simplified legacy functions, no longer need magic number
diff --git a/lib/legacy/zstd_legacy.h b/lib/legacy/zstd_legacy.h
index 56b3e82..ab9634b 100644
--- a/lib/legacy/zstd_legacy.h
+++ b/lib/legacy/zstd_legacy.h
@@ -54,8 +54,11 @@
@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 @@
{
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 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 @@
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);