Fully Objective-C Port Of Open Source Barcode Scanner/Creator ZXing

CGImageRef imageToDecode;  // Given a CGImage in which we are looking for barcodes

ZXLuminanceSource* source = [[[ZXCGImageLuminanceSource alloc] initWithCGImage:imageToDecode] autorelease];
ZXBinaryBitmap* bitmap = [ZXBinaryBitmap binaryBitmapWithBinarizer:[ZXHybridBinarizer binarizerWithSource:source]];

NSError* error = nil;

// There are a number of hints we can give to the reader, including
// possible formats, allowed lengths, and the string encoding.
ZXDecodeHints* hints = [ZXDecodeHints hints];

ZXMultiFormatReader* reader = [ZXMultiFormatReader reader];
ZXResult* result = [reader decode:bitmap
                            hints:hints
                            error:&error];
if (result) {
  // The coded result as a string. The raw data can be accessed with
  // result.rawBytes and result.length.
  NSString* contents = result.text;

  // The barcode format, such as a QR code or UPC-A
  ZXBarcodeFormat format = result.barcodeFormat;
} else {
  // Use error to determine why we didn’t get a result, such as a barcode
  // not being found, an invalid checksum, or a format inconsistency.
}