introduced FSE_decompress_wksp(), to use less stack space

diff --git a/lib/common/entropy_common.c b/lib/common/entropy_common.c
index 18bba0e87b06dc370c00b1eb0091e23f0587582e..8a31c4696de287a71fa3acf5eff6b196400ecfb6 100644 (file)
--- a/lib/common/entropy_common.c
+++ b/lib/common/entropy_common.c
@@ -187,8 +187,9 @@ size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
                 huffWeight[n+1] = ip[n/2] & 15;
     }   }   }
     else  {   /* header compressed with FSE (normal case) */
+        FSE_DTable fseWorkspace[FSE_DTABLE_SIZE_U32(5)];  /* 5 is max possible tableLog for HUF header */
         if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
-        oSize = FSE_decompress(huffWeight, hwSize-1, ip+1, iSize);   /* max (hwSize-1) values decoded, as last one is implied */
+        oSize = FSE_decompress_wksp(huffWeight, hwSize-1, ip+1, iSize, fseWorkspace, 5);   /* max (hwSize-1) values decoded, as last one is implied */
         if (FSE_isError(oSize)) return oSize;
     }
 

diff --git a/lib/common/fse.h b/lib/common/fse.h
index cecb1aef7aa83e59718db675743c89876da029fe..2f4506330abb5bc768ff0b68de6ed9b885d98b96 100644 (file)
--- a/lib/common/fse.h
+++ b/lib/common/fse.h
@@ -286,7 +286,7 @@ If there is an error, the function will return an error code, which can be teste
 #define FSE_BLOCKBOUND(size) (size + (size>>7))
 #define FSE_COMPRESSBOUND(size) (FSE_NCOUNTBOUND + FSE_BLOCKBOUND(size))   /* Macro version, useful for static allocation */
 
-/* It is possible to statically allocate FSE CTable/DTable as a table of unsigned using below macros */
+/* It is possible to statically allocate FSE CTable/DTable as a table of FSE_CTable/FSE_DTable using below macros */
 #define FSE_CTABLE_SIZE_U32(maxTableLog, maxSymbolValue)   (1 + (1<<(maxTableLog-1)) + ((maxSymbolValue+1)*2))
 #define FSE_DTABLE_SIZE_U32(maxTableLog)                   (1 + (1<<maxTableLog))
 
@@ -312,6 +312,9 @@ size_t FSE_buildDTable_raw (FSE_DTable* dt, unsigned nbBits);
 size_t FSE_buildDTable_rle (FSE_DTable* dt, unsigned char symbolValue);
 /**< build a fake FSE_DTable, designed to always generate the same symbolValue */
 
+size_t FSE_decompress_wksp(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize, FSE_DTable* workSpace, unsigned maxLog);
+/**< same as FSE_decompress(), using an externally allocated `workSpace` produced with `FSE_DTABLE_SIZE_U32(maxLog)` */
+
 
 /* *****************************************
 *  FSE symbol compression API

diff --git a/lib/common/fse_decompress.c b/lib/common/fse_decompress.c
index 7492a3832b712647d5b2982de3ea0a2bd4f36566..1479a5e8217b7cbec75548977fa8101157af11a6 100644 (file)
--- a/lib/common/fse_decompress.c
+++ b/lib/common/fse_decompress.c
@@ -75,12 +75,6 @@
 #define CHECK_F(f) { size_t const e = f; if (FSE_isError(e)) return e; }
 
 
-/* **************************************************************
-*  Complex types
-****************************************************************/
-typedef U32 DTable_max_t[FSE_DTABLE_SIZE_U32(FSE_MAX_TABLELOG)];
-
-
 /* **************************************************************
 *  Templates
 ****************************************************************/
@@ -300,28 +294,34 @@ size_t FSE_decompress_usingDTable(void* dst, size_t originalSize,
 }
 
 
-size_t FSE_decompress(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize)
+size_t FSE_decompress_wksp(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize, FSE_DTable* workSpace, unsigned maxLog)
 {
     const BYTE* const istart = (const BYTE*)cSrc;
     const BYTE* ip = istart;
     short counting[FSE_MAX_SYMBOL_VALUE+1];
-    DTable_max_t dt;   /* Static analyzer seems unable to understand this table will be properly initialized later */
     unsigned tableLog;
     unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
 
-    if (cSrcSize<2) return ERROR(srcSize_wrong);   /* too small input size */
-
     /* normal FSE decoding mode */
-    {   size_t const NCountLength = FSE_readNCount (counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
-        if (FSE_isError(NCountLength)) return NCountLength;
-        if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong);   /* too small input size */
-        ip += NCountLength;
-        cSrcSize -= NCountLength;
-    }
+    size_t const NCountLength = FSE_readNCount (counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
+    if (FSE_isError(NCountLength)) return NCountLength;
+    //if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong);   /* too small input size; supposed to be already checked in NCountLength, only remaining case : NCountLength==cSrcSize */
+    if (tableLog > maxLog) return ERROR(tableLog_tooLarge);
+    ip += NCountLength;
+    cSrcSize -= NCountLength;
 
-    CHECK_F( FSE_buildDTable (dt, counting, maxSymbolValue, tableLog) );
+    CHECK_F( FSE_buildDTable (workSpace, counting, maxSymbolValue, tableLog) );
 
-    return FSE_decompress_usingDTable (dst, maxDstSize, ip, cSrcSize, dt);   /* always return, even if it is an error code */
+    return FSE_decompress_usingDTable (dst, dstCapacity, ip, cSrcSize, workSpace);   /* always return, even if it is an error code */
+}
+
+
+typedef FSE_DTable DTable_max_t[FSE_DTABLE_SIZE_U32(FSE_MAX_TABLELOG)];
+
+size_t FSE_decompress(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize)
+{
+    DTable_max_t dt;   /* Static analyzer seems unable to understand this table will be properly initialized later */
+    return FSE_decompress_wksp(dst, dstCapacity, cSrc, cSrcSize, dt, FSE_MAX_TABLELOG);
 }