diff options
Diffstat (limited to 'lib/zlib/src/adler32.c')
-rw-r--r-- | lib/zlib/src/adler32.c | 96 |
1 files changed, 48 insertions, 48 deletions
diff --git a/lib/zlib/src/adler32.c b/lib/zlib/src/adler32.c index f900609..eeffe9b 100644 --- a/lib/zlib/src/adler32.c +++ b/lib/zlib/src/adler32.c @@ -1,48 +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: adler32.c,v 1.1 2003-09-14 18:16:26 pixel Exp $ */ - -#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; -} +/* 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: adler32.c,v 1.2 2004-11-27 21:35:22 pixel Exp $ */
+
+#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;
+}
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