mediocre-blog/assets/trading-in-the-rain/MIDI.js/inc/shim/Base64binary.js
2020-04-26 18:15:15 -06:00

81 lines
3.0 KiB
JavaScript

/**
* @license -------------------------------------------------------------------
* module: Base64Binary
* src: http://blog.danguer.com/2011/10/24/base64-binary-decoding-in-javascript/
* license: Simplified BSD License
* -------------------------------------------------------------------
* Copyright 2011, Daniel Guerrero. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL DANIEL GUERRERO BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
var Base64Binary = {
_keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
/* will return a Uint8Array type */
decodeArrayBuffer: function(input) {
var bytes = Math.ceil( (3*input.length) / 4.0);
var ab = new ArrayBuffer(bytes);
this.decode(input, ab);
return ab;
},
decode: function(input, arrayBuffer) {
//get last chars to see if are valid
var lkey1 = this._keyStr.indexOf(input.charAt(input.length-1));
var lkey2 = this._keyStr.indexOf(input.charAt(input.length-1));
var bytes = Math.ceil( (3*input.length) / 4.0);
if (lkey1 == 64) bytes--; //padding chars, so skip
if (lkey2 == 64) bytes--; //padding chars, so skip
var uarray;
var chr1, chr2, chr3;
var enc1, enc2, enc3, enc4;
var i = 0;
var j = 0;
if (arrayBuffer)
uarray = new Uint8Array(arrayBuffer);
else
uarray = new Uint8Array(bytes);
input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
for (i=0; i<bytes; i+=3) {
//get the 3 octects in 4 ascii chars
enc1 = this._keyStr.indexOf(input.charAt(j++));
enc2 = this._keyStr.indexOf(input.charAt(j++));
enc3 = this._keyStr.indexOf(input.charAt(j++));
enc4 = this._keyStr.indexOf(input.charAt(j++));
chr1 = (enc1 << 2) | (enc2 >> 4);
chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
chr3 = ((enc3 & 3) << 6) | enc4;
uarray[i] = chr1;
if (enc3 != 64) uarray[i+1] = chr2;
if (enc4 != 64) uarray[i+2] = chr3;
}
return uarray;
}
};