+++ /dev/null
-module.exports = preferredEncodings;
-preferredEncodings.preferredEncodings = preferredEncodings;
-
-function parseAcceptEncoding(accept) {
- var accepts = accept.split(',');
- var hasIdentity = false;
- var minQuality = 1;
-
- for (var i = 0, j = 0; i < accepts.length; i++) {
- var encoding = parseEncoding(accepts[i].trim(), i);
-
- if (encoding) {
- accepts[j++] = encoding;
- hasIdentity = hasIdentity || specify('identity', encoding);
- minQuality = Math.min(minQuality, encoding.q || 1);
- }
- }
-
- if (!hasIdentity) {
- /*
- * If identity doesn't explicitly appear in the accept-encoding header,
- * it's added to the list of acceptable encoding with the lowest q
- */
- accepts[j++] = {
- encoding: 'identity',
- q: minQuality,
- i: i
- };
- }
-
- // trim accepts
- accepts.length = j;
-
- return accepts;
-}
-
-function parseEncoding(s, i) {
- var match = s.match(/^\s*(\S+?)\s*(?:;(.*))?$/);
-
- if (!match) return null;
-
- var encoding = match[1];
- var q = 1;
- if (match[2]) {
- var params = match[2].split(';');
- for (var i = 0; i < params.length; i ++) {
- var p = params[i].trim().split('=');
- if (p[0] === 'q') {
- q = parseFloat(p[1]);
- break;
- }
- }
- }
-
- return {
- encoding: encoding,
- q: q,
- i: i
- };
-}
-
-function getEncodingPriority(encoding, accepted, index) {
- var priority = {o: -1, q: 0, s: 0};
-
- for (var i = 0; i < accepted.length; i++) {
- var spec = specify(encoding, accepted[i], index);
-
- if (spec && (priority.s - spec.s || priority.q - spec.q || priority.o - spec.o) < 0) {
- priority = spec;
- }
- }
-
- return priority;
-}
-
-function specify(encoding, spec, index) {
- var s = 0;
- if(spec.encoding.toLowerCase() === encoding.toLowerCase()){
- s |= 1;
- } else if (spec.encoding !== '*' ) {
- return null
- }
-
- return {
- i: index,
- o: spec.i,
- q: spec.q,
- s: s
- }
-};
-
-function preferredEncodings(accept, provided) {
- var accepts = parseAcceptEncoding(accept || '');
-
- if (!provided) {
- // sorted list of all encodings
- return accepts.filter(isQuality).sort(compareSpecs).map(function getEncoding(spec) {
- return spec.encoding;
- });
- }
-
- var priorities = provided.map(function getPriority(type, index) {
- return getEncodingPriority(type, accepts, index);
- });
-
- // sorted list of accepted encodings
- return priorities.filter(isQuality).sort(compareSpecs).map(function getEncoding(priority) {
- return provided[priorities.indexOf(priority)];
- });
-}
-
-function compareSpecs(a, b) {
- return (b.q - a.q) || (b.s - a.s) || (a.o - b.o) || (a.i - b.i) || 0;
-}
-
-function isQuality(spec) {
- return spec.q > 0;
-}