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authorIgor Pashev <pashev.igor@gmail.com>2012-06-24 22:28:35 +0000
committerIgor Pashev <pashev.igor@gmail.com>2012-06-24 22:28:35 +0000
commit3950ffe2a485479f6561c27364d3d7df5a21d124 (patch)
tree468c6e14449d1b1e279222ec32f676b0311917d2 /src/lib/libast/include/hashpart.h
downloadksh-upstream.tar.gz
Imported Upstream version 93u+upstream
Diffstat (limited to 'src/lib/libast/include/hashpart.h')
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1 files changed, 51 insertions, 0 deletions
diff --git a/src/lib/libast/include/hashpart.h b/src/lib/libast/include/hashpart.h
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+++ b/src/lib/libast/include/hashpart.h
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+/***********************************************************************
+* *
+* This software is part of the ast package *
+* Copyright (c) 1985-2011 AT&T Intellectual Property *
+* and is licensed under the *
+* Eclipse Public License, Version 1.0 *
+* by AT&T Intellectual Property *
+* *
+* A copy of the License is available at *
+* http://www.eclipse.org/org/documents/epl-v10.html *
+* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
+* *
+* Information and Software Systems Research *
+* AT&T Research *
+* Florham Park NJ *
+* *
+* Glenn Fowler <gsf@research.att.com> *
+* David Korn <dgk@research.att.com> *
+* Phong Vo <kpv@research.att.com> *
+* *
+***********************************************************************/
+#pragma prototyped
+/*
+ * K. P. Vo
+ * G. S. Fowler
+ * AT&T Research
+ *
+ * ``the best'' combined linear congruent checksum/hash/PRNG
+ */
+
+#ifndef _HASHPART_H
+#define _HASHPART_H
+
+#define HASH_ADD(h) (0x9c39c33dL)
+
+#if __sparc__ || __sparc || sparc
+
+#define HASH_A(h,n) ((((h) << 2) - (h)) << (n))
+#define HASH_B(h,n) ((((h) << 4) - (h)) << (n))
+#define HASH_C(h,n) ((HASH_A(h,7) + HASH_B(h,0)) << (n))
+#define HASH_MPY(h) (HASH_C(h,22)+HASH_C(h,10)+HASH_A(h,6)+HASH_A(h,3)+(h))
+
+#else
+
+#define HASH_MPY(h) ((h)*0x63c63cd9L)
+
+#endif
+
+#define HASHPART(h,c) (h = HASH_MPY(h) + HASH_ADD(h) + (c))
+
+#endif