reader.min.js

(function(){var Reader=function(type){this.type=type||Reader.OPEN_URI;this.size=null;this.file=null};Reader.OPEN_FILE=1;Reader.OPEN_URI=2;Reader.OPEN_LOCAL=3;if(typeof require==="function"){var fs=require("fs")}Reader.prototype.open=function(file,callback){this.file=file;var self=this;switch(this.type){case Reader.OPEN_LOCAL:fs.stat(this.file,function(err,stat){if(err){return callback(err)}self.size=stat.size;fs.open(self.file,"r",function(err,fd){if(err){return callback(err)}self.fd=fd;callback()})});break;case Reader.OPEN_FILE:this.size=this.file.size;callback();break;default:this.ajax({uri:this.file,type:"HEAD"},function(err,resp,xhr){if(err){return callback(err)}self.size=parseInt(xhr.getResponseHeader("Content-Length"));callback()});break}};Reader.prototype.close=function(){if(this.type===Reader.OPEN_LOCAL){fs.close(this.fd)}};Reader.prototype.read=function(length,position,callback){if(typeof position==="function"){callback=position;position=0}if(this.type===Reader.OPEN_LOCAL){this.readLocal(length,position,callback)}else if(this.type===Reader.OPEN_FILE){this.readFile(length,position,callback)}else{this.readUri(length,position,callback)}};Reader.prototype.readBlob=function(length,position,type,callback){if(typeof position==="function"){callback=position;position=0}else if(typeof type==="function"){callback=type;type="application/octet-stream"}this.read(length,position,function(err,data){if(err){callback(err);return}callback(null,new Blob([data],{type:type}))})};Reader.prototype.readLocal=function(length,position,callback){var buffer=new Buffer(length);fs.read(this.fd,buffer,0,length,position,function(err,bytesRead,buffer){if(err){return callback(err)}var ab=new ArrayBuffer(buffer.length),view=new Uint8Array(ab);for(var i=0;i<buffer.length;i++){view[i]=buffer[i]}callback(null,ab)})};Reader.prototype.ajax=function(opts,callback){var options={type:"GET",uri:null,responseType:"text"};if(typeof opts==="string"){opts={uri:opts}}for(var k in opts){options[k]=opts[k]}var xhr=new XMLHttpRequest;xhr.onreadystatechange=function(){if(xhr.readyState!==4)return;if(xhr.status!==200&&xhr.status!==206){return callback("Received non-200/206 response ("+xhr.status+")")}callback(null,xhr.response,xhr)};xhr.responseType=options.responseType;xhr.open(options.type,options.uri,true);if(options.range){options.range=[].concat(options.range);if(options.range.length===2){xhr.setRequestHeader("Range","bytes="+options.range[0]+"-"+options.range[1])}else{xhr.setRequestHeader("Range","bytes="+options.range[0])}}xhr.send()};Reader.prototype.readUri=function(length,position,callback){this.ajax({uri:this.file,type:"GET",responseType:"arraybuffer",range:[position,position+length-1]},function(err,buffer){if(err){return callback(err)}return callback(null,buffer)})};Reader.prototype.readFile=function(length,position,callback){var slice=this.file.slice(position,position+length),fr=new FileReader;fr.onload=function(e){callback(null,e.target.result)};fr.onerror=function(e){callback("File read failed")};fr.readAsArrayBuffer(slice)};if(typeof module!=="undefined"&&module.exports){module.exports=Reader}else{if(typeof define==="function"&&define.amd){define("reader",[],function(){return Reader})}else{window.Reader=Reader}}})();