使用 CCHmac() 生成 HMAC swift sdk8.3

在 SDK8.3 之前，我是通过这种方式生成 hmac 的。现在我在 CCHmac() 函数上遇到错误。由于我是初学者，我不知道如何解决它。在此先感谢您的帮助！

xcode 警告：无法使用类型为 (UInt32, [CChar]?, UInt, [CChar]?, UInt, inout[(CUnsignedChar)] 的参数列表调用“CCHmac”

func generateHMAC(key: String, data: String) -> String {

    let cKey = key.cStringUsingEncoding(NSUTF8StringEncoding)
    let cData = data.cStringUsingEncoding(NSUTF8StringEncoding)

    var result = [CUnsignedChar](count: Int(CC_SHA512_DIGEST_LENGTH), repeatedValue: 0)
    CCHmac(CCHmacAlgorithm(kCCHmacAlgSHA512), cKey, strlen(cKey!), cData, strlen(cData!), &result)


    let hash = NSMutableString()
    for var i = 0; i < result.count; i++ {
        hash.appendFormat("%02hhx", result[i])
    }

    return hash as String
}

问题是strlen返回一个UInt, while CCHmac的长度参数是Ints.

虽然您可以进行一些强制，但您也可以使用count两个数组的属性而不是调用strlen.

func generateHMAC(key: String, data: String) -> String {

    var result: [CUnsignedChar]
    if let cKey = key.cStringUsingEncoding(NSUTF8StringEncoding),
           cData = data.cStringUsingEncoding(NSUTF8StringEncoding)
    {
        let algo  = CCHmacAlgorithm(kCCHmacAlgSHA512)
        result = Array(count: Int(CC_SHA512_DIGEST_LENGTH), repeatedValue: 0)

        CCHmac(algo, cKey, cKey.count-1, cData, cData.count-1, &result)
    }
    else {
        // as @MartinR points out, this is in theory impossible 
        // but personally, I prefer doing this to using `!`
        fatalError("Nil returned when processing input strings as UTF8")
    }

    let hash = NSMutableString()
    for val in result {
        hash.appendFormat("%02hhx", val)
    }

    return hash as String
}