// Loaded from https://raw.githubusercontent.com/nats-io/nkeys.js/v1.0.0-9/src/base32.ts


/*
 * Copyright 2018-2021 The NATS Authors
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// Fork of https://github.com/LinusU/base32-encode
// and https://github.com/LinusU/base32-decode to support returning
// buffers without padding.
/**
 * @ignore
 */
const b32Alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";

/**
 * @ignore
 */
export class base32 {
  static encode(src: Uint8Array): Uint8Array {
    let bits = 0;
    let value = 0;
    let a = new Uint8Array(src);
    let buf = new Uint8Array(src.byteLength * 2);
    let j = 0;
    for (let i = 0; i < a.byteLength; i++) {
      value = (value << 8) | a[i];
      bits += 8;
      while (bits >= 5) {
        let index = (value >>> (bits - 5)) & 31;
        buf[j++] = b32Alphabet.charAt(index).charCodeAt(0);
        bits -= 5;
      }
    }
    if (bits > 0) {
      let index = (value << (5 - bits)) & 31;
      buf[j++] = b32Alphabet.charAt(index).charCodeAt(0);
    }
    return buf.slice(0, j);
  }

  static decode(src: Uint8Array): Uint8Array {
    let bits = 0;
    let byte = 0;
    let j = 0;
    let a = new Uint8Array(src);
    let out = new Uint8Array(a.byteLength * 5 / 8 | 0);
    for (let i = 0; i < a.byteLength; i++) {
      let v = String.fromCharCode(a[i]);
      let vv = b32Alphabet.indexOf(v);
      if (vv === -1) {
        throw new Error("Illegal Base32 character: " + a[i]);
      }
      byte = (byte << 5) | vv;
      bits += 5;
      if (bits >= 8) {
        out[j++] = (byte >>> (bits - 8)) & 255;
        bits -= 8;
      }
    }
    return out.slice(0, j);
  }
}