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