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Diffstat (limited to 'ext/standard/metaphone.c')
| -rw-r--r-- | ext/standard/metaphone.c | 480 |
1 files changed, 480 insertions, 0 deletions
diff --git a/ext/standard/metaphone.c b/ext/standard/metaphone.c new file mode 100644 index 0000000..62c6df6 --- /dev/null +++ b/ext/standard/metaphone.c @@ -0,0 +1,480 @@ +/* + +----------------------------------------------------------------------+ + | PHP Version 5 | + +----------------------------------------------------------------------+ + | Copyright (c) 1997-2013 The PHP Group | + +----------------------------------------------------------------------+ + | This source file is subject to version 3.01 of the PHP license, | + | that is bundled with this package in the file LICENSE, and is | + | available through the world-wide-web at the following url: | + | http://www.php.net/license/3_01.txt | + | If you did not receive a copy of the PHP license and are unable to | + | obtain it through the world-wide-web, please send a note to | + | license@php.net so we can mail you a copy immediately. | + +----------------------------------------------------------------------+ + | Author: Thies C. Arntzen <thies@thieso.net> | + +----------------------------------------------------------------------+ +*/ + +/* $Id$ */ + +/* + Based on CPANs "Text-Metaphone-1.96" by Michael G Schwern <schwern@pobox.com> +*/ + +#include "php.h" +#include "php_metaphone.h" + +static int metaphone(unsigned char *word, int word_len, long max_phonemes, char **phoned_word, int traditional); + +/* {{{ proto string metaphone(string text[, int phones]) + Break english phrases down into their phonemes */ +PHP_FUNCTION(metaphone) +{ + char *str; + char *result = 0; + int str_len; + long phones = 0; + + if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s|l", &str, &str_len, + &phones) == FAILURE) { + return; + } + + if (metaphone((unsigned char *)str, str_len, phones, &result, 1) == 0) { + RETVAL_STRING(result, 0); + } else { + if (result) { + efree(result); + } + RETURN_FALSE; + } +} +/* }}} */ + +/* + this is now the original code by Michael G Schwern: + i've changed it just a slightly bit (use emalloc, + get rid of includes etc) + - thies - 13.09.1999 +*/ + +/*----------------------------- */ +/* this used to be "metaphone.h" */ +/*----------------------------- */ + +/* Special encodings */ +#define SH 'X' +#define TH '0' + +/*----------------------------- */ +/* end of "metaphone.h" */ +/*----------------------------- */ + +/*----------------------------- */ +/* this used to be "metachar.h" */ +/*----------------------------- */ + +/* Metachar.h ... little bits about characters for metaphone */ +/*-- Character encoding array & accessing macros --*/ +/* Stolen directly out of the book... */ +char _codes[26] = +{ + 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 +/* 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 */ +}; + + +#define ENCODE(c) (isalpha(c) ? _codes[((toupper(c)) - 'A')] : 0) + +#define isvowel(c) (ENCODE(c) & 1) /* AEIOU */ + +/* These letters are passed through unchanged */ +#define NOCHANGE(c) (ENCODE(c) & 2) /* FJMNR */ + +/* These form dipthongs when preceding H */ +#define AFFECTH(c) (ENCODE(c) & 4) /* CGPST */ + +/* These make C and G soft */ +#define MAKESOFT(c) (ENCODE(c) & 8) /* EIY */ + +/* These prevent GH from becoming F */ +#define NOGHTOF(c) (ENCODE(c) & 16) /* BDH */ + +/*----------------------------- */ +/* end of "metachar.h" */ +/*----------------------------- */ + +/* I suppose I could have been using a character pointer instead of + * accesssing the array directly... */ + +/* Look at the next letter in the word */ +#define Next_Letter (toupper(word[w_idx+1])) +/* Look at the current letter in the word */ +#define Curr_Letter (toupper(word[w_idx])) +/* Go N letters back. */ +#define Look_Back_Letter(n) (w_idx >= n ? toupper(word[w_idx-n]) : '\0') +/* Previous letter. I dunno, should this return null on failure? */ +#define