xref: /illumos-gate/usr/src/cmd/spell/hashlook.c (revision 0d8b5334)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include <stdlib.h>
33 #include <stdio.h>
34 #include "hash.h"
35 #include "huff.h"
36 
37 unsigned *table;
38 int hindex[NI];
39 
40 #define	B (BYTE * sizeof (unsigned))
41 #define	L (BYTE * sizeof (long)-1)
42 #define	MASK (~((unsigned long)1L<<L))
43 
44 #ifdef pdp11	/* sizeof (unsigned)==sizeof(long)/2 */
45 #define	fetch(wp, bp)\
46 	(((((long)wp[0]<<B)|wp[1])<<(B-bp))|(wp[2]>>bp))
47 #else 		/* sizeof (unsigned)==sizeof(long) */
48 #define	fetch(wp, bp) ((wp[0] << (B - bp)) | (wp[1] >> bp))
49 #endif
50 
51 int
hashlook(char * s)52 hashlook(char *s)
53 {
54 	unsigned long h;
55 	unsigned long t;
56 	int bp;
57 	unsigned *wp;
58 	long sum;
59 	unsigned *tp;
60 
61 	h = hash(s);
62 	t = h>>(HASHWIDTH-INDEXWIDTH);
63 	wp = &table[hindex[t]];
64 	tp = &table[hindex[t+1]];
65 	bp = B;
66 	sum = (long)t<<(HASHWIDTH-INDEXWIDTH);
67 	for (;;) {
68 		{
69 			/*
70 			 * this block is equivalent to:
71 			 * bp -= decode((fetch(wp, bp) >> 1) & MASK, &t);
72 			 */
73 			long y;
74 			long v;
75 
76 			/*
77 			 * shift 32 on those machines leaves destination
78 			 * unchanged
79 			 */
80 			if (bp == 0)
81 				y = 0;
82 			else
83 				y = wp[0] << (B - bp);
84 			if (bp < 32)
85 				y |= (wp[1] >> bp);
86 			y = (y >> 1) & MASK;
87 			if (y < cs) {
88 				t = y >> (long) (L+1-w);
89 				bp -= w-1;
90 			} else {
91 				for (bp -= w, v = v0; y >= qcs;
92 				    y = (y << 1) & MASK, v += n)
93 					bp -= 1;
94 				t = v + (y>> (long)(L-w));
95 			}
96 		}
97 		while (bp <= 0) {
98 			bp += B;
99 			wp++;
100 		}
101 		if (wp >= tp && (wp > tp||bp < B))
102 			return (0);
103 		sum += t;
104 		if (sum < h)
105 			continue;
106 		return (sum == h);
107 	}
108 }
109 
110 
111 int
prime(char * file)112 prime(char *file)
113 {
114 	FILE *f;
115 
116 #ifdef pdp11	/* because of insufficient address space for buffers */
117 	fd = dup(0);
118 	close(0);
119 	if (open(file, 0) != 0)
120 		return (0);
121 	f = stdin;
122 	if (rhuff(f) == 0 || read(fileno(f), (char *)hindex,
123 	    NI * sizeof (*hindex)) != NI * sizeof (*hindex) ||
124 	    (table = (unsigned *)malloc(hindex[NI-1] * sizeof (*table))) == 0 ||
125 	    read(fileno(f), (char *)table, sizeof (*table) * hindex[NI-1]) !=
126 	    hindex[NI-1] * sizeof (*table))
127 		return (0);
128 	close(0);
129 	if (dup(fd) != 0)
130 		return (0);
131 	close(fd);
132 #else
133 	if ((f = fopen(file, "r")) == NULL)
134 		return (0);
135 	if (rhuff(f) == 0 ||
136 	    fread((char *)hindex, sizeof (*hindex),  NI, f) != NI ||
137 	    (table = (unsigned *)malloc(hindex[NI-1] * sizeof (*table))) == 0 ||
138 	    fread((char *)table, sizeof (*table), hindex[NI-1], f) !=
139 	    hindex[NI-1])
140 		return (0);
141 	(void) fclose(f);
142 #endif
143 	hashinit();
144 	return (1);
145 }
146