OTP/OTPKit/Vendor/Base32.swift

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2021-08-24 22:19:31 +00:00
//
// Base32.swift
// TOTP
//
// Created by on 1/24/15.
//
// Copyright (c) 2015 Norio Nomura
//
// 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
// https://tools.ietf.org/html/rfc4648
// MARK: - Base32 Data <-> String
public func base32Encode(_ data: Data) -> String {
return data.withUnsafeBytes {
base32encode($0.baseAddress!, $0.count, alphabetEncodeTable)
}
}
public func base32HexEncode(_ data: Data) -> String {
return data.withUnsafeBytes {
base32encode($0.baseAddress!, $0.count, extendedHexAlphabetEncodeTable)
}
}
public func base32DecodeToData(_ string: String) -> Data? {
return base32decode(string, alphabetDecodeTable).flatMap(Data.init(_:))
}
public func base32HexDecodeToData(_ string: String) -> Data? {
return base32decode(string, extendedHexAlphabetDecodeTable).flatMap(Data.init(_:))
}
// MARK: - Base32 [UInt8] <-> String
public func base32Encode(_ array: [UInt8]) -> String {
return base32encode(array, array.count, alphabetEncodeTable)
}
public func base32HexEncode(_ array: [UInt8]) -> String {
return base32encode(array, array.count, extendedHexAlphabetEncodeTable)
}
public func base32Decode(_ string: String) -> [UInt8]? {
return base32decode(string, alphabetDecodeTable)
}
public func base32HexDecode(_ string: String) -> [UInt8]? {
return base32decode(string, extendedHexAlphabetDecodeTable)
}
// MARK: extensions
extension String {
// base32
public var base32DecodedData: Data? {
return base32DecodeToData(self)
}
public var base32EncodedString: String {
return utf8CString.withUnsafeBufferPointer {
base32encode($0.baseAddress!, $0.count - 1, alphabetEncodeTable)
}
}
public func base32DecodedString(_ encoding: String.Encoding = .utf8) -> String? {
return base32DecodedData.flatMap {
String(data: $0, encoding: .utf8)
}
}
// base32Hex
public var base32HexDecodedData: Data? {
return base32HexDecodeToData(self)
}
public var base32HexEncodedString: String {
return utf8CString.withUnsafeBufferPointer {
base32encode($0.baseAddress!, $0.count - 1, extendedHexAlphabetEncodeTable)
}
}
public func base32HexDecodedString(_ encoding: String.Encoding = .utf8) -> String? {
return base32HexDecodedData.flatMap {
String(data: $0, encoding: .utf8)
}
}
}
extension Data {
// base32
public var base32EncodedString: String {
return base32Encode(self)
}
public var base32EncodedData: Data {
return base32EncodedString.dataUsingUTF8StringEncoding
}
public var base32DecodedData: Data? {
return String(data: self, encoding: .utf8).flatMap(base32DecodeToData)
}
// base32Hex
public var base32HexEncodedString: String {
return base32HexEncode(self)
}
public var base32HexEncodedData: Data {
return base32HexEncodedString.dataUsingUTF8StringEncoding
}
public var base32HexDecodedData: Data? {
return String(data: self, encoding: .utf8).flatMap(base32HexDecodeToData)
}
}
// MARK: - private
private extension String {
var dataUsingUTF8StringEncoding: Data {
return utf8CString.withUnsafeBufferPointer {
Data($0.dropLast().map(UInt8.init))
}
}
}
// MARK: encode
private let alphabetEncodeTable: [Int8] = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","2","3","4","5","6","7"].map { (c: UnicodeScalar) -> Int8 in Int8(c.value) }
private let extendedHexAlphabetEncodeTable: [Int8] = ["0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V"].map { (c: UnicodeScalar) -> Int8 in Int8(c.value) }
private func base32encode(_ data: UnsafeRawPointer, _ length: Int, _ table: [Int8]) -> String {
if length == 0 {
return ""
}
var length = length
var bytes = data.assumingMemoryBound(to: UInt8.self)
let resultBufferSize = Int(ceil(Double(length) / 5)) * 8 + 1 // need null termination
let resultBuffer = UnsafeMutablePointer<Int8>.allocate(capacity: resultBufferSize)
var encoded = resultBuffer
// encode regular blocks
while length >= 5 {
encoded[0] = table[Int(bytes[0] >> 3)]
encoded[1] = table[Int((bytes[0] & 0b00000111) << 2 | bytes[1] >> 6)]
encoded[2] = table[Int((bytes[1] & 0b00111110) >> 1)]
encoded[3] = table[Int((bytes[1] & 0b00000001) << 4 | bytes[2] >> 4)]
encoded[4] = table[Int((bytes[2] & 0b00001111) << 1 | bytes[3] >> 7)]
encoded[5] = table[Int((bytes[3] & 0b01111100) >> 2)]
