Using CommonCrypto in a Swift Script

common-crypto.h

#include <CommonCrypto/CommonCrypto.h>
#include <CommonCrypto/CommonRandom.h>

module.map

module CommonCrypto [system] {
    header "common-crypto.h"
    export *
}

sha1.swift

#!/usr/bin/env swift -I /usr/local/include

import CommonCrypto
import Foundation

extension NSData {
    var hex: String {
        var result = ""
        let buffer = UnsafeMutablePointer<UInt8>(bytes)
        for i in 0..<length {
            result += NSString(format: "%02x", buffer[i]) as String
        }
        return result
    }
}

func sha1(url: NSURL) -> String? {
    guard let inputStream = NSInputStream(URL: url) else {
        return nil
    }

    defer {
        inputStream.close()
    }

    inputStream.open()

    var ctx = CC_SHA1_CTX()
    CC_SHA1_Init(&ctx)
    let bufferLength = Int(CC_SHA1_BLOCK_BYTES)
    var buffer = Array<UInt8>(count: bufferLength, repeatedValue: 0)
    var read = 0
    repeat {
        read = inputStream.read(&buffer, maxLength: bufferLength)
        guard read != -1 else {
            return nil
        }

        CC_SHA1_Update(&ctx, buffer, CC_LONG(read))
    } while read > 0

    guard let data = NSMutableData(length: Int(CC_SHA1_DIGEST_LENGTH)) else {
        return nil
    }

    CC_SHA1_Final(UnsafeMutablePointer<UInt8>(data.mutableBytes), &ctx)

    return data.hex
}

let arguments = Process.arguments.dropFirst()
let fileManager = NSFileManager.defaultManager()

for argument in arguments {
    let url = NSURL(fileURLWithPath: argument, isDirectory: false)
    guard let path = url.path where fileManager.fileExistsAtPath(path), let hash = sha1(url) else {
        print("\(argument) could not be hashed")
        continue
    }

    print("SHA1(\(path))= \(hash)")
}