Thank you all for your input.

I know that this problem may be solved in Perl or PDL, but now I am interested in exploring how it can be solved with Inline::C. I need speed, and I need compact.

Next, I see no problem in casting a bytestring using pack from Perl as a way of allocating a block of memory to be used in C as long as the block size is sufficient. That way the block of memory will be under Perl's memory management and garbage collection.

As I understand, you can overrule the Perl type from C by type casting, so the pack bytestring does not have to be an array of pointers.

Now, what is the problem with The "built-in" C 2D array? I should say that is exactly what I want - a 2D table of numbers. However, I will try my own index calculations as suggested.

Here is the code mock-up again - this time in code tags :o).


sub perl_routine
{
   $byte_string = pack "I*", (0) x ( $x_dimension x $y_dimension );

   c_function( $byte_string, $x_dimension, $y_dimension );
}

void c_function( char *byte_string, int x_dimension, y_dimension )
{
   int **table = ( int ** ) byte_string;
   int i, j;

   for ( i = 0; i < x_dimension, i++ )
   {
      for ( j = 0; j < y_dimension, j++ )
      {
         table[ i ][ j ]++;
      }
   }
}

[download]

Martin

In reply to Re: Passing a bytestring from Perl to Inline::C as a 2d array by Anonymous Monk
in thread Passing a bytestring from Perl to Inline::C as a 2d array by maasha

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