sdlStrcasestr function

Pointer<Int8> sdlStrcasestr(String? haystack, String? needle)

Search a UTF-8 string for the first instance of a specific substring, case-insensitively.

This will work with Unicode strings, using a technique called "case-folding" to handle the vast majority of case-sensitive human languages regardless of system locale. It can deal with expanding values: a German Eszett character can compare against two ASCII 's' chars and be considered a match, for example. A notable exception: it does not handle the Turkish 'i' character; human language is complicated!

Since this handles Unicode, it expects the strings to be well-formed UTF-8 and not a null-terminated string of arbitrary bytes. Bytes that are not valid UTF-8 are treated as Unicode character U+FFFD (REPLACEMENT CHARACTER), which is to say two strings of random bits may turn out to match if they convert to the same amount of replacement characters.

\param haystack the string to search. Must not be NULL. \param needle the string to search for. Must not be NULL. \returns a pointer to the first instance of needle in the string, or NULL if not found.

\threadsafety It is safe to call this function from any thread.

\since This function is available since SDL 3.1.3.

extern SDL_DECLSPEC char * SDLCALL SDL_strcasestr(const char *haystack, const char *needle)

Implementation

Pointer<Int8> sdlStrcasestr(String? haystack, String? needle) {
  final sdlStrcasestrLookupFunction = libSdl3.lookupFunction<
      Pointer<Int8> Function(Pointer<Utf8> haystack, Pointer<Utf8> needle),
      Pointer<Int8> Function(
          Pointer<Utf8> haystack, Pointer<Utf8> needle)>('SDL_strcasestr');
  final haystackPointer = haystack != null ? haystack.toNativeUtf8() : nullptr;
  final needlePointer = needle != null ? needle.toNativeUtf8() : nullptr;
  final result = sdlStrcasestrLookupFunction(haystackPointer, needlePointer);
  calloc.free(haystackPointer);
  calloc.free(needlePointer);
  return result;
}