How to map typdef and struct

[phanthanhliem]

Hi, I have a struct like the one below:

typedef std::vector<double*>        Vector_p_Double;
struct structTimeSeriesResults
{   
    Vector_p_Double         vpd_result;
    double*                 p_time;
    int                     nbPoints;
};

I've tried to use std:vector<double*> directly, it works. For example: std:vector<double*> vpd_result; But the problem appears when I use:

typedef std::vector<double*>        Vector_p_Double;

I've read this thread, which has the similar problem: https://groups.google.com/forum/#!searchin/javacpp-project/typedef/javacpp-project/YhOOggLfkzc/0i7kp3YqrFoJ

but I really don't understand the code.

How could you map this into javacpp?

Thanks for your help

[saudet]

There's a discussion about that at issue https://github.com/bytedeco/javacpp/issues/22. Let me know if that doesn't answer the question.

[saudet]

Ah same guy, so I guess it doesn't answer your question. So, what is the question? Could you provide more details about what steps you are taking, what errors you are getting, etc? Thanks

[phanthanhliem]

Hi Saudet,

Sorry for my incomprehensible question. The problem is when I used typedef like this:

typedef std::vector<double*>        Vector_p_Double;
struct structTimeSeriesResults
{   
    Vector_p_Double         vpd_result;
...
}

There is an error when I compile: which tells that javacpp cannot convert from Vector_p_Double to std::vector<double *,std::allocator<_Ty>> *. It seems that javacpp does not understand the new type Vector_p_Double defined by the typedef command.

Without using typedef std::vector<double*> Vector_p_Double;, or more exactly using directly std::vector<double*> it works fine like in https://github.com/bytedeco/javacpp/issues/22

So the question is how could I use typedef std::vector<double*> Vector_p_Double;? Hope that you understand my question now.

Thank you for your help. Thanh Liem.

[saudet]

Ok... Would you have a complete self-contained example that I could try to run here? Thanks!

[phanthanhliem]

Hi Samuel, I've send a self contained example to your email. Thanks for your help.

[saudet]

I mean some small code example, of less than 100 lines...

[phanthanhliem]

Hi Samuel

This is the header spider.h

#ifndef SPIDER_H
#define SPIDER_H

#ifdef SPIDER_CPP_LIBRARY
#define SPIDERDLL_API __declspec(dllexport)
#else
#define SPIDERDLL_API __declspec(dllimport)
#endif

namespace Spider_CPP {
class spider {
public:
    SPIDERDLL_API spider();
    SPIDERDLL_API Struct_Simulation_Results * runSingleSimulation(std::string Simulator_Parameters_Full_File_Name);
}
}

typedef std::vector<double>         Vector_Double;
struct Struct_Simulation_Results
{
    Simulation_Flag         Flag;
    structTimeSeriesResults * s_timeSeriesResults;
    Vector_Double           vd_Indicators;    
};

enum Simulation_Flag
{
    Simulation_OK = 0,
    Initialisation_Failed = 1,
    Simulation_Failed = 2
};

typedef std::vector<double*>        Vector_p_Double;
struct structTimeSeriesResults
{
    Vector_p_Double  *     vpd_result;    
    double*                 p_time;
    int                     nbPoints;
};

And the javacpp source code, testspiderdll.cpp

@Platform(include={"spider.h"}, link="SPIDER")

@Namespace("Spider_CPP")
public class testspidercpp {
    public static class spider extends Pointer {
        static { 
            System.loadLibrary("jnitestspidercpp");             
        }
        public spider() { allocate(); }     
        private native void allocate();
        public native Struct_Simulation_Results runSingleSimulation(@StdString String Simulator_Parameters_Full_File_Name);
    }

