base32.js

/*
Copyright (C) 2011 by Isaac Wolkerstorfer

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.
*/

;(function(){

var alphabet = '0123456789abcdefghjkmnpqrtuvwxyz'

/**
 * A streaming encoder
 *
 *     var encoder = new base32.Encoder()
 *     var output1 = encoder.update(input1)
 *     var output2 = encoder.update(input2)
 *     var lastoutput = encode.update(lastinput, true)
 */

function Encoder() {
    var skip = 0 // how many bits we will skip from the first byte
    var bits = 0 // 5 high bits, carry from one byte to the next

    this.output = ''

    // Read one byte of input
    // Should not really be used except by "update"
    this.readByte = function(byte) {
        // coerce the byte to an int
        if (typeof byte == 'string') byte = byte.charCodeAt(0)

        if (skip < 0) { // we have a carry from the previous byte
            bits |= (byte >> (-skip))
        } else { // no carry
            bits = (byte << skip) & 248
        }

        if (skip > 3) {
            // not enough data to produce a character, get us another one
            skip -= 8
            return 1
        }

        if (skip < 4) {
            // produce a character
            this.output += alphabet[bits >> 3]
            skip += 5
        }

        return 0
    }

    // Flush any remaining bits left in the stream
    this.finish = function(check) {
        var output = this.output + (skip < 0 ? alphabet[bits >> 3] : '') + (check ? '$' : '')
        this.output = ''
        return output
    }
}

/**
 * Process additional input
 *
 * input: string of bytes to convert
 * flush: boolean, should we flush any trailing bits left
 *        in the stream
 * returns: a string of characters representing 'input' in base32
 */

Encoder.prototype.update = function(input, flush) {
    for (var i = 0; i < input.length; ) {
        i += this.readByte(input[i])
    }
    // consume all output
    var output = this.output
    this.output = ''
    if (flush) {
      output += this.finish()
    }
    return output
}


/** Convenience functions
 *
 * These are the ones to use if you just have a string and
 * want to convert it without dealing with streams and whatnot.
 */

function getInt64Bytes( x ){
    var bytes = [];
    var i = 8;
    do {
    bytes[--i] = x & (255);
    x = x>>8;
    } while ( i )
    return bytes;
}

function encode_int(input) {
  bytes = getInt64Bytes(input);
  var encoder = new Encoder()
  var output = encoder.update(bytes, true)
  return output
}

function short_id(input) {
  return encode_int(Date.now()).substring(6);
}

var base32 = {
    short_id: short_id,
    encode_int: encode_int,
}

if (typeof window !== 'undefined') {
  // we're in a browser - OMG!
  window.base32 = base32
}

if (typeof module !== 'undefined' && module.exports) {
  // nodejs/browserify
  module.exports = base32
}
})();