#ifndef DRSNAP_H
#define DRSNAP_H

class SUPERBLOCK;

class SNAPFILE: public ARRAY_OBJ{
	SSTRING dir;		// Directory holding the data file
	SSTRING map;		// Classification map
	SSTRING branch;		// Logical name of the branch
	int rev;			// Sequence number
	SSTRING path;		// Full path of the data file
	unsigned *bitmap;	// Tell if a chunk is contain is this snapshot
	unsigned bitmapsize;
	SNAPFILE *parent;
	int fd;
	unsigned long long size;	// Volume size
	bool root;			// This is the original volume. No bitmap
						// needed
	bool in_use;		// Only one client per data file
	/*~PROTOBEG~ SNAPFILE */
public:
	SNAPFILE (const char *_dir,
		 const char *_map,
		 const char *_branch,
		 int _rev);
	void bitmap_or (SNAPFILE *common, unsigned *res);
	int checkrange (unsigned long long from, int len);
private:
	int copy_from_parent (unsigned long long from,
		 int len);
	int copy_on_write (unsigned long long from, int len);
public:
	unsigned getbitmapsize (void)const;
	void getbranchname (SSTRING&_branch)const;
	void getmap (SSTRING&_map)const;
	const char *getpath (void)const;
	int getrevision (void)const;
	unsigned long long getsize (void)const;
	bool is_inuse (void)const;
	bool is_ok (void);
	bool is_root (void)const;
private:
	int raw_read (unsigned long long from,
		 int len,
		 int tofd);
public:
	int read (unsigned long long from, int len, int tofd);
private:
	int read_part (unsigned long long from,
		 int len,
		 int tofd);
public:
	int readsb (SUPERBLOCK&sb);
private:
	int seek (unsigned long long from);
public:
	void set_inuse (void);
	void setparent (SNAPFILE *_parent);
	void setsize (unsigned long long _size);
	void setsize_fromfile (void);
	SNAPFILE *snap (const char suffix,
		 const char *newbranch);
	SNAPFILE *snap (void);
	void unset_inuse (void);
	int write (unsigned long long from,
		 const char *buf,
		 int len);
	~SNAPFILE (void);
	/*~PROTOEND~ SNAPFILE */
};

typedef ARRAY_OBJS<SNAPFILE> SNAPFILES;

#include "drsnap.p"

#endif