Generated GetHashCode in the C# front-end.

Signed-off-by: Dimitar Dobrev <dpldobrev@yahoo.com>

Author: ddobrev

src/Generator/Generators/CSharp/CSharpTextTemplate.cs

@@ -2199,7 +2199,7 @@ public void GenerateMethod(Method method, Class @class)
 
             if (method.OperatorKind == CXXOperatorKind.EqualEqual)
             {
-                GenerateEquals(method, @class);
+                GenerateEqualsAndGetHashCode(method, @class);
             }
 
             PopBlock(NewLineKind.BeforeNextBlock);
@@ -2246,7 +2246,7 @@ private void GenerateManagedCall(Function function, bool prependBase = false)
                                 (p.Usage == ParameterUsage.InOut ? "ref " : string.Empty) + p.Name)));
         }
 
-        private void GenerateEquals(Function method, Class @class)
+        private void GenerateEqualsAndGetHashCode(Function method, Class @class)
         {
             Class leftHandSide;
             Class rightHandSide;
@@ -2268,6 +2268,22 @@ private void GenerateEquals(Function method, Class @class)
                     WriteLine("return this == ({0}) obj;", @class.Name);
                 }
                 WriteCloseBraceIndent();
+
+                NewLine();
+
+                WriteLine("public override int GetHashCode()");
+                WriteStartBraceIndent();
+                if (@class.IsRefType)
+                {
+                    WriteLine("if ({0} == global::System.IntPtr.Zero)", Helpers.InstanceIdentifier);
+                    WriteLineIndent("return global::System.IntPtr.Zero.GetHashCode();");
+                    WriteLine("return (*(Internal*) {0}).GetHashCode();", Helpers.InstanceIdentifier);   
+                }
+                else
+                {
+                    WriteLine("return {0}.GetHashCode();", Helpers.InstanceIdentifier);                       
+                }
+                WriteCloseBraceIndent();
             }
         }
 

tests/CSharp/CSharp.Tests.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Reflection;
 using CppSharp.Utils;
 using CSharp;
@@ -447,4 +448,17 @@ public void TestReferenceToArrayWithConstSize()
         var result = CSharp.CSharp.PassConstantArrayRef(array);
         Assert.That(result, Is.EqualTo(array[0]));
     }
+
+    [Test]
+    public void TestComparison()
+    {
+        var testComparison1 = new TestComparison { A = 5, B = 5.5f };
+        var testComparison2 = new TestComparison { A = 5, B = 5.5f };
+        Assert.IsTrue(testComparison1 == testComparison2);
+        Assert.IsTrue(testComparison1.Equals(testComparison2));
+        var testHashes = new Dictionary<TestComparison, int>();
+        testHashes[testComparison1] = 1;
+        testHashes[testComparison2] = 2;
+        Assert.That(testHashes[testComparison1], Is.EqualTo(2));
+    }
 }

tests/CSharp/CSharp.cpp

@@ -803,3 +803,12 @@ int PassConstantArrayRef(int(&arr)[2])
 {
     return arr[0];
 }
+
+TestComparison::TestComparison()
+{
+}
+
+bool TestComparison::operator ==(const TestComparison& other) const
+{
+    return A == other.A && B == other.B;
+}

tests/CSharp/CSharp.h

@@ -733,3 +733,12 @@ class DerivesFromTemplateInstantiation : public TemplateWithDependentField<int>
 };
 
 DLL_API int PassConstantArrayRef(int(&arr)[2]);
+
+class DLL_API TestComparison
+{
+public:
+    TestComparison();
+    int A;
+    float B;
+    bool operator ==(const TestComparison& other) const;
+};