Scanner+Swift.swift

// NSScanner+Swift.swift
// A set of Swift-idiomatic methods for NSScanner
//
// (c) 2015 Nate Cook, licensed under the MIT license

import Foundation

extension Scanner {

  // MARK: Strings

  /// Returns a string, scanned as long as characters from a given character set are encountered, or `nil` if none are found.
  func scanCharactersFromSet(set: CharacterSet) -> String? {
    var value: NSString?
    if scanCharacters(from: set, into: &value) {
      return value as String?
    }
    return nil
  }

  /// Returns a string, scanned until a character from a given character set are encountered, or the remainder of the scanner's string. Returns `nil` if the scanner is already `atEnd`.
  func scanUpToCharactersFromSet(set: CharacterSet) -> String? {
    var value: NSString?
    if scanUpToCharacters(from: set, into: &value) {
      return value as String?
    }
    return nil
  }

  /// Returns the given string if scanned, or `nil` if not found.
  func scanString(str: String) -> String? {
    var value: NSString?
    if scanString(str, into: &value) {
      return value as String?
    }
    return nil
  }

  /// Returns a string, scanned until the given string is found, or the remainder of the scanner's string. Returns `nil` if the scanner is already `atEnd`.
  func scanUpToString(str: String) -> String? {
    var value: NSString?
    if scanUpTo(str, into: &value) {
      return value as String?
    }
    return nil
  }

  // MARK: Numbers

  /// Returns a Double if scanned, or `nil` if not found.
  func scanDouble() -> Double? {
    var value = 0.0
    if scanDouble(&value) {
      return value
    }
    return nil
  }

  /// Returns a Float if scanned, or `nil` if not found.
  func scanFloat() -> Float? {
    var value: Float = 0.0
    if scanFloat(&value) {
      return value
    }
    return nil
  }

  /// Returns an Int if scanned, or `nil` if not found.
  func scanInt() -> Int? {
    var value = 0
    if scanInt(&value) {
      return value
    }
    return nil
  }

  /// Returns an Int32 if scanned, or `nil` if not found.
  func scanInt32() -> Int32? {
    var value: Int32 = 0
    if scanInt32(&value) {
      return value
    }
    return nil
  }

  /// Returns an Int64 if scanned, or `nil` if not found.
  func scanLongLong() -> Int64? {
    var value: Int64 = 0
    if scanInt64(&value) {
      return value
    }
    return nil
  }

  /// Returns a UInt64 if scanned, or `nil` if not found.
  func scanUnsignedLongLong() -> UInt64? {
    var value: UInt64 = 0
    if scanUnsignedLongLong(&value) {
      return value
    }
    return nil
  }

  /// Returns an NSDecimal if scanned, or `nil` if not found.
  func scanDecimal() -> Decimal? {
    var value = Decimal()
    if scanDecimal(&value) {
      return value
    }
    return nil
  }

  // MARK: Hex Numbers

  /// Returns a Double if scanned in hexadecimal, or `nil` if not found.
  func scanHexDouble() -> Double? {
    var value = 0.0
    if scanHexDouble(&value) {
      return value
    }
    return nil
  }

  /// Returns a Float if scanned in hexadecimal, or `nil` if not found.
  func scanHexFloat() -> Float? {
    var value: Float = 0.0
    if scanHexFloat(&value) {
      return value
    }
    return nil
  }

  /// Returns a UInt32 if scanned in hexadecimal, or `nil` if not found.
  func scanHexInt() -> UInt32? {
    var value: UInt32 = 0
    if scanHexInt32(&value) {
      return value
    }
    return nil
  }

  /// Returns a UInt64 if scanned in hexadecimal, or `nil` if not found.
  func scanHexLongLong() -> UInt64? {
    var value: UInt64 = 0
    if scanHexInt64(&value) {
      return value
    }
    return nil
  }
}