new modules soundex.c and environment.c

1 files changed, 141 insertions, 0 deletions

diff --git a/Modules/soundex.c b/Modules/soundex.c
new file mode 100644
index 0000000..b481e1c
--- /dev/null
+++ b/Modules/soundex.c
@@ -0,0 +1,141 @@
+/*
+  $Header$
+  
+  Perform soundex comparisons on strings.
+
+  Soundex is an algorithm that hashes English strings into numerical value.
+  Strings that sound the same are hashed to the same value.  This allows 
+  for non-literal string matching.
+
+  From: David Wayne Williams <dwwillia@iucf.indiana.edu>
+*/
+
+#include <string.h>
+#include <ctype.h>
+#include "Python.h"
+
+void soundex_hash(char *str, char *result)
+{
+    char *sptr = str;           /* pointer into str */
+    char *rptr = result;        /* pointer into result */
+    
+    if(*str == NULL)
+    {
+        strcpy(result,"000000");
+        return;
+    }
+            
+    /*  Preserve the first character of the input string.
+     */
+    *(rptr++) = toupper(*(sptr++));
+    
+    /* Translate the rest of the input string into result.  The following
+       transformations are used:
+
+       1) All vowles, W, and H, are skipped.
+
+       2) BFPV = 1
+          CGJKQSXZ = 2
+          DT = 3
+          L = 4
+          MN = 5
+
+       3) Only translate the first of adjacent equal translations.  I.E.
+          remove duplicate digits.
+    */
+
+    for(;(rptr - result) < 6 &&  *sptr != NULL;sptr++)
+    {
+        switch (toupper(*sptr))
+        {
+        case 'W':
+        case 'H':
+        case 'A':
+        case 'I':
+        case 'O':
+        case 'U':
+        case 'Y':
+            break;
+        case 'B':
+        case 'F':
+        case 'P':
+        case 'V':
+            if(*(rptr - 1) != '1')
+                *(rptr++) = '1';
+            break;
+        case 'C':
+        case 'G':
+        case 'J':
+        case 'K':
+        case 'Q':
+        case 'S':
+        case 'X':
+        case 'Z':
+            if(*(rptr - 1) != '2')
+                *(rptr++) = '2';
+            break;
+        case 'D':
+        case 'T':
+            if(*(rptr - 1) != '3')
+                *(rptr++) = '3';
+            break;
+        case 'L':
+            if(*(rptr - 1) != '4')
+                *(rptr++) = '4';
+            break;
+        case 'M':
+        case 'N':
+            if(*(rptr - 1) != '5')
+                *(rptr++) = '5';
+            break;
+        default:
+            break;
+        }
+    }
+
+    /* Pad 0's on right side of string out to 6 characters.
+     */
+    for(; rptr < result + 6; rptr++)
+        *rptr = '0';
+
+    /* Terminate the result string.
+     */
+    *(result + 6) = NULL;
+}
+
+
+static PyObject *
+sound_similar(PyObject *self, PyObject *args)
+{
+    char *str1, *str2;
+    int return_value;
+    char res1[7], res2[7];
+    
+    if(!PyArg_ParseTuple(args, "ss", &str1, &str2))
+        return NULL;
+
+    soundex_hash(str1, res1);
+    soundex_hash(str2, res2);
+
+    if(!strcmp(res1,res2))
+        return Py_BuildValue("i",1);
+    else
+        return Py_BuildValue("i",0);
+}
+
+/* Python Method Table.
+ */
+static PyMethodDef SoundexMethods[] =
+{
+    {"sound_similar", sound_similar, 1},
+    {NULL, NULL }               /* sentinel */
+};
+
+
+/* Register the method table.
+ */
+void
+initsoundex()
+{
+    (void) Py_InitModule("soundex",SoundexMethods);
+}