1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
// -*- C++ -*-
/* Copyright (C) 1989, 1990, 1991, 1992, 2001 Free Software Foundation, Inc.
Written by James Clark (jjc@jclark.com)
This file is part of groff.
groff is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.
groff is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License along
with groff; see the file COPYING. If not, write to the Free Software
Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#include "troff.h"
#include "symbol.h"
#include "dictionary.h"
// is `p' a good size for a hash table
static int is_good_size(unsigned int p)
{
const unsigned int SMALL = 10;
unsigned int i;
for (i = 2; i <= p/2; i++)
if (p % i == 0)
return 0;
for (i = 0x100; i != 0; i <<= 8)
if (i % p <= SMALL || i % p > p - SMALL)
return 0;
return 1;
}
dictionary::dictionary(int n) : size(n), used(0), threshold(0.5), factor(1.5)
{
table = new association[n];
}
// see Knuth, Sorting and Searching, p518, Algorithm L
// we can't use double-hashing because we want a remove function
void *dictionary::lookup(symbol s, void *v)
{
int i;
for (i = int(s.hash() % size);
table[i].v != 0;
i == 0 ? i = size - 1: --i)
if (s == table[i].s) {
if (v != 0) {
void *temp = table[i].v;
table[i].v = v;
return temp;
}
else
return table[i].v;
}
if (v == 0)
return 0;
++used;
table[i].v = v;
table[i].s = s;
if ((double)used/(double)size >= threshold || used + 1 >= size) {
int old_size = size;
size = int(size*factor);
while (!is_good_size(size))
++size;
association *old_table = table;
table = new association[size];
used = 0;
for (i = 0; i < old_size; i++)
if (old_table[i].v != 0)
(void)lookup(old_table[i].s, old_table[i].v);
a_delete old_table;
}
return 0;
}
void *dictionary::lookup(const char *p)
{
symbol s(p, MUST_ALREADY_EXIST);
if (s.is_null())
return 0;
else
return lookup(s);
}
// see Knuth, Sorting and Searching, p527, Algorithm R
void *dictionary::remove(symbol s)
{
// this relies on the fact that we are using linear probing
int i;
for (i = int(s.hash() % size);
table[i].v != 0 && s != table[i].s;
i == 0 ? i = size - 1: --i)
;
void *p = table[i].v;
while (table[i].v != 0) {
table[i].v = 0;
int j = i;
int r;
do {
--i;
if (i < 0)
i = size - 1;
if (table[i].v == 0)
break;
r = int(table[i].s.hash() % size);
} while ((i <= r && r < j) || (r < j && j < i) || (j < i && i <= r));
table[j] = table[i];
}
if (p != 0)
--used;
return p;
}
dictionary_iterator::dictionary_iterator(dictionary &d) : dict(&d), i(0)
{
}
int dictionary_iterator::get(symbol *sp, void **vp)
{
for (; i < dict->size; i++)
if (dict->table[i].v) {
*sp = dict->table[i].s;
*vp = dict->table[i].v;
i++;
return 1;
}
return 0;
}
object_dictionary_iterator::object_dictionary_iterator(object_dictionary &od)
: di(od.d)
{
}
object::object() : rcount(0)
{
}
object::~object()
{
}
void object::add_reference()
{
rcount += 1;
}
void object::remove_reference()
{
if (--rcount == 0)
delete this;
}
object_dictionary::object_dictionary(int n) : d(n)
{
}
object *object_dictionary::lookup(symbol nm)
{
return (object *)d.lookup(nm);
}
void object_dictionary::define(symbol nm, object *obj)
{
obj->add_reference();
obj = (object *)d.lookup(nm, obj);
if (obj)
obj->remove_reference();
}
void object_dictionary::rename(symbol oldnm, symbol newnm)
{
object *obj = (object *)d.remove(oldnm);
if (obj) {
obj = (object *)d.lookup(newnm, obj);
if (obj)
obj->remove_reference();
}
}
void object_dictionary::remove(symbol nm)
{
object *obj = (object *)d.remove(nm);
if (obj)
obj->remove_reference();
}
// Return non-zero if oldnm was defined.
int object_dictionary::alias(symbol newnm, symbol oldnm)
{
object *obj = (object *)d.lookup(oldnm);
if (obj) {
obj->add_reference();
obj = (object *)d.lookup(newnm, obj);
if (obj)
obj->remove_reference();
return 1;
}
return 0;
}
|
