Closes #25

Lawo · May 23, 2016 · 5772696 · 5772696
1 parent 1d3310f
commit 5772696
Show file tree

Hide file tree

Showing 2 changed files with 19 additions and 2 deletions.
diff --git a/Lawo.EmberPlusSharp/Ember/EmberReader.cs b/Lawo.EmberPlusSharp/Ember/EmberReader.cs
@@ -537,6 +537,19 @@ private static double ReadReal(ReadBuffer readBuffer, int length)
             }
 
             var exponent = Read8Bit(readBuffer, exponentLength, true);
+            var mantissa = Read8Bit(readBuffer, mantissaLength, false);
+
+            if (exponent == 1024)
+            {
+                if (mantissa == 0)
+                {
+                    return signBits == 0 ? double.PositiveInfinity : double.NegativeInfinity;
+                }
+                else if (mantissa == Constants.DoubleMantissaMask)
+                {
+                    return double.NaN;
+                }
+            }
 
             // https://en.wikipedia.org/wiki/Double-precision_floating-point_format
             if ((exponent <= -Constants.DoubleExponentBias) || (exponent > Constants.DoubleExponentBias))
@@ -545,8 +558,6 @@ private static double ReadReal(ReadBuffer readBuffer, int length)
                     "The exponent of the Real at position {0} exceeds the expected range.", position);
             }
 
-            var mantissa = Read8Bit(readBuffer, mantissaLength, false);
-
             if (mantissa == 0)
             {
                 throw CreateEmberException("The mantissa of the Real at position {0} is zero.", position);

diff --git a/Lawo.EmberPlusSharpTest/Ember/EmberReaderTest.cs b/Lawo.EmberPlusSharpTest/Ember/EmberReaderTest.cs
@@ -136,6 +136,12 @@ public void RealTest()
             AssertDecode(InnerNumber.Real, double.PositiveInfinity, 0x60, 0x03, 0x09, 0x01, 0x40);
             AssertDecode(InnerNumber.Real, double.NegativeInfinity, 0x60, 0x03, 0x09, 0x01, 0x41);
             AssertDecode(InnerNumber.Real, double.NaN, 0x60, 0x03, 0x09, 0x01, 0x42);
+
+            // Incorrectly encoded special values
+            AssertDecode(InnerNumber.Real, double.PositiveInfinity, 0x60, 0x06, 0x09, 0x04, 0x81, 0x04, 0x00, 0x00);
+            AssertDecode(InnerNumber.Real, double.NegativeInfinity, 0x60, 0x06, 0x09, 0x04, 0xC1, 0x04, 0x00, 0x00);
+            AssertDecode(InnerNumber.Real, double.NaN, 0x60, 0x0C, 0x09, 0x0A, 0x81, 0x04, 0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF);
+
             AssertDecode(InnerNumber.Real, -0.0, 0x60, 0x03, 0x09, 0x01, 0x43);
             AssertDecode(InnerNumber.Real, 1.0, 0x60, 0x05, 0x09, 0x03, 0x80, 0x00, 0x01);
             AssertDecode(InnerNumber.Real, -1.0, 0x60, 0x05, 0x09, 0x03, 0xC0, 0x00, 0x01);