var isDigit = require('../../tokenizer').isDigit;
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var TYPE = require('../../tokenizer').TYPE;
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var NUMBER = TYPE.Number;
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var DELIM = TYPE.Delim;
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var SOLIDUS = 0x002F; // U+002F SOLIDUS (/)
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var FULLSTOP = 0x002E; // U+002E FULL STOP (.)
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// Terms of <ratio> should be a positive numbers (not zero or negative)
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// (see https://drafts.csswg.org/mediaqueries-3/#values)
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// However, -o-min-device-pixel-ratio takes fractional values as a ratio's term
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// and this is using by various sites. Therefore we relax checking on parse
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// to test a term is unsigned number without an exponent part.
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// Additional checking may be applied on lexer validation.
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function consumeNumber() {
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this.scanner.skipWS();
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var value = this.consume(NUMBER);
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for (var i = 0; i < value.length; i++) {
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var code = value.charCodeAt(i);
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if (!isDigit(code) && code !== FULLSTOP) {
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this.error('Unsigned number is expected', this.scanner.tokenStart - value.length + i);
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}
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}
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if (Number(value) === 0) {
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this.error('Zero number is not allowed', this.scanner.tokenStart - value.length);
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}
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return value;
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}
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// <positive-integer> S* '/' S* <positive-integer>
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module.exports = {
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name: 'Ratio',
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structure: {
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left: String,
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right: String
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},
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parse: function() {
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var start = this.scanner.tokenStart;
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var left = consumeNumber.call(this);
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var right;
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this.scanner.skipWS();
|
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if (!this.scanner.isDelim(SOLIDUS)) {
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this.error('Solidus is expected');
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}
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this.eat(DELIM);
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right = consumeNumber.call(this);
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return {
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type: 'Ratio',
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loc: this.getLocation(start, this.scanner.tokenStart),
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left: left,
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right: right
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};
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},
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generate: function(node) {
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this.chunk(node.left);
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this.chunk('/');
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this.chunk(node.right);
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}
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};
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