Amir Shrestha
457 lines
14 KiB
JavaScript
457 lines
14 KiB
JavaScript
/* Blob.js
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* A Blob, File, FileReader & URL implementation.
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* 2018-08-09
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*
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* By Eli Grey, http://eligrey.com
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* By Jimmy Wärting, https://github.com/jimmywarting
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* License: MIT
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* See https://github.com/eligrey/Blob.js/blob/master/LICENSE.md
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*/
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;(function(){
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var global = typeof window === 'object'
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? window : typeof self === 'object'
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? self : this
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var BlobBuilder = global.BlobBuilder
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|| global.WebKitBlobBuilder
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|| global.MSBlobBuilder
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|| global.MozBlobBuilder;
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global.URL = global.URL || global.webkitURL || function(href, a) {
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a = document.createElement('a')
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a.href = href
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return a
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}
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var origBlob = global.Blob
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var createObjectURL = URL.createObjectURL
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var revokeObjectURL = URL.revokeObjectURL
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var strTag = global.Symbol && global.Symbol.toStringTag
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var blobSupported = false
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var blobSupportsArrayBufferView = false
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var arrayBufferSupported = !!global.ArrayBuffer
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var blobBuilderSupported = BlobBuilder
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&& BlobBuilder.prototype.append
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&& BlobBuilder.prototype.getBlob;
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try {
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// Check if Blob constructor is supported
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blobSupported = new Blob(['ä']).size === 2
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// Check if Blob constructor supports ArrayBufferViews
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// Fails in Safari 6, so we need to map to ArrayBuffers there.
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blobSupportsArrayBufferView = new Blob([new Uint8Array([1,2])]).size === 2
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} catch(e) {}
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/**
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* Helper function that maps ArrayBufferViews to ArrayBuffers
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* Used by BlobBuilder constructor and old browsers that didn't
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* support it in the Blob constructor.
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*/
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function mapArrayBufferViews(ary) {
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return ary.map(function(chunk) {
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if (chunk.buffer instanceof ArrayBuffer) {
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var buf = chunk.buffer;
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// if this is a subarray, make a copy so we only
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// include the subarray region from the underlying buffer
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if (chunk.byteLength !== buf.byteLength) {
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var copy = new Uint8Array(chunk.byteLength);
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copy.set(new Uint8Array(buf, chunk.byteOffset, chunk.byteLength));
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buf = copy.buffer;
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}
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return buf;
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}
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return chunk;
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});
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}
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function BlobBuilderConstructor(ary, options) {
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options = options || {};
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var bb = new BlobBuilder();
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mapArrayBufferViews(ary).forEach(function(part) {
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bb.append(part);
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});
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return options.type ? bb.getBlob(options.type) : bb.getBlob();
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};
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function BlobConstructor(ary, options) {
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return new origBlob(mapArrayBufferViews(ary), options || {});
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};
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if (global.Blob) {
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BlobBuilderConstructor.prototype = Blob.prototype;
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BlobConstructor.prototype = Blob.prototype;
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}
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function FakeBlobBuilder() {
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function toUTF8Array(str) {
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var utf8 = [];
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for (var i=0; i < str.length; i++) {
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var charcode = str.charCodeAt(i);
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if (charcode < 0x80) utf8.push(charcode);
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else if (charcode < 0x800) {
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utf8.push(0xc0 | (charcode >> 6),
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0x80 | (charcode & 0x3f));
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}
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else if (charcode < 0xd800 || charcode >= 0xe000) {
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utf8.push(0xe0 | (charcode >> 12),
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0x80 | ((charcode>>6) & 0x3f),
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0x80 | (charcode & 0x3f));
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}
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// surrogate pair
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else {
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i++;
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// UTF-16 encodes 0x10000-0x10FFFF by
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// subtracting 0x10000 and splitting the
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// 20 bits of 0x0-0xFFFFF into two halves
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charcode = 0x10000 + (((charcode & 0x3ff)<<10)
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| (str.charCodeAt(i) & 0x3ff));
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utf8.push(0xf0 | (charcode >>18),
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0x80 | ((charcode>>12) & 0x3f),
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0x80 | ((charcode>>6) & 0x3f),
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0x80 | (charcode & 0x3f));
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}
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}
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return utf8;
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}
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function fromUtf8Array(array) {
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var out, i, len, c;
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var char2, char3;
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out = "";
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len = array.length;
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i = 0;
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while (i < len) {
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c = array[i++];
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switch (c >> 4)
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{
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case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
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// 0xxxxxxx
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out += String.fromCharCode(c);
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break;
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case 12: case 13:
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// 110x xxxx 10xx xxxx
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char2 = array[i++];
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out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
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break;
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case 14:
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// 1110 xxxx 10xx xxxx 10xx xxxx
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char2 = array[i++];
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char3 = array[i++];
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out += String.fromCharCode(((c & 0x0F) << 12) |
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((char2 & 0x3F) << 6) |
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((char3 & 0x3F) << 0));
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break;
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}
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}
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return out;
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}
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function isDataView(obj) {
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return obj && DataView.prototype.isPrototypeOf(obj)
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}
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function bufferClone(buf) {
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var view = new Array(buf.byteLength)
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var array = new Uint8Array(buf)
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var i = view.length
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while(i--) {
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view[i] = array[i]
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}
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return view
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}
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function encodeByteArray(input) {
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var byteToCharMap = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
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var output = [];
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for (var i = 0; i < input.length; i += 3) {
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var byte1 = input[i];
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var haveByte2 = i + 1 < input.length;
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var byte2 = haveByte2 ? input[i + 1] : 0;
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var haveByte3 = i + 2 < input.length;
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var byte3 = haveByte3 ? input[i + 2] : 0;
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var outByte1 = byte1 >> 2;
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var outByte2 = ((byte1 & 0x03) << 4) | (byte2 >> 4);
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var outByte3 = ((byte2 & 0x0F) << 2) | (byte3 >> 6);
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var outByte4 = byte3 & 0x3F;
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if (!haveByte3) {
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outByte4 = 64;
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if (!haveByte2) {
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outByte3 = 64;
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}
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}
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output.push(
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byteToCharMap[outByte1], byteToCharMap[outByte2],
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byteToCharMap[outByte3], byteToCharMap[outByte4])
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}
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return output.join('')
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}
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var create = Object.create || function (a) {
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function c() {}
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c.prototype = a;
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return new c
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}
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if (arrayBufferSupported) {
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var viewClasses = [
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'[object Int8Array]',
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'[object Uint8Array]',
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'[object Uint8ClampedArray]',
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'[object Int16Array]',
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'[object Uint16Array]',
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'[object Int32Array]',
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'[object Uint32Array]',
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'[object Float32Array]',
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'[object Float64Array]'
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]
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var isArrayBufferView = ArrayBuffer.isView || function(obj) {
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return obj && viewClasses.indexOf(Object.prototype.toString.call(obj)) > -1
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}
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}
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/********************************************************/
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/* Blob constructor */
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/********************************************************/
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function Blob(chunks, opts) {
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chunks = chunks || []
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for (var i = 0, len = chunks.length; i < len; i++) {
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var chunk = chunks[i]
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if (chunk instanceof Blob) {
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chunks[i] = chunk._buffer
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} else if (typeof chunk === 'string') {
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chunks[i] = toUTF8Array(chunk)
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} else if (arrayBufferSupported && (ArrayBuffer.prototype.isPrototypeOf(chunk) || isArrayBufferView(chunk))) {
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chunks[i] = bufferClone(chunk)
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} else if (arrayBufferSupported && isDataView(chunk)) {
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chunks[i] = bufferClone(chunk.buffer)
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} else {
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chunks[i] = toUTF8Array(String(chunk))
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}
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}
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this._buffer = [].concat.apply([], chunks)
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this.size = this._buffer.length
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this.type = opts ? opts.type || '' : ''
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}
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Blob.prototype.slice = function(start, end, type) {
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var slice = this._buffer.slice(start || 0, end || this._buffer.length)
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return new Blob([slice], {type: type})
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}
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Blob.prototype.toString = function() {
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return '[object Blob]'
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}
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/********************************************************/
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/* File constructor */
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/********************************************************/
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function File(chunks, name, opts) {
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opts = opts || {}
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var a = Blob.call(this, chunks, opts) || this
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a.name = name
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a.lastModifiedDate = opts.lastModified ? new Date(opts.lastModified) : new Date
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a.lastModified = +a.lastModifiedDate
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return a
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}
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File.prototype = create(Blob.prototype);
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File.prototype.constructor = File;
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if (Object.setPrototypeOf)
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Object.setPrototypeOf(File, Blob);
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else {
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try {File.__proto__ = Blob} catch (e) {}
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}
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File.prototype.toString = function() {
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return '[object File]'
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}
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/********************************************************/
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/* FileReader constructor */
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/********************************************************/
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function FileReader() {
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if (!(this instanceof FileReader))
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throw new TypeError("Failed to construct 'FileReader': Please use the 'new' operator, this DOM object constructor cannot be called as a function.")
