Import Dev86src-0.0.11.tar.gzv0.0.11

1 files changed, 54 insertions, 0 deletions

diff --git a/unproto/hash.c b/unproto/hash.c
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+/*++
+/* NAME
+/*	hash 3
+/* SUMMARY
+/*	compute hash value for string
+/* SYNOPSIS
+/*	int hash(string, size)
+/*	char *string;
+/*	int size;
+/* DESCRIPTION
+/*	This function computes for the given null-terminated string an
+/*	integer hash value in the range 0..size-1.
+/* SEE ALSO
+/* .fi
+/*	Alfred V. Aho, Ravi Sethi and Jeffrey D. Ullman: Compilers: 
+/*	principles, techniques and tools; Addison-Wesley, Amsterdam, 1986.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	Eindhoven University of Technology
+/*	Department of Mathematics and Computer Science
+/*	Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
+/*
+/*	Originally written by: P. J. Weinberger at Bell Labs.
+/* LAST MODIFICATION
+/*	92/01/15 21:53:12
+/* VERSION/RELEASE
+/*	%I
+/*--*/
+
+static char hash_sccsid[] = "@(#) hash.c 1.1 92/01/15 21:53:12";
+
+/* hash - hash a string; original author: P. J. Weinberger at Bell Labs. */
+
+int     hash(s, size)
+register char *s;
+unsigned size;
+{
+    register unsigned long h = 0;
+    register unsigned long g;
+
+    /*
+     * For a performance comparison with the hash function presented in K&R,
+     * first edition, see the "Dragon" book by Aho, Sethi and Ullman.
+     */
+
+    while (*s) {
+	h = (h << 4) + *s++;
+	if (g = (h & 0xf0000000)) {
+	    h ^= (g >> 24);
+	    h ^= g;
+	}
+    }
+    return (h % size);
+}