memsum.c revision 3e14f97f673e8a630f076077de35afdd43dc1587
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2010 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Glenn Fowler
* AT&T Bell Laboratories
*
* hash table library
*/
#include "hashlib.h"
/*
* return a running 32 bit checksum of buffer b of length n
*
* c is the return value from a previous
* memsum() or strsum() call, 0 on the first call
*
* the result is the same on all implementations
*/
unsigned long
{
register const unsigned char* p = (const unsigned char*)ap;
register const unsigned char* e = p + n;
while (p < e) HASHPART(c, *p++);
#if LONG_MAX > 2147483647
return(c & 0xffffffff);
#else
return(c);
#endif
}