Refactor Base32 encoder / decoder
This commit is contained in:
Yasuhiro Hatta
parent
c0d5346d88
commit
7664bd83d9
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@ -9,41 +9,26 @@ import Foundation
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enum Base32 {
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static let crockfordsEncodingTable: [Character] = Array("0123456789ABCDEFGHJKMNPQRSTVWXYZ")
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static let crockfordsEncodingTable: [UInt8] = "0123456789ABCDEFGHJKMNPQRSTVWXYZ".utf8.map({ $0 })
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static let crockfordsDecodingTable: [Character: UInt8] = [
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"0": 0x00, "O": 0x00, "o": 0x00,
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"1": 0x01, "I": 0x01, "i": 0x01, "L": 0x01, "l": 0x01,
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"2": 0x02,
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"3": 0x03,
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"4": 0x04,
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"5": 0x05,
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"6": 0x06,
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"7": 0x07,
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"8": 0x08,
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"9": 0x09,
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"A": 0x0a, "a": 0x0a,
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"B": 0x0b, "b": 0x0b,
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"C": 0x0c, "c": 0x0c,
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"D": 0x0d, "d": 0x0d,
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"E": 0x0e, "e": 0x0e,
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"F": 0x0f, "f": 0x0f,
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"G": 0x10, "g": 0x10,
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"H": 0x11, "h": 0x11,
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"J": 0x12, "j": 0x12,
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"K": 0x13, "k": 0x13,
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"M": 0x14, "m": 0x14,
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"N": 0x15, "n": 0x15,
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"P": 0x16, "p": 0x16,
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"Q": 0x17, "q": 0x17,
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"R": 0x18, "r": 0x18,
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"S": 0x19, "s": 0x19,
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"T": 0x1a, "t": 0x1a,
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"V": 0x1b, "v": 0x1b,
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"W": 0x1c, "w": 0x1c,
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"X": 0x1d, "x": 0x1d,
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"Y": 0x1e, "y": 0x1e,
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"Z": 0x1f, "z": 0x1f
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static let crockfordsDecodingTable: [UInt8] = [
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// 0 1 2 3 4 5 6 7 8 9 a b c d e f
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // 0
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // 1
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // 2
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0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // 3
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0xff, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x01, 0x12, 0x13, 0x01, 0x14, 0x15, 0x00, // 4
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0x16, 0x17, 0x18, 0x19, 0x1a, 0xff, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, // 5
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0xff, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x01, 0x12, 0x13, 0x01, 0x14, 0x15, 0x00, // 6
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0x16, 0x17, 0x18, 0x19, 0x1a, 0xff, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, // 7
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // 8
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // 9
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // a
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // b
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // c
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // d
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // e
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff // f
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]
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}
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@ -55,37 +40,80 @@ enum Base32Error: Error {
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extension Data {
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/// Decode Crockford's Base32
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init?(base32Encoded base32String: String, using table: [Character: UInt8] = Base32.crockfordsDecodingTable) {
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var str: [Character] = Array(base32String)
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while let last = str.last, last == "=" {
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str.removeLast()
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init?(base32Encoded base32String: String, using table: [UInt8] = Base32.crockfordsDecodingTable) {
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guard base32String.unicodeScalars.allSatisfy({ $0.isASCII }) else {
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return nil
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}
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let div = str.count / 8
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let mod = str.count % 8
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var buffer = Data()
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do {
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func unwrap(_ value: UInt8?) throws -> UInt8 {
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guard let value = value else { throw Base32Error.invalidCharacter }
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return value
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var base32String = base32String
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while let last = base32String.last, last == "=" {
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base32String.removeLast()
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}
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guard [0, 2, 4, 5, 7].contains(base32String.count % 8) else {
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return nil
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}
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for i in 0 ... div {
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if i == div, mod == 0 { break }
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let offset = 8 * i
