xref: /external/chromium/chrome/common/extensions/docs/examples/extensions/imageinfo/imageinfo/binaryajax.js

/*
 * Binary Ajax 0.1.5
 * Copyright (c) 2008 Jacob Seidelin, cupboy@gmail.com, http://blog.nihilogic.dk/
 * MIT License [http://www.opensource.org/licenses/mit-license.php]
 */


var BinaryFile = function(strData, iDataOffset, iDataLength) {
  var data = strData;
  var dataOffset = iDataOffset || 0;
  var dataLength = 0;

  this.getRawData = function() {
    return data;
  }

  if (typeof strData == "string") {
    dataLength = iDataLength || data.length;

    this.getByteAt = function(iOffset) {
      return data.charCodeAt(iOffset + dataOffset) & 0xFF;
    }
  } else if (typeof strData == "unknown") {
    dataLength = iDataLength || IEBinary_getLength(data);

    this.getByteAt = function(iOffset) {
      return IEBinary_getByteAt(data, iOffset + dataOffset);
    }
  }

  this.getLength = function() {
    return dataLength;
  }

  this.getSByteAt = function(iOffset) {
    var iByte = this.getByteAt(iOffset);
    if (iByte > 127)
      return iByte - 256;
    else
      return iByte;
  }

  this.getShortAt = function(iOffset, bBigEndian) {
    var iShort = bBigEndian ?
      (this.getByteAt(iOffset) << 8) + this.getByteAt(iOffset + 1)
      : (this.getByteAt(iOffset + 1) << 8) + this.getByteAt(iOffset)
    if (iShort < 0) iShort += 65536;
    return iShort;
  }
  this.getSShortAt = function(iOffset, bBigEndian) {
    var iUShort = this.getShortAt(iOffset, bBigEndian);
    if (iUShort > 32767)
      return iUShort - 65536;
    else
      return iUShort;
  }
  this.getLongAt = function(iOffset, bBigEndian) {
    var iByte1 = this.getByteAt(iOffset),
      iByte2 = this.getByteAt(iOffset + 1),
      iByte3 = this.getByteAt(iOffset + 2),
      iByte4 = this.getByteAt(iOffset + 3);

    var iLong = bBigEndian ?
      (((((iByte1 << 8) + iByte2) << 8) + iByte3) << 8) + iByte4
      : (((((iByte4 << 8) + iByte3) << 8) + iByte2) << 8) + iByte1;
    if (iLong < 0) iLong += 4294967296;
    return iLong;
  }
  this.getSLongAt = function(iOffset, bBigEndian) {
    var iULong = this.getLongAt(iOffset, bBigEndian);
    if (iULong > 2147483647)
      return iULong - 4294967296;
    else
      return iULong;
  }
  this.getStringAt = function(iOffset, iLength) {
    var aStr = [];
    for (var i=iOffset,j=0;i<iOffset+iLength;i++,j++) {
      aStr[j] = String.fromCharCode(this.getByteAt(i));
    }
    return aStr.join("");
  }

  this.getCharAt = function(iOffset) {
    return String.fromCharCode(this.getByteAt(iOffset));
  }
  this.toBase64 = function() {
    return window.btoa(data);
  }
  this.fromBase64 = function(strBase64) {
    data = window.atob(strBase64);
  }
}


var BinaryAjax = (function() {

  function createRequest() {
    var oHTTP = null;
    if (window.XMLHttpRequest) {
      oHTTP = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
      oHTTP = new ActiveXObject("Microsoft.XMLHTTP");
    }
    return oHTTP;
  }

  function getHead(strURL, fncCallback, fncError) {
    var oHTTP = createRequest();
    if (oHTTP) {
      if (fncCallback) {
        if (typeof(oHTTP.onload) != "undefined") {
          oHTTP.onload = function() {
            if (oHTTP.status == "200") {
              fncCallback(this);
            } else {
              if (fncError) fncError();
            }
            oHTTP = null;
          };
        } else {
          oHTTP.onreadystatechange = function() {
            if (oHTTP.readyState == 4) {
              if (oHTTP.status == "200") {
                fncCallback(this);
              } else {
                if (fncError) fncError();
              }
              oHTTP = null;
            }
          };
        }
      }
      oHTTP.open("HEAD", strURL, true);
      oHTTP.send(null);
    } else {
      if (fncError) fncError();
    }
  }

  function sendRequest(strURL, fncCallback, fncError, aRange, bAcceptRanges, iFileSize) {
    var oHTTP = createRequest();
    if (oHTTP) {

      var iDataOffset = 0;
      if (aRange && !bAcceptRanges) {
        iDataOffset = aRange[0];
      }
      var iDataLen = 0;
      if (aRange) {
        iDataLen = aRange[1]-aRange[0]+1;
      }

      if (fncCallback) {
        if (typeof(oHTTP.onload) != "undefined") {
          oHTTP.onload = function() {

            if (oHTTP.status == "200" || oHTTP.status == "206") {
              this.binaryResponse = new BinaryFile(this.responseText, iDataOffset, iDataLen);
              this.fileSize = iFileSize || this.getResponseHeader("Content-Length");
              fncCallback(this);
            } else {
              if (fncError) fncError();
            }
            oHTTP = null;
          };
        } else {
          oHTTP.onreadystatechange = function() {
            if (oHTTP.readyState == 4) {
              if (oHTTP.status == "200" || oHTTP.status == "206") {
                this.binaryResponse = new BinaryFile(oHTTP.responseBody, iDataOffset, iDataLen);
                this.fileSize = iFileSize || this.getResponseHeader("Content-Length");
                fncCallback(this);
              } else {
                if (fncError) fncError();
              }
              oHTTP = null;
            }
          };
        }
      }
      oHTTP.open("GET", strURL, true);

      if (oHTTP.overrideMimeType) oHTTP.overrideMimeType('text/plain; charset=x-user-defined');

      if (aRange && bAcceptRanges) {
        oHTTP.setRequestHeader("Range", "bytes=" + aRange[0] + "-" + aRange[1]);
      }

      oHTTP.setRequestHeader("If-Modified-Since", "Sat, 1 Jan 1970 00:00:00 GMT");

      oHTTP.send(null);
    } else {
      if (fncError) fncError();
    }
  }

  return function(strURL, fncCallback, fncError, aRange) {

    if (aRange) {
      getHead(
        strURL,
        function(oHTTP) {
          var iLength = parseInt(oHTTP.getResponseHeader("Content-Length"),10);
          var strAcceptRanges = oHTTP.getResponseHeader("Accept-Ranges");

          var iStart, iEnd;
          iStart = aRange[0];
          if (aRange[0] < 0)
            iStart += iLength;
          iEnd = iStart + aRange[1] - 1;

          sendRequest(strURL, fncCallback, fncError, [iStart, iEnd], (strAcceptRanges == "bytes"), iLength);
        }
      );

    } else {
      sendRequest(strURL, fncCallback, fncError);
    }
  }

}());


document.write(
  "<script type='text/vbscript'>\r\n"
  + "Function IEBinary_getByteAt(strBinary, iOffset)\r\n"
  + "	IEBinary_getByteAt = AscB(MidB(strBinary,iOffset+1,1))\r\n"
  + "End Function\r\n"
  + "Function IEBinary_getLength(strBinary)\r\n"
  + "	IEBinary_getLength = LenB(strBinary)\r\n"
  + "End Function\r\n"
  + "</script>\r\n"
);