source: trip-planner-front/node_modules/negotiator/lib/charset.js@ 6fe77af

Last change on this file since 6fe77af was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

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1/**
2 * negotiator
3 * Copyright(c) 2012 Isaac Z. Schlueter
4 * Copyright(c) 2014 Federico Romero
5 * Copyright(c) 2014-2015 Douglas Christopher Wilson
6 * MIT Licensed
7 */
8
9'use strict';
10
11/**
12 * Module exports.
13 * @public
14 */
15
16module.exports = preferredCharsets;
17module.exports.preferredCharsets = preferredCharsets;
18
19/**
20 * Module variables.
21 * @private
22 */
23
24var simpleCharsetRegExp = /^\s*([^\s;]+)\s*(?:;(.*))?$/;
25
26/**
27 * Parse the Accept-Charset header.
28 * @private
29 */
30
31function parseAcceptCharset(accept) {
32 var accepts = accept.split(',');
33
34 for (var i = 0, j = 0; i < accepts.length; i++) {
35 var charset = parseCharset(accepts[i].trim(), i);
36
37 if (charset) {
38 accepts[j++] = charset;
39 }
40 }
41
42 // trim accepts
43 accepts.length = j;
44
45 return accepts;
46}
47
48/**
49 * Parse a charset from the Accept-Charset header.
50 * @private
51 */
52
53function parseCharset(str, i) {
54 var match = simpleCharsetRegExp.exec(str);
55 if (!match) return null;
56
57 var charset = match[1];
58 var q = 1;
59 if (match[2]) {
60 var params = match[2].split(';')
61 for (var j = 0; j < params.length; j++) {
62 var p = params[j].trim().split('=');
63 if (p[0] === 'q') {
64 q = parseFloat(p[1]);
65 break;
66 }
67 }
68 }
69
70 return {
71 charset: charset,
72 q: q,
73 i: i
74 };
75}
76
77/**
78 * Get the priority of a charset.
79 * @private
80 */
81
82function getCharsetPriority(charset, accepted, index) {
83 var priority = {o: -1, q: 0, s: 0};
84
85 for (var i = 0; i < accepted.length; i++) {
86 var spec = specify(charset, accepted[i], index);
87
88 if (spec && (priority.s - spec.s || priority.q - spec.q || priority.o - spec.o) < 0) {
89 priority = spec;
90 }
91 }
92
93 return priority;
94}
95
96/**
97 * Get the specificity of the charset.
98 * @private
99 */
100
101function specify(charset, spec, index) {
102 var s = 0;
103 if(spec.charset.toLowerCase() === charset.toLowerCase()){
104 s |= 1;
105 } else if (spec.charset !== '*' ) {
106 return null
107 }
108
109 return {
110 i: index,
111 o: spec.i,
112 q: spec.q,
113 s: s
114 }
115}
116
117/**
118 * Get the preferred charsets from an Accept-Charset header.
119 * @public
120 */
121
122function preferredCharsets(accept, provided) {
123 // RFC 2616 sec 14.2: no header = *
124 var accepts = parseAcceptCharset(accept === undefined ? '*' : accept || '');
125
126 if (!provided) {
127 // sorted list of all charsets
128 return accepts
129 .filter(isQuality)
130 .sort(compareSpecs)
131 .map(getFullCharset);
132 }
133
134 var priorities = provided.map(function getPriority(type, index) {
135 return getCharsetPriority(type, accepts, index);
136 });
137
138 // sorted list of accepted charsets
139 return priorities.filter(isQuality).sort(compareSpecs).map(function getCharset(priority) {
140 return provided[priorities.indexOf(priority)];
141 });
142}
143
144/**
145 * Compare two specs.
146 * @private
147 */
148
149function compareSpecs(a, b) {
150 return (b.q - a.q) || (b.s - a.s) || (a.o - b.o) || (a.i - b.i) || 0;
151}
152
153/**
154 * Get full charset string.
155 * @private
156 */
157
158function getFullCharset(spec) {
159 return spec.charset;
160}
161
162/**
163 * Check if a spec has any quality.
164 * @private
165 */
166
167function isQuality(spec) {
168 return spec.q > 0;
169}
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