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106 lines
3.4 KiB
C
106 lines
3.4 KiB
C
/* Copyright (c) 2000, 2002, 2004, 2007 MySQL AB
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Use is subject to license terms
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
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/****************************************************************
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* SOUNDEX ALGORITHM in C *
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* *
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* The basic Algorithm source is taken from EDN Nov. *
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* 14, 1985 pg. 36. *
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* *
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* As a test Those in Illinois will find that the *
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* first group of numbers in their drivers license *
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* number is the soundex number for their last name. *
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* *
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* RHW PC-IBBS ID. #1230 *
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* *
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* As an extension if remove_garbage is set then all non- *
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* alpha characters are skipped *
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* *
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* Note, that this implementation corresponds to the *
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* original version of the algorithm, not to the more *
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* popular "enhanced" version, described by Knuth. *
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****************************************************************/
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#include "mysys_priv.h"
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#include <m_ctype.h>
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#include "my_static.h"
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static char get_scode(CHARSET_INFO * cs, char **ptr,pbool remove_garbage);
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/* outputed string is 4 byte long */
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/* out_pntr can be == in_pntr */
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void soundex(CHARSET_INFO * cs,register char * out_pntr, char * in_pntr,
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pbool remove_garbage)
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{
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char ch,last_ch;
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reg3 char * end;
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register const uchar *map=cs->to_upper;
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if (remove_garbage)
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{
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while (*in_pntr && !my_isalpha(cs,*in_pntr)) /* Skip pre-space */
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in_pntr++;
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}
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*out_pntr++ = map[(uchar)*in_pntr]; /* Copy first letter */
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last_ch = get_scode(cs,&in_pntr,0); /* code of the first letter */
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/* for the first 'double-letter */
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/* check. */
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end=out_pntr+3; /* Loop on input letters until */
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/* end of input (null) or output */
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/* letter code count = 3 */
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in_pntr++;
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while (out_pntr < end && (ch = get_scode(cs,&in_pntr,remove_garbage)) != 0)
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{
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in_pntr++;
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if ((ch != '0') && (ch != last_ch)) /* if not skipped or double */
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{
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*out_pntr++ = ch; /* letter, copy to output */
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} /* for next double-letter check */
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last_ch = ch; /* save code of last input letter */
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}
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while (out_pntr < end)
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*out_pntr++ = '0';
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*out_pntr=0; /* end string */
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return;
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} /* soundex */
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/*
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If alpha, map input letter to soundex code.
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If not alpha and remove_garbage is set then skip to next char
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else return 0
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*/
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static char get_scode(CHARSET_INFO * cs,char **ptr, pbool remove_garbage)
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{
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uchar ch;
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if (remove_garbage)
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{
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while (**ptr && !my_isalpha(cs,**ptr))
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(*ptr)++;
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}
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ch=my_toupper(cs,**ptr);
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if (ch < 'A' || ch > 'Z')
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{
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if (my_isalpha(cs,ch)) /* If extended alfa (country spec) */
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return '0'; /* threat as vokal */
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return 0; /* Can't map */
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}
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return(soundex_map[ch-'A']);
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} /* get_scode */
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