Prev_Letter (Look_Back_Letter(1)) +/* Look two letters down. It makes sure you don't walk off the string. */ +#define After_Next_Letter (Next_Letter != '\0' ? toupper(word[w_idx+2]) \ + : '\0') +#define Look_Ahead_Letter(n) (toupper(Lookahead(word+w_idx, n))) + + +/* Allows us to safely look ahead an arbitrary # of letters */ +/* I probably could have just used strlen... */ +static char Lookahead(char *word, int how_far) +{ + char letter_ahead = '\0'; /* null by default */ + int idx; + for (idx = 0; word[idx] != '\0' && idx < how_far; idx++); + /* Edge forward in the string... */ + + letter_ahead = word[idx]; /* idx will be either == to how_far or + * at the end of the string + */ + return letter_ahead; +} + + +/* phonize one letter + * We don't know the buffers size in advance. On way to solve this is to just + * re-allocate the buffer size. We're using an extra of 2 characters (this + * could be one though; or more too). */ +#define Phonize(c) { \ + if (p_idx >= max_buffer_len) { \ + *phoned_word = safe_erealloc(*phoned_word, 2, sizeof(char), max_buffer_len); \ + max_buffer_len += 2; \ + } \ + (*phoned_word)[p_idx++] = c; \ + } +/* Slap a null character on the end of the phoned word */ +#define End_Phoned_Word { \ + if (p_idx == max_buffer_len) { \ + *phoned_word = safe_erealloc(*phoned_word, 1, sizeof(char), max_buffer_len); \ + } \ + (*phoned_word)[p_idx] = '\0'; \ + } +/* How long is the phoned word? */ +#define Phone_Len (p_idx) + +/* Note is a letter is a 'break' in the word */ +#define Isbreak(c) (!isalpha(c)) + +/* {{{ metaphone + */ +static int metaphone(unsigned char *word, int word_len, long max_phonemes, char **phoned_word, int traditional) +{ + int w_idx = 0; /* point in the phonization we're at. */ + int p_idx = 0; /* end of the phoned phrase */ + int max_buffer_len = 0; /* maximum length of the destination buffer */ + +/*-- Parameter checks --*/ + /* Negative phoneme length is meaningless */ + + if (max_phonemes < 0) + return -1; + + /* Empty/null string is meaningless */ + /* Overly paranoid */ + /* assert(word != NULL && word[0] != '\0'); */ + + if (word == NULL) + return -1; + +/*-- Allocate memory for our phoned_phrase --*/ + if (max_phonemes == 0) { /* Assume largest possible */ + max_buffer_len = word_len; + *phoned_word = safe_emalloc(sizeof(char), word_len, 1); + } else { + max_buffer_len = max_phonemes; + *phoned_word = safe_emalloc(sizeof(char), max_phonemes, 1); + } + + +/*-- The first phoneme has to be processed specially. --*/ + /* Find our first letter */ + for (; !isalpha(Curr_Letter); w_idx++) { + /* On the off chance we were given nothing but crap... */ + if (Curr_Letter == '\0') { + End_Phoned_Word + return SUCCESS; /* For testing */ + } + } + + switch (Curr_Letter) { + /* AE becomes E */ + case 'A': + if (Next_Letter == 'E') { + Phonize('E'); + w_idx += 2; + } + /* Remember, preserve vowels at the beginning */ + else { + Phonize('A'); + w_idx++; + } + break; + /* [GKP]N becomes N */ + case 'G': + case 'K': + case 'P': + if (Next_Letter == 'N') { + Phonize('N'); + w_idx += 2; + } + break; + /* WH becomes W, + WR becomes R + W if followed by a vowel */ + case 'W': + if (Next_Letter == 'R') { + Phonize(Next_Letter); + w_idx += 2; + } else if (Next_Letter == 'H' || isvowel(Next_Letter)) { + Phonize('W'); + w_idx += 2; + } + /* else ignore */ + break; + /* X becomes S */ + case 'X': + Phonize('S'); + w_idx++; + break; + /* Vowels are kept */ + /* We did A already + case 'A': + case 'a': + */ + case 'E': + case 'I': + case 'O': + case 'U': + Phonize(Curr_Letter); + w_idx++; + break; + default: + /* do nothing */ + break; + } + + + + /* On to the metaphoning */ + for (; Curr_Letter != '\0' && + (max_phonemes == 0 || Phone_Len < max_phonemes); + w_idx++) { + /* How many letters to skip because an eariler encoding handled + * multiple letters */ + unsigned short int skip_letter = 0; + + + /* THOUGHT: It would be nice if, rather than having things like... + * well, SCI. For SCI you encode the S, then