simplified legacy functions, no longer need magic number

diff --git a/NEWS b/NEWS
index cc9a59d2e8b3b5d7eb48b826db7bacfd56d0d10f..06c94ce9c80d3ff8d9d066222334905e5148ef32 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -1,10 +1,12 @@
 v0.7.3
-added : `--` separator, stating that all following arguments are file names. Suggested by Chip Turner.
-added : `ZSTD_getDecompressedSize()`
-added : OpenBSD target, by Juan Francisco Cantero Hurtado
+New : `--` separator, stating that all following arguments are file names. Suggested by Chip Turner.
+New : `ZSTD_getDecompressedSize()`
+New : OpenBSD target, by Juan Francisco Cantero Hurtado
+New : `examples` directory
 fixed : dictBuilder using HC levels, reported by Bartosz Taudul
 fixed : legacy support from ZSTD_decompress_usingDDict(), reported by Felix Handte
-modified : removed `mem.h` dependency from `zstd.h` (experimental section)
+modified : removed "mem.h" and "error_public.h" dependencies from "zstd.h" (experimental section)
+modified : legacy functions no longer need magic number
 
 v0.7.2
 fixed : ZSTD_decompressBlock() using multiple consecutive blocks. Reported by Greg Slazinski.

diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index a43e803597d25b2f9325ac43f52aaf8ca1c498f4..c1d9197d4df42ead2cd9458709f3a6b5ecce9148 100644 (file)
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -398,12 +398,10 @@ size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t
                    - decompressed size is not provided within frame header
                    - frame header unknown / not supported
                    - frame header not completely provided (`srcSize` too small) */
-unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize) {
-#if ZSTD_LEGACY_SUPPORT
-    if (srcSize < 4) return 0;
-    {   U32 const magic = MEM_readLE32(src);
-        if (ZSTD_isLegacy(magic)) return ZSTD_getDecompressedSize_legacy(src, srcSize);
-    }
+unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize)
+{
+#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT==1)
+    if (ZSTD_isLegacy(src, srcSize)) return ZSTD_getDecompressedSize_legacy(src, srcSize);
 #endif
     {   ZSTD_frameParams fparams;
         size_t const frResult = ZSTD_getFrameParams(&fparams, src, srcSize);
@@ -1047,10 +1045,7 @@ size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
                                  const void* dict, size_t dictSize)
 {
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT==1)
-    {   U32 const magicNumber = MEM_readLE32(src);
-        if (ZSTD_isLegacy(magicNumber))
-            return ZSTD_decompressLegacy(dst, dstCapacity, src, srcSize, dict, dictSize, magicNumber);
-    }
+    if (ZSTD_isLegacy(src, srcSize)) return ZSTD_decompressLegacy(dst, dstCapacity, src, srcSize, dict, dictSize);
 #endif
     ZSTD_decompressBegin_usingDict(dctx, dict, dictSize);
     ZSTD_checkContinuity(dctx, dst);
@@ -1357,10 +1352,7 @@ ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
                                      const ZSTD_DDict* ddict)
 {
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT==1)
-    {   U32 const magicNumber = MEM_readLE32(src);
-        if (ZSTD_isLegacy(magicNumber))
-            return ZSTD_decompressLegacy(dst, dstCapacity, src, srcSize, ddict->dictContent, ddict->dictContentSize, magicNumber);
-    }
+    if (ZSTD_isLegacy(src, srcSize)) return ZSTD_decompressLegacy(dst, dstCapacity, src, srcSize, ddict->dictContent, ddict->dictContentSize);
 #endif
     return ZSTD_decompress_usingPreparedDCtx(dctx, ddict->refContext,
                                            dst, dstCapacity,

