Corrected : default to Software Bit Count for GCC earlier than 3.4. Thanks to Gray.

Corrected : ARM compilation under Visual Studio : now generates cautious code, like GCC, to ensure compatibility with strict-align CPUs. Thanks to Joe WoodBury.
Minor : bench.c : Hash verification changed to MurmurHash3A
Minor : bench.c : selectable block size

git-svn-id: https://lz4.googlecode.com/svn/trunk@56 650e7d94-2a16-8b24-b05c-7c0b3f6821cd

1 files changed, 35 insertions, 43 deletions

diff --git a/lz4.c b/lz4.c
index 2c3f1c4..a131a81 100644
--- a/lz4.c
+++ b/lz4.c
@@ -70,15 +70,15 @@
 // Little Endian assumed. PDP Endian and other very rare endian format are unsupported.

 #endif

 

-// Unaligned memory access ?

-// This feature is automatically enabled for "common" CPU, such as x86.

-// For others CPU, you may want to force this option manually to improve performance if your target CPU supports unaligned memory access

+// Unaligned memory access is automatically enabled for "common" CPU, such as x86.

+// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected

+// If you know your target CPU supports unaligned memory access, you may want to force this option manually to improve performance

 #if defined(__ARM_FEATURE_UNALIGNED)

 #define LZ4_FORCE_UNALIGNED_ACCESS 1

 #endif

 

-// Uncomment this parameter if your target system does not support hardware bit count

-//#define _FORCE_SW_BITCOUNT

+// Uncomment this parameter if your target system or compiler does not support hardware bit count

+//#define LZ4_FORCE_SW_BITCOUNT

 

 

 

@@ -95,12 +95,6 @@
 #define inline __forceinline    // Visual is not C99, but supports inline

 #endif

 

-#if (defined(__GNUC__) && (!defined(LZ4_FORCE_UNALIGNED_ACCESS)))

-#define _PACKED __attribute__ ((packed))

-#else

-#define _PACKED

-#endif

-

 #ifdef _MSC_VER  // Visual Studio

 #define bswap16(i) _byteswap_ushort(i)

 #else

@@ -134,11 +128,32 @@
 #define U64		uint64_t

 #endif

 

+#ifndef LZ4_FORCE_UNALIGNED_ACCESS

+#pragma pack(push, 1) 

+#endif

+

+typedef struct _U16_S { U16 v; } U16_S;

+typedef struct _U32_S { U32 v; } U32_S;

+typedef struct _U64_S { U64 v; } U64_S;

+

+#ifndef LZ4_FORCE_UNALIGNED_ACCESS

+#pragma pack(pop) 

+#endif

+

+#define A64(x) (((U64_S *)(x))->v)

+#define A32(x) (((U32_S *)(x))->v)

+#define A16(x) (((U16_S *)(x))->v)

+

 

 //**************************************

 // Constants

 //**************************************

 #define MINMATCH 4

+

+#define HASH_LOG COMPRESSIONLEVEL

+#define HASHTABLESIZE (1 << HASH_LOG)

+#define HASH_MASK (HASHTABLESIZE - 1)

+

 #define SKIPSTRENGTH (NOTCOMPRESSIBLE_CONFIRMATION>2?NOTCOMPRESSIBLE_CONFIRMATION:2)

 #define STACKLIMIT 13

 #define HEAPMODE (HASH_LOG>STACKLIMIT)  // Defines if memory is allocated into the stack (local variable), or into the heap (malloc()).

@@ -150,10 +165,6 @@
 #define MAXD_LOG 16

 #define MAX_DISTANCE ((1 << MAXD_LOG) - 1)

 

-#define HASH_LOG COMPRESSIONLEVEL

-#define HASHTABLESIZE (1 << HASH_LOG)

-#define HASH_MASK (HASHTABLESIZE - 1)

-

 #define ML_BITS 4

 #define ML_MASK ((1U<<ML_BITS)-1)

 #define RUN_BITS (8-ML_BITS)

@@ -200,25 +211,6 @@ struct refTables
 	HTYPE hashTable[HASHTABLESIZE];

 };

 

-typedef struct _U64_S

-{

-	U64 v;

-} _PACKED U64_S;

-

-typedef struct _U32_S

-{

-	U32 v;

-} _PACKED U32_S;

-

-typedef struct _U16_S

-{

-	U16 v;

-} _PACKED U16_S;

-

-#define A64(x) (((U64_S *)(x))->v)

-#define A32(x) (((U32_S *)(x))->v)

-#define A16(x) (((U16_S *)(x))->v)

-

 

 //**************************************

 // Macros

@@ -237,11 +229,11 @@ typedef struct _U16_S
 inline static int LZ4_NbCommonBytes (register U64 val)

 {

 #if defined(LZ4_BIG_ENDIAN)

-    #if defined(_MSC_VER) && !defined(_FORCE_SW_BITCOUNT)

+    #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)

     unsigned long r = 0;

     _BitScanReverse64( &r, val );

     return (int)(r>>3);

-    #elif defined(__GNUC__) && !defined(_FORCE_SW_BITCOUNT)

+    #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)

     return (__builtin_clzll(val) >> 3); 

     #else

 	int r;

@@ -251,11 +243,11 @@ inline static int LZ4_NbCommonBytes (register U64 val)
 	return r;

     #endif

 #else

-    #if defined(_MSC_VER) && !defined(_FORCE_SW_BITCOUNT)

+    #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)

     unsigned long r = 0;

     _BitScanForward64( &r, val );

     return (int)(r>>3);

-    #elif defined(__GNUC__) && !defined(_FORCE_SW_BITCOUNT)

+    #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)

     return (__builtin_ctzll(val) >> 3); 

     #else

 	static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };

@@ -269,11 +261,11 @@ inline static int LZ4_NbCommonBytes (register U64 val)
 inline static int LZ4_NbCommonBytes (register U32 val)

 {

 #if defined(LZ4_BIG_ENDIAN)

-    #if defined(_MSC_VER) && !defined(_FORCE_SW_BITCOUNT)

+    #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)

     unsigned long r = 0;

     _BitScanReverse( &r, val );

     return (int)(r>>3);

-    #elif defined(__GNUC__) && !defined(_FORCE_SW_BITCOUNT)

+    #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)

     return (__builtin_clz(val) >> 3); 

     #else

 	int r;

@@ -282,15 +274,15 @@ inline static int LZ4_NbCommonBytes (register U32 val)
 	return r;

     #endif

 #else

-    #if defined(_MSC_VER) && !defined(_FORCE_SW_BITCOUNT)

+    #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)

     unsigned long r = 0;

     _BitScanForward( &r, val );

     return (int)(r>>3);

-    #elif defined(__GNUC__) && !defined(_FORCE_SW_BITCOUNT)

+    #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)

     return (__builtin_ctz(val) >> 3); 

     #else

 	static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };

-	return DeBruijnBytePos[((U32)((val & -val) * 0x077CB531U)) >> 27];

+	return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];

     #endif

 #endif

 }