encoded[6] = table[Int((bytes[3] & 0b00000011) << 3 | bytes[4] >> 5)]
encoded[7] = table[Int((bytes[4] & 0b00011111))]
length -= 5
encoded = encoded.advanced(by: 8)
bytes = bytes.advanced(by: 5)
}
// encode last block
var byte0, byte1, byte2, byte3, byte4: UInt8
(byte0, byte1, byte2, byte3, byte4) = (0,0,0,0,0)
switch length {
case 4:
byte3 = bytes[3]
encoded[6] = table[Int((byte3 & 0b00000011) << 3 | byte4 >> 5)]
encoded[5] = table[Int((byte3 & 0b01111100) >> 2)]
fallthrough
case 3:
byte2 = bytes[2]
encoded[4] = table[Int((byte2 & 0b00001111) << 1 | byte3 >> 7)]
fallthrough
case 2:
byte1 = bytes[1]
encoded[3] = table[Int((byte1 & 0b00000001) << 4 | byte2 >> 4)]
encoded[2] = table[Int((byte1 & 0b00111110) >> 1)]
fallthrough
case 1:
byte0 = bytes[0]
encoded[1] = table[Int((byte0 & 0b00000111) << 2 | byte1 >> 6)]
encoded[0] = table[Int(byte0 >> 3)]
default: break
}
// padding
let pad = Int8(UnicodeScalar("=").value)
switch length {
case 0:
encoded[0] = 0
case 1:
encoded[2] = pad
encoded[3] = pad
fallthrough
case 2:
encoded[4] = pad
fallthrough
case 3:
encoded[5] = pad
encoded[6] = pad
fallthrough
case 4:
encoded[7] = pad
fallthrough
default:
encoded[8] = 0
break
}
// return
if let base32Encoded = String(validatingUTF8: resultBuffer) {
resultBuffer.deallocate()
return base32Encoded
} else {
resultBuffer.deallocate()
fatalError("internal error")
}
}
// MARK: decode
private let __: UInt8 = 255
private let alphabetDecodeTable: [UInt8] = [
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x00 - 0x0F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x10 - 0x1F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x20 - 0x2F
__,__,26,27, 28,29,30,31, __,__,__,__, __,__,__,__, // 0x30 - 0x3F
__, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14, // 0x40 - 0x4F
15,16,17,18, 19,20,21,22, 23,24,25,__, __,__,__,__, // 0x50 - 0x5F
__, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14, // 0x60 - 0x6F
15,16,17,18, 19,20,21,22, 23,24,25,__, __,__,__,__, // 0x70 - 0x7F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x80 - 0x8F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x90 - 0x9F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xA0 - 0xAF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xB0 - 0xBF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xC0 - 0xCF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xD0 - 0xDF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xE0 - 0xEF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xF0 - 0xFF
]
private let extendedHexAlphabetDecodeTable: [UInt8] = [
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x00 - 0x0F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x10 - 0x1F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x20 - 0x2F
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,__,__, __,__,__,__, // 0x30 - 0x3F
__,10,11,12, 13,14,15,16, 17,18,19,20, 21,22,23,24, // 0x40 - 0x4F
25,26,27,28, 29,30,31,__, __,__,__,__, __,__,__,__, // 0x50 - 0x5F
__,10,11,12, 13,14,15,16, 17,18,19,20, 21,22,23,24, // 0x60 - 0x6F
25,26,27,28, 29,30,31,__, __,__,__,__, __,__,__,__, // 0x70 - 0x7F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x80 - 0x8F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0x90 - 0x9F
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xA0 - 0xAF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xB0 - 0xBF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xC0 - 0xCF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xD0 - 0xDF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xE0 - 0xEF
__,__,__,__, __,__,__,__, __,__,__,__, __,__,__,__, // 0xF0 - 0xFF
]
private func base32decode(_ string: String, _ table: [UInt8]) -> [UInt8]? {
let length = string.unicodeScalars.count
if length == 0 {
return []
}
// calc padding length
func getLeastPaddingLength(_ string: String) -> Int {
if string.hasSuffix("======") {
return 6
} else if string.hasSuffix("====") {
return 4
} else if string.hasSuffix("===") {
return 3
} else if string.hasSuffix("=") {
return 1
} else {
return 0
}
}
// validate string
let leastPaddingLength = getLeastPaddingLength(string)
if let index = string.unicodeScalars.firstIndex(where: {$0.value > 0xff || table[Int($0.value)] > 31}) {
// index points padding "=" or invalid character that table does not contain.