diff --git a/lib/legacy/zstd_legacy.h b/lib/legacy/zstd_legacy.h
index 56b3e82150b58297dedda5e34c18ad5f8835e6db..ab9634b3247c35faccc62f5ebe026bcfd3745485 100644 (file)
--- a/lib/legacy/zstd_legacy.h
+++ b/lib/legacy/zstd_legacy.h
@@ -54,8 +54,11 @@ extern "C" {
     @return : > 0 if supported by legacy decoder. 0 otherwise.
               return value is the version.
 */
-MEM_STATIC unsigned ZSTD_isLegacy (U32 magicNumberLE)
+MEM_STATIC unsigned ZSTD_isLegacy(const void* src, size_t srcSize)
 {
+    U32 magicNumberLE;
+    if (srcSize<4) return 0;
+    magicNumberLE = MEM_readLE32(src);
     switch(magicNumberLE)
     {
         case ZSTDv01_magicNumberLE:return 1;
@@ -73,10 +76,8 @@ MEM_STATIC unsigned long long ZSTD_getDecompressedSize_legacy(const void* src, s
 {
     if (srcSize < 4) return 0;
 
-    {   U32 const magic = MEM_readLE32(src);
-        U32 const version = ZSTD_isLegacy(magic);
-        if (!version) return 0;   /* not a supported legacy format */
-        if (version < 5) return 0;  /* no decompressed size in frame header */
+    {   U32 const version = ZSTD_isLegacy(src, srcSize);
+        if (version < 5) return 0;  /* no decompressed size in frame header, or not a legacy format */
         if (version==5) {
             ZSTDv05_parameters fParams;
             size_t const frResult = ZSTDv05_getFrameParams(&fParams, src, srcSize);
@@ -96,20 +97,20 @@ MEM_STATIC unsigned long long ZSTD_getDecompressedSize_legacy(const void* src, s
 MEM_STATIC size_t ZSTD_decompressLegacy(
                      void* dst, size_t dstCapacity,
                const void* src, size_t compressedSize,
-               const void* dict,size_t dictSize,
-                     U32 magicNumberLE)
+               const void* dict,size_t dictSize)
 {
-    switch(magicNumberLE)
+    U32 const version = ZSTD_isLegacy(src, compressedSize);
+    switch(version)
     {
-        case ZSTDv01_magicNumberLE :
+        case 1 :
             return ZSTDv01_decompress(dst, dstCapacity, src, compressedSize);
-        case ZSTDv02_magicNumber :
+        case 2 :
             return ZSTDv02_decompress(dst, dstCapacity, src, compressedSize);
-        case ZSTDv03_magicNumber :
+        case 3 :
             return ZSTDv03_decompress(dst, dstCapacity, src, compressedSize);
-        case ZSTDv04_magicNumber :
+        case 4 :
             return ZSTDv04_decompress(dst, dstCapacity, src, compressedSize);
-        case ZSTDv05_MAGICNUMBER :
+        case 5 :
             {   size_t result;
                 ZSTDv05_DCtx* const zd = ZSTDv05_createDCtx();
                 if (zd==NULL) return ERROR(memory_allocation);
@@ -117,7 +118,7 @@ MEM_STATIC size_t ZSTD_decompressLegacy(
                 ZSTDv05_freeDCtx(zd);
                 return result;
             }
-        case ZSTDv06_MAGICNUMBER :
+        case 6 :
             {   size_t result;
                 ZSTDv06_DCtx* const zd = ZSTDv06_createDCtx();
                 if (zd==NULL) return ERROR(memory_allocation);

diff --git a/programs/fileio.c b/programs/fileio.c
index 6081e4af7d01062b2b7435b7d87b7d0a1b862f99..3eb8d881e68b421678fd21d44dd33688b884fa28 100644 (file)
--- a/programs/fileio.c
+++ b/programs/fileio.c
@@ -700,7 +700,7 @@ static int FIO_decompressSrcFile(dRess_t ress, const char* srcFileName)
         if (sizeCheck != toRead) EXM_THROW(31, "zstd: %s read error : cannot read header", srcFileName);
         {   U32 const magic = MEM_readLE32(ress.srcBuffer);
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
-            if (ZSTD_isLegacy(magic)) {
+            if (ZSTD_isLegacy(ress.srcBuffer, 4)) {
                 filesize += FIO_decompressLegacyFrame(dstFile, srcFile, ress.dictBuffer, ress.dictBufferSize, magic);
                 continue;
             }