#include <cstdio>

#include "write_rgb.h"

inline static void print_short(short s, FILE*F)
{
	fputc(s>>8, F);
	fputc(s & 0xFF, F);
}

inline static void print_long(long L, FILE*F)
{
	print_short(L >> 16, F);
	print_short(L & 0xFFFF, F);
}

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

	print_short(474, F); // MAGIC, 474=SGI
	fputc(0, F); // STORAGE, 0=no compression
	fputc(1, F); // BPC, 1 byte per R, G, or B value
	print_short(2, F); // DIMENSION
	print_short(w, F); // XSIZE
	print_short(h, F); // YSIZE
	print_short(3, F); // ZSIZE
	print_long(0, F); // PINMIN
	print_long(255, F); // PINMAX
	print_long(0, F); // DUMMY
	fwrite(zeros, 1, 80, F); // IMAGENAME
	print_long(0, F); // COLORMAP, 0=normal
	fwrite(zeros, 1, 404, F); // DUMMY
	for(int j=0; j<h; j++)
		for(int i=0; i<w; i++)
			fputc(screen[i][j] >> 16, F);
	for(int j=0; j<h; j++)
		for(int i=0; i<w; i++)
			fputc((screen[i][j] >> 8) & 255, F);
	for(int j=0; j<h; j++)
		for(int i=0; i<w; i++)
			fputc(screen[i][j] & 255, F);
	fclose(F);
	return 0;
}