138 lines
4.6 KiB
JavaScript
138 lines
4.6 KiB
JavaScript
/*
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Copyright (c) 2011, Chris Umbel
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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*/
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(function (exports) {
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'use strict';
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var charTable = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
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var byteTable = [
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0xff, 0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
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0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
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0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
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0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
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0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
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0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
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0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff
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];
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function quintetCount(buff) {
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var quintets = Math.floor(buff.length / 5);
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return buff.length % 5 === 0 ? quintets: quintets + 1;
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}
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exports.bufferToBase32 = function(plain) {
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// plain MUST come in either as Array or Uint8Array
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if('undefined' !== typeof Uint8Array) {
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if (!(plain instanceof Uint8Array)){
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plain = new Uint8Array(plain);
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}
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}
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var i = 0;
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var j = 0;
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var shiftIndex = 0;
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var digit = 0;
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var encoded = new Array(quintetCount(plain) * 8);
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/* byte by byte isn't as pretty as quintet by quintet but tests a bit
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faster. will have to revisit. */
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while(i < plain.length) {
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var current = plain[i];
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if(shiftIndex > 3) {
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digit = current & (0xff >> shiftIndex);
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shiftIndex = (shiftIndex + 5) % 8;
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digit = (digit << shiftIndex) | ((i + 1 < plain.length) ?
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plain[i + 1] : 0) >> (8 - shiftIndex);
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i++;
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} else {
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digit = (current >> (8 - (shiftIndex + 5))) & 0x1f;
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shiftIndex = (shiftIndex + 5) % 8;
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if(shiftIndex === 0) { i++; }
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}
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encoded[j] = charTable[digit];
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j++;
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}
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for(i = j; i < encoded.length; i++) {
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encoded[i] = '=';
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}
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return encoded.join('');
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};
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exports.base32ToBuffer = function(encoded) {
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var shiftIndex = 0;
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var plainDigit = 0;
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var plainChar;
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var plainPos = 0;
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var len = Math.ceil(encoded.length * 5 / 8);
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var decoded;
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encoded = encoded.split('').map(function (ch) {
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return ch.charCodeAt(0);
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});
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if('undefined' !== typeof Uint8Array) {
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encoded = new Uint8Array(encoded);
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decoded = new Uint8Array(len);
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} else {
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decoded = new Array(len);
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}
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/* byte by byte isn't as pretty as octet by octet but tests a bit
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faster. will have to revisit. */
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for(var i = 0; i < encoded.length; i++) {
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if(encoded[i] === 0x3d){ //'='
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break;
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}
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var encodedByte = encoded[i] - 0x30;
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if(encodedByte < byteTable.length) {
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plainDigit = byteTable[encodedByte];
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if(shiftIndex <= 3) {
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shiftIndex = (shiftIndex + 5) % 8;
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if(shiftIndex === 0) {
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plainChar |= plainDigit;
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decoded[plainPos] = plainChar;
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plainPos++;
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plainChar = 0;
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} else {
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plainChar |= 0xff & (plainDigit << (8 - shiftIndex));
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}
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} else {
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shiftIndex = (shiftIndex + 5) % 8;
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plainChar |= 0xff & (plainDigit >>> shiftIndex);
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decoded[plainPos] = plainChar;
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plainPos++;
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plainChar = 0xff & (plainDigit << (8 - shiftIndex));
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}
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} else {
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throw new Error('Invalid input - it is not base32 encoded string');
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}
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}
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return decoded.slice(0, plainPos);
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};
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}(window.Unibabel || window));
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