CODEWITHSUNDEEP
c#java
Léon Pelletier
Léon Pelletier

Reputation: 2741

How would such a java code look in C#?

I was porting a java code to C# and came across this code. I can't figure how this can be ported, as it seems to declare class arrays. My knowledge in C# is too limited to figure out how this action is achieved in C#. Is there an equivalent to this Stub declaration in C#, and how would it look like? I shrank it to the minimum, because it was declaring 10 objects. Here's how looks the code:

        public interface IcodecWeightFunctionStub
        {
                void hcodec_weight_func(int[] block, int block_offset, int stride, int log2_denom, int weight, int offset);
        }

        public interface IHcodecBiWeightFunctionStub
        {
                void hcodec_biweight_func(int[] dst, int dst_offset, int[] src, int src_offset, int stride, int log2_denom, int weightd, int weights, int offset);
        }


        public IHcodecWeightFunctionStub[] weight_hcodec_pixels_tab = new IHcodecWeightFunctionStub[]               {
    new IHcodecWeightFunctionStub() {
            public void hcodec_weight_func(int []block, int block_offset, int stride, int log2_denom, int weight, int offset) {
                    weight_hcodec_pixels_c(16, 16, block, block_offset, stride, log2_denom, weight, offset);
            }
    },
    new IHcodecWeightFunctionStub() {
            public void hcodec_weight_func(int []block, int block_offset, int stride, int log2_denom, int weight, int offset) {
                    weight_hcodec_pixels_c(16, 8, block, block_offset, stride, log2_denom, weight, offset);
            }
    }
};

The problem is not about instantiating interfaces in C#, but more about returning new classes in C#.

Upvotes: 1

Views: 178

Answers (2)

Dave Doknjas
Dave Doknjas

Reputation: 6542

Your example is a little inconsistent - the interface method names don't match, but hopefully my array example and C# equivalent will help. You could use delegates and lambdas, but there is no need to do this. For the following Java code:

public interface Foo
{
    void Bar(int i);
}

class test
{
    //array of anonymous inner classes:
    public Foo[] x = new Foo[] {
        new Foo() {
            public void Bar(int i) {
                //code 1
            }
        },
        new Foo() {
            public void Bar(int i) {
                //code 2
            }
        }
    };
}

The following C# code is equivalent:

public interface Foo
{
    void Bar(int i);
}

class Test
{
    public Foo[] x = new Foo[] { new FooAnonymousInnerClassHelper1(), new FooAnonymousInnerClassHelper2() };

    private class FooAnonymousInnerClassHelper1 : Foo
    {
        public virtual void Bar(int i)
        {
            //code 1
        }
    }

    private class FooAnonymousInnerClassHelper2 : Foo
    {
        public virtual void Bar(int i)
        {
            //code 2
        }
    }
}

Upvotes: 1

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726899

Anonymous delegate implementations and lambdas of C# are the closest thing to anonymous interface implementations of Java, but the interface needs to have a single method. Both your interfaces have a single method, so your code can be converted to C# as follows:

public delegate void HcodecWeightDelegate(int[] block, int block_offset, int stride, int log2_denom, int weight, int offset);
public delegate void HcodecBiweightDelegate(int[] dst, int dst_offset, int[] src, int src_offset, int stride, int log2_denom, int weightd, int weights, int offset);

public HcodecBiweightDelegate[] WeightHcodecPixelsTab = new HcodecBiweightDelegate[] {
    (block, block_offset, stride, log2_denom, weight, offset) => {
        weight_hcodec_pixels_c(16, 16, block, block_offset, stride, log2_denom, weight, offset);
    }
,   (block, block_offset, stride, log2_denom, weight, offset) => {
        weight_hcodec_pixels_c(16, 8, block, block_offset, stride, log2_denom, weight, offset);
    }
};

Note that calling the delegates is different, too: in Java you would call them like this:

weight_hcodec_pixels_tab[i].hcodec_weight_func(block, block_offset, stride, log2_denom, weight, offset);

In C#, you do not have a method name (because delegates encapsulate a single method), so the same call would look like this:

HcodecBiweightDelegate[i](block, block_offset, stride, log2_denom, weight, offset);

Upvotes: 3

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