mirror of
https://github.com/whscullin/apple2js.git
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113 lines
3.4 KiB
JavaScript
113 lines
3.4 KiB
JavaScript
/*exported base64_encode, base64_decode */
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function base64_encode (data) {
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// Twacked by Will Scullin to handle arrays of "bytes"
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// http://kevin.vanzonneveld.net
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// + original by: Tyler Akins (http://rumkin.com)
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// + improved by: Bayron Guevara
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// + improved by: Thunder.m
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// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
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// + bugfixed by: Pellentesque Malesuada
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// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
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// - depends on: utf8_encode
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// * example 1: base64_encode('Kevin van Zonneveld');
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// * returns 1: 'S2V2aW4gdmFuIFpvbm5ldmVsZA=='
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// mozilla has this native
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// - but breaks in 2.0.0.12!
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//if (typeof this.window['atob'] == 'function') {
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// return atob(data);
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//}
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var b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
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var o1, o2, o3, h1, h2, h3, h4, bits, i = 0, ac = 0, enc='', tmp_arr = [];
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if (!data) {
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return data;
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}
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do { // pack three octets into four hexets
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o1 = data[i++];
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o2 = data[i++];
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o3 = data[i++];
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bits = o1<<16 | o2<<8 | o3;
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h1 = bits>>18 & 0x3f;
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h2 = bits>>12 & 0x3f;
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h3 = bits>>6 & 0x3f;
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h4 = bits & 0x3f;
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// use hexets to index into b64, and append result to encoded string
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tmp_arr[ac++] = b64.charAt(h1) + b64.charAt(h2) + b64.charAt(h3) + b64.charAt(h4);
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} while (i < data.length);
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enc = tmp_arr.join('');
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switch (data.length % 3) {
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case 1:
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enc = enc.slice(0, -2) + '==';
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break;
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case 2:
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enc = enc.slice(0, -1) + '=';
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break;
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}
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return enc;
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}
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function base64_decode(data) {
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// Twacked by Will Scullin to handle arrays of "bytes"
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// http://kevin.vanzonneveld.net
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// + original by: Tyler Akins (http://rumkin.com)
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// + improved by: Thunder.m
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// + input by: Aman Gupta
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// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
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// + bugfixed by: Onno Marsman
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// + bugfixed by: Pellentesque Malesuada
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// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
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// + input by: Brett Zamir (http://brett-zamir.me)
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// + bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
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// - depends on: utf8_decode
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// * example 1: base64_decode('S2V2aW4gdmFuIFpvbm5ldmVsZA==');
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// * returns 1: 'Kevin van Zonneveld'
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// mozilla has this native
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// - but breaks in 2.0.0.12!
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//if (typeof this.window['btoa'] == 'function') {
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// return btoa(data);
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//}
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var b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
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var o1, o2, o3, h1, h2, h3, h4, bits, i = 0, ac = 0, tmp_arr = [];
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if (!data) {
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return data;
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}
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do { // unpack four hexets into three octets using index points in b64
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h1 = b64.indexOf(data.charAt(i++));
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h2 = b64.indexOf(data.charAt(i++));
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h3 = b64.indexOf(data.charAt(i++));
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h4 = b64.indexOf(data.charAt(i++));
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bits = h1<<18 | h2<<12 | h3<<6 | h4;
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o1 = bits>>16 & 0xff;
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o2 = bits>>8 & 0xff;
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o3 = bits & 0xff;
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tmp_arr[ac++] = o1;
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if (h3 != 64) {
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tmp_arr[ac++] = o2;
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}
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if (h4 != 64) {
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tmp_arr[ac++] = o3;
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}
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} while (i < data.length);
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return tmp_arr;
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}
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