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adam-fowleradam-fowler
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Base32 (#29)
* Add Base32 support and integration tests * Moved Base64 code into Base64.swift
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‎.gitignore

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.build
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/*.xcodeproj
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xcuserdata
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/.swiftpm

‎IntegrationTests/tests_04_performance/test_01_resources/test_base32_decoding.swift

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import ExtrasBase64
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func run(identifier: String) {
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let base32 = "AAAQEAYEAUDAOCAJBIFQYDIOB4IBCEQTCQKRMFYYDENBWHA5DYPSAIJCEMSCKJRHFAUSUKZMFUXC6MBRGIZTINJWG44DSOR3HQ6T4P2AIFBEGRCFIZDUQSKKJNGE2TSPKBIVEU2UKVLFOWCZLJNVYXK6L5QGCYTDMRSWMZ3INFVGW3DNNZXXA4LSON2HK5TXPB4XU634PV7H7AEBQKBYJBMGQ6EITCULRSGY5D4QSGJJHFEVS2LZRGM2TOOJ3HU7UCQ2FI5EUWTKPKFJVKV2ZLNOV6YLDMVTWS23NN5YXG5LXPF5X274BQOCYPCMLRWHZDE4VS6MZXHM7UGR2LJ5JVOW27MNTWW33TO55X7A4HROHZHF43T6R2PK5PWO33XP6DY7F47U6X3PP6HZ7L57Z7P674"
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var bytes: [UInt8]?
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measure(identifier: identifier) {
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for _ in 0 ..< 1000 {
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bytes = try! Base32.decode(string: base32)
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}
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return bytes?.count ?? 0
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}
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}

‎IntegrationTests/tests_04_performance/test_01_resources/test_base32_encoding.swift

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import ExtrasBase64
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func run(identifier: String) {
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let bytes = Array(UInt8(0) ... UInt8(255))
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var base32: String?
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measure(identifier: identifier) {
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for _ in 0 ..< 1000 {
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base32 = Base32.encodeString(bytes: bytes)
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}
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return base32?.count ?? 0
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}
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}

