92 lines
1.7 KiB
JavaScript
92 lines
1.7 KiB
JavaScript
(function (global, factory) {
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typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
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typeof define === 'function' && define.amd ? define(['exports'], factory) :
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(factory((global.vlq = global.vlq || {})));
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}(this, (function (exports) { 'use strict';
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var charToInteger = {};
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var integerToChar = {};
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'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='.split( '' ).forEach( function ( char, i ) {
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charToInteger[ char ] = i;
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integerToChar[ i ] = char;
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});
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function decode ( string ) {
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var result = [];
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var shift = 0;
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var value = 0;
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for ( var i = 0; i < string.length; i += 1 ) {
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var integer = charToInteger[ string[i] ];
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if ( integer === undefined ) {
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throw new Error( 'Invalid character (' + string[i] + ')' );
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}
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var hasContinuationBit = integer & 32;
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integer &= 31;
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value += integer << shift;
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if ( hasContinuationBit ) {
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shift += 5;
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} else {
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var shouldNegate = value & 1;
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value >>= 1;
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result.push( shouldNegate ? -value : value );
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// reset
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value = shift = 0;
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}
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}
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return result;
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}
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function encode ( value ) {
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var result;
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if ( typeof value === 'number' ) {
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result = encodeInteger( value );
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} else {
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result = '';
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for ( var i = 0; i < value.length; i += 1 ) {
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result += encodeInteger( value[i] );
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}
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}
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return result;
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}
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function encodeInteger ( num ) {
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var result = '';
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if ( num < 0 ) {
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num = ( -num << 1 ) | 1;
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} else {
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num <<= 1;
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}
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do {
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var clamped = num & 31;
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num >>= 5;
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if ( num > 0 ) {
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clamped |= 32;
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}
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result += integerToChar[ clamped ];
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} while ( num > 0 );
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return result;
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}
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exports.decode = decode;
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exports.encode = encode;
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Object.defineProperty(exports, '__esModule', { value: true });
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})));
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