Small compression speed improvement

git-svn-id: https://lz4.googlecode.com/svn/trunk@24 650e7d94-2a16-8b24-b05c-7c0b3f6821cd

1 files changed, 27 insertions, 16 deletions

diff --git a/lz4.c b/lz4.c
index 534b42b..54895a6 100644
--- a/lz4.c
+++ b/lz4.c
@@ -67,6 +67,7 @@
 //**************************************

 #define MINMATCH 4

 #define SKIPSTRENGTH 6

+#define HEAPLIMIT 13

 

 #define MAXD_LOG 16

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

@@ -106,8 +107,12 @@ int LZ4_compressCtx(void** ctx,
 				 char* dest,

 				 int isize)

 {	

+#if HASH_LOG>HEAPLIMIT

 	struct refTables *srt = (struct refTables *) (*ctx);

 	const BYTE**  HashTable;

+#else

+	const BYTE* HashTable[HASHTABLESIZE] = {0};

+#endif

 

 	const BYTE* ip = (BYTE*) source;       

 	const BYTE* anchor = ip;

@@ -124,6 +129,7 @@ int LZ4_compressCtx(void** ctx,
 

 

 	// Init 

+#if HASH_LOG>HEAPLIMIT

 	if (*ctx == NULL) 

 	{

 		srt = (struct refTables *) malloc ( sizeof(struct refTables) );

@@ -131,6 +137,7 @@ int LZ4_compressCtx(void** ctx,
 	}

 	HashTable = srt->hashTable;

 	memset((void*)HashTable, 0, sizeof(srt->hashTable));

+#endif

 

 

 	// First Byte

@@ -138,26 +145,26 @@ int LZ4_compressCtx(void** ctx,
 	ip++; forwardH = HASH_VALUE(ip);

 	

 	// Main Loop

-    for ( ; ; ) 
-	{
-		int segmentSize = (1U << skipStrength) + 3;
-		const BYTE* forwardIp = ip;
-		const BYTE* ref;
-
+    for ( ; ; ) 

+	{

+		int segmentSize = (1U << skipStrength) + 3;

+		const BYTE* forwardIp = ip;

+		const BYTE* ref;

+

 		// Find a match

-		do {
-			U32 h = forwardH;
-			int skipped = segmentSize++ >> skipStrength;
-			ip = forwardIp;
-			forwardIp = ip + skipped;
-
-			if (forwardIp > ilimit) { goto _last_literals; }
+		do {

+			U32 h = forwardH;

+			int skipped = segmentSize++ >> skipStrength;

+			ip = forwardIp;

+			forwardIp = ip + skipped;

+

+			if (forwardIp > ilimit) { goto _last_literals; }

 

 			forwardH = HASH_VALUE(forwardIp);

 			ref = HashTable[h];

 			HashTable[h] = ip;

-
-		} while ((ref < ip - MAX_DISTANCE) || (*(U32*)ref != *(U32*)ip));
+

+		} while ((ref < ip - MAX_DISTANCE) || (*(U32*)ref != *(U32*)ip));

 

 		// Catch up

 		while ((ip>anchor) && (ref>(BYTE*)source) && (ip[-1]==ref[-1])) { ip--; ref--; }  

@@ -230,15 +237,19 @@ int LZ4_compress(char* source,
 				 char* dest,

 				 int isize)

 {

+#if HASH_LOG>HEAPLIMIT

 	void* ctx = malloc(sizeof(struct refTables));

 	int result = LZ4_compressCtx(&ctx, source, dest, isize);

 	free(ctx);

-

 	return result;

+#else

+	return LZ4_compressCtx(NULL, source, dest, isize);

+#endif

 }

 

 

 

+

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

 // Decompression CODE

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