c++ hextree crash testcase

hex-crash.cpp

/*

Testcase demonstrating https://github.com/mapnik/mapnik/issues/1087

To replicate, on Ubuntu Oneiric compile mapnik master **before**:

https://github.com/mapnik/mapnik/commit/5dee576df26b4aeafd182c41b510c4aa67b14b29

Then do:

    wget https://raw.github.com/gist/1886226/hex-crash.cpp
    wget http://f.cl.ly/items/450Y0f2A461p3u292X07/11_1277_544.png
    g++ -o hex-crash hex-crash.cpp `mapnik-config --libs --cflags`
    ./hex-crash 
    Segmentation fault

*/


extern "C"
{
#include <png.h>
}

#include <mapnik/graphics.hpp>
#include <mapnik/image_util.hpp>
#include <mapnik/png_io.hpp>
#include <mapnik/image_reader.hpp>
#include <mapnik/image_view.hpp>

#include <iostream>
#include <string>

int main()
{
    std::string filename("11_1277_544.png");
    std::string format("png8:m=h:g=1.0");
    
    // open image from filesystem
    std::auto_ptr<mapnik::image_reader> reader(mapnik::get_image_reader(filename,"png"));
    mapnik::image_32 image(reader->width(),reader->height());
    reader->read(0,0,image.data());
    
    // get view
    mapnik::image_view<mapnik::image_data_32> view =  image.get_view(0,256,256,256);
    
    // will segfault here
    std::string s = save_to_string(view, format);
    
    return 0;

}