Checksum

Extends String, Data, and URL to easily and efficiently calculate large file content checksums synchronously and asynchronously with optional progress reporting.

Support for calculating checksums of arrays of Data and URL is also included and showcased in the examples below.

String

checksum(algorithm:)

Data

checksum(algorithm:chunkSize:queue:progress:completion:)

URL

checksum(algorithm:chunkSize:)
checksum(algorithm:chunkSize:queue:progress:completion:)

Data & URL arrays

checksum(algorithm:chunkSize:queue:progress:completion:)

Supported digests:

MD5
SHA1
SHA224
SHA256
SHA384
SHA512

Examples

Calculating the checksum of a string:

let string = "Just a simple string"

// Calculate MD5 checksum
if let checksum = string.checksum(algorithm: .md5) {
    // Use computed checksum
}

Calculating the checksum of some data synchronously:

let data = Data(...) // some data object

// Calculate MD5 checksum
if let checksum = data.checksum(algorithm: .md5) {
    // Use computed checksum
}

Calculating the checksum of some data asynchronously with progress reporting:

let data = Data(...) // some data object

let progress: ProgressHandler = { (bytesProcessed, totalBytes) in
    print("Bytes processed: \(bytesProcessed), bytes total: \(totalBytes), bytes left: \(totalBytes - bytesProcessed)")
}

// Calculate MD5 checksum asynchronously
data.checksum(algorithm: .md5, progress: progress) { (checksum) in
    if let checksum = checksum {
        print("MD5 checksum of \(imageURL) is \(checksum)"
    } else {
        print("Unable to obtain checksum.")
    }
}

Calculating the checksum of a local file synchronously:

  if let imageURL = Bundle(for: type(of: self)).url(forResource: "image", withExtension: "jpg") {
    // Calculate image SHA256 checksum
    if let checksum = imageURL.checksum(algorithm: .sha256) {
        // Use computed checksum
    }
  }

Calculating the checksum of a remote file asynchronously with progress reporting:

  let progress: ProgressHandler = { (bytesProcessed, totalBytes) in
      print("Bytes processed: \(bytesProcessed), bytes total: \(totalBytes), bytes left: \(totalBytes - bytesProcessed)")
  }

  if let imageURL = URL(string: "https://github.com/rnine/Checksum/raw/master/ChecksumTests/Fixtures/image.jpg") {
      // Calculate image SHA256 checksum asynchronously with progress reporting
      imageURL.checksum(algorithm: .sha256, progress: progress) { (checksum) in
          if let checksum = checksum {
            print("SHA256 checksum of \(imageURL) is \(checksum)"
          } else {
            print("Unable to obtain checksum.")
          }
      }
  }

Calculating checksums of the contents of multiple URLs:

(Added in beta1)

  let progress: ProgressHandler = { (bytesProcessed, totalBytes) in
      print("Bytes processed: \(bytesProcessed), bytes total: \(totalBytes), bytes left: \(totalBytes - bytesProcessed)")
  }

  let urls = [someURL, anotherURL, yetAnotherURL, oneFinalURL]
  
  urls.checksum(algorithm: .md5, progress: progress) { (checksums) in
      // Please notice that `checksums` is returned with the checksums of the contents  of the URLs 
      // in our `urls` array exactly in the same order.
      // TODO: Add your handling code here.
  }

Calculating checksums of multiple Data objects: