source: trip-planner-front/node_modules/css-tree/lib/lexer/generic-urange.js@ bdd6491

Last change on this file since bdd6491 was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

  • Property mode set to 100644
File size: 4.6 KB
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1var isHexDigit = require('../tokenizer').isHexDigit;
2var cmpChar = require('../tokenizer').cmpChar;
3var TYPE = require('../tokenizer').TYPE;
4
5var IDENT = TYPE.Ident;
6var DELIM = TYPE.Delim;
7var NUMBER = TYPE.Number;
8var DIMENSION = TYPE.Dimension;
9var PLUSSIGN = 0x002B; // U+002B PLUS SIGN (+)
10var HYPHENMINUS = 0x002D; // U+002D HYPHEN-MINUS (-)
11var QUESTIONMARK = 0x003F; // U+003F QUESTION MARK (?)
12var U = 0x0075; // U+0075 LATIN SMALL LETTER U (u)
13
14function isDelim(token, code) {
15 return token !== null && token.type === DELIM && token.value.charCodeAt(0) === code;
16}
17
18function startsWith(token, code) {
19 return token.value.charCodeAt(0) === code;
20}
21
22function hexSequence(token, offset, allowDash) {
23 for (var pos = offset, hexlen = 0; pos < token.value.length; pos++) {
24 var code = token.value.charCodeAt(pos);
25
26 if (code === HYPHENMINUS && allowDash && hexlen !== 0) {
27 if (hexSequence(token, offset + hexlen + 1, false) > 0) {
28 return 6; // dissallow following question marks
29 }
30
31 return 0; // dash at the ending of a hex sequence is not allowed
32 }
33
34 if (!isHexDigit(code)) {
35 return 0; // not a hex digit
36 }
37
38 if (++hexlen > 6) {
39 return 0; // too many hex digits
40 };
41 }
42
43 return hexlen;
44}
45
46function withQuestionMarkSequence(consumed, length, getNextToken) {
47 if (!consumed) {
48 return 0; // nothing consumed
49 }
50
51 while (isDelim(getNextToken(length), QUESTIONMARK)) {
52 if (++consumed > 6) {
53 return 0; // too many question marks
54 }
55
56 length++;
57 }
58
59 return length;
60}
61
62// https://drafts.csswg.org/css-syntax/#urange
63// Informally, the <urange> production has three forms:
64// U+0001
65// Defines a range consisting of a single code point, in this case the code point "1".
66// U+0001-00ff
67// Defines a range of codepoints between the first and the second value, in this case
68// the range between "1" and "ff" (255 in decimal) inclusive.
69// U+00??
70// Defines a range of codepoints where the "?" characters range over all hex digits,
71// in this case defining the same as the value U+0000-00ff.
72// In each form, a maximum of 6 digits is allowed for each hexadecimal number (if you treat "?" as a hexadecimal digit).
73//
74// <urange> =
75// u '+' <ident-token> '?'* |
76// u <dimension-token> '?'* |
77// u <number-token> '?'* |
78// u <number-token> <dimension-token> |
79// u <number-token> <number-token> |
80// u '+' '?'+
81module.exports = function urange(token, getNextToken) {
82 var length = 0;
83
84 // should start with `u` or `U`
85 if (token === null || token.type !== IDENT || !cmpChar(token.value, 0, U)) {
86 return 0;
87 }
88
89 token = getNextToken(++length);
90 if (token === null) {
91 return 0;
92 }
93
94 // u '+' <ident-token> '?'*
95 // u '+' '?'+
96 if (isDelim(token, PLUSSIGN)) {
97 token = getNextToken(++length);
98 if (token === null) {
99 return 0;
100 }
101
102 if (token.type === IDENT) {
103 // u '+' <ident-token> '?'*
104 return withQuestionMarkSequence(hexSequence(token, 0, true), ++length, getNextToken);
105 }
106
107 if (isDelim(token, QUESTIONMARK)) {
108 // u '+' '?'+
109 return withQuestionMarkSequence(1, ++length, getNextToken);
110 }
111
112 // Hex digit or question mark is expected
113 return 0;
114 }
115
116 // u <number-token> '?'*
117 // u <number-token> <dimension-token>
118 // u <number-token> <number-token>
119 if (token.type === NUMBER) {
120 if (!startsWith(token, PLUSSIGN)) {
121 return 0;
122 }
123
124 var consumedHexLength = hexSequence(token, 1, true);
125 if (consumedHexLength === 0) {
126 return 0;
127 }
128
129 token = getNextToken(++length);
130 if (token === null) {
131 // u <number-token> <eof>
132 return length;
133 }
134
135 if (token.type === DIMENSION || token.type === NUMBER) {
136 // u <number-token> <dimension-token>
137 // u <number-token> <number-token>
138 if (!startsWith(token, HYPHENMINUS) || !hexSequence(token, 1, false)) {
139 return 0;
140 }
141
142 return length + 1;
143 }
144
145 // u <number-token> '?'*
146 return withQuestionMarkSequence(consumedHexLength, length, getNextToken);
147 }
148
149 // u <dimension-token> '?'*
150 if (token.type === DIMENSION) {
151 if (!startsWith(token, PLUSSIGN)) {
152 return 0;
153 }
154
155 return withQuestionMarkSequence(hexSequence(token, 1, true), ++length, getNextToken);
156 }
157
158 return 0;
159};
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