BinaryFile over XMLHttpRequest

1 files changed, 232 insertions, 0 deletions

diff --git a/src/lib/binaryXHR.js b/src/lib/binaryXHR.js
new file mode 100644
index 0000000..14d06fe
--- /dev/null
+++ b/src/lib/binaryXHR.js
@@ -0,0 +1,232 @@
+

+/*

+ * BinaryFile over XMLHttpRequest

+ * Part of the javascriptRRD package

+ * Copyright (c) 2009 Frank Wuerthwein, fkw@ucsd.edu

+ * MIT License [http://www.opensource.org/licenses/mit-license.php]

+ *

+ * Original repository: http://javascriptrrd.sourceforge.net/

+ *

+ * Based on:

+ *   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]

+ */

+

+// ============================================================

+// Exception class

+function InvalidBinaryFile(msg) {

+  this.message=msg;

+  this.name="Invalid BinaryFile";

+}

+

+// pretty print

+InvalidBinaryFile.prototype.toString = function() {

+  return this.name + ': "' + this.message + '"';

+}

+

+// =====================================================================

+// BinaryFile class

+//   Allows access to element inside a binary stream

+function BinaryFile(strData, iDataOffset, iDataLength) {

+	var data = strData;

+	var dataOffset = iDataOffset || 0;

+	var dataLength = 0;

+	// added 

+	var doubleMantExpHi=Math.pow(2,-28);

+	var doubleMantExpLo=Math.pow(2,-52);

+	var doubleMantExpFast=Math.pow(2,-20);

+

+	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);

+		}

+	} else {

+	  throw new InvalidBinaryFile("Unsupported type " + (typeof strData));

+	}

+

+	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("");

+	}

+

+	// Added

+	this.getCStringAt = function(iOffset, iMaxLength) {

+		var aStr = [];

+		for (var i=iOffset,j=0;(i<iOffset+iMaxLength) && (this.getByteAt(i)>0);i++,j++) {

+			aStr[j] = String.fromCharCode(this.getByteAt(i));

+		}

+		return aStr.join("");

+	}

+

+	// Added

+	this.getDoubleAt = function(iOffset) {

+		var iByte1 = this.getByteAt(iOffset),

+			iByte2 = this.getByteAt(iOffset + 1),

+			iByte3 = this.getByteAt(iOffset + 2),

+		        iByte4 = this.getByteAt(iOffset + 3),

+		        iByte5 = this.getByteAt(iOffset + 4),

+			iByte6 = this.getByteAt(iOffset + 5),

+			iByte7 = this.getByteAt(iOffset + 6),

+			iByte8 = this.getByteAt(iOffset + 7);

+		var iSign=iByte8 >> 7;

+		var iExpRaw=((iByte8 & 0x7F)<< 4) + (iByte7 >> 4);

+		var iMantHi=((((((iByte7 & 0x0F) << 8) + iByte6) << 8) + iByte5) << 8) + iByte4;

+		var iMantLo=((((iByte3) << 8) + iByte2) << 8) + iByte1;

+

+		if (iExpRaw==0) return 0.0;

+		if (iExpRaw==0x7ff) return false;

+

+		var iExp=(iExpRaw & 0x7FF)-1023;

+

+		var dDouble = ((iSign==1)?-1:1)*Math.pow(2,iExp)*(1.0 + iMantLo*doubleMantExpLo + iMantHi*doubleMantExpHi);

+		return dDouble;

+	}

+	// added

+	// Extracts only 4 bytes out of 8, loosing in precision (20 bit mantissa)

+	this.getFastDoubleAt = function(iOffset) {

+		var iByte5 = this.getByteAt(iOffset + 4),

+			iByte6 = this.getByteAt(iOffset + 5),

+			iByte7 = this.getByteAt(iOffset + 6),

+			iByte8 = this.getByteAt(iOffset + 7);

+		var iSign=iByte8 >> 7;

+		var iExpRaw=((iByte8 & 0x7F)<< 4) + (iByte7 >> 4);

+		var iMant=((((iByte7 & 0x0F) << 8) + iByte6) << 8) + iByte5;

+

+		if (iExpRaw==0) return 0.0;

+		if (iExpRaw==0x7ff) return false;

+

+		var iExp=(iExpRaw & 0x7FF)-1023;

+

+		var dDouble = ((iSign==1)?-1:1)*Math.pow(2,iExp)*(1.0 + iMant*doubleMantExpFast);

+		return dDouble;

+	}

+

+	this.getCharAt = function(iOffset) {

+		return String.fromCharCode(this.getByteAt(iOffset));

+	}

+}

+

+

+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"

+);

+

+

+

+// ===============================================================

+// Load a binary file from the specified URL 

+// Will return an object of type BinaryFile

+function FetchBinaryURL(url) {

+  var request =  new XMLHttpRequest();

+  request.open("GET", url,false);

+  try {

+    request.overrideMimeType('text/plain; charset=x-user-defined');

+  } catch (err) {

+    // ignore any error, just to make both FF and IE work

+  }

+  request.send(null);

+

+  var response=request.responseBody;

+  if (response==undefined){ // responseBody is non standard, but the only way to make it work in IE

+    response=request.responseText;

+  }

+  var bf=new BinaryFile(response);

+  return bf;

+}

+

+

+// ===============================================================

+// Asyncronously load a binary file from the specified URL 

+//

+// callback must be a function with a single argument:

+//  bf = an object of type BinaryFile

+function FetchBinaryURLAsync(url, callback) {

+  var callback_wrapper = function() {

+    if(this.readyState == 4) {

+      var response=this.responseBody;

+      if (response==undefined){ // responseBody is non standard, but the only way to make it work in IE

+	response=this.responseText;

+      }

+      var bf=new BinaryFile(response);

+      callback(bf);

+    }

+  }

+

+  var request =  new XMLHttpRequest();

+  request.onreadystatechange = callback_wrapper;

+  request.open("GET", url,true);

+  try {

+    request.overrideMimeType('text/plain; charset=x-user-defined');

+  } catch (err) {

+    // ignore any error, just to make both FF and IE work

+  }

+  request.send(null);

+}