diff options
Diffstat (limited to 'src/lib/binaryXHR.js')
| -rw-r--r-- | src/lib/binaryXHR.js | 232 |
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);
+}
|