From 7795edd6c683a5b82701cfa825304ac48bf79fef Mon Sep 17 00:00:00 2001 From: Jean-André Santoni Date: Sun, 13 Jan 2019 11:12:32 +0700 Subject: Embed zlib --- deps/adler32.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 deps/adler32.c (limited to 'deps/adler32.c') diff --git a/deps/adler32.c b/deps/adler32.c new file mode 100644 index 0000000..cccb3a2 --- /dev/null +++ b/deps/adler32.c @@ -0,0 +1,75 @@ +/* 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 + */ + +/* @(#) $Id$ */ + +#define ZLIB_INTERNAL +#include +#include +#include "zutil.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 adler32(uLong adler, const Bytef *buf, uInt len) +{ + uint32_t s1 = adler & 0xffff; + uint32_t s2 = (adler >> 16) & 0xffff; + int k; + + if (buf == 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; +} + -- cgit v1.2.3