    @Namespace("")  
    public static class Struct_Simulation_Results extends Pointer {
        static { Loader.load(); }

        public Struct_Simulation_Results () { allocate(); }     
        private native void allocate();

        public native @Cast("Simulation_Flag") int Flag(); public native Struct_Simulation_Results Flag(@Cast("Simulation_Flag") int Flag); 

        public native structTimeSeriesResults s_timeSeriesResults(); public native Struct_Simulation_Results s_timeSeriesResults(structTimeSeriesResults s_timeSeriesResults);

        public native @StdVector DoublePointer vd_Indicators(); public native Struct_Simulation_Results vd_Indicators(@StdVector DoublePointer vd_Indicators);
    }

    @Namespace("")
    public static enum Simulation_Flag {
        Simulation_OK(0), Initialisation_Failed(1), Simulation_Failed(2);
        private int value;
        private Simulation_Flag(int value) {
            this.value = value;
        }

        public static Simulation_Flag fromInt(int v) {
            return Simulation_Flag.values()[v];
        } 

        public Simulation_Flag getType() {
            return Simulation_Flag.fromInt(nativeGetType());
        }

        private native @Name("getType") int nativeGetType();
    }

    @Namespace("")
    public static class structTimeSeriesResults extends Pointer {
        static { Loader.load(); }
        public structTimeSeriesResults () { allocate(); }       
        private native void allocate();

        public native VectorDoublePointer vpd_result(); public native structTimeSeriesResults vpd_result(VectorDoublePointer vpd_result);
        public native DoublePointer p_time();   public native structTimeSeriesResults p_time(DoublePointer p_time);
        public native int nbPoints();   public native structTimeSeriesResults nbPoints(int nbPoints);       
    }

    @Namespace("")
        // std:::vector<double*> in the line below works fine 
    //@Name("std::vector<double*>") public static class VectorDoublePointer extends Pointer {
    @Name("Vector_p_Double") public static class VectorDoublePointer extends Pointer {
        static { Loader.load(); }

        public VectorDoublePointer(Pointer p) { super(p); }
        public VectorDoublePointer(DoublePointer ... array) { this(array.length); put(array); }
        public VectorDoublePointer()       { allocate();  }
        public VectorDoublePointer(long n) { allocate(n); }
        private native void allocate();
        private native void allocate(@Cast("size_t") long n);
        public native @Name("operator=") @ByRef VectorDoublePointer put(@ByRef VectorDoublePointer x);

        public native long size();
        public native void resize(@Cast("size_t") long n);

        @Index public native @Cast("double*") DoublePointer get(@Cast("size_t") long i);
        public native VectorDoublePointer put(@Cast("size_t") long i, DoublePointer value);

        public VectorDoublePointer put(DoublePointer ... array) {
            if (size() != array.length) { resize(array.length); }
            for (int i = 0; i < array.length; i++) {
                put(i, array[i]);
            }
            return this;
        }
    }   

    public static void main(String[] args) {
        spider dllInstance = new spider();      
        System.out.println("spider.dll is successfully loading!!\n");
        String simulator_param_fullpath = "C:\\Users\\tp242786\\MyPostdoc-INES\\SPIDER\\SPIDER Qt5.4.2_MSVC2013_64bit\\Plant_And_Controls.parameters";
        dllInstance.runSingleSimulation(simulator_param_fullpath);
    }   
}

So how could i write the javacpp code for using:

typedef std::vector<double>         Vector_Double;
typedef std::vector<double*>        Vector_p_Double;

Hope that these source codes is enough for you to reproduce a running example. Thanks for your support.

[saudet]

Vector_Double and Vector_p_Double are declared in the Spider_CPP namespace, so their effective types are Spider_CPP::Vector_Double and Spider_CPP::Vector_p_Double, respectively. They are NOT Vector_Double and Vector_p_Double.

