178 lines
4.0 KiB
C
178 lines
4.0 KiB
C
/*
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[Header: soundexmodule.c,v 1.2 95/05/02 15:40:45 dwwillia Exp ]
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Perform soundex comparisons on strings.
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Soundex is an algorithm that hashes English strings into numerical value.
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Strings that sound the same are hashed to the same value. This allows
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for non-literal string matching.
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From: David Wayne Williams <dwwillia@iucf.indiana.edu>
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Apr 29 1996 - added get_soundex method that returns the soundex of a
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string (chrish@qnx.com)
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May 2 1996 - added doc strings (chrish@qnx.com)
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*/
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#include <string.h>
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#include <ctype.h>
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#include "Python.h"
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static char soundex_module__doc__[] =
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"Perform Soundex comparisons on strings, allowing non-literal matching.";
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static void soundex_hash(char *str, char *result)
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{
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char *sptr = str; /* pointer into str */
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char *rptr = result; /* pointer into result */
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if(*str == '\0')
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{
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strcpy(result,"000000");
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return;
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}
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/* Preserve the first character of the input string.
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*/
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*(rptr++) = toupper(*(sptr++));
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/* Translate the rest of the input string into result. The following
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transformations are used:
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1) All vowels, W, and H, are skipped.
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2) BFPV = 1
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CGJKQSXZ = 2
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DT = 3
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L = 4
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MN = 5
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R = 6
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3) Only translate the first of adjacent equal translations. I.E.
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remove duplicate digits.
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*/
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for(;(rptr - result) < 6 && *sptr != '\0';sptr++)
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{
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switch (toupper(*sptr))
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{
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case 'W':
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case 'H':
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case 'A':
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case 'I':
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case 'O':
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case 'U':
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case 'Y':
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break;
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case 'B':
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case 'F':
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case 'P':
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case 'V':
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if(*(rptr - 1) != '1')
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*(rptr++) = '1';
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break;
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case 'C':
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case 'G':
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case 'J':
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case 'K':
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case 'Q':
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case 'S':
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case 'X':
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case 'Z':
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if(*(rptr - 1) != '2')
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*(rptr++) = '2';
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break;
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case 'D':
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case 'T':
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if(*(rptr - 1) != '3')
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*(rptr++) = '3';
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break;
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case 'L':
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if(*(rptr - 1) != '4')
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*(rptr++) = '4';
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break;
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case 'M':
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case 'N':
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if(*(rptr - 1) != '5')
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*(rptr++) = '5';
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break;
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case 'R':
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if(*(rptr -1) != '6')
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*(rptr++) = '6';
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default:
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break;
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}
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}
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/* Pad 0's on right side of string out to 6 characters.
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*/
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for(; rptr < result + 6; rptr++)
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*rptr = '0';
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/* Terminate the result string.
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*/
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*(result + 6) = '\0';
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}
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/* Return the actual soundex value. */
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/* Added by Chris Herborth (chrish@qnx.com) */
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static char soundex_get_soundex__doc__[] =
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"Return the (English) Soundex hash value for a string.";
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static PyObject *
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get_soundex(PyObject *self, PyObject *args)
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{
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char *str;
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char sdx[7];
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if(!PyArg_ParseTuple( args, "s", &str))
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return NULL;
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soundex_hash(str, sdx);
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return PyString_FromString(sdx);
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}
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static char soundex_sound_similar__doc__[] =
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"Compare two strings to see if they sound similar (English).";
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static PyObject *
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sound_similar(PyObject *self, PyObject *args)
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{
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char *str1, *str2;
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char res1[7], res2[7];
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if(!PyArg_ParseTuple(args, "ss", &str1, &str2))
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return NULL;
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soundex_hash(str1, res1);
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soundex_hash(str2, res2);
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if(!strcmp(res1,res2))
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return Py_BuildValue("i",1);
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else
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return Py_BuildValue("i",0);
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}
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/* Python Method Table.
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*/
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static PyMethodDef SoundexMethods[] =
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{
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{"sound_similar", sound_similar, 1, soundex_sound_similar__doc__},
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{"get_soundex", get_soundex, 1, soundex_get_soundex__doc__},
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{NULL, NULL } /* sentinel */
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};
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/* Register the method table.
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*/
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void
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initsoundex()
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{
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(void) Py_InitModule4("soundex",
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SoundexMethods,
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soundex_module__doc__,
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(PyObject *)NULL,
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PYTHON_API_VERSION);
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}
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