extract HomeModel from ContentView
huge refactor Signed-off-by: William Casarin <jb55@jb55.com>
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William Casarin
207
damus/Util/Bech32.swift
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207
damus/Util/Bech32.swift
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//
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// Bech32.swift
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//
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// Modified by William Casarin in 2022
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// Created by Evolution Group Ltd on 12.02.2018.
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// Copyright © 2018 Evolution Group Ltd. All rights reserved.
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//
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// Base32 address format for native v0-16 witness outputs implementation
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// https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki
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// Inspired by Pieter Wuille C++ implementation
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import Foundation
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/// Bech32 checksum implementation
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fileprivate let gen: [UInt32] = [0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3]
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/// Bech32 checksum delimiter
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fileprivate let checksumMarker: String = "1"
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/// Bech32 character set for encoding
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fileprivate let encCharset: Data = "qpzry9x8gf2tvdw0s3jn54khce6mua7l".data(using: .utf8)!
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/// Bech32 character set for decoding
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fileprivate let decCharset: [Int8] = [
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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15, -1, 10, 17, 21, 20, 26, 30, 7, 5, -1, -1, -1, -1, -1, -1,
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-1, 29, -1, 24, 13, 25, 9, 8, 23, -1, 18, 22, 31, 27, 19, -1,
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1, 0, 3, 16, 11, 28, 12, 14, 6, 4, 2, -1, -1, -1, -1, -1,
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-1, 29, -1, 24, 13, 25, 9, 8, 23, -1, 18, 22, 31, 27, 19, -1,
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1, 0, 3, 16, 11, 28, 12, 14, 6, 4, 2, -1, -1, -1, -1, -1
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]
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/// Find the polynomial with value coefficients mod the generator as 30-bit.
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public func bech32_polymod(_ values: Data) -> UInt32 {
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var chk: UInt32 = 1
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for v in values {
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let top = (chk >> 25)
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chk = (chk & 0x1ffffff) << 5 ^ UInt32(v)
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for i: UInt8 in 0..<5 {
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chk ^= ((top >> i) & 1) == 0 ? 0 : gen[Int(i)]
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}
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}
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return chk
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}
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/// Expand a HRP for use in checksum computation.
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func bech32_expand_hrp(_ s: String) -> Data {
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var left: [UInt8] = []
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var right: [UInt8] = []
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for x in Array(s) {
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let scalars = String(x).unicodeScalars
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left.append(UInt8(scalars[scalars.startIndex].value) >> 5)
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right.append(UInt8(scalars[scalars.startIndex].value) & 31)
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}
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return Data(left + [0] + right)
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}
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/// Verify checksum
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public func bech32_verify(hrp: String, checksum: Data) -> Bool {
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var data = bech32_expand_hrp(hrp)
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data.append(checksum)
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return bech32_polymod(data) == 1
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}
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/// Create checksum
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public func bech32_create_checksum(hrp: String, values: Data) -> Data {
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var enc = bech32_expand_hrp(hrp)
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enc.append(values)
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enc.append(Data(repeating: 0x00, count: 6))
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let mod: UInt32 = bech32_polymod(enc) ^ 1
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var ret: Data = Data(repeating: 0x00, count: 6)
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for i in 0..<6 {
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ret[i] = UInt8((mod >> (5 * (5 - i))) & 31)
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}
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return ret
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}
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public func bech32_encode(hrp: String, _ input: [UInt8]) -> String {
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let table: [Character] = Array("qpzry9x8gf2tvdw0s3jn54khce6mua7l")
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let bits = eightToFiveBits(input)
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let check_sum = bech32_checksum(hrp: hrp, data: bits)
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let separator = "1"
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return "\(hrp)" + separator + String((bits + check_sum).map { table[Int($0)] })
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}
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func bech32_checksum(hrp: String, data: [UInt8]) -> [UInt8] {
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let values = bech32_expand_hrp(hrp) + data
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let polymod = bech32_polymod(values + [0,0,0,0,0,0]) ^ 1
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var result: [UInt32] = []
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for i in (0..<6) {
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result.append((polymod >> (5 * (5 - UInt32(i)))) & 31)
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}
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return result.map { UInt8($0) }
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}
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func eightToFiveBits(_ input: [UInt8]) -> [UInt8] {
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guard !input.isEmpty else { return [] }
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var outputSize = (input.count * 8) / 5
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if ((input.count * 8) % 5) != 0 {
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outputSize += 1
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}
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var outputArray: [UInt8] = []
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for i in (0..<outputSize) {
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let devision = (i * 5) / 8
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let reminder = (i * 5) % 8
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var element = input[devision] << reminder
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element >>= 3
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if (reminder > 3) && (i + 1 < outputSize) {
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element = element | (input[devision + 1] >> (8 - reminder + 3))
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}
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outputArray.append(element)
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}
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return outputArray
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}
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/// Decode Bech32 string
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public func bech32_decode(_ str: String) throws -> (hrp: String, data: Data) {
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guard let strBytes = str.data(using: .utf8) else {
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throw Bech32Error.nonUTF8String
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}
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guard strBytes.count <= 90 else {
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throw Bech32Error.stringLengthExceeded
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}
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var lower: Bool = false
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var upper: Bool = false
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for c in strBytes {
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// printable range
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if c < 33 || c > 126 {
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throw Bech32Error.nonPrintableCharacter
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}
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// 'a' to 'z'
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if c >= 97 && c <= 122 {
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lower = true
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}
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// 'A' to 'Z'
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if c >= 65 && c <= 90 {
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upper = true
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}
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}
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if lower && upper {
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throw Bech32Error.invalidCase
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}
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guard let pos = str.range(of: checksumMarker, options: .backwards)?.lowerBound else {
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throw Bech32Error.noChecksumMarker
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}
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let intPos: Int = str.distance(from: str.startIndex, to: pos)
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guard intPos >= 1 else {
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throw Bech32Error.incorrectHrpSize
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}
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guard intPos + 7 <= str.count else {
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throw Bech32Error.incorrectChecksumSize
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}
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let vSize: Int = str.count - 1 - intPos
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var values: Data = Data(repeating: 0x00, count: vSize)
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for i in 0..<vSize {
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let c = strBytes[i + intPos + 1]
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let decInt = decCharset[Int(c)]
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if decInt == -1 {
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throw Bech32Error.invalidCharacter
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}
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values[i] = UInt8(decInt)
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}
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let hrp = String(str[..<pos]).lowercased()
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guard bech32_verify(hrp: hrp, checksum: values) else {
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throw Bech32Error.checksumMismatch
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}
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return (hrp, Data(values[..<(vSize-6)]))
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}
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public enum Bech32Error: LocalizedError {
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case nonUTF8String
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case nonPrintableCharacter
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case invalidCase
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case noChecksumMarker
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case incorrectHrpSize
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case incorrectChecksumSize
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case stringLengthExceeded
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case invalidCharacter
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case checksumMismatch
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public var errorDescription: String? {
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switch self {
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case .checksumMismatch:
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return "Checksum doesn't match"
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case .incorrectChecksumSize:
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return "Checksum size too low"
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case .incorrectHrpSize:
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return "Human-readable-part is too small or empty"
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case .invalidCase:
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return "String contains mixed case characters"
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case .invalidCharacter:
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return "Invalid character met on decoding"
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case .noChecksumMarker:
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return "Checksum delimiter not found"
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case .nonPrintableCharacter:
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return "Non printable character in input string"
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case .nonUTF8String:
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return "String cannot be decoded by utf8 decoder"
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case .stringLengthExceeded:
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return "Input string is too long"
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}
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}
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}
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