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#include <stddef.h>
#include <string.h>
/***********************************************************************
** **
** Function : patmat **
** **
** Purpose : Pattern Matching **
** **
** Usage : Pass two string pointers as parameters.The first **
** being a raw string & the second a pattern the raw **
** string is to be matched against.If the raw string **
** matches the pattern,then the function returns a **
** 1,else it returns a 0. **
** **
** e.g patmat("abcdefghi","*ghi") returns a 1. **
** patmat("abcdefghi","??c??f*") returns a 1. **
** patmat("abcdefghi","*dh*") returns a 0. **
** patmat("abcdefghi","*def") returns a 0. **
** **
** The asterisk is a wild card to allow any charac- **
** ters from its first appearance to the next spec- **
** ific character.The character ? is a wild card **
** for only one character in the position it appears.**
** Combinations such as "*?" or "?*" or "**" are **
** illegal for obvious reasons & the functions may **
** goof,though I think it will still work. **
** **
** Author : Sreenath Chary Nov 29 1988 **
** **
** Logic : The only simple way I could devise is to use **
** recursion.Each character in the pattern is **
** taken & compared with the character in the raw **
** string.If it matches then the remaining amount **
** of the string & the remaining amount of the **
** pattern are passed as parameters to patmat again **
** until the end of the pattern.If at any stage **
** the pattern does not match,then we go back one **
** level & at this level if the previous character **
** was a asterisk in the pattern,we hunt again from **
** where we left off,otherwise we return back one **
** more level with a not found & the process goes **
** on till the first level call. **
** **
** Only one character at a time is considered,except **
** when the character is an asterisk.You'll get the **
** logic as the program unfolds. **
** **
***********************************************************************/
patmat(char *raw,char *pat)
{ int i, slraw;
if ((*pat == '\0') && (*raw == '\0')) /* if it is end of both */
return( 1 ) ; /* strings,then match */
if (*pat == '\0') /* if it is end of only */
return( 0 ) ; /* pat tehn mismatch */
if (*pat == '*') /* if pattern is a '*' */
{ if (*(pat+1) == '\0') /* if it is end of pat */
return( 1 ) ; /* then match */
for(i=0,slraw=strlen(raw);i<=slraw;i++)/* else hunt for match*/
if ((*(raw+i) == *(pat+1)) || /* or wild card */
(*(pat+1) == '?'))
if (patmat(raw+i+1,pat+2) == 1) /* if found,match */
return( 1 ) ; /* rest of pat */
}
else
{ if (*raw == '\0') /* if end of raw then */
return( 0 ) ; /* mismatch */
if ((*pat == '?') || (*pat == *raw)) /* if chars match then */
if (patmat(raw+1,pat+1) == 1) /* try & match rest of it*/
return( 1 ) ;
}
return( 0 ) ; /* no match found */
}
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