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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 | ||
*/ | ||
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/* @(#) $Id$ */ | ||
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#include "zutil.h" | ||
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#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 */ | ||
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#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); | ||
#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4); | ||
#define DO16(buf) DO8(buf,0); DO8(buf,8); | ||
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/* use NO_DIVIDE if your processor does not do division in hardware -- | ||
try it both ways to see which is faster */ | ||
#ifdef NO_DIVIDE | ||
/* note that this assumes BASE is 65521, where 65536 % 65521 == 15 | ||
(thank you to John Reiser for pointing this out) */ | ||
# define CHOP(a) \ | ||
do { \ | ||
unsigned long tmp = a >> 16; \ | ||
a &= 0xffffUL; \ | ||
a += (tmp << 4) - tmp; \ | ||
} while (0) | ||
# define MOD28(a) \ | ||
do { \ | ||
CHOP(a); \ | ||
if (a >= BASE) a -= BASE; \ | ||
} while (0) | ||
# define MOD(a) \ | ||
do { \ | ||
CHOP(a); \ | ||
MOD28(a); \ | ||
} while (0) | ||
# define MOD63(a) \ | ||
do { /* this assumes a is not negative */ \ | ||
z_off64_t tmp = a >> 32; \ | ||
a &= 0xffffffffL; \ | ||
a += (tmp << 8) - (tmp << 5) + tmp; \ | ||
tmp = a >> 16; \ | ||
a &= 0xffffL; \ | ||
a += (tmp << 4) - tmp; \ | ||
tmp = a >> 16; \ | ||
a &= 0xffffL; \ | ||
a += (tmp << 4) - tmp; \ | ||
if (a >= BASE) a -= BASE; \ | ||
} while (0) | ||
#else | ||
# define MOD(a) a %= BASE | ||
# define MOD28(a) a %= BASE | ||
# define MOD63(a) a %= BASE | ||
#endif | ||
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/* ========================================================================= */ | ||
uLong ZEXPORT adler32_z(uLong adler, const Bytef *buf, z_size_t len) { | ||
unsigned long sum2; | ||
unsigned n; | ||
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/* split Adler-32 into component sums */ | ||
sum2 = (adler >> 16) & 0xffff; | ||
adler &= 0xffff; | ||
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/* in case user likes doing a byte at a time, keep it fast */ | ||
if (len == 1) { | ||
adler += buf[0]; | ||
if (adler >= BASE) | ||
adler -= BASE; | ||
sum2 += adler; | ||
if (sum2 >= BASE) | ||
sum2 -= BASE; | ||
return adler | (sum2 << 16); | ||
} | ||
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/* initial Adler-32 value (deferred check for len == 1 speed) */ | ||
if (buf == Z_NULL) | ||
return 1L; | ||
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/* in case short lengths are provided, keep it somewhat fast */ | ||
if (len < 16) { | ||
while (len--) { | ||
adler += *buf++; | ||
sum2 += adler; | ||
} | ||
if (adler >= BASE) | ||
adler -= BASE; | ||
MOD28(sum2); /* only added so many BASE's */ | ||
return adler | (sum2 << 16); | ||
} | ||
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/* do length NMAX blocks -- requires just one modulo operation */ | ||
while (len >= NMAX) { | ||
len -= NMAX; | ||
n = NMAX / 16; /* NMAX is divisible by 16 */ | ||
do { | ||
DO16(buf); /* 16 sums unrolled */ | ||
buf += 16; | ||
} while (--n); | ||
MOD(adler); | ||
MOD(sum2); | ||
} | ||
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/* do remaining bytes (less than NMAX, still just one modulo) */ | ||
if (len) { /* avoid modulos if none remaining */ | ||
while (len >= 16) { | ||
len -= 16; | ||
DO16(buf); | ||
buf += 16; | ||
} | ||
while (len--) { | ||
adler += *buf++; | ||
sum2 += adler; | ||
} | ||
MOD(adler); | ||
MOD(sum2); | ||
} | ||
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/* return recombined sums */ | ||
return adler | (sum2 << 16); | ||
} | ||
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/* ========================================================================= */ | ||
uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len) { | ||
return adler32_z(adler, buf, len); | ||
} | ||
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/* ========================================================================= */ | ||
local uLong adler32_combine_(uLong adler1, uLong adler2, z_off64_t len2) { | ||
unsigned long sum1; | ||
unsigned long sum2; | ||
unsigned rem; | ||