‎Sources/ExtrasBase64/Base32.swift

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/// String extensions
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public extension String {
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init<Buffer: Collection>(base32Encoding bytes: Buffer) where Buffer.Element == UInt8 {
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self = Base32.encodeString(bytes: bytes)
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}
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func base32decoded() throws -> [UInt8] {
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try Base32.decode(string: self)
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}
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}
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public enum Base32 {
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public enum DecodingError: Swift.Error, Equatable {
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case invalidCharacter(UInt8)
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}
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/// Base32 Encode a buffer to an array of bytes
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public static func encodeBytes<Buffer: Collection>(bytes: Buffer) -> [UInt8] where Buffer.Element == UInt8 {
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let capacity = (bytes.count * 8 + 4) / 5
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let result = bytes.withContiguousStorageIfAvailable { input -> [UInt8] in
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[UInt8](unsafeUninitializedCapacity: capacity) { buffer, length in
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length = Self._encode(from: input, into: buffer)
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}
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}
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if let result = result {
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return result
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}
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return self.encodeBytes(bytes: Array(bytes))
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}
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/// Base32 Encode a buffer to a string
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public static func encodeString<Buffer: Collection>(bytes: Buffer) -> String where Buffer.Element == UInt8 {
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let capacity = (bytes.count * 8 + 4) / 5
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#if swift(>=5.3)
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if #available(OSX 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *) {
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let result = bytes.withContiguousStorageIfAvailable { input in
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String(unsafeUninitializedCapacity: capacity) { buffer -> Int in
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Self._encode(from: input, into: buffer)
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}
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}
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if let result = result {
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return result
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}
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return self.encodeString(bytes: Array(bytes))
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} else {
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let bytes: [UInt8] = self.encodeBytes(bytes: bytes)
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return String(decoding: bytes, as: Unicode.UTF8.self)
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}
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#else
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let bytes: [UInt8] = self.encodeBytes(bytes: bytes)
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return String(decoding: bytes, as: Unicode.UTF8.self)
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#endif
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}
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/// Base32 decode string
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public static func decode(string encoded: String) throws -> [UInt8] {
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let decoded = try encoded.utf8.withContiguousStorageIfAvailable { (characterPointer) -> [UInt8] in
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guard characterPointer.count > 0 else {
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return []
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}
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let capacity = (encoded.utf8.count * 5 + 4) / 8
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return try characterPointer.withMemoryRebound(to: UInt8.self) { (input) -> [UInt8] in
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try [UInt8](unsafeUninitializedCapacity: capacity) { output, length in
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length = try Self._decode(from: input, into: output)
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}
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}
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}
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if let decoded = decoded {
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return decoded
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}
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var encoded = encoded
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encoded.makeContiguousUTF8()
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return try Self.decode(string: encoded)
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}
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public static func decode<Buffer: Collection>(bytes: Buffer) throws -> [UInt8] where Buffer.Element == UInt8 {
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guard bytes.count > 0 else {
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return []
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}
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let decoded = try bytes.withContiguousStorageIfAvailable { (input) -> [UInt8] in
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let outputLength = ((input.count + 3) / 4) * 3
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return try [UInt8](unsafeUninitializedCapacity: outputLength) { output, length in
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length = try Self._decode(from: input, into: output)
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}
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}
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if decoded != nil {
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return decoded!
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}
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return try self.decode(bytes: Array(bytes))
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}
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}
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extension Base32 {
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private static let decodeTable: [UInt32] = [
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/* 00 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 08 */ 0x80, 0x40, 0x40, 0x80, 0x80, 0x40, 0x80, 0x80,
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/* 10 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 18 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 20 */ 0x40, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 28 */ 0x80, 0x80, 0x80, 0x40, 0x80, 0x80, 0x80, 0x80,
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/* 30 */ 0x80, 0x80, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
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/* 38 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 40 */ 0x80, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
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/* 48 */ 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
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/* 50 */ 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
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/* 58 */ 0x17, 0x18, 0x19, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 60 */ 0x80, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
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/* 68 */ 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
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/* 60 */ 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
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/* 68 */ 0x17, 0x18, 0x19, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 80 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 88 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 90 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* 98 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* A0 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* A8 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* B0 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* B8 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* C0 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* C8 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* D0 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* D8 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* E0 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* E8 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* F0 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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/* F8 */ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
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]
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private static let encodeTable: [UInt8] = [
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/* 00 */ 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
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/* 08 */ 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
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/* 10 */ 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
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/* 18 */ 0x59, 0x5A, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
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]
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private static func _decode(from input: UnsafeBufferPointer<UInt8>, into output: UnsafeMutableBufferPointer<UInt8>) throws -> Int {
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guard input.count != 0 else { return 0 }
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return try self.decodeTable.withUnsafeBufferPointer { decodeTable in
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var bitsLeft: Int = 0
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var buffer: UInt32 = 0
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var outputIndex = 0
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for i in 0 ..< input.count {
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let index = Int(input[i])
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let v = decodeTable[index]
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// check for unexpected character
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guard v != 0x80 else { throw DecodingError.invalidCharacter(input[i]) }
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// check for ignorable character
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guard v != 0x40 else { continue }
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buffer <<= 5
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buffer |= v
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bitsLeft += 5
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if bitsLeft >= 8 {
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let result = (buffer >> (bitsLeft - 8))
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output[outputIndex] = UInt8(result & 0xFF)
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outputIndex += 1
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bitsLeft -= 8
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}
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}
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return outputIndex
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}
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}
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private static func _encode(from input: UnsafeBufferPointer<UInt8>, into output: UnsafeMutableBufferPointer<UInt8>) -> Int {
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guard input.count != 0 else { return 0 }
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return self.encodeTable.withUnsafeBufferPointer { encodeTable in
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var outputIndex = 0
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var i = 1
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var bitsLeft = 8
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var buffer = Int(input[0])
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while i < input.count {
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if bitsLeft < 5 {
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buffer <<= 8
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buffer |= Int(input[i])
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i += 1
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bitsLeft += 8
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}
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let unmaskedIndex = (buffer >> (bitsLeft - 5))
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let index = 0x1F & unmaskedIndex
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bitsLeft -= 5
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output[outputIndex] = encodeTable[index]
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outputIndex += 1
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}
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while bitsLeft > 0 {
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if bitsLeft < 5 {
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let pad = 5 - bitsLeft
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buffer <<= pad
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bitsLeft += pad
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}
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let unmaskedIndex = (buffer >> (bitsLeft - 5))
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let index = 0x1F & unmaskedIndex
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bitsLeft -= 5
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output[outputIndex] = encodeTable[index]
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outputIndex += 1
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}
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return outputIndex
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}
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}
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}

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