mastodon-ios/Mastodon/Extension/Array.swift

//
//  Array.swift
//  Mastodon
//
//  Created by BradGao on 2021/3/31.
//

import Foundation

/// https://www.hackingwithswift.com/example-code/language/how-to-remove-duplicate-items-from-an-array
extension Array where Element: Hashable {
    func removingDuplicates() -> [Element] {
        var addedDict = [Element: Bool]()

        return filter {
            addedDict.updateValue(true, forKey: $0) == nil
        }
    }

    mutating func removeDuplicates() {
        self = self.removingDuplicates()
    }
}

//
//  CryptoSwift
//
//  Copyright (C) 2014-2017 Marcin Krzyżanowski <marcin@krzyzanowskim.com>
//  This software is provided 'as-is', without any express or implied warranty.
//
//  In no event will the authors be held liable for any damages arising from the use of this software.
//
//  Permission is granted to anyone to use this software for any purpose,including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
//
//  - The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation is required.
//  - Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
//  - This notice may not be removed or altered from any source or binary distribution.
//

extension Array {
  init(reserveCapacity: Int) {
    self = Array<Element>()
    self.reserveCapacity(reserveCapacity)
  }

  var slice: ArraySlice<Element> {
    self[self.startIndex ..< self.endIndex]
  }
}

extension Array where Element == UInt8 {
  public init(hex: String) {
    self.init(reserveCapacity: hex.unicodeScalars.lazy.underestimatedCount)
    var buffer: UInt8?
    var skip = hex.hasPrefix("0x") ? 2 : 0
    for char in hex.unicodeScalars.lazy {
      guard skip == 0 else {
        skip -= 1
        continue
      }
      guard char.value >= 48 && char.value <= 102 else {
        removeAll()
        return
      }
      let v: UInt8
      let c: UInt8 = UInt8(char.value)
      switch c {
        case let c where c <= 57:
          v = c - 48
        case let c where c >= 65 && c <= 70:
          v = c - 55
        case let c where c >= 97:
          v = c - 87
        default:
          removeAll()
          return
      }
      if let b = buffer {
        append(b << 4 | v)
        buffer = nil
      } else {
        buffer = v
      }
    }
    if let b = buffer {
      append(b)
    }
  }

  public func toHexString() -> String {
    `lazy`.reduce(into: "") {
      var s = String($1, radix: 16)
      if s.count == 1 {
        s = "0" + s
      }
      $0 += s
    }
  }
}