1 /*
2 +----------------------------------------------------------------------+
3 | PHP Version 5 |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 1997-2016 The PHP Group |
6 +----------------------------------------------------------------------+
7 | This source file is subject to version 3.01 of the PHP license, |
8 | that is bundled with this package in the file LICENSE, and is |
9 | available through the world-wide-web at the following url: |
10 | http://www.php.net/license/3_01.txt |
11 | If you did not receive a copy of the PHP license and are unable to |
12 | obtain it through the world-wide-web, please send a note to |
13 | license@php.net so we can mail you a copy immediately. |
14 +----------------------------------------------------------------------+
15 | Author: Thies C. Arntzen <thies@thieso.net> |
16 +----------------------------------------------------------------------+
17 */
18
19 /* $Id$ */
20
21 /*
22 Based on CPANs "Text-Metaphone-1.96" by Michael G Schwern <schwern@pobox.com>
23 */
24
25 #include "php.h"
26 #include "php_metaphone.h"
27
28 static int metaphone(unsigned char *word, int word_len, long max_phonemes, char **phoned_word, int traditional);
29
30 /* {{{ proto string metaphone(string text[, int phones])
31 Break english phrases down into their phonemes */
32 PHP_FUNCTION(metaphone)
33 {
34 char *str;
35 char *result = 0;
36 int str_len;
37 long phones = 0;
38
39 if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s|l", &str, &str_len,
40 &phones) == FAILURE) {
41 return;
42 }
43
44 if (metaphone((unsigned char *)str, str_len, phones, &result, 1) == 0) {
45 RETVAL_STRING(result, 0);
46 } else {
47 if (result) {
48 efree(result);
49 }
50 RETURN_FALSE;
51 }
52 }
53 /* }}} */
54
55 /*
56 this is now the original code by Michael G Schwern:
57 i've changed it just a slightly bit (use emalloc,
58 get rid of includes etc)
59 - thies - 13.09.1999
60 */
61
62 /*----------------------------- */
63 /* this used to be "metaphone.h" */
64 /*----------------------------- */
65
66 /* Special encodings */
67 #define SH 'X'
68 #define TH '0'
69
70 /*----------------------------- */
71 /* end of "metaphone.h" */
72 /*----------------------------- */
73
74 /*----------------------------- */
75 /* this used to be "metachar.h" */
76 /*----------------------------- */
77
78 /* Metachar.h ... little bits about characters for metaphone */
79 /*-- Character encoding array & accessing macros --*/
80 /* Stolen directly out of the book... */
81 char _codes[26] =
82 {
83 1, 16, 4, 16, 9, 2, 4, 16, 9, 2, 0, 2, 2, 2, 1, 4, 0, 2, 4, 4, 1, 0, 0, 0, 8, 0
84 /* a b c d e f g h i j k l m n o p q r s t u v w x y z */
85 };
86
87
88 #define ENCODE(c) (isalpha(c) ? _codes[((toupper(c)) - 'A')] : 0)
89
90 #define isvowel(c) (ENCODE(c) & 1) /* AEIOU */
91
92 /* These letters are passed through unchanged */
93 #define NOCHANGE(c) (ENCODE(c) & 2) /* FJMNR */
94
95 /* These form dipthongs when preceding H */
96 #define AFFECTH(c) (ENCODE(c) & 4) /* CGPST */
97
98 /* These make C and G soft */
99 #define MAKESOFT(c) (ENCODE(c) & 8) /* EIY */
100
101 /* These prevent GH from becoming F */
