export namespace Base64 {
    // adapted from https://gist.github.com/Juszczak/63e6d9e01decc850de03
    /**
     * base64 encoding/decoding
     */
  
    // @ts-ignore: decorator
    @lazy
      const PADCHAR = "=";
    // @ts-ignore: decorator
    @lazy
      const ALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
    // @ts-ignore: decorator
    @lazy
      const ALPHAVALUES = StaticArray.fromArray<u8>([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 63, 62, 62, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0, 0, 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, 63, 0, 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]);
  
  
    /**
      * Decode a base64-encoded string and return a Uint8Array.
      * @param s Base64 encoded string.
      * @example
      * ```ts
      * const signatureData = Base64.decode('IHhJwlD7P-o6x7L38den1MnumUhnYmNhTZhIUQQhezvEMf7rx89NbIIioNCIQSk1PQYdQ9mOI4-rDYiwO2pLvM4=');
      * ```
      */
    export function decode(s: string): Uint8Array {
      let i: u32, b10: u32;
      let pads = 0,
          imax = s.length as u32;
  
      if (imax == 0) {
        return new Uint8Array(0);
      }
  
      if (s.charAt(imax - 1) == PADCHAR) {
        pads = 1;
        if (s.charAt(imax - 2) == PADCHAR) {
          pads = 2;
        }
        imax -= 4;
      }
  
      let main_chunk = (imax / 4) * 3;
      let pad_size = pads > 0 ? 3 - pads : 0;
      let size = main_chunk + pad_size;
  
      let x = new Uint8Array(size),
          index = 0;
  
      for (i = 0; i < imax; i += 4) {
        b10 =
          (getByte64(s, i) << 18) |
          (getByte64(s, i + 1) << 12) |
          (getByte64(s, i + 2) << 6) |
          getByte64(s, i + 3);
        x[index++] = b10 >> 16;
        x[index++] = (b10 >> 8) & 255;
        x[index++] = b10 & 255;
      }
      switch (pads) {
        case 1:
          b10 =
            (getByte64(s, i) << 18) |
            (getByte64(s, i + 1) << 12) |
            (getByte64(s, i + 2) << 6);
          x[index++] = b10 >> 16;
          x[index++] = (b10 >> 8) & 255;
          break;
        case 2:
          b10 = (getByte64(s, i) << 18) | (getByte64(s, i + 1) << 12);
          x[index++] = b10 >> 16;
          break;
      }
  
      return x;
    }
  
    /**
      * Encode Uint8Array as a base64 string.
      * @param bytes Byte array of type Uint8Array.
      * @example
      * ```ts
      * const base64encodedStr = Base64.encode('Hello world!');
      * ```
      */
    export function encode(bytes: Uint8Array): string {
      let i: i32, b10: u32;
  
      const extrabytes = (bytes.length % 3);
      let imax = bytes.length - extrabytes;
      const len = ((bytes.length / 3) as i32) * 4 + (extrabytes == 0 ? 0 : 4);
      
      //@ts-ignore
      let x = changetype<string>(__new(<usize>(len << 1), idof<string>()));
  
      if (bytes.length == 0) {
        return "";
      }
  
      let ptr = changetype<usize>(x) - 2;
      for (i = 0; i < imax; i += 3) {
        b10 =
          ((bytes[i] as u32) << 16) |
          ((bytes[i + 1] as u32) << 8) |
          (bytes[i + 2] as u32);
        store<u16>(ptr += 2, (ALPHA.charCodeAt(b10 >> 18) as u16));
        store<u16>(ptr += 2, (ALPHA.charCodeAt(((b10 >> 12) & 63)) as u16));
        store<u16>(ptr += 2, (ALPHA.charCodeAt(((b10 >> 6) & 63)) as u16));
        store<u16>(ptr += 2, (ALPHA.charCodeAt((b10 & 63)) as u16));
      }
  
      switch (bytes.length - imax) {
        case 1:
          b10 = (bytes[i] as u32) << 16;
          store<u16>(ptr += 2, ((ALPHA.charCodeAt(b10 >> 18)) as u16));
          store<u16>(ptr += 2, ((ALPHA.charCodeAt((b10 >> 12) & 63)) as u16));
          store<u16>(ptr += 2, ((PADCHAR.charCodeAt(0)) as u16));
          store<u16>(ptr += 2, ((PADCHAR.charCodeAt(0)) as u16));
          break;
        case 2:
          b10 = ((bytes[i] as u32) << 16) | ((bytes[i + 1] as u32) << 8);
          store<u16>(ptr += 2, ((ALPHA.charCodeAt(b10 >> 18)) as u16));
          store<u16>(ptr += 2, ((ALPHA.charCodeAt((b10 >> 12) & 63)) as u16));
          store<u16>(ptr += 2, ((ALPHA.charCodeAt((b10 >> 6) & 63)) as u16));
          store<u16>(ptr += 2, ((PADCHAR.charCodeAt(0)) as u16));
          break;
      }
  
      return x;
    }
  
    // @ts-ignore: decorator
    @inline
    function getByte64(s: string, i: u32): u32 {
      return ALPHAVALUES[s.charCodeAt(i)];
    }
  }