1*4887Schin /*********************************************************************** 2*4887Schin * * 3*4887Schin * This software is part of the ast package * 4*4887Schin * Copyright (c) 1985-2007 AT&T Knowledge Ventures * 5*4887Schin * and is licensed under the * 6*4887Schin * Common Public License, Version 1.0 * 7*4887Schin * by AT&T Knowledge Ventures * 8*4887Schin * * 9*4887Schin * A copy of the License is available at * 10*4887Schin * http://www.opensource.org/licenses/cpl1.0.txt * 11*4887Schin * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * 12*4887Schin * * 13*4887Schin * Information and Software Systems Research * 14*4887Schin * AT&T Research * 15*4887Schin * Florham Park NJ * 16*4887Schin * * 17*4887Schin * Glenn Fowler <gsf@research.att.com> * 18*4887Schin * David Korn <dgk@research.att.com> * 19*4887Schin * Phong Vo <kpv@research.att.com> * 20*4887Schin * * 21*4887Schin ***********************************************************************/ 22*4887Schin #pragma prototyped 23*4887Schin /* 24*4887Schin * Glenn Fowler 25*4887Schin * AT&T Bell Laboratories 26*4887Schin * 27*4887Schin * hash table library 28*4887Schin */ 29*4887Schin 30*4887Schin #include "hashlib.h" 31*4887Schin 32*4887Schin /* 33*4887Schin * return a running 32 bit checksum of buffer b of length n 34*4887Schin * 35*4887Schin * c is the return value from a previous 36*4887Schin * memsum() or strsum() call, 0 on the first call 37*4887Schin * 38*4887Schin * the result is the same on all implementations 39*4887Schin */ 40*4887Schin 41*4887Schin unsigned long 42*4887Schin memsum(const void* ap, int n, register unsigned long c) 43*4887Schin { 44*4887Schin register const unsigned char* p = (const unsigned char*)ap; 45*4887Schin register const unsigned char* e = p + n; 46*4887Schin 47*4887Schin while (p < e) HASHPART(c, *p++); 48*4887Schin #if LONG_MAX > 2147483647 49*4887Schin return(c & 0xffffffff); 50*4887Schin #else 51*4887Schin return(c); 52*4887Schin #endif 53*4887Schin } 54