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/* for negative len, return invalid adler32 as a clue for debugging */ | ||
if (len2 < 0) | ||
return 0xffffffffUL; | ||
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/* the derivation of this formula is left as an exercise for the reader */ | ||
MOD63(len2); /* assumes len2 >= 0 */ | ||
rem = (unsigned)len2; | ||
sum1 = adler1 & 0xffff; | ||
sum2 = rem * sum1; | ||
MOD(sum2); | ||
sum1 += (adler2 & 0xffff) + BASE - 1; | ||
sum2 += ((adler1 >> 16) & 0xffff) + ((adler2 >> 16) & 0xffff) + BASE - rem; | ||
if (sum1 >= BASE) sum1 -= BASE; | ||
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); | ||
} | ||
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/* ========================================================================= */ | ||
uLong ZEXPORT adler32_combine(uLong adler1, uLong adler2, z_off_t len2) { | ||
return adler32_combine_(adler1, adler2, len2); | ||
} | ||
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uLong ZEXPORT adler32_combine64(uLong adler1, uLong adler2, z_off64_t len2) { | ||
return adler32_combine_(adler1, adler2, len2); | ||
} |
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/* compress.c -- compress a memory buffer | ||
* Copyright (C) 1995-2005, 2014, 2016 Jean-loup Gailly, Mark Adler | ||
* For conditions of distribution and use, see copyright notice in zlib.h | ||
*/ | ||
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/* @(#) $Id$ */ | ||
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#define ZLIB_INTERNAL | ||
#include "zlib.h" | ||
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/* =========================================================================== | ||
Compresses the source buffer into the destination buffer. The level | ||
parameter has the same meaning as in deflateInit. sourceLen is the byte | ||
length of the source buffer. Upon entry, destLen is the total size of the | ||
destination buffer, which must be at least 0.1% larger than sourceLen plus | ||
12 bytes. Upon exit, destLen is the actual size of the compressed buffer. | ||
compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough | ||
memory, Z_BUF_ERROR if there was not enough room in the output buffer, | ||
Z_STREAM_ERROR if the level parameter is invalid. | ||
*/ | ||
int ZEXPORT compress2(Bytef *dest, uLongf *destLen, const Bytef *source, | ||
uLong sourceLen, int level) { | ||
z_stream stream; | ||
int err; | ||
const uInt max = (uInt)-1; | ||
uLong left; | ||
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left = *destLen; | ||
*destLen = 0; | ||
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stream.zalloc = (alloc_func)0; | ||
stream.zfree = (free_func)0; | ||
stream.opaque = (voidpf)0; | ||
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err = deflateInit(&stream, level); | ||
if (err != Z_OK) return err; | ||
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stream.next_out = dest; | ||
stream.avail_out = 0; | ||
stream.next_in = (z_const Bytef *)source; | ||
stream.avail_in = 0; | ||
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do { | ||
if (stream.avail_out == 0) { | ||
stream.avail_out = left > (uLong)max ? max : (uInt)left; | ||
left -= stream.avail_out; | ||
} | ||
if (stream.avail_in == 0) { | ||
stream.avail_in = sourceLen > (uLong)max ? max : (uInt)sourceLen; | ||
sourceLen -= stream.avail_in; | ||
} | ||
err = deflate(&stream, sourceLen ? Z_NO_FLUSH : Z_FINISH); | ||
} while (err == Z_OK); | ||
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*destLen = stream.total_out; | ||
deflateEnd(&stream); | ||
return err == Z_STREAM_END ? Z_OK : err; | ||
} | ||
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/* =========================================================================== | ||
*/ | ||
int ZEXPORT compress(Bytef *dest, uLongf *destLen, const Bytef *source, | ||
uLong sourceLen) { | ||
return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION); | ||
} | ||
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/* =========================================================================== | ||
If the default memLevel or windowBits for deflateInit() is changed, then | ||
this function needs to be updated. | ||
*/ | ||
uLong ZEXPORT compressBound(uLong sourceLen) { | ||
return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + | ||
(sourceLen >> 25) + 13; | ||
} |
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