// Snippets NSData+Snippets.swift
//
// Copyright © 2015, Roy Ratcliffe, Pioneering Software, United Kingdom
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the “Software”), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS,” WITHOUT WARRANTY OF ANY KIND, EITHER
// EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO
// EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
// OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
//------------------------------------------------------------------------------

import Foundation

extension NSData {

  /// Converts the data object to a hexadecimal string. Each byte from the data
  /// becomes two hexadecimal digits in the resulting character string. That
  /// makes the length of the string twice as long as the data. The string
  /// contains lower-case hexadecimal digits for 10 through 15, i.e. `a` through
  /// `f`.
  ///
  /// The `bytes` getter answers an unsafe pointer to `Void`. Cast this to an
  /// unsafe C character pointer; a pointer to signed 8-bit integers. On its
  /// own, format specifier `%x` formats a 32-bit unsigned integer. Length
  /// modifier `hh` adjusts this to a `char`.
  public var hexString: String {
    var hexString = ""
    let bytes = UnsafePointer<CChar>(self.bytes)
    for var index = 0; index < length; index++ {
      hexString += String(format: "%02.2hhx", arguments: [bytes[index]])
    }
    return hexString
  }

}

Convert data to a hexadecimal string
Convert data to a hexadecimal string
