381 lines
11 KiB
JavaScript
381 lines
11 KiB
JavaScript
'use strict';
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var TokenType = require('./const.js').TokenType;
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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 DOUBLE_QUOTE = 34;
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var QUOTE = 39;
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var RIGHT_PARENTHESIS = 41;
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var STAR = 42;
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var SLASH = 47;
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var BACK_SLASH = 92;
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var UNDERSCORE = 95;
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var LEFT_CURLY_BRACE = 123;
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var RIGHT_CURLY_BRACE = 125;
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var WHITESPACE = 1;
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var PUNCTUATOR = 2;
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var DIGIT = 3;
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var STRING = 4;
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var PUNCTUATION = {
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9: TokenType.Tab, // '\t'
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10: TokenType.Newline, // '\n'
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13: TokenType.Newline, // '\r'
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32: TokenType.Space, // ' '
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33: TokenType.ExclamationMark, // '!'
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34: TokenType.QuotationMark, // '"'
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35: TokenType.NumberSign, // '#'
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36: TokenType.DollarSign, // '$'
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37: TokenType.PercentSign, // '%'
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38: TokenType.Ampersand, // '&'
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39: TokenType.Apostrophe, // '\''
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40: TokenType.LeftParenthesis, // '('
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41: TokenType.RightParenthesis, // ')'
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42: TokenType.Asterisk, // '*'
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43: TokenType.PlusSign, // '+'
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44: TokenType.Comma, // ','
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45: TokenType.HyphenMinus, // '-'
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46: TokenType.FullStop, // '.'
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47: TokenType.Solidus, // '/'
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58: TokenType.Colon, // ':'
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59: TokenType.Semicolon, // ';'
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60: TokenType.LessThanSign, // '<'
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61: TokenType.EqualsSign, // '='
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62: TokenType.GreaterThanSign, // '>'
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63: TokenType.QuestionMark, // '?'
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64: TokenType.CommercialAt, // '@'
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91: TokenType.LeftSquareBracket, // '['
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93: TokenType.RightSquareBracket, // ']'
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94: TokenType.CircumflexAccent, // '^'
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95: TokenType.LowLine, // '_'
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123: TokenType.LeftCurlyBracket, // '{'
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124: TokenType.VerticalLine, // '|'
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125: TokenType.RightCurlyBracket, // '}'
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126: TokenType.Tilde // '~'
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};
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var SYMBOL_CATEGORY_LENGTH = Math.max.apply(null, Object.keys(PUNCTUATION)) + 1;
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var SYMBOL_CATEGORY = new Uint32Array(SYMBOL_CATEGORY_LENGTH);
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var IS_PUNCTUATOR = new Uint32Array(SYMBOL_CATEGORY_LENGTH);
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// fill categories
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Object.keys(PUNCTUATION).forEach(function(key) {
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SYMBOL_CATEGORY[Number(key)] = PUNCTUATOR;
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IS_PUNCTUATOR[Number(key)] = PUNCTUATOR;
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}, SYMBOL_CATEGORY);
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// don't treat as punctuator
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IS_PUNCTUATOR[UNDERSCORE] = 0;
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for (var i = 48; i <= 57; i++) {
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SYMBOL_CATEGORY[i] = DIGIT;
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}
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SYMBOL_CATEGORY[SPACE] = WHITESPACE;
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SYMBOL_CATEGORY[TAB] = WHITESPACE;
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SYMBOL_CATEGORY[N] = WHITESPACE;
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SYMBOL_CATEGORY[R] = WHITESPACE;
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SYMBOL_CATEGORY[F] = WHITESPACE;
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SYMBOL_CATEGORY[QUOTE] = STRING;
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SYMBOL_CATEGORY[DOUBLE_QUOTE] = STRING;
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//
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// scanner
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//
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var Scanner = function(source, initBlockMode, initLine, initColumn) {
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this.source = source;
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this.pos = source.charCodeAt(0) === 0xFEFF ? 1 : 0;
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this.eof = this.pos === this.source.length;
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this.line = typeof initLine === 'undefined' ? 1 : initLine;
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this.lineStartPos = typeof initColumn === 'undefined' ? -1 : -initColumn;
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this.minBlockMode = initBlockMode ? 1 : 0;
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this.blockMode = this.minBlockMode;
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this.urlMode = false;
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this.prevToken = null;
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this.token = null;
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this.buffer = [];
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};
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Scanner.prototype = {
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lookup: function(offset) {
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if (offset === 0) {
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return this.token;
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}
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for (var i = this.buffer.length; !this.eof && i < offset; i++) {
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this.buffer.push(this.getToken());
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}
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return offset <= this.buffer.length ? this.buffer[offset - 1] : null;
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},
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lookupType: function(offset, type) {
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var token = this.lookup(offset);
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return token !== null && token.type === type;
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},
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next: function() {
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var newToken = null;
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if (this.buffer.length !== 0) {
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newToken = this.buffer.shift();
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} else if (!this.eof) {
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newToken = this.getToken();
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}
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this.prevToken = this.token;
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this.token = newToken;
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return newToken;
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},
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tokenize: function() {
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var tokens = [];
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for (; this.pos < this.source.length; this.pos++) {
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tokens.push(this.getToken());
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}
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return tokens;
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},
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getToken: function() {
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var code = this.source.charCodeAt(this.pos);
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var line = this.line;
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var column = this.pos - this.lineStartPos;
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var offset = this.pos;
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var next;
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var type;
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var value;
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switch (code < SYMBOL_CATEGORY_LENGTH ? SYMBOL_CATEGORY[code] : 0) {
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case DIGIT:
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type = TokenType.DecimalNumber;
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value = this.readDecimalNumber();
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break;
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case STRING:
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type = TokenType.String;
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value = this.readString(code);
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break;
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case WHITESPACE:
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type = TokenType.Space;
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value = this.readSpaces();
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break;
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case PUNCTUATOR:
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if (code === SLASH) {
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next = this.pos + 1 < this.source.length ? this.source.charCodeAt(this.pos + 1) : 0;
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if (next === STAR) { // /*
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type = TokenType.Comment;
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value = this.readComment();
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break;
