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authorReinhard Tartler <siretart@tauware.de>2011-10-10 17:43:39 +0200
committerReinhard Tartler <siretart@tauware.de>2011-10-10 17:43:39 +0200
commitf4092abdf94af6a99aff944d6264bc1284e8bdd4 (patch)
tree2ac1c9cc16ceb93edb2c4382c088dac5aeafdf0f /nx-X11/extras/zlib/adler32.c
parenta840692edc9c6d19cd7c057f68e39c7d95eb767d (diff)
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Summary: Imported nx-X11-3.1.0-1.tar.gz Keywords: Imported nx-X11-3.1.0-1.tar.gz into Git repository
Diffstat (limited to 'nx-X11/extras/zlib/adler32.c')
-rw-r--r--nx-X11/extras/zlib/adler32.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/nx-X11/extras/zlib/adler32.c b/nx-X11/extras/zlib/adler32.c
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+++ b/nx-X11/extras/zlib/adler32.c
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+/* 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
+ */
+
+#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);
+
+/* ========================================================================= */
+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 ? 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;
+}