strcasestr.cpp File Reference

#include <stdlib.h>
#include <string.h>
#include <ctype.h>

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Functions
char *	strcasestr (const char *haystack, const char *needle)
	Locatea substring into a string, ignoring case. More...

Function Documentation

char* strcasestr	(	const char *	haystack,
		const char *	needle
	)

Locatea substring into a string, ignoring case.

Parameters

haystack	The string to search in.
needle	The substring to find.

Returns

This function locates the string needle into the string haystack, ignoring the case of the characters. It returns apointer to the beginning of the substring, or NULL if the substring is not found. If haystack or needle are NULL, this function returns NULL.

Conformity: Non applicable.

Supported OS: Windows XP, Windows CE

Definition at line 43 of file strcasestr.cpp.

                                                           {
   size_t length_needle;
   size_t length_haystack;
   size_t i;

   if (!haystack || !needle)
     return NULL;

   length_needle = strlen(needle);
   length_haystack = strlen(haystack) - length_needle + 1;

   for (i = 0; i < length_haystack; i++)
     {
        size_t j;

        for (j = 0; j < length_needle; j++)
          {
            unsigned char c1;
            unsigned char c2;

            c1 = haystack[i+j];
            c2 = needle[j];
            if (toupper(c1) != toupper(c2))
              goto next;
          }
        return (char *) haystack + i;
     next:
        ;
     }

   return NULL;
}