NSRange, CFRange Utilities

NSCFRange+Z.swift

//	NSCFRange+Z.swift
//	ZKit
//
//	The MIT License (MIT)
//
//	Copyright (c) 2016 Electricwoods LLC, Kaz Yoshikawa.
//
//	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, EXPRESS OR 
//	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
//	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 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 CFRange {

	init(range: NSRange) {
		self = CFRangeMake(range.location == NSNotFound ? kCFNotFound : range.location, range.length)
	}

}

extension NSRange: CustomStringConvertible {

	init(range: CFRange) {
		self = NSMakeRange(range.location == kCFNotFound ? NSNotFound : range.location, range.length)
	}

	func sliceHead(amount: Int, remainder: UnsafeMutablePointer<NSRange> = nil) -> NSRange {
		if location != NSNotFound {
			let tailLocation =  min(location + amount, NSMaxRange(self))
			let head = NSMakeRange(location, tailLocation - location)
			if remainder != nil {
				remainder.memory = NSMakeRange(tailLocation, NSMaxRange(self) - tailLocation)
			}
			return head
		}
		return self
	}

	func sliceTail(amount: Int, remainder: UnsafeMutablePointer<NSRange> = nil) -> NSRange {
		if location != NSNotFound {
			let tailLocation =  max(NSMaxRange(self) - amount, location)
			let tail = NSMakeRange(tailLocation, min(amount, length))
			if remainder != nil {
				remainder.memory = NSMakeRange(location, tailLocation - location)
			}
			return tail
		}
		return self
	}

	public var description: String {
		return location != NSNotFound ? "{NSRange: \(location) ..< \(location + length)}" : "{NSRange: NSNotFound}"
	}

}