changed validateParams() into checkParams() + adjustParams()

lib/error_private.h

@@ -95,6 +95,7 @@ ERR_STATIC const char* ERR_getErrorName(size_t code)
     case PREFIX(prefix_unknown): return "Unknown frame descriptor";
     case PREFIX(frameParameter_unsupported): return "Unsupported frame parameter";
     case PREFIX(frameParameter_unsupportedBy32bits): return "Frame parameter unsupported in 32-bits mode";
+    case PREFIX(compressionParameter_unsupported): return "Compression parameter is out of bound";
     case PREFIX(init_missing): return "Context should be init first";
     case PREFIX(memory_allocation): return "Allocation error : not enough memory";
     case PREFIX(stage_wrong): return "Operation not authorized at current processing stage";

lib/error_public.h

@@ -47,6 +47,7 @@ typedef enum {
   ZSTD_error_prefix_unknown,
   ZSTD_error_frameParameter_unsupported,
   ZSTD_error_frameParameter_unsupportedBy32bits,
+  ZSTD_error_compressionParameter_unsupported,
   ZSTD_error_init_missing,
   ZSTD_error_memory_allocation,
   ZSTD_error_stage_wrong,

lib/zbuff.c

@@ -128,7 +128,9 @@ size_t ZBUFF_compressInit_advanced(ZBUFF_CCtx* zbc, const void* dict, size_t dic
 {
     size_t neededInBuffSize;
 
-    ZSTD_validateParams(&params);
+    { size_t const errorCode = ZSTD_checkParams(params);
+      if (ZSTD_isError(errorCode)) return errorCode; }
+    ZSTD_adjustParams(&params, 0, dictSize);
     neededInBuffSize = (size_t)1 << params.windowLog;
 
     /* allocate buffers */
@@ -157,6 +159,7 @@ size_t ZBUFF_compressInit_advanced(ZBUFF_CCtx* zbc, const void* dict, size_t dic
     return 0;   /* ready to go */
 }
 
+
 size_t ZBUFF_compressInit(ZBUFF_CCtx* zbc, int compressionLevel)
 {
     return ZBUFF_compressInit_advanced(zbc, NULL, 0, ZSTD_getParams(compressionLevel, 0));

lib/zstd_compress.c

@@ -133,35 +133,51 @@ const seqStore_t* ZSTD_getSeqStore(const ZSTD_CCtx* ctx)   /* hidden interface *
 }
 
 
+#define CLAMP(val,min,max) { if (val<min) val=min; else if (val>max) val=max; }
+#define CLAMPCHECK(val,min,max) { if ((val<min) || (val>max)) return ERROR(compressionParameter_unsupported); }
+
+/** ZSTD_checkParams() :
+    ensure param values remain within authorized range.
+    @return : 0, or an error code if one value is beyond authorized range */
+size_t ZSTD_checkParams(ZSTD_parameters params)
+{
+    { U32 const windowLog_max = MEM_32bits() ? 25 : ZSTD_WINDOWLOG_MAX;   /* 32 bits mode cannot flush > 24 bits */
+      CLAMPCHECK(params.windowLog, ZSTD_WINDOWLOG_MIN, windowLog_max); }
+    CLAMPCHECK(params.contentLog, ZSTD_CONTENTLOG_MIN, ZSTD_CONTENTLOG_MAX);
+    CLAMPCHECK(params.hashLog, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
+    CLAMPCHECK(params.searchLog, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
+    { U32 const searchLengthMin = (params.strategy == ZSTD_btopt) ? ZSTD_SEARCHLENGTH_MIN : ZSTD_SEARCHLENGTH_MIN+1;
+      U32 const searchLengthMax = (params.strategy == ZSTD_fast) ? ZSTD_SEARCHLENGTH_MAX : ZSTD_SEARCHLENGTH_MAX-1;
+      CLAMPCHECK(params.searchLength, searchLengthMin, searchLengthMax); }
+    CLAMPCHECK(params.targetLength, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
+    CLAMPCHECK((U32)(params.strategy), 0, (U32)ZSTD_btopt);
+    return 0;
+}
+
+
 static unsigned ZSTD_highbit(U32 val);
 
-#define CLAMP(val,min,max) { if (val<min) val=min; else if (val>max) val=max; }
+/** ZSTD_adjustParams() :
-
+    optimize params for q given input (`srcSize` and `dictSize`).
-/** ZSTD_validateParams() :
+    mostly downsizing to reduce memory consumption and initialization.
-    correct params value to remain within authorized range,
+    Both `srcSize` and `dictSize` are optional (use 0 if unknown),
-    optimize for `srcSize` if srcSize > 0 */
+    but if both are 0, no optimization can be done.
-void ZSTD_validateParams(ZSTD_parameters* params)
+    Note : params is considered validated at this stage. Use ZSTD_checkParams() to ensure that. */
+void ZSTD_adjustParams(ZSTD_parameters* params, size_t srcSize, size_t dictSize)
 {
-    /* validate params */
+    if (srcSize+dictSize == 0) return;   /* no size information available : no adjustment */
-    if (MEM_32bits()) if (params->windowLog > 25) params->windowLog = 25;   /* 32 bits mode cannot flush > 24 bits */
-    CLAMP(params->windowLog, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
-    CLAMP(params->contentLog, ZSTD_CONTENTLOG_MIN, ZSTD_CONTENTLOG_MAX);
-    CLAMP(params->hashLog, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
-    CLAMP(params->searchLog, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
-    { U32 const searchLengthMin = (params->strategy == ZSTD_btopt) ? ZSTD_SEARCHLENGTH_MIN : ZSTD_SEARCHLENGTH_MIN+1;
-      U32 const searchLengthMax = (params->strategy == ZSTD_fast) ? ZSTD_SEARCHLENGTH_MAX : ZSTD_SEARCHLENGTH_MAX-1;
-      CLAMP(params->searchLength, searchLengthMin, searchLengthMax); }
-    CLAMP(params->targetLength, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
-    if ((U32)params->strategy>(U32)ZSTD_btopt) params->strategy = ZSTD_btopt;
 