have to remember + * to skip the C. So the phonome SCI invades both S and C. It would + * be better, IMHO, to skip the C from the S part of the encoding. + * Hell, I'm trying it. + */ + + /* Ignore non-alphas */ + if (!isalpha(Curr_Letter)) + continue; + + /* Drop duplicates, except CC */ + if (Curr_Letter == Prev_Letter && + Curr_Letter != 'C') + continue; + + switch (Curr_Letter) { + /* B -> B unless in MB */ + case 'B': + if (Prev_Letter != 'M') + Phonize('B'); + break; + /* 'sh' if -CIA- or -CH, but not SCH, except SCHW. + * (SCHW is handled in S) + * S if -CI-, -CE- or -CY- + * dropped if -SCI-, SCE-, -SCY- (handed in S) + * else K + */ + case 'C': + if (MAKESOFT(Next_Letter)) { /* C[IEY] */ + if (After_Next_Letter == 'A' && + Next_Letter == 'I') { /* CIA */ + Phonize(SH); + } + /* SC[IEY] */ + else if (Prev_Letter == 'S') { + /* Dropped */ + } else { + Phonize('S'); + } + } else if (Next_Letter == 'H') { + if ((!traditional) && (After_Next_Letter == 'R' || Prev_Letter == 'S')) { /* Christ, School */ + Phonize('K'); + } else { + Phonize(SH); + } + skip_letter++; + } else { + Phonize('K'); + } + break; + /* J if in -DGE-, -DGI- or -DGY- + * else T + */ + case 'D': + if (Next_Letter == 'G' && + MAKESOFT(After_Next_Letter)) { + Phonize('J'); + skip_letter++; + } else + Phonize('T'); + break; + /* F if in -GH and not B--GH, D--GH, -H--GH, -H---GH + * else dropped if -GNED, -GN, + * else dropped if -DGE-, -DGI- or -DGY- (handled in D) + * else J if in -GE-, -GI, -GY and not GG + * else K + */ + case 'G': + if (Next_Letter == 'H') { + if (!(NOGHTOF(Look_Back_Letter(3)) || + Look_Back_Letter(4) == 'H')) { + Phonize('F'); + skip_letter++; + } else { + /* silent */ + } + } else if (Next_Letter == 'N') { + if (Isbreak(After_Next_Letter) || + (After_Next_Letter == 'E' && + Look_Ahead_Letter(3) == 'D')) { + /* dropped */ + } else + Phonize('K'); + } else if (MAKESOFT(Next_Letter) && + Prev_Letter != 'G') { + Phonize('J'); + } else { + Phonize('K'); + } + break; + /* H if before a vowel and not after C,G,P,S,T */ + case 'H': + if (isvowel(Next_Letter) && + !AFFECTH(Prev_Letter)) + Phonize('H'); + break; + /* dropped if after C + * else K + */ + case 'K': + if (Prev_Letter != 'C') + Phonize('K'); + break; + /* F if before H + * else P + */ + case 'P': + if (Next_Letter == 'H') { + Phonize('F'); + } else { + Phonize('P'); + } + break; + /* K + */ + case 'Q': + Phonize('K'); + break; + /* 'sh' in -SH-, -SIO- or -SIA- or -SCHW- + * else S + */ + case 'S': + if (Next_Letter == 'I' && + (After_Next_Letter == 'O' || + After_Next_Letter == 'A')) { + Phonize(SH); + } else if (Next_Letter == 'H') { + Phonize(SH); + skip_letter++; + } else if ((!traditional) && (Next_Letter == 'C' && Look_Ahead_Letter(2) == 'H' && Look_Ahead_Letter(3) == 'W')) { + Phonize(SH); + skip_letter += 2; + } else { + Phonize('S'); + } + break; + /* 'sh' in -TIA- or -TIO- + * else 'th' before H + * else T + */ + case 'T': + if (Next_Letter == 'I' && + (After_Next_Letter == 'O' || + After_Next_Letter == 'A')) { + Phonize(SH); + } else if (Next_Letter == 'H') { + Phonize(TH); + skip_letter++; + } else if (!(Next_Letter == 'C' && After_Next_Letter == 'H')) { + Phonize('T'); + } + break; + /* F */ + case 'V': + Phonize('F'); + break; + /* W before a vowel, else dropped */ + case 'W': + if (isvowel(Next_Letter)) + Phonize('W'); + break; + /* KS */ + case 'X': + Phonize('K'); + Phonize('S'); + break; + /* Y if followed by a vowel */ + case 'Y': + if (isvowel(Next_Letter)) + Phonize('Y'); + break; + /* S */ + case 'Z': + Phonize('S'); + break; + /* No transformation */ + case 'F': + case 'J': + case 'L': + case 'M': + case 'N': + case 'R': + Phonize(Curr_Letter); + break; + default: + /* nothing */ + break; + } /* END SWITCH */ + + w_idx += skip_letter; + } /* END FOR */ + + End_Phoned_Word; + + return 0; +} /* END metaphone */ +/* }}} */ + +/* + * Local variables: + * tab-width: 4 + * c-basic-offset: 4 + * End: + * vim600: sw=4 ts=4 fdm=marker + * vim<600: sw=4 ts=4 + */ |