Re: [Swig-user] Binary data and C#

[Mathieu M. <mat...@gm...>]

On Thu, Nov 13, 2008 at 8:19 PM, Mathieu Malaterre
<mat...@gm...> wrote:
> Antti,
>
> On Wed, Nov 12, 2008 at 8:19 AM, Antti Karanta <ant...@na...> wrote:
>>
>> On Mon, 10 Nov 2008 12:53:10 +0200, Mathieu Malaterre
>> <mat...@xx...> wrote:
>>
>>> Alright. I tried using my installed swig: SWIG Version 1.3.36. I
>>> grabbed the .i file you mentioned. During compilation I am getting:
>>>
>>> /home/mathieu/Projects/gdcm/trunk/Examples/Csharp/DecompressImage.cs(64,8):
>>> error CS1502: The best overloaded method match for
>>> `gdcm.Pixmap.GetBuffer(string)' has some invalid arguments
>>> /home/mathieu/Projects/gdcm/debug-gcc/bin/gdcm_csharp.dll (Location of
>>> the symbol related to previous error)
>>> /home/mathieu/Projects/gdcm/trunk/Examples/Csharp/DecompressImage.cs(64,8):
>>> error CS1503: Argument 1: Cannot convert type `byte[]' to `string'
>>
>>   What about output from swig? Did it complain about anything?
>>
>>
>>> If I check the generated .cs file, I can still find:
>>>
>>>   public bool GetBuffer(string buffer) {
>>>     bool ret = gdcmPINVOKE.Pixmap_GetBuffer(swigCPtr, buffer);
>>>     return ret;
>>>   }
>>>
>>>
>>> Here is how I used your suggestion:
>>>
>>> %include "gdcm_arrays_csharp.i" // local copy of arrays_csharp.i from svn
>>> %apply byte OUTPUT[] { char* buffer } ;
>>> %include "gdcmPixmap.h"
>>>
>>> and gdcmPixmap.h contains:
>>>
>>> class GDCM_EXPORT Pixmap : public Object
>>> {
>>> public:
>>> ...
>>>   bool GetBuffer(char *buffer) const;
>>> };
>>
>>   Looks perfectly ok to me. I have to admit, though, that I have only been
>> using swig to wrap c, not c++, but I would not think that makes a
>> difference about using basic typemaps.
>
>
> Ok I have spent way too much time on this issue. So here is my minimal example:
>
> I copy all files from:
> http://swig.svn.sourceforge.net/viewvc/swig/trunk/Examples/csharp/arrays/
>
> Changed example.h into:
>
> --------------------------------------------------------
> void myArrayCopy( char*sourceArray, char* targetArray, int nitems );
> void myArraySwap( char* array1, char* array2, int nitems );
> --------------------------------------------------------
>
> (modified example.c accordingly)
>
> then modified example.i
>
> --------------------------------------------------------
> /* File : example.i */
> %module example
>
> %include "arrays_csharp.i"
>
> %apply byte INPUT[]  { char* sourceArray }
> %apply byte OUTPUT[] { char* targetArray }
>
> %include "example.h"
>
> %clear int* sourceArray;
> %clear int* targetArray;
> --------------------------------------------------------
>
>
> and finally runme.cs is :
>
>
> using System;
>
> public class runme
> {
>  static void Main()
>  {
>    byte[] source = { 1, 2, 3 };
>    byte[] target = new byte[ source.Length ];
>
>    example.myArrayCopy( source, target, target.Length );
>
>    Console.WriteLine( "Contents of copy target array using default
> marshaling" );
>    PrintArray( target );
>
>  }
>
>  static void PrintArray( byte[] a )
>  {
>    foreach ( byte i in a )
>      Console.Write( "{0} ", i );
>    Console.WriteLine();
>  }
> }
>
>
> During compilation I am getting:
>
> make[1]: Entering directory `/home/mathieu/Software/swig/Examples/csharp/arrays'
> gmcs -nologo -unsafe -out:runme.exe *.cs
> runme.cs(10,13): error CS1502: The best overloaded method match for
> `example.myArrayCopy(string, string, int)' has some invalid arguments
> example.cs(14,22): (Location of the symbol related to previous error)
> runme.cs(10,13): error CS1503: Argument 1: Cannot convert type
> `byte[]' to `string'
> Compilation failed: 2 error(s), 0 warnings
> make[1]: *** [csharp_compile] Error 1
> make[1]: Leaving directory `/home/mathieu/Software/swig/Examples/csharp/arrays'
> make: *** [csharp] Error 2
>
>
>
> I am now convinced that 'char' is a *very* special case, it would be
> nice if someone could comment on that, and in particular on how to
> change that behavior.
>
> changing to 'unsigned char' leads to a little improvement:
>
>
> gmcs -nologo -unsafe -out:runme.exe *.cs
> runme.cs(10,13): error CS1502: The best overloaded method match for
> `example.myArrayCopy(SWIGTYPE_p_unsigned_char,
> SWIGTYPE_p_unsigned_char, int)' has some invalid arguments
> example.cs(14,22): (Location of the symbol related to previous error)
> runme.cs(10,13): error CS1503: Argument 1: Cannot convert type
> `byte[]' to `SWIGTYPE_p_unsigned_char'
> Compilation failed: 2 error(s), 0 warnings
> make[1]: *** [csharp_compile] Error 1
> make[1]: Leaving directory `/home/mathieu/Software/swig/Examples/csharp/arrays'
> make: *** [csharp] Error 2

this thing is driving me nuts ! I can get it to work with 'short', but
not 'unsigned short'...



gmcs -nologo -unsafe -out:runme.exe *.cs
runme.cs(10,13): error CS1502: The best overloaded method match for
`example.myArrayCopy(SWIGTYPE_p_unsigned_short,
SWIGTYPE_p_unsigned_short, int)' has some invalid arguments
example.cs(14,22): (Location of the symbol related to previous error)
runme.cs(10,13): error CS1503: Argument 1: Cannot convert type
`ushort[]' to `SWIGTYPE_p_unsigned_short'
Compilation failed: 2 error(s), 0 warnings
make[1]: *** [csharp_compile] Error 1
make[1]: Leaving directory `/home/mathieu/Software/swig/Examples/csharp/arrays'
make: *** [csharp] Error 2

-- 
Mathieu