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} else if (next === SLASH && !this.urlMode) { // //
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if (this.blockMode > 0) {
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var skip = 2;
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while (this.source.charCodeAt(this.pos + 2) === SLASH) {
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skip++;
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}
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type = TokenType.Identifier;
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value = this.readIdentifier(skip);
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this.urlMode = this.urlMode || value === 'url';
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} else {
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type = TokenType.Unknown;
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value = this.readUnknown();
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}
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break;
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}
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}
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type = PUNCTUATION[code];
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value = String.fromCharCode(code);
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this.pos++;
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if (code === RIGHT_PARENTHESIS) {
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this.urlMode = false;
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} else if (code === LEFT_CURLY_BRACE) {
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this.blockMode++;
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} else if (code === RIGHT_CURLY_BRACE) {
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if (this.blockMode > this.minBlockMode) {
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this.blockMode--;
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}
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}
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break;
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default:
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type = TokenType.Identifier;
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value = this.readIdentifier(0);
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this.urlMode = this.urlMode || value === 'url';
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}
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this.eof = this.pos === this.source.length;
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return {
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type: type,
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value: value,
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offset: offset,
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line: line,
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column: column
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};
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},
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isNewline: function(code) {
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if (code === N || code === F || code === R) {
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if (code === R && this.pos + 1 < this.source.length && this.source.charCodeAt(this.pos + 1) === N) {
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this.pos++;
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}
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this.line++;
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this.lineStartPos = this.pos;
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return true;
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}
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return false;
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},
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readSpaces: function() {
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var start = this.pos;
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for (; this.pos < this.source.length; this.pos++) {
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var code = this.source.charCodeAt(this.pos);
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if (!this.isNewline(code) && code !== SPACE && code !== TAB) {
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break;
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}
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}
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return this.source.substring(start, this.pos);
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},
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readComment: function() {
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var start = this.pos;
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for (this.pos += 2; this.pos < this.source.length; this.pos++) {
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var code = this.source.charCodeAt(this.pos);
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if (code === STAR) { // */
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if (this.source.charCodeAt(this.pos + 1) === SLASH) {
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this.pos += 2;
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break;
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}
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} else {
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this.isNewline(code);
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}
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}
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return this.source.substring(start, this.pos);
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},
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readUnknown: function() {
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var start = this.pos;
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for (this.pos += 2; this.pos < this.source.length; this.pos++) {
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if (this.isNewline(this.source.charCodeAt(this.pos), this.source)) {
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break;
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}
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}
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return this.source.substring(start, this.pos);
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},
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readString: function(quote) {
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var start = this.pos;
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var res = '';
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for (this.pos++; this.pos < this.source.length; this.pos++) {
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var code = this.source.charCodeAt(this.pos);
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if (code === BACK_SLASH) {
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var end = this.pos++;
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if (this.isNewline(this.source.charCodeAt(this.pos), this.source)) {
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res += this.source.substring(start, end);
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start = this.pos + 1;
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}
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} else if (code === quote) {
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this.pos++;
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break;
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}
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}
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return res + this.source.substring(start, this.pos);
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},
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readDecimalNumber: function() {
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var start = this.pos;
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var code;
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for (this.pos++; this.pos < this.source.length; this.pos++) {
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code = this.source.charCodeAt(this.pos);
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if (code < 48 || code > 57) { // 0 .. 9
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break;
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}
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}
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return this.source.substring(start, this.pos);
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},
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readIdentifier: function(skip) {
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var start = this.pos;
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for (this.pos += skip; this.pos < this.source.length; this.pos++) {
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var code = this.source.charCodeAt(this.pos);
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if (code === BACK_SLASH) {
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this.pos++;
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// skip escaped unicode sequence that can ends with space
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// [0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?
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for (var i = 0; i < 7 && this.pos + i < this.source.length; i++) {
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code = this.source.charCodeAt(this.pos + i);
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if (i !== 6) {
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if ((code >= 48 && code <= 57) || // 0 .. 9
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(code >= 65 && code <= 70) || // A .. F
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(code >= 97 && code <= 102)) { // a .. f
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continue;
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}
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}
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if (i > 0) {
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this.pos += i - 1;
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if (code === SPACE || code === TAB || this.isNewline(code)) {
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this.pos++;
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}
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}
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break;
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}
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} else if (code < SYMBOL_CATEGORY_LENGTH &&
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IS_PUNCTUATOR[code] === PUNCTUATOR) {
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break;
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}
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}
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return this.source.substring(start, this.pos);
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}
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};
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// warm up tokenizer to elimitate code branches that never execute
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// fix soft deoptimizations (insufficient type feedback)
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new Scanner('\n\r\r\n\f//""\'\'/**/1a;.{url(a)}').lookup(1e3);
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module.exports = Scanner;
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