[phanthanhliem]

Hi Samuel,

No, Vector_Double and Vector_p_Double are NOT declared in the Spider_CPP namespace. In fact, Spider_CPP namespace contains just this:

namespace Spider_CPP {
  class spider {
     public:
        SPIDERDLL_API spider();
        SPIDERDLL_API Struct_Simulation_Results * runSingleSimulation(std::string     Simulator_Parameters_Full_File_Name);
  }
}

I put @Namespace("") to escape the Spider_CPP namespace, and this works well for other structs. So do you have an example with the typedef structure?

Thanks and best regards.

[phanthanhliem]

Hi Samuel,

It's ok now, in the spider.h, I need to declare like this

Vector_p_Double       * vpd_result;

instead of

Vector_p_Double       vpd_result;

So, vpd_result must be declared like a pointer, which is compatible with the javacpp source code:

@Name("Vector_p_Double") public static class VectorDoublePointer extends Pointer { ...}

I have one more question, if I don't want to use the pointer * in C++, so I got `Vector_p_Double vpd_result;. How do I define the class VectorDoublePointer in javacpp now?

Thanks for your support.

[saudet]

I see, well I just tried your example here and after fixing a few issues with your C++ code, it works just fine with Vector_p_Double. So, I still don't understand what the issue is. Please provide some sample code so that I can reproduce the issue here. Thank you.

[phanthanhliem]

Hi Samuel,

Thanks for your patient. I will reexplain the problem :

With the definition of VectorDoublePointer in testspidercpp.java,

@Name("Vector_p_Double") public static class VectorDoublePointer extends Pointer { ...}

you could only declare Vector_p_Double * vpd_result; in C++ because VectorDoublePointer extends the class Pointer. Otherwise, a definition without pointer *, for example Vector_p_Double vpd_result; will cause an error in the compilation.

However, the C++ code in my project is developped by some one else, so in this case, I have to insert the pointer notation *, for example, before all the struct defined in the C++ module.

- Struct_Simulation_Results        *       spider::runSingleSimulation(std::string Simulator_Parameters_Full_File_Name)
- Struct_Simulation_Results   *    s_simulationResults
- Vector_p_Double       * vpd_result; 
- ...

So the question is how could I redefine the class VectorDoublePointer or structTimeSeriesResult to remove the usage of the pointer * in the C++ side. Or Which predefined class should I extend instead of Pointer. If this is possible, do you have an example? In javacpp-presets, most classes extend Pointer.

Hope that my question is clearer now. Thanks for your help.

[saudet]

Ah I see. Because it's just a typedef we can simply use the original name std::vector<double*>. They are just synonyms!

[phanthanhliem]

Hi Samuel,

The problem of using Vector_p_Double or std::vector<doubble*> is OK now. In fact, using one of these two definitions is OK, we got the same result:

@Name("Vector_p_Double") public static class VectorDoublePointer extends Pointer { ...}
@Name("std::vector<double*>") public static class VectorDoublePointer extends Pointer { ...}

However in C++ side, I have to declare a pointer (ex: Vector_p_Double * vdp or std::vector<double*> * vdp), because the class VectorDoublePointer extends Pointer class. I can not declare a variable without pointer like this Vector_p_Double vdp or std::vector<double*> vdp.

My problem is: I want to use a var without pointer in C++ side (Vector_p_Double vdp or std::vector<double*> vdp), and how could I change correspondingly the definition of class in javacpp. In this case, the old definition of VectorDoublePointer which extends Pointer doesn't work anymore, there will be always a compilation error.

Hope that it is clearer for you, Samuel.

[saudet]

For something like this:

typedef std::vector<double*>*  Vector_p_Double;
Vector_p_Double vdp();

Of course we can do something like this:

@Name("std::vector<double*>") public static class VectorDoublePointer extends Pointer { ... }
public static native VectorDoublePointer vdp();

That works just fine, no problem. So, your question must be about something else.

