#include <vector>

#include <stdint.h>

typedef uint16_t depth;
typedef std::vector<depth> column;
typedef std::vector<column> grid;
static const depth BOTTOM = 65535;

static inline int xsize(grid const& g) { return g.size(); }
static inline int ysize(grid const& g) { return g.empty() ? 0 : g[0].size(); }
static inline int get(grid const& g, int x, int y, int def = BOTTOM) {
  return x >= 0 && y >= 0 && x < xsize(g) && y < ysize(g) ? g[x][y] : def;
}

void resize(int xsize, int ysize, grid*, depth def = BOTTOM);

void read_pgm(char const* filename, grid*, depth* zsize = NULL);
void write_pgm(grid const&, char const* filename, depth zsize = 0);

static inline depth color(int r, int g, int b) { return r>>3<<11|g>>2<<5|b>>3; }
void write_ppm(grid const&, char const* filename);