From 37da2899f40661e3e9631e497da8dc59b971cbd0 Mon Sep 17 00:00:00 2001
From: "Charles.Forsyth" <devnull@localhost>
Date: Fri, 22 Dec 2006 17:07:39 +0000
Subject: 20060303a

---
 appl/lib/hash.b | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 appl/lib/hash.b

(limited to 'appl/lib/hash.b')

diff --git a/appl/lib/hash.b b/appl/lib/hash.b
new file mode 100644
index 00000000..a039e2dc
--- /dev/null
+++ b/appl/lib/hash.b
@@ -0,0 +1,80 @@
+# ehg@research.bell-labs.com 14Dec1996
+implement Hash;
+
+include "hash.m";
+
+# from Aho Hopcroft Ullman
+fun1(s:string, n:int):int
+{
+	h := 0;
+	m := len s;
+	for(i:=0; i<m; i++){
+		h = 65599*h+s[i];
+	}
+	return (h & 16r7fffffff) % n;
+}
+
+# from Limbo compiler
+fun2(s:string, n:int):int
+{
+	h := 0;
+	m := len s;
+	for(i := 0; i < m; i++){
+		c := s[i];
+		d := c;
+		c ^= c << 6;
+		h += (c << 11) ^ (c >> 1);
+		h ^= (d << 14) + (d << 7) + (d << 4) + d;
+	}
+	return (h & 16r7fffffff) % n;
+}
+
+new(size: int):ref HashTable
+{
+	return ref HashTable(array[size] of list of HashNode);
+}
+
+HashTable.find(h: self ref HashTable, key: string): ref HashVal
+{
+	j := fun1(key,len h.a);
+	for(q := h.a[j]; q!=nil; q = tl q){
+		if((hd q).key==key)
+			return (hd q).val;
+	}
+	return nil;
+}
+
+HashTable.insert(h: self ref HashTable, key: string, val: HashVal)
+{
+	j := fun1(key,len h.a);
+	for(q := h.a[j]; q!=nil; q = tl q){
+		if((hd q).key==key){
+			p := (hd q).val;
+			p.i = val.i;
+			p.r = val.r;
+			p.s = val.s;
+			return;
+		}
+	}
+	h.a[j] = HashNode(key,ref HashVal(val.i,val.r,val.s)) :: h.a[j];
+}
+
+HashTable.delete(h:self ref HashTable, key:string)
+{
+	j := fun1(key,len h.a);
+	dl:list of HashNode; dl = nil;
+	for(q := h.a[j]; q!=nil; q = tl q){
+		if((hd q).key!=key)
+			dl = (hd q) :: dl;
+	}
+	h.a[j] = dl;
+}
+
+HashTable.all(h:self ref HashTable): list of HashNode
+{
+	dl:list of HashNode; dl = nil;
+	for(j:=0; j<len h.a; j++)
+		for(q:=h.a[j]; q!=nil; q = tl q)
+			dl = (hd q) :: dl;
+	return dl;
+}
-- 
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