[phanthanhliem]

Hi Samuel,

Sorry, :D, I don't know how to explain my prob clearer. I need to use this declaration in C++: typedef std::vector<double*> Vector_p_Double;

But the code in javacpp which I found in the preset @Name("std::vector<double*>") public static class VectorDoublePointer extends Pointer { ... } just support some thing like this: typedef std::vector<double*> * Vector_p_Double;

How could I modify the class definition in javacpp code? For example, by removing extends Pointer, we need to change many things in the body ?

[saudet]

typedef has no effect on Pointer, or vice-versa: the issue is something else...

[phanthanhliem]

Hi Samuel, Yes, the prob is not typedef. But between typedef std::vector<double*> Vector_p_Double; and typedef std::vector<double*> * Vector_p_Double; The difference here is Vector_p_Double vs * Vector_p_Double

The second one is ok as we discussed, but how about the first one? Thanks for your help.

[saudet]

I'm afraid I still don't understand the issue.

Have you tried to use the Parser instead?

[phanthanhliem]

Yes, i've tried to use the Parser. The following sourceds are the content of Stuff.h and Stuff.java (generated from StuffConfig).

Stuff.h
std::vector<unsigned char> foo();
std::vector<double*> vpd_result;
std::vector<double*> * vpd_result_pointer;

Stuff.java
// Parsed from Stuff.h
// #include <vector> 

public static native @Cast("unsigned char*") @StdVector BytePointer foo();
public static native @Cast("double**") @StdVector PointerPointer vpd_result(); public static native void vpd_result(PointerPointer vpd_result);
public static native @Cast("double**") @StdVector PointerPointer vpd_result_pointer(); public static native void vpd_result_pointer(PointerPointer vpd_result_pointer);

I didn't understand why there is no difference between vpd_result & vpd_result_pointer in Stuff.java, although in Stuff.h, they are not the same thing.

[saudet]

The @StdVector adapter just copies the whole vector and returns the copy. It doesn't matter if the original vector is returned by pointer or by value.

[phanthanhliem]

Hi Samuel,

I still couldn't figure out how does it work. I've tried this example this works well.

stuff.h
std::vector<std::string>           vd_Indicators;

stuff.java
public native @StdVector DoublePointer vd_Indicators(); 
public native Struct_Simulation_Results vd_Indicators(@StdVector DoublePointer vd_Indicators);

However if I changed the definition in stuff.h

stuff.h
//std::vector<std::string>           vd_Indicators;
std::vector<std::string>          * vd_Indicators = new std::vector<std::string>();

It causes immediately a crash in the java virtual machine. I assume that in this case the Java definition @StdVector DoublePointer vd_Indicators() could not be used with std::vector<std::string> * vd_Indicators.

So I don't understand your phrase Samuel. A pointer or a value is really a problem here.

[phanthanhliem]

Another example,

stuff.h
std::vector<std::string>  *  vs_labels = new std::vector<std::string>();

stuff.java
@Name("std::vector<std::string>") public static class StringVector extends Pointer { }

Here I retakes the definition in open_cv.core. There no problems with the pointer std::vector<std::string> * vs_labels.

How ever if I use a value instead

stuff.h
//std::vector<std::string>  *  vs_labels = new std::vector<std::string>();
std::vector<std::string>  vs_labels;

then the JVM is crashed as the previous example.

Somes observations here:

• the java definition of a class can't not be used for both pointer and value.
• @StdVector DoublePointer can not be used for a pointer in C++
• Class StringVector can not be used for a value in C++.

[saudet]

You're right that there was some native support missing for vector pointers to work with @StdVector. It should work with the changes from the latest commit: https://github.com/bytedeco/javacpp/commit/f61ac32ec07bb0c1e0e96e40480ebac40823c6bd Let me know! Thanks

[phanthanhliem]

Hi Samuel,

But it's ok now, by placing a @ByVal before StringVector in the class (struct) that use this StringVector, for ex:

public native @ByVal VectorStringPointer vs_labels();
public native structTimeSeriesResults vs_labels(@ByVal VectorStringPointer vs_labels);

I understand JavaCPP better now. Thanks for your help.