     /* resize params, to use less memory when necessary */
-    if ((params->srcSize > 0) && (params->srcSize < (1<<ZSTD_WINDOWLOG_MAX))) {
+    {   size_t const minSrcSize = (srcSize==0) ? 500 : 0;
-        U32 const srcLog = ZSTD_highbit((U32)(params->srcSize)-1) + 1;
+        size_t const rSize = srcSize + dictSize + minSrcSize;
+        if (rSize < (1<<ZSTD_WINDOWLOG_MAX)) {
+            U32 const srcLog = ZSTD_highbit((U32)(rSize)-1) + 1;
             if (params->windowLog > srcLog) params->windowLog = srcLog;
-    }
+    }   }
     if (params->hashLog > params->windowLog) params->hashLog = params->windowLog;
     {   U32 const btPlus = (params->strategy == ZSTD_btlazy2) || (params->strategy == ZSTD_btopt);
-      if (params->contentLog > params->windowLog+btPlus) params->contentLog = params->windowLog+btPlus; }   /* <= ZSTD_CONTENTLOG_MAX */
+        U32 const maxContentLog = params->windowLog+btPlus;
+        if (params->contentLog > maxContentLog) params->contentLog = maxContentLog; }   /* <= ZSTD_CONTENTLOG_MAX */
 
     if (params->windowLog  < ZSTD_WINDOWLOG_ABSOLUTEMIN) params->windowLog = ZSTD_WINDOWLOG_ABSOLUTEMIN;  /* required for frame header */
 }
@@ -2207,7 +2223,11 @@ size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* zc,
                              const void* dict, size_t dictSize,
                                    ZSTD_parameters params)
 {
-    ZSTD_validateParams(&params);
+    /* compression parameters verification and optimization */
+    { size_t const errorCode = ZSTD_checkParams(params);
+      if (ZSTD_isError(errorCode)) return errorCode; }
+
+    ZSTD_adjustParams(&params, 0, dictSize);
 
     { size_t const errorCode = ZSTD_resetCCtx_advanced(zc, params);
       if (ZSTD_isError(errorCode)) return errorCode; }
@@ -2295,7 +2315,7 @@ size_t ZSTD_compress_usingPreparedCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* prepare
 }
 
 
-size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx,
+static size_t ZSTD_compress_internal (ZSTD_CCtx* ctx,
                                void* dst, size_t dstCapacity,
                          const void* src, size_t srcSize,
                          const void* dict,size_t dictSize,
@@ -2322,16 +2342,29 @@ size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx,
     return (op - ostart);
 }
 
+size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx,
+                               void* dst, size_t dstCapacity,
+                         const void* src, size_t srcSize,
+                         const void* dict,size_t dictSize,
+                               ZSTD_parameters params)
+{
+    size_t const errorCode = ZSTD_checkParams(params);
+    if (ZSTD_isError(errorCode)) return errorCode;
+    return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, dict, dictSize, params);
+}
+
 size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, const void* dict, size_t dictSize, int compressionLevel)
 {
+    ZSTD_parameters params = ZSTD_getParams(compressionLevel, srcSize+dictSize);
     ZSTD_LOG_BLOCK("%p: ZSTD_compress_usingDict srcSize=%d dictSize=%d compressionLevel=%d\n", ctx->base, (int)srcSize, (int)dictSize, compressionLevel);
-    return ZSTD_compress_advanced(ctx, dst, dstCapacity, src, srcSize, dict, dictSize, ZSTD_getParams(compressionLevel, srcSize));
+    ZSTD_adjustParams(&params, srcSize, dictSize);
+    return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, dict, dictSize, params);
 }
 
 size_t ZSTD_compressCCtx (ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel)
 {
     ZSTD_LOG_BLOCK("%p: ZSTD_compressCCtx srcSize=%d compressionLevel=%d\n", ctx->base, (int)srcSize, compressionLevel);
-    return ZSTD_compress_advanced(ctx, dst, dstCapacity, src, srcSize, NULL, 0, ZSTD_getParams(compressionLevel, srcSize));
+    return ZSTD_compress_usingDict(ctx, dst, dstCapacity, src, srcSize, NULL, 0, compressionLevel);
 }
 
 size_t ZSTD_compress(void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel)

lib/zstd_static.h

@@ -95,9 +95,14 @@ ZSTDLIB_API unsigned ZSTD_maxCLevel (void);
 *   `srcSize` value is optional, select 0 if not known */
 ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, U64 srcSize);
 
-/*! ZSTD_validateParams() :
+/*! ZSTD_checkParams() :
-*   correct params value to remain within authorized range */
+*   Ensure param values remain within authorized range */
-ZSTDLIB_API void ZSTD_validateParams(ZSTD_parameters* params);
+ZSTDLIB_API size_t ZSTD_checkParams(ZSTD_parameters params);
+
+/*! ZSTD_adjustParams() :
+*   optimize params for a given `srcSize` and `dictSize`.
+*   both values are optional, select `0` if unknown. */
+ZSTDLIB_API void ZSTD_adjustParams(ZSTD_parameters* params, size_t srcSize, size_t dictSize);
 
 /*! ZSTD_compress_advanced() :
 *   Same as ZSTD_compress_usingDict(), with fine-tune control of each compression parameter */