Correctly decode uint options from bytes

NZSmartie · Aug 27, 2017 · 45d9715 · 45d9715
1 parent b1719d2
commit 45d9715
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Showing 2 changed files with 31 additions and 7 deletions.
diff --git a/CoAPNet.Tests/CoapOptionsTests.cs b/CoAPNet.Tests/CoapOptionsTests.cs
@@ -370,5 +370,25 @@ public void TestOptionSize1()
             Assert.AreEqual(OptionType.UInt, option.Type, "Type is incorrect");
             Assert.AreEqual(0u, option.DefaultUInt, "Default value is incorrect");
         }
+
+        [TestCase(0u, 0, new byte[] { })]
+        [TestCase(0x12u, 1, new byte[] {0x12})]
+        [TestCase(0x1234u, 2, new byte[] {0x12, 0x34})]
+        [TestCase(0x123456u, 3, new byte[] {0x12, 0x34, 0x56})]
+        [TestCase(0x12345678u, 4, new byte[] {0x12, 0x34, 0x56, 0x78})]
+        public void TestValueOption(uint value, int length, byte[] expected)
+        {
+            var optionToBytes = new CoapOption(0, type: OptionType.UInt);
+
+            optionToBytes.ValueUInt = value;
+            Assert.AreEqual(length, optionToBytes.Length);
+            Assert.AreEqual(expected, optionToBytes.GetBytes());
+
+            var optionFromBytes = new CoapOption(0, type: OptionType.UInt);
+
+            optionFromBytes.FromBytes(expected);
+            Assert.AreEqual(length, optionFromBytes.Length);
+            Assert.AreEqual(value, optionFromBytes.ValueUInt);
+        }
     }
 }
diff --git a/CoAPNet/CoapOptions.cs b/CoAPNet/CoapOptions.cs
@@ -296,8 +296,12 @@ public byte[] GetBytes()
 
         public void FromBytes(byte[] data)
         {
-            if (_type == OptionType.Empty && (data == null || data.Length > 0))
-                throw new InvalidCastException("Empty option does not accept any data");
+            if (_type == OptionType.Empty)
+            {
+                if ((data?.Length ?? 0) > 0)
+                    throw new InvalidCastException("Empty option does not accept any data");
+                return;
+            }
 
             if (_type == OptionType.Opaque)
             {
@@ -312,15 +316,15 @@ public void FromBytes(byte[] data)
             }
 
 
-            uint value = 0;
+            uint i=0, value = 0;
             if (data.Length == 4)
-                value = (uint)(data[3] << 24);
+                value = (uint)(data[i++] << 24);
             if (data.Length >= 3)
-                value |= (uint)(data[2] << 16);
+                value |= (uint)(data[i++] << 16);
             if (data.Length >= 2)
-                value |= (uint)(data[1] << 8);
+                value |= (uint)(data[i++] << 8);
             if (data.Length >= 1)
-                value |= data[0];
+                value |= data[i++];
             ValueUInt = value;
         }