102 #define NOGHTOF(c) (ENCODE(c) & 16) /* BDH */
103
104 /*----------------------------- */
105 /* end of "metachar.h" */
106 /*----------------------------- */
107
108 /* I suppose I could have been using a character pointer instead of
109 * accesssing the array directly... */
110
111 /* Look at the next letter in the word */
112 #define Next_Letter (toupper(word[w_idx+1]))
113 /* Look at the current letter in the word */
114 #define Curr_Letter (toupper(word[w_idx]))
115 /* Go N letters back. */
116 #define Look_Back_Letter(n) (w_idx >= n ? toupper(word[w_idx-n]) : '\0')
117 /* Previous letter. I dunno, should this return null on failure? */
118 #define Prev_Letter (Look_Back_Letter(1))
119 /* Look two letters down. It makes sure you don't walk off the string. */
120 #define After_Next_Letter (Next_Letter != '\0' ? toupper(word[w_idx+2]) \
121 : '\0')
122 #define Look_Ahead_Letter(n) (toupper(Lookahead(word+w_idx, n)))
123
124
125 /* Allows us to safely look ahead an arbitrary # of letters */
126 /* I probably could have just used strlen... */
127 static char Lookahead(char *word, int how_far)
128 {
129 char letter_ahead = '\0'; /* null by default */
130 int idx;
131 for (idx = 0; word[idx] != '\0' && idx < how_far; idx++);
132 /* Edge forward in the string... */
133
134 letter_ahead = word[idx]; /* idx will be either == to how_far or
135 * at the end of the string
136 */
137 return letter_ahead;
138 }
139
140
141 /* phonize one letter
142 * We don't know the buffers size in advance. On way to solve this is to just
143 * re-allocate the buffer size. We're using an extra of 2 characters (this
144 * could be one though; or more too). */
145 #define Phonize(c) { \
146 if (p_idx >= max_buffer_len) { \
147 *phoned_word = safe_erealloc(*phoned_word, 2, sizeof(char), max_buffer_len); \
148 max_buffer_len += 2; \
149 } \
150 (*phoned_word)[p_idx++] = c; \
151 }
152 /* Slap a null character on the end of the phoned word */
153 #define End_Phoned_Word { \
154 if (p_idx == max_buffer_len) { \
155 *phoned_word = safe_erealloc(*phoned_word, 1, sizeof(char), max_buffer_len); \
156 } \
157 (*phoned_word)[p_idx] = '\0'; \
158 }
159 /* How long is the phoned word? */
160 #define Phone_Len (p_idx)
161
162 /* Note is a letter is a 'break' in the word */
163 #define Isbreak(c) (!isalpha(c))
164
165 /* {{{ metaphone
166 */
167 static int metaphone(unsigned char *word, int word_len, long max_phonemes, char **phoned_word, int traditional)
168 {
169 int w_idx = 0; /* point in the phonization we're at. */
170 int p_idx = 0; /* end of the phoned phrase */
171 int max_buffer_len = 0; /* maximum length of the destination buffer */
172
173 /*-- Parameter checks --*/
174 /* Negative phoneme length is meaningless */
175
176 if (max_phonemes < 0)
177 return -1;
178
179 /* Empty/null string is meaningless */
180 /* Overly paranoid */
181 /* assert(word != NULL && word[0] != '\0'); */
182
183 if (word == NULL)
184 return -1;
185
186 /*-- Allocate memory for our phoned_phrase --*/
187 if (max_phonemes == 0) { /* Assume largest possible */
188 max_buffer_len = word_len;
189 *phoned_word = safe_emalloc(sizeof(char), word_len, 1);