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var delegate = document.createDocumentFragment()
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this.addEventListener = delegate.addEventListener
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this.dispatchEvent = function(evt) {
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var local = this['on' + evt.type]
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if (typeof local === 'function') local(evt)
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delegate.dispatchEvent(evt)
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}
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this.removeEventListener = delegate.removeEventListener
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}
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function _read(fr, blob, kind) {
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if (!(blob instanceof Blob))
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throw new TypeError("Failed to execute '" + kind + "' on 'FileReader': parameter 1 is not of type 'Blob'.")
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fr.result = ''
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setTimeout(function(){
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this.readyState = FileReader.LOADING
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fr.dispatchEvent(new Event('load'))
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fr.dispatchEvent(new Event('loadend'))
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})
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}
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FileReader.EMPTY = 0
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FileReader.LOADING = 1
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FileReader.DONE = 2
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FileReader.prototype.error = null
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FileReader.prototype.onabort = null
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FileReader.prototype.onerror = null
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FileReader.prototype.onload = null
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FileReader.prototype.onloadend = null
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FileReader.prototype.onloadstart = null
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FileReader.prototype.onprogress = null
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FileReader.prototype.readAsDataURL = function(blob) {
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_read(this, blob, 'readAsDataURL')
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this.result = 'data:' + blob.type + ';base64,' + encodeByteArray(blob._buffer)
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}
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FileReader.prototype.readAsText = function(blob) {
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_read(this, blob, 'readAsText')
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this.result = fromUtf8Array(blob._buffer)
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}
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FileReader.prototype.readAsArrayBuffer = function(blob) {
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_read(this, blob, 'readAsText')
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this.result = blob._buffer.slice()
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}
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FileReader.prototype.abort = function() {}
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/********************************************************/
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/* URL */
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/********************************************************/
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URL.createObjectURL = function(blob) {
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return blob instanceof Blob
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? 'data:' + blob.type + ';base64,' + encodeByteArray(blob._buffer)
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: createObjectURL.call(URL, blob)
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}
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URL.revokeObjectURL = function(url) {
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revokeObjectURL && revokeObjectURL.call(URL, url)
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}
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/********************************************************/
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/* XHR */
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/********************************************************/
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var _send = global.XMLHttpRequest && global.XMLHttpRequest.prototype.send
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if (_send) {
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XMLHttpRequest.prototype.send = function(data) {
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if (data instanceof Blob) {
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this.setRequestHeader('Content-Type', data.type)
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_send.call(this, fromUtf8Array(data._buffer))
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} else {
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_send.call(this, data)
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}
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}
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}
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global.FileReader = FileReader
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global.File = File
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global.Blob = Blob
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}
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if (strTag) {
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File.prototype[strTag] = 'File'
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Blob.prototype[strTag] = 'Blob'
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FileReader.prototype[strTag] = 'FileReader'
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}
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function fixFileAndXHR() {
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var isIE = !!global.ActiveXObject || (
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'-ms-scroll-limit' in document.documentElement.style &&
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'-ms-ime-align' in document.documentElement.style
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)
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// Monkey patched
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// IE don't set Content-Type header on XHR whose body is a typed Blob
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// https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/6047383
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var _send = global.XMLHttpRequest && global.XMLHttpRequest.prototype.send
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if (isIE && _send) {
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XMLHttpRequest.prototype.send = function(data) {
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if (data instanceof Blob) {
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this.setRequestHeader('Content-Type', data.type)
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_send.call(this, data)
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} else {
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_send.call(this, data)
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}
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}
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}
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try {
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new File([], '')
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} catch(e) {
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try {
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var klass = new Function('class File extends Blob {' +
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'constructor(chunks, name, opts) {' +
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'opts = opts || {};' +
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'super(chunks, opts || {});' +
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'this.name = name;' +
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'this.lastModifiedDate = opts.lastModified ? new Date(opts.lastModified) : new Date;' +
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'this.lastModified = +this.lastModifiedDate;' +
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'}};' +
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'return new File([], ""), File'
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)()
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global.File = klass
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} catch(e) {
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var klass = function(b, d, c) {
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var blob = new Blob(b, c)
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var t = c && void 0 !== c.lastModified ? new Date(c.lastModified) : new Date
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blob.name = d
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blob.lastModifiedDate = t
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blob.lastModified = +t
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blob.toString = function() {
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return '[object File]'
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}
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if (strTag)
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blob[strTag] = 'File'
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return blob
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}
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global.File = klass
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}
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}
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}
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if (blobSupported) {
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fixFileAndXHR()
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global.Blob = blobSupportsArrayBufferView ? global.Blob : BlobConstructor
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} else if (blobBuilderSupported) {
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fixFileAndXHR()
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global.Blob = BlobBuilderConstructor;
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} else {
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FakeBlobBuilder()
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}
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})();
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