| 1 | /* adler32.c -- compute the Adler-32 checksum of a data stream
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| 2 | * Copyright (C) 1995-2002 Mark Adler
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| 3 | * For conditions of distribution and use, see copyright notice in zlib.h
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| 4 | */
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| 5 |
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| 6 | /* @(#) $Id: adler32.c,v 1.1.1.2 2002/03/11 21:53:23 tromey Exp $ */
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| 7 |
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| 8 | #include "zlib.h"
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| 9 |
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| 10 | #define BASE 65521L /* largest prime smaller than 65536 */
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| 11 | #define NMAX 5552
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| 12 | /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
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| 13 |
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| 14 | #define DO1(buf,i) {s1 += buf[i]; s2 += s1;}
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| 15 | #define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);
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| 16 | #define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);
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| 17 | #define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);
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| 18 | #define DO16(buf) DO8(buf,0); DO8(buf,8);
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| 19 |
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| 20 | /* ========================================================================= */
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| 21 | uLong ZEXPORT adler32(adler, buf, len)
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| 22 | uLong adler;
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| 23 | const Bytef *buf;
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| 24 | uInt len;
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| 25 | {
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