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define([], function () {
var exports = {};
// Licence: PUBLIC DOMAIN <http://unlicense.org/>
// Author: Austin Wright <http://github.com/Acubed>
function MediaType(s, p){
this.type = '';
this.params = {};
if(typeof s=='string'){
var c = splitQuotedString(s);
this.type = c.shift();
for(var i=0; i<c.length; i++){
this.parseParameter(c[i]);
}
}else if(s instanceof MediaType){
this.type = s.type;
this.q = s.q;
for(var n in s.params) this.params[n]=s.params[n];
}
if(typeof p=='string'){
var c = splitQuotedString(p);
for(var i=0; i<c.length; i++){
this.parseParameter(c[i]);
}
}else if(typeof p=='object'){
for(var n in p) this.params[n]=p[n];
}
}
MediaType.prototype.parseParameter = function parseParameter(s){
var param = s.split('=',1);
var name = param[0].trim();
var value = s.substr(param[0].length+1).trim();
if(!value || !name) return;
if(name=='q' && this.q===undefined){
this.q=parseFloat(value);
}else{
if(value[0]=='"' && value[value.length-1]=='"'){
value = value.substr(1, value.length-2);
value = value.replace(/\\(.)/g, function(a,b){return b;});
}
this.params[name]=value;
}
}
MediaType.prototype.toString = function toString(){
var str = this.type + ';q='+this.q;
for(var n in this.params){
str += ';'+n+'=';
if(this.params[n].match(/["=;<>\[\]\(\) ,\-]/)){
str += '"' + this.params[n].replace(/["\\]/g, function(a){return '\\'+a;}) + '"';
}else{
str += this.params[n];
}
}
return str;
}
exports.MediaType = MediaType;
// Split a string by character, but ignore quoted parts and backslash-escaped characters
function splitQuotedString(str, delim, quote){
delim = delim || ';';
quote = quote || '"';
var res = [];
var start = 0;
var offset = 0;
function findNextChar(v, c, i, a){
var p = str.indexOf(c, offset+1);
return (p<0)?v:Math.min(p,v);
}
while(offset>=0){
offset = [delim,quote].reduce(findNextChar, 1/0);
if(offset===1/0) break;
switch(str[offset]){
case quote:
// Skip to end of quoted string
while(1){
offset=str.indexOf(quote, offset+1);
if(offset<0) break;
if(str[offset-1]==='\\') continue;
break;
}
continue;
case delim:
res.push(str.substr(start, offset-start).trim());
start = ++offset;
break;
}
}
res.push(str.substr(start).trim());
return res;
}
exports.splitQuotedString = splitQuotedString;
// Split a list of content types found in an Accept header
// Maybe use it like: splitContentTypes(request.headers.accept).map(parseMedia)
function splitContentTypes(str){
return splitQuotedString(str, ',');
}
exports.splitContentTypes = splitContentTypes;
function parseMedia(str){
var o = new MediaType(str);
if(o.q===undefined) o.q=1;
return o;
}
exports.parseMedia = parseMedia;
// Pick an ideal representation to send given a list of representations to choose from and the client-preferred list
function select(reps, accept){
var cr = {q:0};
var ca = {q:0};
var cq = 0;
for(var i=0; i<reps.length; i++){
var r = reps[i];
var rq = r.q || 1;
for(var j=0; j<accept.length; j++){
var a=accept[j];
var aq = a.q || 1;
var cmp = mediaCmp(a, r);
if(cmp!==null && cmp>=0){
if(aq*rq>cq){
ca = a;
cr = r;
cq = ca.q*cr.q;
if(cq===1 && cr.type) return cr;
}
}
}
}
return cr.type&&cr;
}
exports.select = select;
// Determine if one media type is a subset of another
// If a is a superset of b (b is smaller than a), return 1
// If b is a superset of a, return -1
// If they are the exact same, return 0
// If they are disjoint, return null
function mediaCmp(a, b){
if(a.type==='*/*' && b.type!=='*/*') return 1;
else if(a.type!=='*/*' && b.type==='*/*') return -1;
var ac = (a.type||'').split('/');
var bc = (b.type||'').split('/');
if(ac[0]=='*' && bc[0]!='*') return 1;
if(ac[0]!='*' && bc[0]=='*') return -1;
if(a.type!==b.type) return null;
var ap = a.params || {};
var bp = b.params || {};
var ak = Object.keys(ap);
var bk = Object.keys(bp);
if(ak.length < bk.length) return 1;
if(ak.length > bk.length) return -1;
var k = ak.concat(bk).sort();
var dir = 0;
for(var n in ap){
if(ap[n] && !bp[n]){ if(dir<0) return null; else dir=1; }
if(!ap[n] && bp[n]){ if(dir>0) return null; else dir=-1; }
}
return dir;
}
exports.mediaCmp = mediaCmp;
return exports;
});
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