let pos = string.unicodeScalars.distance(from: string.unicodeScalars.startIndex, to: index)
// if pos points padding "=", it's valid.
if pos != length - leastPaddingLength {
print("string contains some invalid characters.")
return nil
}
}
var remainEncodedLength = length - leastPaddingLength
var additionalBytes = 0
switch remainEncodedLength % 8 {
// valid
case 0: break
case 2: additionalBytes = 1
case 4: additionalBytes = 2
case 5: additionalBytes = 3
case 7: additionalBytes = 4
default:
print("string length is invalid.")
return nil
}
// validated
let dataSize = remainEncodedLength / 8 * 5 + additionalBytes
// Use UnsafePointer<UInt8>
return string.utf8CString.withUnsafeBufferPointer {
(data: UnsafeBufferPointer<CChar>) -> [UInt8] in
var encoded = data.baseAddress!
var result = Array<UInt8>(repeating: 0, count: dataSize)
var decodedOffset = 0
// decode regular blocks
var value0, value1, value2, value3, value4, value5, value6, value7: UInt8
(value0, value1, value2, value3, value4, value5, value6, value7) = (0,0,0,0,0,0,0,0)
while remainEncodedLength >= 8 {
value0 = table[Int(encoded[0])]
value1 = table[Int(encoded[1])]
value2 = table[Int(encoded[2])]
value3 = table[Int(encoded[3])]
value4 = table[Int(encoded[4])]
value5 = table[Int(encoded[5])]
value6 = table[Int(encoded[6])]
value7 = table[Int(encoded[7])]
result[decodedOffset] = value0 << 3 | value1 >> 2
result[decodedOffset + 1] = value1 << 6 | value2 << 1 | value3 >> 4
result[decodedOffset + 2] = value3 << 4 | value4 >> 1
result[decodedOffset + 3] = value4 << 7 | value5 << 2 | value6 >> 3
result[decodedOffset + 4] = value6 << 5 | value7
remainEncodedLength -= 8
decodedOffset += 5
encoded = encoded.advanced(by: 8)
}
// decode last block
(value0, value1, value2, value3, value4, value5, value6, value7) = (0,0,0,0,0,0,0,0)
switch remainEncodedLength {
case 7:
value6 = table[Int(encoded[6])]
value5 = table[Int(encoded[5])]
fallthrough
case 5:
value4 = table[Int(encoded[4])]
fallthrough
case 4:
value3 = table[Int(encoded[3])]
value2 = table[Int(encoded[2])]
fallthrough
case 2:
value1 = table[Int(encoded[1])]
value0 = table[Int(encoded[0])]
default: break
}
switch remainEncodedLength {
case 7:
result[decodedOffset + 3] = value4 << 7 | value5 << 2 | value6 >> 3
fallthrough
case 5:
result[decodedOffset + 2] = value3 << 4 | value4 >> 1
fallthrough
case 4:
result[decodedOffset + 1] = value1 << 6 | value2 << 1 | value3 >> 4
fallthrough
case 2:
result[decodedOffset] = value0 << 3 | value1 >> 2
default: break
}
return result
}
}