jsrrdgraph: Remove unused getStringAt, move implementation

Rename switch_endian to littleEndian to be more explicit (the meaning
is now inversed too). Make getEndianByteAt private since it is an
implementation detail.

Drop getStringAt as this is not used in this library. Move getCharAt
above getCStringAt since they are more related.

Move the methods definition for the current implementation to a new
function.

1 files changed, 43 insertions, 48 deletions

diff --git a/js/binaryXHR.js b/js/binaryXHR.js
index 8ce4b0f..2cd02dd 100644
--- a/js/binaryXHR.js
+++ b/js/binaryXHR.js
@@ -33,12 +33,8 @@ InvalidBinaryFile.prototype.toString = function() {
 function BinaryFile(data) {
         "use strict";
         var dataLength;
-        // added 
-        var doubleMantExpHi=Math.pow(2,-28);
-        var doubleMantExpLo=Math.pow(2,-52);
-        var doubleMantExpFast=Math.pow(2,-20);
-
-        var switch_endian = false;
+        // whether the data is in little endian format
+        var littleEndian = true;
 
         this.getRawData = function() {
                 return data;
@@ -61,20 +57,32 @@ function BinaryFile(data) {
                 throw new InvalidBinaryFile("Unsupported type " + (typeof data));
         }
 
-        if (switch_endian) {
-                this.getEndianByteAt = function(iOffset, width, delta) {
-                        return this.getByteAt(iOffset + width - delta - 1);
+        this.getLength = function() {
+                return dataLength;
+        };
+
+        // antique browser, use slower fallback implementation
+        this.extendWithFallback(data, littleEndian);
+}
+
+BinaryFile.prototype.extendWithFallback = function(data, littleEndian) {
+        "use strict";
+        var doubleMantExpHi = Math.pow(2,-28);
+        var doubleMantExpLo = Math.pow(2,-52);
+        var doubleMantExpFast = Math.pow(2,-20);
+
+        // private function for getting bytes depending on endianess
+        var that = this, getEndianByteAt;
+        if (littleEndian) {
+                getEndianByteAt = function(iOffset, width, delta) {
+                        return that.getByteAt(iOffset + delta);
                 };
         } else {
-                this.getEndianByteAt = function(iOffset, width, delta) {
-                        return this.getByteAt(iOffset + delta);
+                getEndianByteAt = function(iOffset, width, delta) {
+                        return that.getByteAt(iOffset + width - delta - 1);
                 };
         }
 
-        this.getLength = function() {
-                return dataLength;
-        };
-
         this.getSByteAt = function(iOffset) {
                 var iByte = this.getByteAt(iOffset);
                 if (iByte > 127)
@@ -82,9 +90,8 @@ function BinaryFile(data) {
                 else
                         return iByte;
         };
-
         this.getShortAt = function(iOffset) {
-                var iShort = (this.getEndianByteAt(iOffset,2,1) << 8) + this.getEndianByteAt(iOffset,2,0);
+                var iShort = (getEndianByteAt(iOffset,2,1) << 8) + getEndianByteAt(iOffset,2,0);
                 if (iShort < 0) iShort += 65536;
                 return iShort;
         };
@@ -96,10 +103,10 @@ function BinaryFile(data) {
                         return iUShort;
         };
         this.getLongAt = function(iOffset) {
-                var iByte1 = this.getEndianByteAt(iOffset,4,0),
-                        iByte2 = this.getEndianByteAt(iOffset,4,1),
-                        iByte3 = this.getEndianByteAt(iOffset,4,2),
-                        iByte4 = this.getEndianByteAt(iOffset,4,3);
+                var iByte1 = getEndianByteAt(iOffset,4,0),
+                        iByte2 = getEndianByteAt(iOffset,4,1),
+                        iByte3 = getEndianByteAt(iOffset,4,2),
+                        iByte4 = getEndianByteAt(iOffset,4,3);
 
                 var iLong = (((((iByte4 << 8) + iByte3) << 8) + iByte2) << 8) + iByte1;
                 if (iLong < 0) iLong += 4294967296;
@@ -112,15 +119,9 @@ function BinaryFile(data) {
                 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));
         };
-
-        // Added
         this.getCStringAt = function(iOffset, iMaxLength) {
                 var aStr = [];
                 for (var i=iOffset,j=0;(i<iOffset+iMaxLength) && (this.getByteAt(i)>0);i++,j++) {
@@ -128,17 +129,15 @@ function BinaryFile(data) {
                 }
                 return aStr.join("");
         };
-
-        // Added
         this.getDoubleAt = function(iOffset) {
-                var iByte1 = this.getEndianByteAt(iOffset,8,0),
-                        iByte2 = this.getEndianByteAt(iOffset,8,1),
-                        iByte3 = this.getEndianByteAt(iOffset,8,2),
-                        iByte4 = this.getEndianByteAt(iOffset,8,3),
-                        iByte5 = this.getEndianByteAt(iOffset,8,4),
-                        iByte6 = this.getEndianByteAt(iOffset,8,5),
-                        iByte7 = this.getEndianByteAt(iOffset,8,6),
-                        iByte8 = this.getEndianByteAt(iOffset,8,7);
+                var iByte1 = getEndianByteAt(iOffset,8,0),
+                        iByte2 = getEndianByteAt(iOffset,8,1),
+                        iByte3 = getEndianByteAt(iOffset,8,2),
+                        iByte4 = getEndianByteAt(iOffset,8,3),
+                        iByte5 = getEndianByteAt(iOffset,8,4),
+                        iByte6 = getEndianByteAt(iOffset,8,5),
+                        iByte7 = getEndianByteAt(iOffset,8,6),
+                        iByte8 = getEndianByteAt(iOffset,8,7);
                 var iSign=iByte8 >> 7;
                 var iExpRaw=((iByte8 & 0x7F)<< 4) + (iByte7 >> 4);
                 var iMantHi=((((((iByte7 & 0x0F) << 8) + iByte6) << 8) + iByte5) << 8) + iByte4;
@@ -152,13 +151,12 @@ function BinaryFile(data) {
                 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.getEndianByteAt(iOffset,8,4),
-                        iByte6 = this.getEndianByteAt(iOffset,8,5),
-                        iByte7 = this.getEndianByteAt(iOffset,8,6),
-                        iByte8 = this.getEndianByteAt(iOffset,8,7);
+                var iByte5 = getEndianByteAt(iOffset,8,4),
+                        iByte6 = getEndianByteAt(iOffset,8,5),
+                        iByte7 = getEndianByteAt(iOffset,8,6),
+                        iByte8 = getEndianByteAt(iOffset,8,7);
                 var iSign=iByte8 >> 7;
                 var iExpRaw=((iByte8 & 0x7F)<< 4) + (iByte7 >> 4);
                 var iMant=((((iByte7 & 0x0F) << 8) + iByte6) << 8) + iByte5;
@@ -172,11 +170,8 @@ function BinaryFile(data) {
                 dDouble *= Math.pow(2,iExp) * (1.0 + iMant*doubleMantExpFast);
                 return dDouble;
         };
+};
 
-        this.getCharAt = function(iOffset) {
-                return String.fromCharCode(this.getByteAt(iOffset));
-        };
-}
 
 
 // Use document.write only for stone-age browsers.