md5 - How to use CC_MD5 method in swift language

Question

in Objective-c, we can hash a string like this:

const char *cStr = [someString UTF8String];
unsigned char result[16];
CC_MD5( cStr, strlen(cStr), result );
md5String = [NSString stringWithFormat:
        @"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
        result[0], result[1], result[2], result[3],
        result[4], result[5], result[6], result[7],
        result[8], result[9], result[10], result[11],
        result[12], result[13], result[14], result[15]
        ];

But CC_MD5 doesn't work in Swift. How do we deal with this?

Answer 1

This is what I came up with. It's an extension to String. Don't forget to add #import <CommonCrypto/CommonCrypto.h> to the ObjC-Swift bridging header that Xcode creates.

extension String  {
    var md5: String! {
        let str = self.cStringUsingEncoding(NSUTF8StringEncoding)
        let strLen = CC_LONG(self.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
        let digestLen = Int(CC_MD5_DIGEST_LENGTH)
        let result = UnsafeMutablePointer<CUnsignedChar>.alloc(digestLen)

        CC_MD5(str!, strLen, result)

        let hash = NSMutableString()
        for i in 0..<digestLen {
            hash.appendFormat("%02x", result[i])
        }

        result.dealloc(digestLen)

        return String(format: hash as String)
    }
 }