[geos-devel] An Immodest Proposal

[Paul Ramsey]

It turns out it is a quite small modification, and works pretty well:

http://trac.osgeo.org/geos/attachment/ticket/208/memdiff.patch

My patch adds the ability to override, and also has some printfs to
show what is happening. When the overridden allocator is called
without the runtime callback set, it prints "std alloc" and when it's
called with the callback set, it prints "geos alloc".

Here's a little program that exercises it:

#include <stdio.h>
#include "/usr/local/include/geos_c.h"
#include <stdlib.h>

int main() {
  printf("main\n");

  GEOSCoordSequence* cs;
  GEOSGeometry* g;
  int r;

  printf("initgeos\n");
  initGEOSMemory(malloc, free);
  printf("coordseqcreate\n");
  cs = GEOSCoordSeq_create(1, 2);
  printf("coordseqsetx\n");
  r = GEOSCoordSeq_setX(cs, 0, 1.0);
  printf("coordseqsety\n");
  r = GEOSCoordSeq_setY(cs, 0, 1.0);
  printf("createpoint\n");
  g = GEOSGeom_createPoint(cs);

  return 0;

}


And here is the output:

Heron:tmp pramsey$ ./a.out
std alloc!
std alloc!
main
initgeos
coordseqcreate
geos alloc!
geos alloc!
geos alloc!
coordseqsetx
coordseqsety
createpoint
geos alloc!

So, something in C++ is doing a couple allocations before we can slip
in and get our other function in place. But we can get all the big
stuff caught no problem.

P.