src/lib/wapi/helper/array-buffer-to-base64.js

/*
 * This file is part of WPPConnect.
 *
 * WPPConnect is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * WPPConnect is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with WPPConnect.  If not, see <https://www.gnu.org/licenses/>.
 */

export function arrayBufferToBase64(arrayBuffer) {
  var base64 = '';
  var encodings =
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

  var bytes = new Uint8Array(arrayBuffer);
  var byteLength = bytes.byteLength;
  var byteRemainder = byteLength % 3;
  var mainLength = byteLength - byteRemainder;

  var a, b, c, d;
  var chunk;

  // Main loop deals with bytes in chunks of 3
  for (var i = 0; i < mainLength; i = i + 3) {
    // Combine the three bytes into a single integer
    chunk = (bytes[i] << 16) | (bytes[i + 1] << 8) | bytes[i + 2];

    // Use bitmasks to extract 6-bit segments from the triplet
    a = (chunk & 16515072) >> 18; // 16515072 = (2^6 - 1) << 18
    b = (chunk & 258048) >> 12; // 258048   = (2^6 - 1) << 12
    c = (chunk & 4032) >> 6; // 4032     = (2^6 - 1) << 6
    d = chunk & 63; // 63       = 2^6 - 1

    // Convert the raw binary segments to the appropriate ASCII encoding
    base64 += encodings[a] + encodings[b] + encodings[c] + encodings[d];
  }

  // Deal with the remaining bytes and padding
  if (byteRemainder == 1) {
    chunk = bytes[mainLength];

    a = (chunk & 252) >> 2; // 252 = (2^6 - 1) << 2

    // Set the 4 least significant bits to zero
    b = (chunk & 3) << 4; // 3   = 2^2 - 1

    base64 += encodings[a] + encodings[b] + '==';
  } else if (byteRemainder == 2) {
    chunk = (bytes[mainLength] << 8) | bytes[mainLength + 1];

    a = (chunk & 64512) >> 10; // 64512 = (2^6 - 1) << 10
    b = (chunk & 1008) >> 4; // 1008  = (2^6 - 1) << 4

    // Set the 2 least significant bits to zero
    c = (chunk & 15) << 2; // 15    = 2^4 - 1

    base64 += encodings[a] + encodings[b] + encodings[c] + '=';
  }
  return base64;
}