X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=syslinux%2Fcom32%2Flib%2Fzlib%2Fadler32.c;fp=syslinux%2Fcom32%2Flib%2Fzlib%2Fadler32.c;h=690f062d9abeb85fde266e88229df0ef4eba2081;hb=25c2eed0b59c2ef09e0bdf9694bcbb63984256cb;hp=0000000000000000000000000000000000000000;hpb=ef6997700c4a74c994e99c0eb06c5ccab2ee990b;p=bootcd.git diff --git a/syslinux/com32/lib/zlib/adler32.c b/syslinux/com32/lib/zlib/adler32.c new file mode 100644 index 0000000..690f062 --- /dev/null +++ b/syslinux/com32/lib/zlib/adler32.c @@ -0,0 +1,74 @@ +/* adler32.c -- compute the Adler-32 checksum of a data stream + * Copyright (C) 1995-2003 Mark Adler + * For conditions of distribution and use, see copyright notice in zlib.h + */ + +/* @(#) $Id: adler32.c,v 1.1 2005/01/08 05:38:12 hpa Exp $ */ + +#define ZLIB_INTERNAL +#include "zlib.h" + +#define BASE 65521UL /* 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); + +#ifdef NO_DIVIDE +# define MOD(a) \ + do { \ + if (a >= (BASE << 16)) a -= (BASE << 16); \ + if (a >= (BASE << 15)) a -= (BASE << 15); \ + if (a >= (BASE << 14)) a -= (BASE << 14); \ + if (a >= (BASE << 13)) a -= (BASE << 13); \ + if (a >= (BASE << 12)) a -= (BASE << 12); \ + if (a >= (BASE << 11)) a -= (BASE << 11); \ + if (a >= (BASE << 10)) a -= (BASE << 10); \ + if (a >= (BASE << 9)) a -= (BASE << 9); \ + if (a >= (BASE << 8)) a -= (BASE << 8); \ + if (a >= (BASE << 7)) a -= (BASE << 7); \ + if (a >= (BASE << 6)) a -= (BASE << 6); \ + if (a >= (BASE << 5)) a -= (BASE << 5); \ + if (a >= (BASE << 4)) a -= (BASE << 4); \ + if (a >= (BASE << 3)) a -= (BASE << 3); \ + if (a >= (BASE << 2)) a -= (BASE << 2); \ + if (a >= (BASE << 1)) a -= (BASE << 1); \ + if (a >= BASE) a -= BASE; \ + } while (0) +#else +# define MOD(a) a %= BASE +#endif + +/* ========================================================================= */ +uLong ZEXPORT 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 ? (int)len : NMAX; + len -= k; + while (k >= 16) { + DO16(buf); + buf += 16; + k -= 16; + } + if (k != 0) do { + s1 += *buf++; + s2 += s1; + } while (--k); + MOD(s1); + MOD(s2); + } + return (s2 << 16) | s1; +}