@infinito/id3/lib/valid.js

ID3 Tag Reader/Writer

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = validID3;

var _constants = require("./constants.js");

var _getSyncsafe = _interopRequireDefault(require("./get.syncsafe.js"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function validID3(buf) {
  if (!(buf instanceof ArrayBuffer)) {
    throw new TypeError('parameter buf must be an instance of an ArrayBuffer');
  }

  if (buf.byteLength < _constants.constants.ID3_HEADER_LENGTH_BYTES) {
    throw new Error('buffer provided to validID3 must be at least as big as the ID3 header');
  }

  var res = {
    ver: 0,
    subver: 0,
    flags: 0,
    size: 0
  };
  var header = new Uint8Array(buf, 0, _constants.constants.ID3_HEADER_LENGTH_BYTES - _constants.constants.ID3_HEADER_TAG_SIZE_LENGTH_BYTES);

  for (var i = 0; i < _constants.constants.ID3_HEADER_IDENTIFIER_LENGTH_BYTES; i++) {
    if (header[i] != _constants.constants.ID3_HEADER_IDENTIFIER[i]) {
      throw new Error("No valid id3 tags found");
      return false;
    }
  }

  res.ver = header[_constants.constants.ID3_HEADER_IDENTIFIER_LENGTH_BYTES];
  res.subver = header[_constants.constants.ID3_HEADER_IDENTIFIER_LENGTH_BYTES + 1];
  res.flags = header[_constants.constants.ID3_HEADER_IDENTIFIER_LENGTH_BYTES + 2];
  res.size = (0, _getSyncsafe.default)(new Uint8Array(buf, _constants.constants.ID3_HEADER_IDENTIFIER_LENGTH_BYTES + 3, _constants.constants.ID3_HEADER_TAG_SIZE_LENGTH_BYTES));
  return res;
}

;