int JPGRaster::Data::ExifDir(const char *begin, int offset, IFD_TYPE type)
{
	const char *e = begin + offset;
	int nitems = Exif16(e);
//	puts(NFormat("directory %08x: %d items", dir, nitems));
	e += 2;
	for(int i = 0; i < nitems; i++, e += 12) {
		int tag = Exif16(e);
		int fmt = Exif16(e + 2);
		int count = Exif32(e + 4);
		static const int fmtlen[] = {
			1, 1, 2, 4, 8, 1, 1, 2, 4, 8, 4, 8
		};
		int len = 0;
		if(fmt > 0 && fmt <= __countof(fmtlen))
			len = fmtlen[fmt - 1] * count;
		const char *data = e + 8;
		if(len > 4)
			data = begin + Exif32(data);
//		puts(NFormat("[%d]: tag %04x fmt %d, count %d, data %s",
//			i, tag, fmt, count, BinHexEncode(data, data + len)));
		if(type == BASE_IFD) {
			if(tag == 0x112)
				metadata.Add("orientation", Exif16(data));
			if(tag == 0x132)
				metadata.Add("DateTime", String(data, 20));
			if(tag == 0x8825) {
				int offset = Exif32(data);
	//			puts(NFormat("GPS IFD at %08x", offset));
				ExifDir(begin, offset, GPS_IFD);
			}
		}
		else if(type == GPS_IFD) {
			if((tag == 2 || tag == 4) && fmt == EXIF_RATIONAL && count == 3) {
				metadata.Add(tag == 2 ? "GPSLatitude" : "GPSLongitude",
					ExifF5(data + 0) + ExifF5(data + 8) / 60 + ExifF5(data + 16) / 3600);
//				puts(NFormat("GPSLatitude: %n %n %n", n1, n2, n3));
			}
			else if(tag == 6 && fmt == EXIF_RATIONAL && count == 1)
				metadata.Add("GPSAltitude", ExifF5(data));
			else if(tag == 16 && fmt == EXIF_ASCII && count == 2 && *data)
				metadata.Add("GPSImgDirectionRef", String(*data, 1));
			else if(tag == 17 && fmt == EXIF_RATIONAL && count == 1)
				metadata.Add("GPSImgDirection", ExifF5(data + 0));
		}
	}
	int nextoff = Exif32(e);
//	puts(NFormat("next offset = %08x", nextoff));
	return nextoff;
}

			if(tag == 0x132)
				metadata.Add("DateTime", String(data, 20));