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try buffer.append(unwrap(table[str[offset + 0]]) << 3 | unwrap(table[str[offset + 1]]) >> 2)
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if i == div, mod == 2 { break }
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try buffer.append(unwrap(table[str[offset + 1]]) << 6 | unwrap(table[str[offset + 2]]) << 1 | unwrap(table[str[offset + 3]]) >> 4)
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if i == div, mod == 4 { break }
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try buffer.append(unwrap(table[str[offset + 3]]) << 4 | unwrap(table[str[offset + 4]]) >> 1)
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if i == div, mod == 5 { break }
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try buffer.append(unwrap(table[str[offset + 4]]) << 7 | unwrap(table[str[offset + 5]]) << 2 | unwrap(table[str[offset + 6]]) >> 3)
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if i == div, mod == 7 { break }
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try buffer.append(unwrap(table[str[offset + 6]]) << 5 | unwrap(table[str[offset + 7]]))
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let dstlen = base32String.count * 5 / 8
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var buffer = Data(count: dstlen)
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let success: Bool = buffer.withUnsafeMutableBytes { (dst: UnsafeMutablePointer<UInt8>) in
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base32String.withCString(encodedAs: Unicode.ASCII.self) { (src) in
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func _strlen(_ str: UnsafePointer<UInt8>) -> Int {
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var str = str
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var i = 0
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while str.pointee != 0 {
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str += 1
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i += 1
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}
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} catch {
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return i
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}
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var srcleft = _strlen(src)
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var srcp = src
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var dstp = dst
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let work = UnsafeMutablePointer<UInt8>.allocate(capacity: 8)
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defer { work.deallocate() }
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while srcleft > 0 {
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let worklen = Swift.min(8, srcleft)
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for i in 0 ..< worklen {
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work[i] = table[Int(srcp[i])]
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if work[i] == 0xff {
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return false
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}
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}
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switch worklen {
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case 8:
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dstp[4] = (work[6] << 5) | (work[7] )
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fallthrough
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case 7:
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dstp[3] = (work[4] << 7) | (work[5] << 2) | (work[6] >> 3)
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fallthrough
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case 5:
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dstp[2] = (work[3] << 4) | (work[4] >> 1)
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fallthrough
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case 4:
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dstp[1] = (work[1] << 6) | (work[2] << 1) | (work[3] >> 4)
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fallthrough
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case 2:
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dstp[0] = (work[0] << 3) | (work[1] >> 2)
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default:
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break
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}
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srcp += 8
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srcleft -= 8
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dstp += 5
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}
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return true
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}
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}
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guard success else {
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return nil
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}
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@ -93,36 +121,89 @@ extension Data {
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}
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/// Encode Crockford's Base32
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func base32EncodedString(using table: [Character] = Base32.crockfordsEncodingTable) -> String {
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let div = self.count / 5
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let mod = self.count % 5
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func base32EncodedString(padding: Bool = true, using table: [UInt8] = Base32.crockfordsEncodingTable) -> String {
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var srcleft = self.count
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return self.withUnsafeBytes { (bytes: UnsafePointer<UInt8>) in
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var str = [Character]()
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var pad = 0
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let dstlen: Int
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if padding {
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dstlen = (self.count + 4) / 5 * 8
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} else {
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dstlen = (self.count * 8 + 4) / 5
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}
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var dstleft = dstlen
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for i in 0 ... div {
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if i == div, mod == 0 { break }
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let offset = 5 * i
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str.append(table[Int((bytes[offset + 0] >> 3))])
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str.append(table[Int((bytes[offset + 0] & 0b00000111) << 2 | bytes[offset + 1] >> 6)])
