misc/libfreetype/src/gzip/adler32.c
author koda
Mon, 17 Jun 2013 17:40:01 +0200
changeset 9234 2bf3796c5855
parent 5172 88f2e05288ba
permissions -rw-r--r--
This commit changes many aspect of our cmake build system - shared libraries are compiled by default: * this modifies RPATH of unix executables; * this will prevent a lot of linking issues, esp. from pascal world; * the old behaviour (static libs) is still available with -DBUILD_SHARED_LIBS=off; * of course in this case you have to provide the full list of dependencies with FPFLAGS and CMAKE_C_FLAGS; - pascal is now fully integrated with cmake, meaning you can just do add_sources and use CMAKE_Pascal_FLAGS: * some of the language features are only partially implemented, for example .inc files will not get rebuilt if you modify them; * target_link_libraries for pascal targets is just dummy as linking is determined within pascal files; * universal builds for osx are not available any more; - bundled libraries and system libraries are addressed using the target name: * this avoids depedency tracking; * this allows to name output as we wish.

/* 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;
}