#include <cassert>
#include <cstdio>

#include "read_rgb.h"

inline static short read_short(FILE*F)
{
	short hi = fgetc(F);
	short lo = fgetc(F);
	return (hi << 8) | lo;
}

inline static long read_long(FILE*F)
{
	long hi = read_short(F);
	long lo = read_short(F);
	return (hi << 16) | lo;
}

int load_rgb(const char* filename, int& h, int& w, long **& screen)
{
	char zeros[404] = {0};
	FILE*F = fopen(filename, "r");
	if(!F) return 1;

	/*assert*/(read_short(F) == 474); // MAGIC, 474=SGI
	assert(fgetc(F) == 0); // STORAGE, 0=no compression
	assert(fgetc(F) == 1); // BPC, 1 byte per R, G, or B value
	assert(read_short(F) == 2); // DIMENSION
	w = read_short(F); // XSIZE
	h = read_short(F); // YSIZE
	assert(read_short(F) == 3); // ZSIZE
	assert(read_long(F) == 0); // PINMIN
	assert(read_long(F) == 255); // PINMAX
	read_long(F); // DUMMY
	fread(zeros, 1, 80, F); // IMAGENAME
	assert(read_long(F) == 0); // COLORMAP, 0=normal
	fread(zeros, 1, 404, F); // DUMMY

	screen = new long*[w];
	*screen = new long[w*h];

	for(int i=1; i<w; i++)
		screen[i] = screen[i-1] + h;

	for(int j=0; j<h; j++)
		for(int i=0; i<w; i++)
			screen[i][j] = fgetc(F);
	for(int j=0; j<h; j++)
		for(int i=0; i<w; i++)
			screen[i][j] = (screen[i][j] << 8) | fgetc(F);
	for(int j=0; j<h; j++)
		for(int i=0; i<w; i++)
			screen[i][j] = (screen[i][j] << 8) | fgetc(F);
	fclose(F);
	return 0;
}