chat/modules/ArrayBufferUtils.jsm
author aleth <aleth@instantbird.org>
Sat, 05 Dec 2015 01:33:13 +0100
changeset 23386 55507ff7483eff625ee53bb64660c33f36f2c68a
parent 23193 a66c8906fb9c5f4b38b438ed55f10a806c1a19ff
child 23489 7a2c243821cc79b3a11bc8fae12bc0c6135f35d5
permissions -rw-r--r--
Bug 1224746 - Package mozmill and calendar tests for OS X universal builds too. r=jcranmer, a=rkent

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * JavaScript ArrayBuffers are missing a variety of useful methods which are
 * provided by this module.
 */

const EXPORTED_SYMBOLS = ["copyBytes", "ArrayBufferToBytes",
  "BytesToArrayBuffer", "StringToBytes", "StringToArrayBuffer",
  "ArrayBufferToString", "ArrayBufferToHexString"];

/*
 * aTarget / aSource are ArrayBuffers.
 *
 * Note that this is very similar to ArrayBuffer.slice except that it allows
 * for an offset in the target as well as the source.
 */
function copyBytes(aTarget, aSource, aTargetOffset = 0, aSourceOffset = 0,
                   aLength = aSource.byteLength) {
  // The rest just gets the data copied into it.
  let view = new Uint8Array(aTarget, aTargetOffset);
  view.set(new Uint8Array(aSource, aSourceOffset, aLength));
}

function ArrayBufferToBytes(aBuf) {
  return [...new Uint8Array(aBuf)];
}

function BytesToArrayBuffer(aBytes = []) {
  let buf = new ArrayBuffer(aBytes.length);
  let view = new Uint8Array(buf);
  view.set(aBytes);
  return buf;
}

function StringToBytes(aString) {
  return [aString.charCodeAt(i) for (i in aString)];
}

function StringToArrayBuffer(aString) {
  return BytesToArrayBuffer(StringToBytes(aString));
}

function ArrayBufferToString(aData) {
  return [for (b of new Uint8Array(aData)) String.fromCharCode(b)].join("");
}

function ArrayBufferToHexString(aData) {
  return "0x" + [for (b of new Uint8Array(aData)) ("0" + b.toString(16)).slice(-2)].join(" ");
}