text: ﻿/* BlobBuilder.js
   * A BlobBuilder implementation.
   * 2012-04-21
   * 
   * By Eli Grey, http://eligrey.com
   * License: X11/MIT
   *   See LICENSE.md
   */
  
  /*global self, unescape */
  /*jslint bitwise: true, regexp: true, confusion: true, es5: true, vars: true, white: true,
    plusplus: true */
  
  /*! @source http://purl.eligrey.com/github/BlobBuilder.js/blob/master/BlobBuilder.js */
  
  // var BlobBuilder = BlobBuilder || self.WebKitBlobBuilder || self.MozBlobBuilder || self.MSBlobBuilder || (function (view) {
  var BlobBuilder = (function (view) {
      "use strict";
      var
            get_class = function (object) {
                return Object.prototype.toString.call(object).match(/^\[object\s(.*)\]$/)[1];
            }
          , FakeBlobBuilder = function () {
              this.data = [];
          }
          , FakeBlob = function (data, type, encoding) {
              this.data = data;
              this.size = data.length;
              this.type = type;
              this.encoding = encoding;
          }
          , FBB_proto = FakeBlobBuilder.prototype
          , FB_proto = FakeBlob.prototype
          , FileReaderSync = view.FileReaderSync
          , FileException = function (type) {
              this.code = this[this.name = type];
          }
          , file_ex_codes = (
                "NOT_FOUND_ERR SECURITY_ERR ABORT_ERR NOT_READABLE_ERR ENCODING_ERR "
              + "NO_MODIFICATION_ALLOWED_ERR INVALID_STATE_ERR SYNTAX_ERR"
          ).split(" ")
          , file_ex_code = file_ex_codes.length
          , real_URL = view.URL || view.webkitURL || view
          , real_create_object_URL = real_URL.createObjectURL
          , real_revoke_object_URL = real_URL.revokeObjectURL
          , URL = real_URL
          , btoa = view.btoa
          , atob = view.atob
          , can_apply_typed_arrays = false
          , can_apply_typed_arrays_test = function (pass) {
              can_apply_typed_arrays = !pass;
          }
  
          , ArrayBuffer = view.ArrayBuffer
          , Uint8Array = view.Uint8Array
      ;
      FakeBlobBuilder.fake = FB_proto.fake = true;
      while (file_ex_code--) {
          FileException.prototype[file_ex_codes[file_ex_code]] = file_ex_code + 1;
      }
      try {
          if (Uint8Array) {
              can_apply_typed_arrays_test.apply(0, new Uint8Array(1));
          }
      } catch (ex) { }
      if (!real_URL.createObjectURL) {
          URL = view.URL = {};
      }
      URL.createObjectURL = function (blob) {
          var
                type = blob.type
              , data_URI_header
          ;
          if (type === null) {
              type = "application/octet-stream";
          }
          if (blob instanceof FakeBlob) {
              data_URI_header = "data:" + type;
              if (blob.encoding === "base64") {
                  return data_URI_header + ";base64," + blob.data;
              } else if (blob.encoding === "URI") {
                  return data_URI_header + "," + decodeURIComponent(blob.data);
              } if (btoa) {
                  return data_URI_header + ";base64," + btoa(blob.data);
              } else {
                  return data_URI_header + "," + encodeURIComponent(blob.data);
              }
          } else if (real_create_object_URL) {
              return real_create_object_URL.call(real_URL, blob);
          }
      };
      URL.revokeObjectURL = function (object_URL) {
          if (object_URL.substring(0, 5) !== "data:" && real_revoke_object_URL) {
              real_revoke_object_URL.call(real_URL, object_URL);
          }
      };
      FBB_proto.append = function (data/*, endings*/) {
          var bb = this.data;
          // decode data to a binary string
          if (Uint8Array && data instanceof ArrayBuffer) {
              if (can_apply_typed_arrays) {
                  var array = new Uint8Array(data);
                  var string = '';
                  var i = 64000;
  
                  if (i < array.length) {
                      while (i < array.length) {
                          string += String.fromCharCode.apply(String, array.subarray(i - 64000, i));
                          i += 64000;
                      }
                      string += String.fromCharCode.apply(String, array.subarray(i-64000));
                  } else {
                      string += String.fromCharCode.apply(String, array.subarray(0));
                  }
  
                  //bb.push(String.fromCharCode.apply(String, array));
                  bb.push(string);
              } else {
                  var
                        str = ""
                      , buf = new Uint8Array(data)
                      , i = 0
                      , buf_len = buf.length
                  ;
                  for (; i < buf_len; i++) {
                      str += String.fromCharCode(buf[i]);
                  }
              }
          } else if (get_class(data) === "Blob" || get_class(data) === "File") {
              if (FileReaderSync) {
                  var fr = new FileReaderSync;
                  bb.push(fr.readAsBinaryString(data));
              } else {
                  // async FileReader won't work as BlobBuilder is sync
                  throw new FileException("NOT_READABLE_ERR");
              }
          } else if (data instanceof FakeBlob) {
              if (data.encoding === "base64" && atob) {
                  bb.push(atob(data.data));
              } else if (data.encoding === "URI") {
                  bb.push(decodeURIComponent(data.data));
              } else if (data.encoding === "raw") {
                  bb.push(data.data);
              }
          } else {
              if (typeof data !== "string") {
                  data += ""; // convert unsupported types to strings
              }
              // decode UTF-16 to binary string
              bb.push(unescape(encodeURIComponent(data)));
          }
      };
      FBB_proto.getBlob = function (type) {
          if (!arguments.length) {
              type = null;
          }
          return new FakeBlob(this.data.join(""), type, "raw");
      };
      FBB_proto.toString = function () {
          return "[object BlobBuilder]";
      };
      FB_proto.slice = function (start, end, type) {
          var args = arguments.length;
          if (args < 3) {
              type = null;
          }
          return new FakeBlob(
                this.data.slice(start, args > 1 ? end : this.data.length)
              , type
              , this.encoding
          );
      };
      FB_proto.toString = function () {
          return "[object Blob]";
      };
      return FakeBlobBuilder;
  }(self));