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path: root/pwmanager/libcrypt/zlib/adler32.c
authorzautrix <zautrix>2004-10-19 20:16:14 (UTC)
committer zautrix <zautrix>2004-10-19 20:16:14 (UTC)
commiteca49bb06a71980ef61d078904573f25890fc7f2 (patch) (side-by-side diff)
treec5338e3b12430248979a9ac2c1c7e6646ea9ecdf /pwmanager/libcrypt/zlib/adler32.c
parent53cc32b6e7b1f672bf91b2baf2df6c1e8baf3e0a (diff)
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Initial revision
Diffstat (limited to 'pwmanager/libcrypt/zlib/adler32.c') (more/less context) (ignore whitespace changes)
-rw-r--r--pwmanager/libcrypt/zlib/adler32.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/pwmanager/libcrypt/zlib/adler32.c b/pwmanager/libcrypt/zlib/adler32.c
new file mode 100644
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+++ b/pwmanager/libcrypt/zlib/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);
+
+/* ========================================================================= */
+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;
+}