CFBitVector Swift wrapper

ZBitVector.swift

//
//  ZBitVector.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


class ZBitVector {

	let bitVector: CFMutableBitVector
	
	init(capacity: Int) {
		self.bitVector = CFBitVectorCreateMutable(nil, CFIndex(capacity))
	}

	var count: Int {
		return CFBitVectorGetCount(self.bitVector)
	}

	func append(bits: [Bool]) {
		let count = CFBitVectorGetCount(self.bitVector)
		CFBitVectorSetCount(self.bitVector, count + bits.count)
		for index in 0 ..< bits.count {
			CFBitVectorSetBitAtIndex(self.bitVector, count + index, CFBit(bits[index]))
		}
	}

	subscript(index: Int) -> Bool {
		get {
			assert(index >= 0 && index < CFBitVectorGetCount(self.bitVector))
			let bitValue = CFBitVectorGetBitAtIndex(bitVector, index)
			return !(bitValue == 0)
		}
		set {
			if index > CFBitVectorGetCount(self.bitVector) {
				CFBitVectorSetCount(self.bitVector, index + 1)
			}
			CFBitVectorSetBitAtIndex(bitVector, index, CFBit(newValue))
		}
	}

	subscript(range: NSRange) -> [Bool] {
		get {
			var bitValues = [Bool]()
			for index in range.location ..< NSMaxRange(range) {
				let bit = CFBitVectorGetBitAtIndex(bitVector, CFIndex(index))
				bitValues.append(bit != 0)
			}
			return bitValues
		}
	}

	func setBitsAtIndex(index: Int, bits: [Bool]) {
		let count = CFBitVectorGetCount(self.bitVector)
		if index + bits.count > count {
			CFBitVectorSetCount(self.bitVector, index + bits.count)
		}

		for offset in 0 ..< bits.count {
			CFBitVectorSetBitAtIndex(bitVector, index + offset, CFBit(bits[offset]))
		}
	}

	func data() -> NSData {
		let counts = Int(CFBitVectorGetCount(self.bitVector))
		assert(CFBitVectorGetCount(self.bitVector) > 0)
		let bytes = Int(ceil((Double(counts) / 8.0)))
		let data = NSMutableData()
		for index in 0 ..< bytes {
			let range = CFRange(location: CFIndex(index * 8), length: 8)
			var bits: UInt8 = 0
			CFBitVectorGetBits(self.bitVector, range, &bits)
			data.appendBytes(&bits, length: 1)
		}
		return data
	}
	
	func containsBit(range: NSRange, value: Bool) -> Bool {
		return CFBitVectorContainsBit(self.bitVector, CFRange(range), CFBit(value))
	}
	
	func flipBitAtIndex(index: Int) {
		CFBitVectorFlipBitAtIndex(self.bitVector, index)
	}

	func setAllBits(value: Bool) {
		CFBitVectorSetAllBits(self.bitVector, CFBit(value))
	}

}

extension CFRange {
	init(_ range: NSRange) {
		self = CFRangeMake(range.location, range.length)
	}
}

extension CFBit {
	init(_ bool: Bool) {
		self = CFBit(bool ? 1 : 0)
	}
}