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if i == div, mod == 1 { pad = 6; break }
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str.append(table[Int((bytes[offset + 1] & 0b00111110) >> 1)])
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str.append(table[Int((bytes[offset + 1] & 0b00000001) << 4 | bytes[offset + 2] >> 4)])
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if i == div, mod == 2 { pad = 4; break }
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str.append(table[Int((bytes[offset + 2] & 0b00001111) << 1 | bytes[offset + 3] >> 7)])
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if i == div, mod == 3 { pad = 3; break }
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str.append(table[Int((bytes[offset + 3] & 0b01111100) >> 2)])
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str.append(table[Int((bytes[offset + 3] & 0b00000011) << 3 | bytes[offset + 4] >> 5)])
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if i == div, mod == 4 { pad = 1; break }
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str.append(table[Int((bytes[offset + 4] & 0b00011111))])
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return self.withUnsafeBytes { (src: UnsafePointer<UInt8>) in
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var srcp = src
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let dst = UnsafeMutablePointer<UInt8>.allocate(capacity: dstlen + 1)
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var dstp = dst
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defer { dst.deallocate() }
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let work = UnsafeMutablePointer<UInt8>.allocate(capacity: 8)
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defer { work.deallocate() }
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while srcleft > 0 {
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switch srcleft {
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case _ where 5 <= srcleft:
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work[7] = srcp[4]
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work[6] = srcp[4] >> 5
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fallthrough
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case 4:
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work[6] |= srcp[3] << 3
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work[5] = srcp[3] >> 2
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work[4] = srcp[3] >> 7
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fallthrough
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case 3:
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work[4] |= srcp[2] << 1
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work[3] = srcp[2] >> 4
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fallthrough
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case 2:
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work[3] |= srcp[1] << 4
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work[2] = srcp[1] >> 1
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work[1] = srcp[1] >> 6
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fallthrough
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case 1:
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work[1] |= srcp[0] << 2
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work[0] = srcp[0] >> 3
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default:
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break
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}
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for _ in 0 ..< pad {
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str.append("=")
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for i in 0 ..< Swift.min(8, dstleft) {
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dstp[i] = table[Int(work[i] & 0x1f)]
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}
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return String(str)
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if srcleft < 5 {
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if padding {
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switch srcleft {
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case 1:
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dstp[2] = "=".utf8.first!
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dstp[3] = "=".utf8.first!
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fallthrough
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case 2:
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dstp[4] = "=".utf8.first!
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fallthrough
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case 3:
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dstp[5] = "=".utf8.first!
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dstp[6] = "=".utf8.first!
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fallthrough
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case 4:
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dstp[7] = "=".utf8.first!
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default:
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break
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}
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}
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break
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}
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srcp += 5
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srcleft -= 5
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dstp += 8
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dstleft -= 8
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}
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dst[dstlen] = 0
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return String(cString: dst)
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}
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}
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@ -10,6 +10,9 @@ import XCTest
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final class Base32Tests: XCTestCase {
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// MARK: -
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// MARK: Encode
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func testEncodeBase32() {
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let expected = "00000001D0YX86C6ZTSZJNXFHDQMCYBQ"
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@ -22,6 +25,117 @@ final class Base32Tests: XCTestCase {
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XCTAssertEqual(expected, data.base32EncodedString())
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}
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func testEncode1() {
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let bytes: [UInt8] = [
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0b11111000, 0b00000000, 0b00000000, 0b00000000, 0b00000000
