lepu-test-platform-web/node_modules/css-tree/lib/syntax/node/UnicodeRange.js

174 lines
4.9 KiB
JavaScript

var isHexDigit = require('../../tokenizer').isHexDigit;
var cmpChar = require('../../tokenizer').cmpChar;
var TYPE = require('../../tokenizer').TYPE;
var NAME = require('../../tokenizer').NAME;
var IDENT = TYPE.Ident;
var NUMBER = TYPE.Number;
var DIMENSION = TYPE.Dimension;
var PLUSSIGN = 0x002B; // U+002B PLUS SIGN (+)
var HYPHENMINUS = 0x002D; // U+002D HYPHEN-MINUS (-)
var QUESTIONMARK = 0x003F; // U+003F QUESTION MARK (?)
var U = 0x0075; // U+0075 LATIN SMALL LETTER U (u)
function eatHexSequence(offset, allowDash) {
for (var pos = this.scanner.tokenStart + offset, len = 0; pos < this.scanner.tokenEnd; pos++) {
var code = this.scanner.source.charCodeAt(pos);
if (code === HYPHENMINUS && allowDash && len !== 0) {
if (eatHexSequence.call(this, offset + len + 1, false) === 0) {
this.error();
}
return -1;
}
if (!isHexDigit(code)) {
this.error(
allowDash && len !== 0
? 'HyphenMinus' + (len < 6 ? ' or hex digit' : '') + ' is expected'
: (len < 6 ? 'Hex digit is expected' : 'Unexpected input'),
pos
);
}
if (++len > 6) {
this.error('Too many hex digits', pos);
};
}
this.scanner.next();
return len;
}
function eatQuestionMarkSequence(max) {
var count = 0;
while (this.scanner.isDelim(QUESTIONMARK)) {
if (++count > max) {
this.error('Too many question marks');
}
this.scanner.next();
}
}
function startsWith(code) {
if (this.scanner.source.charCodeAt(this.scanner.tokenStart) !== code) {
this.error(NAME[code] + ' is expected');
}
}
// https://drafts.csswg.org/css-syntax/#urange
// Informally, the <urange> production has three forms:
// U+0001
// Defines a range consisting of a single code point, in this case the code point "1".
// U+0001-00ff
// Defines a range of codepoints between the first and the second value, in this case
// the range between "1" and "ff" (255 in decimal) inclusive.
// U+00??
// Defines a range of codepoints where the "?" characters range over all hex digits,
// in this case defining the same as the value U+0000-00ff.
// In each form, a maximum of 6 digits is allowed for each hexadecimal number (if you treat "?" as a hexadecimal digit).
//
// <urange> =
// u '+' <ident-token> '?'* |
// u <dimension-token> '?'* |
// u <number-token> '?'* |
// u <number-token> <dimension-token> |
// u <number-token> <number-token> |
// u '+' '?'+
function scanUnicodeRange() {
var hexLength = 0;
// u '+' <ident-token> '?'*
// u '+' '?'+
if (this.scanner.isDelim(PLUSSIGN)) {
this.scanner.next();
if (this.scanner.tokenType === IDENT) {
hexLength = eatHexSequence.call(this, 0, true);
if (hexLength > 0) {
eatQuestionMarkSequence.call(this, 6 - hexLength);
}
return;
}
if (this.scanner.isDelim(QUESTIONMARK)) {
this.scanner.next();
eatQuestionMarkSequence.call(this, 5);
return;
}
this.error('Hex digit or question mark is expected');
return;
}
// u <number-token> '?'*
// u <number-token> <dimension-token>
// u <number-token> <number-token>
if (this.scanner.tokenType === NUMBER) {
startsWith.call(this, PLUSSIGN);
hexLength = eatHexSequence.call(this, 1, true);
if (this.scanner.isDelim(QUESTIONMARK)) {
eatQuestionMarkSequence.call(this, 6 - hexLength);
return;
}
if (this.scanner.tokenType === DIMENSION ||
this.scanner.tokenType === NUMBER) {
startsWith.call(this, HYPHENMINUS);
eatHexSequence.call(this, 1, false);
return;
}
return;
}
// u <dimension-token> '?'*
if (this.scanner.tokenType === DIMENSION) {
startsWith.call(this, PLUSSIGN);
hexLength = eatHexSequence.call(this, 1, true);
if (hexLength > 0) {
eatQuestionMarkSequence.call(this, 6 - hexLength);
}
return;
}
this.error();
}
module.exports = {
name: 'UnicodeRange',
structure: {
value: String
},
parse: function() {
var start = this.scanner.tokenStart;
// U or u
if (!cmpChar(this.scanner.source, start, U)) {
this.error('U is expected');
}
if (!cmpChar(this.scanner.source, start + 1, PLUSSIGN)) {
this.error('Plus sign is expected');
}
this.scanner.next();
scanUnicodeRange.call(this);
return {
type: 'UnicodeRange',
loc: this.getLocation(start, this.scanner.tokenStart),
value: this.scanner.substrToCursor(start)
};
},
generate: function(node) {
this.chunk(node.value);
}
};