1.1 --- a/compiler-init/zlib/adler32.c Sat Jul 15 05:02:38 2006 +0000
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,149 +0,0 @@
1.4 -/* adler32.c -- compute the Adler-32 checksum of a data stream
1.5 - * Copyright (C) 1995-2004 Mark Adler
1.6 - * For conditions of distribution and use, see copyright notice in zlib.h
1.7 - */
1.8 -
1.9 -/* @(#) $Id$ */
1.10 -
1.11 -#define ZLIB_INTERNAL
1.12 -#include "zlib.h"
1.13 -
1.14 -#define BASE 65521UL /* largest prime smaller than 65536 */
1.15 -#define NMAX 5552
1.16 -/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
1.17 -
1.18 -#define DO1(buf,i) {adler += (buf)[i]; sum2 += adler;}
1.19 -#define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);
1.20 -#define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);
1.21 -#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);
1.22 -#define DO16(buf) DO8(buf,0); DO8(buf,8);
1.23 -
1.24 -/* use NO_DIVIDE if your processor does not do division in hardware */
1.25 -#ifdef NO_DIVIDE
1.26 -# define MOD(a) \
1.27 - do { \
1.28 - if (a >= (BASE << 16)) a -= (BASE << 16); \
1.29 - if (a >= (BASE << 15)) a -= (BASE << 15); \
1.30 - if (a >= (BASE << 14)) a -= (BASE << 14); \
1.31 - if (a >= (BASE << 13)) a -= (BASE << 13); \
1.32 - if (a >= (BASE << 12)) a -= (BASE << 12); \
1.33 - if (a >= (BASE << 11)) a -= (BASE << 11); \
1.34 - if (a >= (BASE << 10)) a -= (BASE << 10); \
1.35 - if (a >= (BASE << 9)) a -= (BASE << 9); \
1.36 - if (a >= (BASE << 8)) a -= (BASE << 8); \
1.37 - if (a >= (BASE << 7)) a -= (BASE << 7); \
1.38 - if (a >= (BASE << 6)) a -= (BASE << 6); \
1.39 - if (a >= (BASE << 5)) a -= (BASE << 5); \
1.40 - if (a >= (BASE << 4)) a -= (BASE << 4); \
1.41 - if (a >= (BASE << 3)) a -= (BASE << 3); \
1.42 - if (a >= (BASE << 2)) a -= (BASE << 2); \
1.43 - if (a >= (BASE << 1)) a -= (BASE << 1); \
1.44 - if (a >= BASE) a -= BASE; \
1.45 - } while (0)
1.46 -# define MOD4(a) \
1.47 - do { \
1.48 - if (a >= (BASE << 4)) a -= (BASE << 4); \
1.49 - if (a >= (BASE << 3)) a -= (BASE << 3); \
1.50 - if (a >= (BASE << 2)) a -= (BASE << 2); \
1.51 - if (a >= (BASE << 1)) a -= (BASE << 1); \
1.52 - if (a >= BASE) a -= BASE; \
1.53 - } while (0)
1.54 -#else
1.55 -# define MOD(a) a %= BASE
1.56 -# define MOD4(a) a %= BASE
1.57 -#endif
1.58 -
1.59 -/* ========================================================================= */
1.60 -uLong ZEXPORT adler32(adler, buf, len)
1.61 - uLong adler;
1.62 - const Bytef *buf;
1.63 - uInt len;
1.64 -{
1.65 - unsigned long sum2;
1.66 - unsigned n;
1.67 -
1.68 - /* split Adler-32 into component sums */
1.69 - sum2 = (adler >> 16) & 0xffff;
1.70 - adler &= 0xffff;
1.71 -
1.72 - /* in case user likes doing a byte at a time, keep it fast */
1.73 - if (len == 1) {
1.74 - adler += buf[0];
1.75 - if (adler >= BASE)
1.76 - adler -= BASE;
1.77 - sum2 += adler;
1.78 - if (sum2 >= BASE)
1.79 - sum2 -= BASE;
1.80 - return adler | (sum2 << 16);
1.81 - }
1.82 -
1.83 - /* initial Adler-32 value (deferred check for len == 1 speed) */
1.84 - if (buf == Z_NULL)
1.85 - return 1L;
1.86 -
1.87 - /* in case short lengths are provided, keep it somewhat fast */
1.88 - if (len < 16) {
1.89 - while (len--) {
1.90 - adler += *buf++;
1.91 - sum2 += adler;
1.92 - }
1.93 - if (adler >= BASE)
1.94 - adler -= BASE;
1.95 - MOD4(sum2); /* only added so many BASE's */
1.96 - return adler | (sum2 << 16);
1.97 - }
1.98 -
1.99 - /* do length NMAX blocks -- requires just one modulo operation */
1.100 - while (len >= NMAX) {
1.101 - len -= NMAX;
1.102 - n = NMAX / 16; /* NMAX is divisible by 16 */
1.103 - do {
1.104 - DO16(buf); /* 16 sums unrolled */
1.105 - buf += 16;
1.106 - } while (--n);
1.107 - MOD(adler);
1.108 - MOD(sum2);
1.109 - }
1.110 -
1.111 - /* do remaining bytes (less than NMAX, still just one modulo) */
1.112 - if (len) { /* avoid modulos if none remaining */
1.113 - while (len >= 16) {
1.114 - len -= 16;
1.115 - DO16(buf);
1.116 - buf += 16;
1.117 - }
1.118 - while (len--) {
1.119 - adler += *buf++;
1.120 - sum2 += adler;
1.121 - }
1.122 - MOD(adler);
1.123 - MOD(sum2);
1.124 - }
1.125 -
1.126 - /* return recombined sums */
1.127 - return adler | (sum2 << 16);
1.128 -}
1.129 -
1.130 -/* ========================================================================= */
1.131 -uLong ZEXPORT adler32_combine(adler1, adler2, len2)
1.132 - uLong adler1;
1.133 - uLong adler2;
1.134 - z_off_t len2;
1.135 -{
1.136 - unsigned long sum1;
1.137 - unsigned long sum2;
1.138 - unsigned rem;
1.139 -
1.140 - /* the derivation of this formula is left as an exercise for the reader */
1.141 - rem = (unsigned)(len2 % BASE);
1.142 - sum1 = adler1 & 0xffff;
1.143 - sum2 = rem * sum1;
1.144 - MOD(sum2);
1.145 - sum1 += (adler2 & 0xffff) + BASE - 1;
1.146 - sum2 += ((adler1 >> 16) & 0xffff) + ((adler2 >> 16) & 0xffff) + BASE - rem;
1.147 - if (sum1 > BASE) sum1 -= BASE;
1.148 - if (sum1 > BASE) sum1 -= BASE;
1.149 - if (sum2 > (BASE << 1)) sum2 -= (BASE << 1);
1.150 - if (sum2 > BASE) sum2 -= BASE;
1.151 - return sum1 | (sum2 << 16);
1.152 -}
