X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2Fhashfunc.h;h=cc799476a87938e6349e786c6b6f4d72de9c2df1;hb=ddb01cbb4eb8431b042918438e6543003851a87f;hp=126b8f243a897967f6bea97bc60f824f44d3e47d;hpb=b23db618057b5aa8905c41df963d6fa865d82c8c;p=libucw.git

diff --git a/lib/hashfunc.h b/lib/hashfunc.h
index 126b8f24..cc799476 100644
--- a/lib/hashfunc.h
+++ b/lib/hashfunc.h
@@ -1,14 +1,45 @@
 /*
- *	Sherlock Library -- Hash Functions
+ *	Hyper-super-meta-alt-control-shift extra fast str_len() and hash_*()
+ *	routines
  *
- *	(c) 2002 Martin Mares <mj@ucw.cz>
+ *	(c) 2002, Robert Spalek <robert@ucw.cz>
+ *
+ *	This software may be freely distributed and used according to the terms
+ *	of the GNU Lesser General Public License.
  */
 
 #ifndef _SHERLOCK_HASHFUNC_H
 #define _SHERLOCK_HASHFUNC_H
 
-uns hash_string(byte *x);
-uns hash_string_nocase(byte *x);
-static inline uns hash_int(uns x) { return 6442450967*x; }
+#include "lib/lib.h"
+
+/* An equivalent of the Intel's rol instruction.  */
+#define	ROL(x, bits)	(((x) << (bits)) | ((x) >> (sizeof(uns)*8 - (bits))))
+
+/* The following functions need str to be aligned to uns.  */
+uns str_len_aligned(const byte *str) CONST;
+uns hash_string_aligned(const byte *str) CONST;
+uns hash_block_aligned(const byte *str, uns len) CONST;
+
+#ifdef	CPU_ALLOW_UNALIGNED
+#define	str_len(str)		str_len_aligned(str)
+#define	hash_string(str)	hash_string_aligned(str)
+#define	hash_block(str, len)	hash_block_aligned(str, len)
+#else
+uns str_len(const byte *str) CONST;
+uns hash_string(const byte *str) CONST;
+uns hash_block(const byte *str, uns len) CONST;
+#endif
+
+uns hash_string_nocase(const byte *str) CONST;
+
+/*
+ *  We hash integers by multiplying by a reasonably large prime with
+ *  few ones in its binary form (to gave the compiler the possibility
+ *  of using shifts and adds on architectures where multiplication
+ *  instructions are slow).
+ */
+static inline uns CONST hash_int(uns x) { return 0x01008041*x; }
+static inline uns CONST hash_pointer(void *x) { return hash_int((uns)x); }
 
 #endif