190 } else {
191 max_buffer_len = max_phonemes;
192 *phoned_word = safe_emalloc(sizeof(char), max_phonemes, 1);
193 }
194
195
196 /*-- The first phoneme has to be processed specially. --*/
197 /* Find our first letter */
198 for (; !isalpha(Curr_Letter); w_idx++) {
199 /* On the off chance we were given nothing but crap... */
200 if (Curr_Letter == '\0') {
201 End_Phoned_Word
202 return SUCCESS; /* For testing */
203 }
204 }
205
206 switch (Curr_Letter) {
207 /* AE becomes E */
208 case 'A':
209 if (Next_Letter == 'E') {
210 Phonize('E');
211 w_idx += 2;
212 }
213 /* Remember, preserve vowels at the beginning */
214 else {
215 Phonize('A');
216 w_idx++;
217 }
218 break;
219 /* [GKP]N becomes N */
220 case 'G':
221 case 'K':
222 case 'P':
223 if (Next_Letter == 'N') {
224 Phonize('N');
225 w_idx += 2;
226 }
227 break;
228 /* WH becomes W,
229 WR becomes R
230 W if followed by a vowel */
231 case 'W':
232 if (Next_Letter == 'R') {
233 Phonize(Next_Letter);
234 w_idx += 2;
235 } else if (Next_Letter == 'H' || isvowel(Next_Letter)) {
236 Phonize('W');
237 w_idx += 2;
238 }
239 /* else ignore */
240 break;
241 /* X becomes S */
242 case 'X':
243 Phonize('S');
244 w_idx++;
245 break;
246 /* Vowels are kept */
247 /* We did A already
248 case 'A':
249 case 'a':
250 */
251 case 'E':
252 case 'I':
253 case 'O':
254 case 'U':
255 Phonize(Curr_Letter);
256 w_idx++;
257 break;
258 default:
259 /* do nothing */
260 break;
261 }
262
263
264
265 /* On to the metaphoning */
266 for (; Curr_Letter != '\0' &&
267 (max_phonemes == 0 || Phone_Len < max_phonemes);
268 w_idx++) {
269 /* How many letters to skip because an eariler encoding handled
270 * multiple letters */
271 unsigned short int skip_letter = 0;
272
273
274 /* THOUGHT: It would be nice if, rather than having things like...
275 * well, SCI. For SCI you encode the S, then have to remember
276 * to skip the C. So the phonome SCI invades both S and C. It would
277 * be better, IMHO, to skip the C from the S part of the encoding.
278 * Hell, I'm trying it.
279 */
280
281 /* Ignore non-alphas */
282 if (!isalpha(Curr_Letter))
283 continue;
284
285 /* Drop duplicates, except CC */
286 if (Curr_Letter == Prev_Letter &&
287 Curr_Letter != 'C')
288 continue;
289
290 switch (Curr_Letter) {
291 /* B -> B unless in MB */
292 case 'B':
293 if (Prev_Letter != 'M')
294 Phonize('B');
295 break;
296 /* 'sh' if -CIA- or -CH, but not SCH, except SCHW.
297 * (SCHW is handled in S)
298 * S if -CI-, -CE- or -CY-
299 * dropped if -SCI-, SCE-, -SCY- (handed in S)
300 * else K
301 */
302 case 'C':
303 if (MAKESOFT(Next_Letter)) { /* C[IEY] */
304 if (After_Next_Letter == 'A' &&
305 Next_Letter == 'I') { /* CIA */
306 Phonize(SH);
307 }
308 /* SC[IEY] */
309 else if (Prev_Letter == 'S') {
310 /* Dropped */
311 } else {
312 Phonize('S');
313 }
314 } else if (Next_Letter == 'H') {
315 if ((!traditional) && (After_Next_Letter == 'R' || Prev_Letter == 'S')) { /* Christ, School */
316 Phonize('K');
317 } else {
318 Phonize(SH);
319 }
320 skip_letter++;
321 } else {
322 Phonize('K');
323 }
324 break;
325 /* J if in -DGE-, -DGI- or -DGY-
326 * else T
