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/* adler32.c -- compute the Adler-32 checksum of a data stream
* Copyright (C) 1995-2011, 2016 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/* @(#) $Id$ */
#include "zutil.h"
local uLong adler32_combine_ OF((uLong adler1, uLong adler2, z_off64_t len2));
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/* adler32.c -- compute the Adler-32 checksum of a data stream
* Copyright (C) 1995-2011, 2016 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/* @(#) $Id$ */
#include "zutil.h"
#define BASE 65521U /* 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) {adler += (buf)[i]; sum2 += adler;}
#define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);
#define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);
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#else
# define MOD(a) a %= BASE
# define MOD28(a) a %= BASE
# define MOD63(a) a %= BASE
#endif
/* ========================================================================= */
uLong ZEXPORT adler32_z(adler, buf, len)
uLong adler;
const Bytef *buf;
z_size_t len;
{
unsigned long sum2;
unsigned n;
/* split Adler-32 into component sums */
sum2 = (adler >> 16) & 0xffff;
adler &= 0xffff;
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#else
# define MOD(a) a %= BASE
# define MOD28(a) a %= BASE
# define MOD63(a) a %= BASE
#endif
/* ========================================================================= */
uLong ZEXPORT adler32_z(uLong adler, const Bytef *buf, z_size_t len) {
unsigned long sum2;
unsigned n;
/* split Adler-32 into component sums */
sum2 = (adler >> 16) & 0xffff;
adler &= 0xffff;
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}
/* return recombined sums */
return adler | (sum2 << 16);
}
/* ========================================================================= */
uLong ZEXPORT adler32(adler, buf, len)
uLong adler;
const Bytef *buf;
uInt len;
{
return adler32_z(adler, buf, len);
}
/* ========================================================================= */
local uLong adler32_combine_(adler1, adler2, len2)
uLong adler1;
uLong adler2;
z_off64_t len2;
{
unsigned long sum1;
unsigned long sum2;
unsigned rem;
/* for negative len, return invalid adler32 as a clue for debugging */
if (len2 < 0)
return 0xffffffffUL;
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}
/* return recombined sums */
return adler | (sum2 << 16);
}
/* ========================================================================= */
uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len) {
return adler32_z(adler, buf, len);
}
/* ========================================================================= */
local uLong adler32_combine_(uLong adler1, uLong adler2, z_off64_t len2) {
unsigned long sum1;
unsigned long sum2;
unsigned rem;
/* for negative len, return invalid adler32 as a clue for debugging */
if (len2 < 0)
return 0xffffffffUL;
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if (sum1 >= BASE) sum1 -= BASE;
if (sum2 >= ((unsigned long)BASE << 1)) sum2 -= ((unsigned long)BASE << 1);
if (sum2 >= BASE) sum2 -= BASE;
return sum1 | (sum2 << 16);
}
/* ========================================================================= */
uLong ZEXPORT adler32_combine(adler1, adler2, len2)
uLong adler1;
uLong adler2;
z_off_t len2;
{
return adler32_combine_(adler1, adler2, len2);
}
uLong ZEXPORT adler32_combine64(adler1, adler2, len2)
uLong adler1;
uLong adler2;
z_off64_t len2;
{
return adler32_combine_(adler1, adler2, len2);
}
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if (sum1 >= BASE) sum1 -= BASE;
if (sum2 >= ((unsigned long)BASE << 1)) sum2 -= ((unsigned long)BASE << 1);
if (sum2 >= BASE) sum2 -= BASE;
return sum1 | (sum2 << 16);
}
/* ========================================================================= */
uLong ZEXPORT adler32_combine(uLong adler1, uLong adler2, z_off_t len2) {
return adler32_combine_(adler1, adler2, len2);
}
uLong ZEXPORT adler32_combine64(uLong adler1, uLong adler2, z_off64_t len2) {
return adler32_combine_(adler1, adler2, len2);
}
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