var isHexDigit = require('../tokenizer').isHexDigit; var cmpChar = require('../tokenizer').cmpChar; var TYPE = require('../tokenizer').TYPE; var CHARCODE = require('../tokenizer').CHARCODE; var IDENT = TYPE.Ident; var DELIM = TYPE.Delim; var NUMBER = TYPE.Number; var DIMENSION = TYPE.Dimension; var PLUSSIGN = CHARCODE.PlusSign; var HYPHENMINUS = CHARCODE.HyphenMinus; var QUESTIONMARK = CHARCODE.QuestionMark; var U = 117; // 'u'.charCodeAt() function isDelim(token, code) { return token !== null && token.type === DELIM && token.value.charCodeAt(0) === code; } function startsWith(token, code) { return token.value.charCodeAt(0) === code; } function hexSequence(token, offset, allowDash) { for (var pos = offset, hexlen = 0; pos < token.value.length; pos++) { var code = token.value.charCodeAt(pos); if (code === HYPHENMINUS && allowDash && hexlen !== 0) { if (hexSequence(token, offset + hexlen + 1, false) > 0) { return 6; // dissallow following question marks } return 0; // dash at the ending of a hex sequence is not allowed } if (!isHexDigit(code)) { return 0; // not a hex digit } if (++hexlen > 6) { return 0; // too many hex digits }; } return hexlen; } function withQuestionMarkSequence(consumed, length, getNextToken) { if (!consumed) { return 0; // nothing consumed } while (isDelim(getNextToken(length), QUESTIONMARK)) { if (++consumed > 6) { return 0; // too many question marks } length++; } return length; } // https://drafts.csswg.org/css-syntax/#urange // Informally, the 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). // // = // u '+' '?'* | // u '?'* | // u '?'* | // u | // u | // u '+' '?'+ module.exports = function urange(token, getNextToken) { var length = 0; // should start with `u` or `U` if (token === null || token.type !== IDENT || !cmpChar(token.value, 0, U)) { return 0; } token = getNextToken(++length); if (token === null) { return 0; } // u '+' '?'* // u '+' '?'+ if (isDelim(token, PLUSSIGN)) { token = getNextToken(++length); if (token === null) { return 0; } if (token.type === IDENT) { // u '+' '?'* return withQuestionMarkSequence(hexSequence(token, 0, true), ++length, getNextToken); } if (isDelim(token, QUESTIONMARK)) { // u '+' '?'+ return withQuestionMarkSequence(1, ++length, getNextToken); } // Hex digit or question mark is expected return 0; } // u '?'* // u // u if (token.type === NUMBER) { if (!startsWith(token, PLUSSIGN)) { return 0; } var consumedHexLength = hexSequence(token, 1, true); if (consumedHexLength === 0) { return 0; } token = getNextToken(++length); if (token === null) { // u return length; } if (token.type === DIMENSION || token.type === NUMBER) { // u // u if (!startsWith(token, HYPHENMINUS) || !hexSequence(token, 1, false)) { return 0; } return length + 1; } // u '?'* return withQuestionMarkSequence(consumedHexLength, length, getNextToken); } // u '?'* if (token.type === DIMENSION) { if (!startsWith(token, PLUSSIGN)) { return 0; } return withQuestionMarkSequence(hexSequence(token, 1, true), ++length, getNextToken); } return 0; };