var SyntaxError = require('./SyntaxError');
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var TAB = 9;
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var N = 10;
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var F = 12;
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var R = 13;
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var SPACE = 32;
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var Tokenizer = function(str) {
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this.str = str;
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this.pos = 0;
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};
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Tokenizer.prototype = {
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charCodeAt: function(pos) {
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return pos < this.str.length ? this.str.charCodeAt(pos) : 0;
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},
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charCode: function() {
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return this.charCodeAt(this.pos);
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},
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nextCharCode: function() {
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return this.charCodeAt(this.pos + 1);
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},
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nextNonWsCode: function(pos) {
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return this.charCodeAt(this.findWsEnd(pos));
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},
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findWsEnd: function(pos) {
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for (; pos < this.str.length; pos++) {
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var code = this.str.charCodeAt(pos);
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if (code !== R && code !== N && code !== F && code !== SPACE && code !== TAB) {
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break;
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}
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}
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return pos;
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},
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substringToPos: function(end) {
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return this.str.substring(this.pos, this.pos = end);
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},
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eat: function(code) {
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if (this.charCode() !== code) {
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this.error('Expect `' + String.fromCharCode(code) + '`');
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}
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this.pos++;
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},
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peek: function() {
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return this.pos < this.str.length ? this.str.charAt(this.pos++) : '';
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},
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error: function(message) {
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throw new SyntaxError(message, this.str, this.pos);
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}
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};
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module.exports = Tokenizer;
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