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
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
/* Copyright (C) 2010-2021 by The D Language Foundation, All Rights Reserved
* http://www.digitalmars.com
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
* https://github.com/D-Programming-Language/dmd/blob/master/src/root/speller.c
*/
#include "dsystem.h"
#include "speller.h"
const char idchars[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";
/**************************************************
* combine a new result from the spell checker to
* find the one with the closest symbol with
* respect to the cost defined by the search function
* Input/Output:
* p best found spelling (NULL if none found yet)
* cost cost of p (INT_MAX if none found yet)
* Input:
* np new found spelling (NULL if none found)
* ncost cost of np if non-NULL
* Returns:
* true if the cost is less or equal 0
* false otherwise
*/
bool combineSpellerResult(void*& p, int& cost, void* np, int ncost)
{
if (np && ncost < cost)
{
p = np;
cost = ncost;
if (cost <= 0)
return true;
}
return false;
}
void *spellerY(const char *seed, size_t seedlen, fp_speller_t fp, void *fparg,
const char *charset, size_t index, int* cost)
{
if (!seedlen)
return NULL;
assert(seed[seedlen] == 0);
char tmp[30];
char *buf;
if (seedlen <= sizeof(tmp) - 2)
buf = tmp;
else
{
buf = (char *)alloca(seedlen + 2); // leave space for extra char
if (!buf)
return NULL; // no matches
}
memcpy(buf, seed, index);
*cost = INT_MAX;
void* p = NULL;
int ncost = 0;
/* Delete at seed[index] */
if (index < seedlen)
{
memcpy(buf + index, seed + index + 1, seedlen - index);
assert(buf[seedlen - 1] == 0);
void* np = (*fp)(fparg, buf, &ncost);
if (combineSpellerResult(p, *cost, np, ncost))
return p;
}
if (charset && *charset)
{
/* Substitutions */
if (index < seedlen)
{
memcpy(buf, seed, seedlen + 1);
for (const char *s = charset; *s; s++)
{
buf[index] = *s;
//printf("sub buf = '%s'\n", buf);
void* np = (*fp)(fparg, buf, &ncost);
if (combineSpellerResult(p, *cost, np, ncost))
return p;
}
assert(buf[seedlen] == 0);
}
/* Insertions */
memcpy (buf + index + 1, seed + index, seedlen + 1 - index);
for (const char *s = charset; *s; s++)
{
buf[index] = *s;
//printf("ins buf = '%s'\n", buf);
void* np = (*fp)(fparg, buf, &ncost);
if (combineSpellerResult(p, *cost, np, ncost))
return p;
}
assert(buf[seedlen + 1] == 0);
}
return p; // return "best" result
}
void *spellerX(const char *seed, size_t seedlen, fp_speller_t fp, void *fparg,
const char *charset, int flag)
{
if (!seedlen)
return NULL;
char tmp[30];
char *buf;
if (seedlen <= sizeof(tmp) - 2)
buf = tmp;
else
{
buf = (char *)alloca(seedlen + 2); // leave space for extra char
if (!buf)
return NULL; // no matches
}
int cost = INT_MAX, ncost = 0;
void *p = NULL, *np;
/* Deletions */
memcpy(buf, seed + 1, seedlen);
for (size_t i = 0; i < seedlen; i++)
{
//printf("del buf = '%s'\n", buf);
if (flag)
np = spellerY(buf, seedlen - 1, fp, fparg, charset, i, &ncost);
else
np = (*fp)(fparg, buf, &ncost);
if (combineSpellerResult(p, cost, np, ncost))
return p;
buf[i] = seed[i];
}
/* Transpositions */
if (!flag)
{
memcpy(buf, seed, seedlen + 1);
for (size_t i = 0; i + 1 < seedlen; i++)
{
// swap [i] and [i + 1]
buf[i] = seed[i + 1];
buf[i + 1] = seed[i];
//printf("tra buf = '%s'\n", buf);
if (combineSpellerResult(p, cost, (*fp)(fparg, buf, &ncost), ncost))
return p;
buf[i] = seed[i];
}
}
if (charset && *charset)
{
/* Substitutions */
memcpy(buf, seed, seedlen + 1);
for (size_t i = 0; i < seedlen; i++)
{
for (const char *s = charset; *s; s++)
{
buf[i] = *s;
//printf("sub buf = '%s'\n", buf);
if (flag)
np = spellerY(buf, seedlen, fp, fparg, charset, i + 1, &ncost);
else
np = (*fp)(fparg, buf, &ncost);
if (combineSpellerResult(p, cost, np, ncost))
return p;
}
buf[i] = seed[i];
}
/* Insertions */
memcpy(buf + 1, seed, seedlen + 1);
for (size_t i = 0; i <= seedlen; i++) // yes, do seedlen+1 iterations
{
for (const char *s = charset; *s; s++)
{
buf[i] = *s;
//printf("ins buf = '%s'\n", buf);
if (flag)
np = spellerY(buf, seedlen + 1, fp, fparg, charset, i + 1, &ncost);
else
np = (*fp)(fparg, buf, &ncost);
if (combineSpellerResult(p, cost, np, ncost))
return p;
}
buf[i] = seed[i]; // going past end of seed[] is ok, as we hit the 0
}
}
return p; // return "best" result
}
/**************************************************
* Looks for correct spelling.
* Currently only looks a 'distance' of one from the seed[].
* This does an exhaustive search, so can potentially be very slow.
* Input:
* seed wrongly spelled word
* fp search function
* fparg argument to search function
* charset character set
* Returns:
* NULL no correct spellings found
* void* value returned by fp() for first possible correct spelling
*/
void *speller(const char *seed, fp_speller_t fp, void *fparg, const char *charset)
{
size_t seedlen = strlen(seed);
size_t maxdist = seedlen < 4 ? seedlen / 2 : 2;
for (size_t distance = 0; distance < maxdist; distance++)
{ void *p = spellerX(seed, seedlen, fp, fparg, charset, distance);
if (p)
return p;
// if (seedlen > 10)
// break;
}
return NULL; // didn't find it
}
|
