const base64DecodeMap = [
  // starts at 0x2B
  62,
  0,
  0,
  0,
  63,
  52,
  53,
  54,
  55,
  56,
  57,
  58,
  59,
  60,
  61,
  0,
  0,
  0,
  0,
  0,
  0,
  0, // 0x3A-0x40
  0,
  1,
  2,
  3,
  4,
  5,
  6,
  7,
  8,
  9,
  10,
  11,
  12,
  13,
  14,
  15,
  16,
  17,
  18,
  19,
  20,
  21,
  22,
  23,
  24,
  25,
  0,
  0,
  0,
  0,
  0,
  0, // 0x5B-0x0x60
  26,
  27,
  28,
  29,
  30,
  31,
  32,
  33,
  34,
  35,
  36,
  37,
  38,
  39,
  40,
  41,
  42,
  43,
  44,
  45,
  46,
  47,
  48,
  49,
  50,
  51
]

const base64DecodeMapOffset = 0x2b
const base64EOF = 0x3d

export function decodeRestrictedBase64ToBytes(encoded: string) {
  let ch: any
  let code: any
  let code2: any

  const len = encoded.length
  const padding = encoded.charAt(len - 2) === '=' ? 2 : encoded.charAt(len - 1) === '=' ? 1 : 0
  const decoded = new Uint8Array((encoded.length >> 2) * 3 - padding)

  for (let i = 0, j = 0; i < encoded.length; ) {
    ch = encoded.charCodeAt(i++)
    code = base64DecodeMap[ch - base64DecodeMapOffset]
    ch = encoded.charCodeAt(i++)
    code2 = base64DecodeMap[ch - base64DecodeMapOffset]
    decoded[j++] = (code << 2) | ((code2 & 0x30) >> 4)

    ch = encoded.charCodeAt(i++)
    if (ch === base64EOF) {
      return decoded
    }
    code = base64DecodeMap[ch - base64DecodeMapOffset]
    decoded[j++] = ((code2 & 0x0f) << 4) | ((code & 0x3c) >> 2)

    ch = encoded.charCodeAt(i++)
    if (ch === base64EOF) {
      return decoded
    }
    code2 = base64DecodeMap[ch - base64DecodeMapOffset]
    decoded[j++] = ((code & 0x03) << 6) | code2
  }
  return decoded
}