#ifndef GZIP_H
#define GZIP_H

#include <stdint.h>

/* RFC 1952 */

#define ID1 31
#define ID2 139

enum compression_method {
	DEFLATE = 8,
};

enum flag {
	FTEXT    = 1 << 0,
	FHCRC    = 1 << 1,
	FEXTRA   = 1 << 2,
	FNAME    = 1 << 3,
	FCOMMENT = 1 << 4,
};

const char *flag_str (enum flag f) {
	switch (f) {
		case FTEXT:    return "Content is probably text";
		case FHCRC:    return "CRC16 is present";
		case FEXTRA:   return "Extra field is populated";
		case FNAME:    return "A file name is present";
		case FCOMMENT: return "A comment is present";
		default:       return "unknown flag";
	}
}

enum operating_system {
	FAT = 0,
	AMIGA,
	VMS,
	UNIX,
	CMS,
	ATARI_TOS,
	HPFS,
	MACINTOSH,
	Z_SYSTEM,
	CP_M,
	TOPS20,
	NTFS,
	QDOS,
	ACORN_RISCOS,
};

const char *os_str(enum operating_system os) {
	switch (os) {
		case FAT:          return "FAT filesystem (MS-DOS, OS/2, NT/Win32)";
		case AMIGA:        return "Amiga";
		case VMS:          return "VMS (or OpenVMS)";
		case UNIX:         return "Unix";
		case CMS:          return "VM/CMS";
		case ATARI_TOS:    return "Atari TOS";
		case HPFS:         return "HPFS filesystem (OS/2, NT)";
		case MACINTOSH:    return "Macintosh";
		case Z_SYSTEM:     return "Z-System";
		case CP_M:         return "CP/M";
		case TOPS20:       return "TOPS-20";
		case NTFS:         return "NTFS filesystem (NT)";
		case QDOS:         return "QDOS";
		case ACORN_RISCOS: return "Acorn RISCOS";
		default:           return "unknown";
	}
}

struct member {
	uint8_t id1, id2, cm, flg;
	uint32_t mtime;
	uint8_t xfl, os;
} __attribute__((packed));

#endif /* GZIP_H */