327 */
328 case 'D':
329 if (Next_Letter == 'G' &&
330 MAKESOFT(After_Next_Letter)) {
331 Phonize('J');
332 skip_letter++;
333 } else
334 Phonize('T');
335 break;
336 /* F if in -GH and not B--GH, D--GH, -H--GH, -H---GH
337 * else dropped if -GNED, -GN,
338 * else dropped if -DGE-, -DGI- or -DGY- (handled in D)
339 * else J if in -GE-, -GI, -GY and not GG
340 * else K
341 */
342 case 'G':
343 if (Next_Letter == 'H') {
344 if (!(NOGHTOF(Look_Back_Letter(3)) ||
345 Look_Back_Letter(4) == 'H')) {
346 Phonize('F');
347 skip_letter++;
348 } else {
349 /* silent */
350 }
351 } else if (Next_Letter == 'N') {
352 if (Isbreak(After_Next_Letter) ||
353 (After_Next_Letter == 'E' &&
354 Look_Ahead_Letter(3) == 'D')) {
355 /* dropped */
356 } else
357 Phonize('K');
358 } else if (MAKESOFT(Next_Letter) &&
359 Prev_Letter != 'G') {
360 Phonize('J');
361 } else {
362 Phonize('K');
363 }
364 break;
365 /* H if before a vowel and not after C,G,P,S,T */
366 case 'H':
367 if (isvowel(Next_Letter) &&
368 !AFFECTH(Prev_Letter))
369 Phonize('H');
370 break;
371 /* dropped if after C
372 * else K
373 */
374 case 'K':
375 if (Prev_Letter != 'C')
376 Phonize('K');
377 break;
378 /* F if before H
379 * else P
380 */
381 case 'P':
382 if (Next_Letter == 'H') {
383 Phonize('F');
384 } else {
385 Phonize('P');
386 }
387 break;
388 /* K
389 */
390 case 'Q':
391 Phonize('K');
392 break;
393 /* 'sh' in -SH-, -SIO- or -SIA- or -SCHW-
394 * else S
395 */
396 case 'S':
397 if (Next_Letter == 'I' &&
398 (After_Next_Letter == 'O' ||
399 After_Next_Letter == 'A')) {
400 Phonize(SH);
401 } else if (Next_Letter == 'H') {
402 Phonize(SH);
403 skip_letter++;
404 } else if ((!traditional) && (Next_Letter == 'C' && Look_Ahead_Letter(2) == 'H' && Look_Ahead_Letter(3) == 'W')) {
405 Phonize(SH);
406 skip_letter += 2;
407 } else {
408 Phonize('S');
409 }
410 break;
411 /* 'sh' in -TIA- or -TIO-
412 * else 'th' before H
413 * else T
414 */
415 case 'T':
416 if (Next_Letter == 'I' &&
417 (After_Next_Letter == 'O' ||
418 After_Next_Letter == 'A')) {
419 Phonize(SH);
420 } else if (Next_Letter == 'H') {
421 Phonize(TH);
422 skip_letter++;
423 } else if (!(Next_Letter == 'C' && After_Next_Letter == 'H')) {
424 Phonize('T');
425 }
426 break;
427 /* F */
428 case 'V':
429 Phonize('F');
430 break;
431 /* W before a vowel, else dropped */
432 case 'W':
433 if (isvowel(Next_Letter))
434 Phonize('W');
435 break;
436 /* KS */
437 case 'X':
438 Phonize('K');
439 Phonize('S');
440 break;
441 /* Y if followed by a vowel */
442 case 'Y':
443 if (isvowel(Next_Letter))
444 Phonize('Y');
445 break;
446 /* S */
447 case 'Z':
448 Phonize('S');
449 break;
450 /* No transformation */
451 case 'F':
452 case 'J':
453 case 'L':
454 case 'M':
455 case 'N':
456 case 'R':
457 Phonize(Curr_Letter);
458 break;
459 default:
460 /* nothing */
461 break;
462 } /* END SWITCH */
463
464 w_idx += skip_letter;
465 } /* END FOR */
466
467 End_Phoned_Word;
468
469 return 0;
470 } /* END metaphone */
471 /* }}} */
472
473 /*
474 * Local variables:
475 * tab-width: 4
476 * c-basic-offset: 4
477 * End:
478 * vim600: sw=4 ts=4 fdm=marker
479 * vim<600: sw=4 ts=4
480 */