#include "image.h"
#include <bio.h>

typedef struct Src {
	char	*name;
	int	fd;
	ImgHdr;
	Biobuf;
} Src;

void
usage(void)
{
	fprint(2, "usage: %s image1 image2\n", argv0);
	exits("usage");
}

void
main(int argc, char **argv)
{
	Src src1, src2;
	Biobuf bout;
	int c1, c2;

	ARGBEGIN {
	default:
		usage();
	} ARGEND
	if(argc != 2)
		usage();

	if(fmtinstall('H', Hfmt) < 0)
		sysfatal("fmtinstall");

	src1.name = argv[0];
	src2.name = argv[1];

	if((src1.fd = open(src1.name, OREAD)) < 0)
		sysfatal("open %s: %r", src1.name);
	if((src2.fd = open(src2.name, OREAD)) < 0)
		sysfatal("open %s: %r", src2.name);

	if(readimghdr(src1.fd, &src1.ImgHdr) < 0)
		sysfatal("%s: read header: %r", src1.name);
	if(readimghdr(src2.fd, &src2.ImgHdr) < 0)
		sysfatal("%s: read header: %r", src2.name);

	if(!eqrect(src1.r, src2.r))
		sysfatal("rect mismatch");
	if(src1.chan == CMAP8)
		sysfatal("%s: color mapped", src1.name);
	if(src2.chan == CMAP8)
		sysfatal("%s: color mapped", src2.name);

	if(src1.compressed)
		sysfatal("%s: compressed", src1.name);
	if(src2.compressed)
		sysfatal("%s: compressed", src2.name);

	if(src1.chan != src2.chan)
		sysfatal("chan mismatch");

	if(Binit(&src1.Biobuf, src1.fd, OREAD) < 0
	|| Binit(&src2.Biobuf, src2.fd, OREAD) < 0
	|| Binit(&bout, 1, OWRITE) < 0 )
		sysfatal("Binit");

	Bprint(&bout, "%H", src1.ImgHdr);
	for(;;) {
		c1 = Bgetc(&src1.Biobuf);
		c2 = Bgetc(&src2.Biobuf);
		if(c1 < 0 || c2 < 0) {
			if(c1 == Beof && c2 == Beof)
				break;
			sysfatal("read error: %d %d", c1, c2);
		}
		if(Bputc(&bout, c1^c2) < 0)
			sysfatal("write error");
	}

	exits(nil);
}