diff options
Diffstat (limited to 'Build/source/libs/freetype2/freetype-2.6/src/gzip/adler32.c')
-rw-r--r-- | Build/source/libs/freetype2/freetype-2.6/src/gzip/adler32.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/Build/source/libs/freetype2/freetype-2.6/src/gzip/adler32.c b/Build/source/libs/freetype2/freetype-2.6/src/gzip/adler32.c new file mode 100644 index 00000000000..c53f9dd125d --- /dev/null +++ b/Build/source/libs/freetype2/freetype-2.6/src/gzip/adler32.c @@ -0,0 +1,48 @@ +/* adler32.c -- compute the Adler-32 checksum of a data stream + * Copyright (C) 1995-2002 Mark Adler + * For conditions of distribution and use, see copyright notice in zlib.h + */ + +/* @(#) $Id$ */ + +#include "zlib.h" + +#define BASE 65521L /* 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); + +/* ========================================================================= */ +ZEXPORT(uLong) adler32( /* adler, buf, len) */ + uLong adler, + const Bytef *buf, + uInt len ) +{ + unsigned long s1 = adler & 0xffff; + unsigned long s2 = (adler >> 16) & 0xffff; + int k; + + if (buf == Z_NULL) return 1L; + + while (len > 0) { + k = len < NMAX ? len : NMAX; + len -= k; + while (k >= 16) { + DO16(buf); + buf += 16; + k -= 16; + } + if (k != 0) do { + s1 += *buf++; + s2 += s1; + } while (--k); + s1 %= BASE; + s2 %= BASE; + } + return (s2 << 16) | s1; +} |