base64.js

Attribute Changed :base64.js

diff --git a/base64.js b/base64.js
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+/*
+ * Copyright (c) 2010 Nick Galbreath
+ * http://code.google.com/p/stringencoders/source/browse/#svn/trunk/javascript
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/* base64 encode/decode compatible with window.btoa/atob
+ *
+ * window.atob/btoa is a Firefox extension to convert binary data (the "b")
+ * to base64 (ascii, the "a").
+ *
+ * It is also found in Safari and Chrome.  It is not available in IE.
+ *
+ * if (!window.btoa) window.btoa = base64.encode
+ * if (!window.atob) window.atob = base64.decode
+ *
+ * The original spec's for atob/btoa are a bit lacking
+ * https://developer.mozilla.org/en/DOM/window.atob
+ * https://developer.mozilla.org/en/DOM/window.btoa
+ *
+ * window.btoa and base64.encode takes a string where charCodeAt is [0,255]
+ * If any character is not [0,255], then an DOMException(5) is thrown.
+ *
+ * window.atob and base64.decode take a base64-encoded string
+ * If the input length is not a multiple of 4, or contains invalid characters
+ *   then an DOMException(5) is thrown.
+ */
+var base64 = {};
+base64.PADCHAR = '=';
+base64.ALPHA = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
+
+base64.makeDOMException = function() {
+    // sadly in FF,Safari,Chrome you can't make a DOMException
+    var e, tmp;
+
+    try {
+        return new DOMException(DOMException.INVALID_CHARACTER_ERR);
+    } catch (tmp) {
+        // not available, just passback a duck-typed equiv
+        // https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Error
+        // https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Error/prototype
+        var ex = new Error("DOM Exception 5");
+
+        // ex.number and ex.description is IE-specific.
+        ex.code = ex.number = 5;
+        ex.name = ex.description = "INVALID_CHARACTER_ERR";
+
+        // Safari/Chrome output format
+        ex.toString = function() { return 'Error: ' + ex.name + ': ' + ex.message; };
+        return ex;
+    }
+}
+
+base64.getbyte64 = function(s,i) {
+    // This is oddly fast, except on Chrome/V8.
+    //  Minimal or no improvement in performance by using a
+    //   object with properties mapping chars to value (eg. 'A': 0)
+    var idx = base64.ALPHA.indexOf(s.charAt(i));
+    if (idx === -1) {
+        throw base64.makeDOMException();
+    }
+    return idx;
+}
+base64.decode = function(s) {
+    return base64.decodeToArray(s).join('');
+}
+base64.decodeToArray = function(s) {
+    // convert to string
+    s = '' + s;
+    var getbyte64 = base64.getbyte64;
+    var pads, i, b10;
+    var imax = s.length
+    if (imax === 0) {
+        return s;
+    }
+
+    if (imax % 4 !== 0) {
+        throw base64.makeDOMException();
+    }
+
+    pads = 0
+    if (s.charAt(imax - 1) === base64.PADCHAR) {
+        pads = 1;
+        if (s.charAt(imax - 2) === base64.PADCHAR) {
+            pads = 2;
+        }
+        // either way, we want to ignore this last block
+        imax -= 4;
+    }
+
+    var x = [];
+    for (i = 0; i < imax; i += 4) {
+        b10 = (getbyte64(s,i) << 18) | (getbyte64(s,i+1) << 12) |
+            (getbyte64(s,i+2) << 6) | getbyte64(s,i+3);
+        x.push(String.fromCharCode(b10 >> 16, (b10 >> 8) & 0xff, b10 & 0xff));
+    }
+
+    switch (pads) {
+    case 1:
+        b10 = (getbyte64(s,i) << 18) | (getbyte64(s,i+1) << 12) | (getbyte64(s,i+2) << 6);
+        x.push(String.fromCharCode(b10 >> 16, (b10 >> 8) & 0xff));
+        break;
+    case 2:
+        b10 = (getbyte64(s,i) << 18) | (getbyte64(s,i+1) << 12);
+        x.push(String.fromCharCode(b10 >> 16));
+        break;
+    }
+    return x;
+}
+
+base64.getbyte = function(s,i) {
+    var x = s.charCodeAt(i);
+    if (x > 255) {
+        throw base64.makeDOMException();
+    }
+    return x;
+}
+
+base64.encode = function(s) {
+    if (arguments.length !== 1) {
+        throw new SyntaxError("Not enough arguments");
+    }
+    var padchar = base64.PADCHAR;
+    var alpha   = base64.ALPHA;
+    var getbyte = base64.getbyte;
+
+    var i, b10;
+    var x = [];
+
+    // convert to string
+    s = '' + s;
+
+    var imax = s.length - s.length % 3;
+
+    if (s.length === 0) {
+        return s;
+    }
+    for (i = 0; i < imax; i += 3) {
+        b10 = (getbyte(s,i) << 16) | (getbyte(s,i+1) << 8) | getbyte(s,i+2);
+        x.push(alpha.charAt(b10 >> 18));
+        x.push(alpha.charAt((b10 >> 12) & 0x3F));
+        x.push(alpha.charAt((b10 >> 6) & 0x3f));
+        x.push(alpha.charAt(b10 & 0x3f));
+    }
+    switch (s.length - imax) {
+    case 1:
+        b10 = getbyte(s,i) << 16;
+        x.push(alpha.charAt(b10 >> 18) + alpha.charAt((b10 >> 12) & 0x3F) +
+               padchar + padchar);
+        break;
+    case 2:
+        b10 = (getbyte(s,i) << 16) | (getbyte(s,i+1) << 8);
+        x.push(alpha.charAt(b10 >> 18) + alpha.charAt((b10 >> 12) & 0x3F) +
+               alpha.charAt((b10 >> 6) & 0x3f) + padchar);
+        break;
+    }
+    return x.join('');
+}
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