, const char* argv[])
                     if (longCommandWArg(&argument, "--memlimit=")) { memLimit = readU32FromChar(&argument); continue; }
                     if (longCommandWArg(&argument, "--memory=")) { memLimit = readU32FromChar(&argument); continue; }
                     if (longCommandWArg(&argument, "--memlimit-decompress=")) { memLimit = readU32FromChar(&argument); continue; }
+                    if (longCommandWArg(&argument, "--zstd=")) { if (!parseCompressionParameters(argument, &compressionParams)) CLEAN_RETURN(badusage(programName)); continue; }
                     /* fall-through, will trigger bad_usage() later on */
                 }
 
@@ -488,7 +517,7 @@ int main(int argCount, const char* argv[])
     if (operation==zom_bench) {
 #ifndef ZSTD_NOBENCH
         BMK_setNotificationLevel(displayLevel);
-        BMK_benchFiles(filenameTable, filenameIdx, dictFileName, cLevel, cLevelLast);
+        BMK_benchFiles(filenameTable, filenameIdx, dictFileName, cLevel, cLevelLast, &compressionParams);
 #endif
         goto _end;
     }
@@ -540,9 +569,9 @@ int main(int argCount, const char* argv[])
     if (operation==zom_compress) {
 #ifndef ZSTD_NOCOMPRESS
         if ((filenameIdx==1) && outFileName)
-          operationResult = FIO_compressFilename(outFileName, filenameTable[0], dictFileName, cLevel);
+          operationResult = FIO_compressFilename(outFileName, filenameTable[0], dictFileName, cLevel, &compressionParams);
         else
-          operationResult = FIO_compressMultipleFilenames(filenameTable, filenameIdx, outFileName ? outFileName : ZSTD_EXTENSION, dictFileName, cLevel);
+          operationResult = FIO_compressMultipleFilenames(filenameTable, filenameIdx, outFileName ? outFileName : ZSTD_EXTENSION, dictFileName, cLevel, &compressionParams);
 #else
         DISPLAY("Compression not supported\n");
 #endif

tests/playTests.sh

@@ -27,7 +27,6 @@ case "$OS" in
   Windows*)
     isWindows=true
     ECHO="echo -e"
-    INTOVOID="nul"
     ;;
 esac
 
@@ -101,6 +100,18 @@ $ZSTD -f tmp && die "tmp not present : should have failed"
 ls tmp.zst && die "tmp.zst should not be created"
 
 
+$ECHO "\n**** Advanced compression parameters **** "
+$ECHO "Hello world!" | $ZSTD --zstd=windowLog=21,      - -o tmp.zst && die "wrong parameters not detected!"
+$ECHO "Hello world!" | $ZSTD --zstd=windowLo=21        - -o tmp.zst && die "wrong parameters not detected!"
+$ECHO "Hello world!" | $ZSTD --zstd=windowLog=21,slog  - -o tmp.zst && die "wrong parameters not detected!"
+ls tmp.zst && die "tmp.zst should not be created"
+roundTripTest -g512K
+roundTripTest -g512K " --zstd=slen=3,tlen=48,strat=6"
+roundTripTest -g512K " --zstd=strat=6,wlog=23,clog=23,hlog=22,slog=6"
+roundTripTest -g512K " --zstd=windowLog=23,chainLog=23,hashLog=22,searchLog=6,searchLength=3,targetLength=48,strategy=6"
+roundTripTest -g512K 19
+
+
 $ECHO "\n**** Pass-Through mode **** "
 $ECHO "Hello world 1!" | $ZSTD -df
 $ECHO "Hello world 2!" | $ZSTD -dcf