#pragma	src	"/sys/src/libndb"#pragma	lib	"libndb.a" /* *  this include file requires includes of <u.h> and <bio.h> */typedef struct Ndb	Ndb;typedef struct Ndbtuple	Ndbtuple;typedef struct Ndbhf	Ndbhf;typedef struct Ndbs	Ndbs;typedef struct Ndbcache	Ndbcache; enum{	Ndbalen=	32,	/* max attribute length */	Ndbvlen=	64,	/* max value length */}; /* *  the database */struct Ndb{	Ndb		*next; 	Biobufhdr	b;		/* buffered input file */	uchar		buf[256];	/* and its buffer */ 	ulong		mtime;		/* mtime of db file */	Qid		qid;		/* qid of db file */	char		file[128];/* path name of db file */	ulong		length;		/* length of db file */ 	int		nohash;		/* don't look for hash files */	Ndbhf		*hf;		/* open hash files */ 	int		ncache;		/* size of tuple cache */	Ndbcache	*cache;		/* cached entries */}; /* *  a parsed entry, doubly linked */struct Ndbtuple{	char		attr[Ndbalen];	/* attribute name */	char		val[Ndbvlen];	/* value(s) */	Ndbtuple	*entry;		/* next tuple in this entry */	Ndbtuple	*line;		/* next tuple on this line */	ulong		ptr;		/* (for the application - starts 0) */}; /* *  each hash file is of the form * *		+---------------------------------------+ *		|	mtime of db file (4 bytes)	| *		+---------------------------------------+ *		|  size of table (in entries - 4 bytes)	| *		+---------------------------------------+ *		|		hash table		| *		+---------------------------------------+ *		|		hash chains		| *		+---------------------------------------+ * *  hash collisions are resolved using chained entries added to the *  the end of the hash table. * *  Hash entries are of the form * *		+-------------------------------+ *		|	offset	(3 bytes) 	| *		+-------------------------------+ * *  Chain entries are of the form * *		+-------------------------------+ *		|	offset1	(3 bytes) 	| *		+-------------------------------+ *		|	offset2	(3 bytes) 	| *		+-------------------------------+ * *  The top bit of an offset set to 1 indicates a pointer to a hash chain entry. */#define NDBULLEN	4		/* unsigned long length in bytes */#define NDBPLEN		3		/* pointer length in bytes */#define NDBHLEN		(2*NDBULLEN)	/* hash file header length in bytes */ /* *  finger pointing to current point in a search */struct Ndbs{	Ndb	*db;	/* data base file being searched */	Ndbhf	*hf;	/* hash file being searched */	int	type;	ulong	ptr;	/* current pointer */	ulong	ptr1;	/* next pointer */	Ndbtuple *t;	/* last attribute value pair found */}; /* *  bit defs for pointers in hash files */#define NDBSPEC 	(1<<23)#define NDBCHAIN	NDBSPEC		/* points to a collision chain */#define NDBNAP		(NDBSPEC|1)	/* not a pointer */ /* *  macros for packing and unpacking pointers */#define NDBPUTP(v,a) { (a)[0] = v; (a)[1] = (v)>>8; (a)[2] = (v)>>16; }#define NDBGETP(a) ((a)[0] | ((a)[1]<<8) | ((a)[2]<<16)) /* *  macros for packing and unpacking unsigned longs */#define NDBPUTUL(v,a) { (a)[0] = v; (a)[1] = (v)>>8; (a)[2] = (v)>>16; (a)[3] = (v)>>24; }#define NDBGETUL(a) ((a)[0] | ((a)[1]<<8) | ((a)[2]<<16) | ((a)[3]<<24)) #define NDB_IPlen 16 ulong		ndbhash(char*, int);Ndbtuple*	ndbparse(Ndb*);void		ndbfree(Ndbtuple*);Ndb*		ndbopen(char*);Ndb*		ndbcat(Ndb*, Ndb*);int		ndbreopen(Ndb*);void		ndbclose(Ndb*);Ndbtuple*	ndblookval(Ndbtuple*, Ndbtuple*, char*, char*);long		ndbseek(Ndb*, long);Ndbtuple*	ndbsearch(Ndb*, Ndbs*, char*, char*);Ndbtuple*	ndbsnext(Ndbs*, char*, char*);Ndbtuple*	ndbgetval(Ndb*, Ndbs*, char*, char*, char*, char*);Ndbtuple*	csgetval(char*, char*, char*, char*, char*);char*		ipattr(char*);Ndbtuple*	ndbipinfo(Ndb*, char*, char*, char**, int);Ndbtuple*	csipinfo(char*, char*, char*, char**, int);Ndbtuple*	dnsquery(char*, char*, char*);