[zstdcli] Add a flag to control literals compression

programs/fileio.c

@@ -296,6 +296,7 @@ struct FIO_prefs_s {
     int ldmMinMatch;
     int ldmBucketSizeLog;
     int ldmHashRateLog;
+    ZSTD_literalCompressionMode_e literalCompressionMode;
 
     /* IO preferences */
     U32 removeSrcFile;
@@ -339,6 +340,7 @@ FIO_prefs_t* FIO_createPreferences(void)
     ret->ldmMinMatch = 0;
     ret->ldmBucketSizeLog = FIO_LDM_PARAM_NOTSET;
     ret->ldmHashRateLog = FIO_LDM_PARAM_NOTSET;
+    ret->literalCompressionMode = ZSTD_lcm_auto;
     return ret;
 }
 
@@ -406,6 +408,12 @@ void FIO_setRsyncable(FIO_prefs_t* const prefs, int rsyncable) {
     prefs->rsyncable = rsyncable;
 }
 
+void FIO_setLiteralCompressionMode(
+        FIO_prefs_t* const prefs,
+        ZSTD_literalCompressionMode_e mode) {
+    prefs->literalCompressionMode = mode;
+}
+
 void FIO_setAdaptMin(FIO_prefs_t* const prefs, int minCLevel)
 {
 #ifndef ZSTD_NOCOMPRESS
@@ -674,6 +682,7 @@ static cRess_t FIO_createCResources(FIO_prefs_t* const prefs,
         CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_minMatch, (int)comprParams.minMatch) );
         CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_targetLength, (int)comprParams.targetLength) );
         CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_strategy, comprParams.strategy) );
+        CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_literalCompressionMode, (int)prefs->literalCompressionMode) );
         /* multi-threading */
 #ifdef ZSTD_MULTITHREAD
         DISPLAYLEVEL(5,"set nb workers = %u \n", prefs->nbWorkers);

programs/fileio.h

@@ -71,6 +71,9 @@ void FIO_setOverlapLog(FIO_prefs_t* const prefs, int overlapLog);
 void FIO_setRemoveSrcFile(FIO_prefs_t* const prefs, unsigned flag);
 void FIO_setSparseWrite(FIO_prefs_t* const prefs, unsigned sparse);  /**< 0: no sparse; 1: disable on stdout; 2: always enabled */
 void FIO_setRsyncable(FIO_prefs_t* const prefs, int rsyncable);
+void FIO_setLiteralCompressionMode(
+        FIO_prefs_t* const prefs,
+        ZSTD_literalCompressionMode_e mode);
 
 void FIO_setNoProgress(unsigned noProgress);
 void FIO_setNotificationLevel(int level);

programs/zstdcli.c

@@ -148,6 +148,7 @@ static int usage_advanced(const char* programName)
 #endif
     DISPLAY( "--no-dictID : don't write dictID into header (dictionary compression)\n");
     DISPLAY( "--[no-]check : integrity check (default: enabled) \n");
+    DISPLAY( "--[no-]compress-literals : force (un)compressed literals \n");
 #endif
 #ifdef UTIL_HAS_CREATEFILELIST
     DISPLAY( " -r     : operate recursively on directories \n");
@@ -483,7 +484,7 @@ static int init_cLevel(void) {
 
         if ((*ptr>='0') && (*ptr<='9')) {
             unsigned absLevel;
-            if (readU32FromCharChecked(&ptr, &absLevel)) { 
+            if (readU32FromCharChecked(&ptr, &absLevel)) {
                 DISPLAYLEVEL(2, "Ignore environment variable setting %s=%s: numeric value too large\n", ENV_CLEVEL, env);
                 return ZSTDCLI_CLEVEL_DEFAULT;
             } else if (*ptr == 0) {
@@ -659,6 +660,8 @@ int main(int argCount, const char* argv[])
                     if (!strcmp(argument, "--format=lz4")) { suffix = LZ4_EXTENSION; FIO_setCompressionType(prefs, FIO_lz4Compression);  continue; }
 #endif
                     if (!strcmp(argument, "--rsyncable")) { rsyncable = 1; continue; }
+                    if (!strcmp(argument, "--compress-literals")) { FIO_setLiteralCompressionMode(prefs, ZSTD_lcm_huffman); continue; }
+                    if (!strcmp(argument, "--no-compress-literals")) { FIO_setLiteralCompressionMode(prefs, ZSTD_lcm_uncompressed); continue; }
                     if (!strcmp(argument, "--no-progress")) { FIO_setNoProgress(1); continue; }
 
                     /* long commands with arguments */