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("Z0000000", data.base32EncodedString())
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}
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func testEncode2() {
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let bytes: [UInt8] = [
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0b00000111, 0b11000000, 0b00000000, 0b00000000, 0b00000000
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("0Z000000", data.base32EncodedString())
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}
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func testEncode3() {
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let bytes: [UInt8] = [
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0b00000000, 0b00111110, 0b00000000, 0b00000000, 0b00000000
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("00Z00000", data.base32EncodedString())
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}
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func testEncode4() {
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let bytes: [UInt8] = [
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0b00000000, 0b00000001, 0b11110000, 0b00000000, 0b00000000
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("000Z0000", data.base32EncodedString())
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}
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func testEncode5() {
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let bytes: [UInt8] = [
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0b00000000, 0b00000000, 0b00001111, 0b10000000, 0b00000000
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("0000Z000", data.base32EncodedString())
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}
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func testEncode6() {
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let bytes: [UInt8] = [
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0b00000000, 0b00000000, 0b00000000, 0b01111100, 0b00000000
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("00000Z00", data.base32EncodedString())
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}
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func testEncode7() {
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let bytes: [UInt8] = [
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0b00000000, 0b00000000, 0b00000000, 0b00000011, 0b11100000
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("000000Z0", data.base32EncodedString())
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}
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func testEncode8() {
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let bytes: [UInt8] = [
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0b00000000, 0b00000000, 0b00000000, 0b00000000, 0b00011111
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("0000000Z", data.base32EncodedString())
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}
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func testEncodePad1() {
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let bytes: [UInt8] = [
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0b10000100
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("GG======", data.base32EncodedString())
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}
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func testEncodePad2() {
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let bytes: [UInt8] = [
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0b10000100, 0b00100001
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("GGGG====", data.base32EncodedString())
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}
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func testEncodePad3() {
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let bytes: [UInt8] = [
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0b10000100, 0b00100001, 0b00001000
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("GGGGG===", data.base32EncodedString())
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}
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func testEncodePad4() {
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let bytes: [UInt8] = [
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0b10000100, 0b00100001, 0b00001000, 0b01000010
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]
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let data = Data(bytes: bytes)
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XCTAssertEqual("GGGGGGG=", data.base32EncodedString())
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}
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// MARK: -
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// MARK: Decode
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func testDecodeBase32() {
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let expected: [UInt8] = [
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0x00, 0x00, 0x00, 0x00, 0x01, 0x68, 0x3D, 0xD4, 0x19, 0x86,
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@ -35,6 +149,52 @@ final class Base32Tests: XCTestCase {
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XCTAssertEqual(expected, Array(data!))
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}
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func testDecodeTable() {
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let table: [Character: UInt8] = [
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"0": 0x00, "O": 0x00, "o": 0x00,
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"1": 0x01, "I": 0x01, "i": 0x01, "L": 0x01, "l": 0x01,
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"2": 0x02,
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"3": 0x03,
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"4": 0x04,
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"5": 0x05,
|
||||
"6": 0x06,
|
||||
"7": 0x07,
|
||||
"8": 0x08,
|
||||
"9": 0x09,
|
||||
"A": 0x0a, "a": 0x0a,
|
||||
"B": 0x0b, "b": 0x0b,
|
||||
"C": 0x0c, "c": 0x0c,
|
||||
"D": 0x0d, "d": 0x0d,
|
||||
"E": 0x0e, "e": 0x0e,
|
||||
"F": 0x0f, "f": 0x0f,
|
||||
"G": 0x10, "g": 0x10,
|
||||
"H": 0x11, "h": 0x11,
|
||||
"J": 0x12, "j": 0x12,
|
||||
"K": 0x13, "k": 0x13,
|
||||
"M": 0x14, "m": 0x14,
|
||||
"N": 0x15, "n": 0x15,
|
||||
"P": 0x16, "p": 0x16,
|
||||
"Q": 0x17, "q": 0x17,
|
||||
"R": 0x18, "r": 0x18,
|
||||
"S": 0x19, "s": 0x19,
|
||||
"T": 0x1a, "t": 0x1a,
|
||||
"V": 0x1b, "v": 0x1b,
|
||||
"W": 0x1c, "w": 0x1c,
|
||||
"X": 0x1d, "x": 0x1d,
|
||||
"Y": 0x1e, "y": 0x1e,
|
||||
"Z": 0x1f, "z": 0x1f
|
||||
]
|
||||
|
||||
for (char, value) in table {
|
||||
let data = Data(base32Encoded: String(char) + "0")
|
||||
XCTAssertNotNil(data)
|
||||
XCTAssertEqual(1, data!.count)
|
||||
XCTAssertEqual(value << 3, data![0])
|
||||
}
|
||||
}
|
||||
|
||||
// MARK: -
|
||||
|
||||
static var allTests = [
|
||||
("testEncodeBase32", testEncodeBase32),
|
||||
("testDecodeBase32", testDecodeBase32)
|
||||
|
|
|
|||
Loading…
Reference in New Issue