1 /*********************************************************************** 2 * * 3 * This software is part of the ast package * 4 * Copyright (c) 1985-2008 AT&T Intellectual Property * 5 * and is licensed under the * 6 * Common Public License, Version 1.0 * 7 * by AT&T Intellectual Property * 8 * * 9 * A copy of the License is available at * 10 * http://www.opensource.org/licenses/cpl1.0.txt * 11 * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * 12 * * 13 * Information and Software Systems Research * 14 * AT&T Research * 15 * Florham Park NJ * 16 * * 17 * Glenn Fowler <gsf@research.att.com> * 18 * David Korn <dgk@research.att.com> * 19 * Phong Vo <kpv@research.att.com> * 20 * * 21 ***********************************************************************/ 22 #pragma prototyped 23 /* 24 * K. P. Vo 25 * G. S. Fowler 26 * AT&T Research 27 * 28 * ``the best'' combined linear congruent checksum/hash/PRNG 29 */ 30 31 #ifndef _HASHPART_H 32 #define _HASHPART_H 33 34 #define HASH_ADD(h) (0x9c39c33dL) 35 36 #if __sparc__ || __sparc || sparc 37 38 #define HASH_A(h,n) ((((h) << 2) - (h)) << (n)) 39 #define HASH_B(h,n) ((((h) << 4) - (h)) << (n)) 40 #define HASH_C(h,n) ((HASH_A(h,7) + HASH_B(h,0)) << (n)) 41 #define HASH_MPY(h) (HASH_C(h,22)+HASH_C(h,10)+HASH_A(h,6)+HASH_A(h,3)+(h)) 42 43 #else 44 45 #define HASH_MPY(h) ((h)*0x63c63cd9L) 46 47 #endif 48 49 #define HASHPART(h,c) (h = HASH_MPY(h) + HASH_ADD(h) + (c)) 50 51 #endif 52