166 lines
4.8 KiB
JavaScript
166 lines
4.8 KiB
JavaScript
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/*! http://mths.be/base64 v0.1.0 by @mathias | MIT license */
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;(function(root) {
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// Detect free variables `exports`.
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var freeExports = typeof exports == 'object' && exports;
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// Detect free variable `module`.
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var freeModule = typeof module == 'object' && module &&
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module.exports == freeExports && module;
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// Detect free variable `global`, from Node.js or Browserified code, and use
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// it as `root`.
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var freeGlobal = typeof global == 'object' && global;
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if (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal) {
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root = freeGlobal;
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}
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/*--------------------------------------------------------------------------*/
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var InvalidCharacterError = function(message) {
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this.message = message;
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};
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InvalidCharacterError.prototype = new Error;
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InvalidCharacterError.prototype.name = 'InvalidCharacterError';
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var error = function(message) {
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// Note: the error messages used throughout this file match those used by
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// the native `atob`/`btoa` implementation in Chromium.
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throw new InvalidCharacterError(message);
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};
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var TABLE = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
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// http://whatwg.org/html/common-microsyntaxes.html#space-character
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var REGEX_SPACE_CHARACTERS = /[\t\n\f\r ]/g;
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// `decode` is designed to be fully compatible with `atob` as described in the
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// HTML Standard. http://whatwg.org/html/webappapis.html#dom-windowbase64-atob
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// The optimized base64-decoding algorithm used is based on @atk’s excellent
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// implementation. https://gist.github.com/atk/1020396
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var decode = function(input) {
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input = String(input)
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.replace(REGEX_SPACE_CHARACTERS, '');
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var length = input.length;
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if (length % 4 == 0) {
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input = input.replace(/==?$/, '');
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length = input.length;
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}
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if (
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length % 4 == 1 ||
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// http://whatwg.org/C#alphanumeric-ascii-characters
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/[^+a-zA-Z0-9/]/.test(input)
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) {
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error(
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'Invalid character: the string to be decoded is not correctly encoded.'
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);
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}
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var bitCounter = 0;
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var bitStorage;
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var buffer;
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var output = '';
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var position = -1;
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while (++position < length) {
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buffer = TABLE.indexOf(input.charAt(position));
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bitStorage = bitCounter % 4 ? bitStorage * 64 + buffer : buffer;
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// Unless this is the first of a group of 4 characters…
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if (bitCounter++ % 4) {
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// …convert the first 8 bits to a single ASCII character.
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output += String.fromCharCode(
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0xFF & bitStorage >> (-2 * bitCounter & 6)
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);
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}
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}
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return output;
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};
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// `encode` is designed to be fully compatible with `btoa` as described in the
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// HTML Standard: http://whatwg.org/html/webappapis.html#dom-windowbase64-btoa
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var encode = function(input) {
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input = String(input);
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if (/[^\0-\xFF]/.test(input)) {
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// Note: no need to special-case astral symbols here, as surrogates are
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// matched, and the input is supposed to only contain ASCII anyway.
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error(
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'The string to be encoded contains characters outside of the ' +
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'Latin1 range.'
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);
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}
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var padding = input.length % 3;
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var output = '';
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var position = -1;
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var a;
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var b;
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var c;
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var d;
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var buffer;
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// Make sure any padding is handled outside of the loop.
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var length = input.length - padding;
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while (++position < length) {
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// Read three bytes, i.e. 24 bits.
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a = input.charCodeAt(position) << 16;
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b = input.charCodeAt(++position) << 8;
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c = input.charCodeAt(++position);
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buffer = a + b + c;
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// Turn the 24 bits into four chunks of 6 bits each, and append the
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// matching character for each of them to the output.
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output += (
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TABLE.charAt(buffer >> 18 & 0x3F) +
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TABLE.charAt(buffer >> 12 & 0x3F) +
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TABLE.charAt(buffer >> 6 & 0x3F) +
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TABLE.charAt(buffer & 0x3F)
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);
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}
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if (padding == 2) {
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a = input.charCodeAt(position) << 8;
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b = input.charCodeAt(++position);
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buffer = a + b;
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output += (
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TABLE.charAt(buffer >> 10) +
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TABLE.charAt((buffer >> 4) & 0x3F) +
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TABLE.charAt((buffer << 2) & 0x3F) +
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'='
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);
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} else if (padding == 1) {
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buffer = input.charCodeAt(position);
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output += (
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TABLE.charAt(buffer >> 2) +
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TABLE.charAt((buffer << 4) & 0x3F) +
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'=='
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);
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}
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return output;
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};
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var base64 = {
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'encode': encode,
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'decode': decode,
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'version': '0.1.0'
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};
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// Some AMD build optimizers, like r.js, check for specific condition patterns
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// like the following:
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if (
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typeof define == 'function' &&
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typeof define.amd == 'object' &&
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define.amd
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) {
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define(function() {
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return base64;
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});
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} else if (freeExports && !freeExports.nodeType) {
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if (freeModule) { // in Node.js or RingoJS v0.8.0+
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freeModule.exports = base64;
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} else { // in Narwhal or RingoJS v0.7.0-
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for (var key in base64) {
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base64.hasOwnProperty(key) && (freeExports[key] = base64[key]);
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}
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}
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} else { // in Rhino or a web browser
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root.base64 = base64;
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}
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}(this));
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