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JS: base62 encode
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| function ( | |
| a, // positive base10 encoded integer | |
| b, // placeholder for result | |
| c // placeholder for modulo | |
| ) { | |
| for ( | |
| a = a !== +a || a % 1 ? -1 : a, b = ""; // if not a base10 integer, 'a' will be '-1' | |
| // for example, '.5 % 1 == .5' but '1 % 1 == 0' | |
| a >= 0; // also prevents the user to use negative base10 integers | |
| a = Math.floor(a / 62) || -1 // using a bitwise hack here will fail with great numbers | |
| ) | |
| // a%62 -> 0-61 | |
| // 0-9 | 36-61 | 10-35 | |
| // 48-57 | 65-90 | 97-121 | |
| // 0-9 | A-Z | a-z | |
| b = String.fromCharCode(((c = a % 62) > 9 ? c > 35 ? 29 : 87 : 48) + c) + b; | |
| return b // will return either an empty or a base62-encoded string | |
| } |
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| function(a,b,c){for(a=a!==+a||a%1?-1:a,b="";a>=0;a=Math.floor(a/62)||-1)b=String.fromCharCode(((c=a%62)>9?c>35?29:87:48)+c)+b;return b} |
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| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| Version 2, December 2004 | |
| Copyright (C) 2011 Sebastien P. https://twitter.com/#!/_sebastienp | |
| Everyone is permitted to copy and distribute verbatim or modified | |
| copies of this license document, and changing it is allowed as long | |
| as the name is changed. | |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 0. You just DO WHAT THE FUCK YOU WANT TO. |
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| { | |
| "name": "base62 encode", | |
| "description": "A JavaScript implementation of base62 encode.", | |
| "keywords": [ | |
| "base62", | |
| "encode", | |
| "integer", | |
| "number", | |
| "string" | |
| ] | |
| } |
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| <!DOCTYPE html> | |
| <title>Foo</title> | |
| <div>Expected value: <b>140bytes</b></div> | |
| <div>Actual value: <b id="ret"></b></div> | |
| <script> | |
| var base62encode = function(a,b,c){for(a=a!==+a||a%1?-1:a,b="";a>=0;a=Math.floor(a/62)||-1)b=String.fromCharCode(((c=a%62)>9?c>35?29:87:48)+c)+b;return b}; | |
| document.getElementById("ret").innerHTML = base62encode(3748986303764) | |
| </script> |
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