/* adler32.c -- compute the Adler-32 checksum of a data stream
		 * Copyright (C) 1995-2003 Mark Adler
		 * For conditions of distribution and use, see copyright notice in zlib.h
		 */
		
		/* @(#) $Id$ */
		
		#define ZLIB_INTERNAL
		#include "zlib.h"
		
		#define BASE 65521UL    /* largest prime smaller than 65536 */
		#define NMAX 5552
		/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
		
		#define DO1(buf,i)  {s1 += buf[i]; s2 += s1;}
		#define DO2(buf,i)  DO1(buf,i); DO1(buf,i+1);
		#define DO4(buf,i)  DO2(buf,i); DO2(buf,i+2);
		#define DO8(buf,i)  DO4(buf,i); DO4(buf,i+4);
		#define DO16(buf)   DO8(buf,0); DO8(buf,8);
		
		#ifdef NO_DIVIDE
		#  define MOD(a) \
		    do { \
		        if (a >= (BASE << 16)) a -= (BASE << 16); \
		        if (a >= (BASE << 15)) a -= (BASE << 15); \
		        if (a >= (BASE << 14)) a -= (BASE << 14); \
		        if (a >= (BASE << 13)) a -= (BASE << 13); \
		        if (a >= (BASE << 12)) a -= (BASE << 12); \
		        if (a >= (BASE << 11)) a -= (BASE << 11); \
		        if (a >= (BASE << 10)) a -= (BASE << 10); \
		        if (a >= (BASE << 9)) a -= (BASE << 9); \
		        if (a >= (BASE << 8)) a -= (BASE << 8); \
		        if (a >= (BASE << 7)) a -= (BASE << 7); \
		        if (a >= (BASE << 6)) a -= (BASE << 6); \
		        if (a >= (BASE << 5)) a -= (BASE << 5); \
		        if (a >= (BASE << 4)) a -= (BASE << 4); \
		        if (a >= (BASE << 3)) a -= (BASE << 3); \
		        if (a >= (BASE << 2)) a -= (BASE << 2); \
		        if (a >= (BASE << 1)) a -= (BASE << 1); \
		        if (a >= BASE) a -= BASE; \
		    } while (0)
		#else
		#  define MOD(a) a %= BASE
		#endif
		
		/* ========================================================================= */
		uLong ZEXPORT adler32(adler, buf, len)
		    uLong adler;
		    const Bytef *buf;
		    uInt len;
         278    {
         278        unsigned long s1 = adler & 0xffff;
         278        unsigned long s2 = (adler >> 16) & 0xffff;
         278        int k;
		
         278        if (buf == Z_NULL) return 1L;
		
         352        while (len > 0) {
         203            k = len < NMAX ? (int)len : NMAX;
         203            len -= k;
       24146            while (k >= 16) {
       23943                DO16(buf);
       23943                buf += 16;
       23943                k -= 16;
		        }
         203            if (k != 0) do {
         556                s1 += *buf++;
         556                s2 += s1;
         556            } while (--k);
         203            MOD(s1);
         203            MOD(s2);
		    }
         149        return (s2 << 16) | s1;
		}