Convert NSData to Base64 Encoded String.

dataToBase64EncodedString.m

- (NSString*)base64forData:(NSData*)theData {
  const uint8_t* input = (const uint8_t*)[theData bytes];
	
	NSInteger length = [theData length];
	
  static char table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
	
  NSMutableData* data = [NSMutableData dataWithLength:((length + 2) / 3) * 4];
  uint8_t* output = (uint8_t*)data.mutableBytes;
	
	NSInteger i,i2;
  for (i=0; i < length; i += 3) {
    NSInteger value = 0;
		for (i2=0; i2<3; i2++) {
      value <<= 8;
      if (i+i2 < length) {
        value |= (0xFF & input[i+i2]);
      }
    }
    NSInteger theIndex = (i / 3) * 4;
    output[theIndex + 0] =                    table[(value >> 18) & 0x3F];
    output[theIndex + 1] =                    table[(value >> 12) & 0x3F];
    output[theIndex + 2] = (i + 1) < length ? table[(value >> 6)  & 0x3F] : '=';
    output[theIndex + 3] = (i + 2) < length ? table[(value >> 0)  & 0x3F] : '=';
  }
  return [[[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding] autorelease];
}