add ndb

include/ndb.h

@@ -0,0 +1,158 @@
+/*
+#pragma	src	"/sys/src/libndb"
+#pragma	lib	"libndb.a"
+*/
+AUTOLIB(ndb)
+
+/*
+ *  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;
+
+/*
+#pragma incomplete Ndbhf
+#pragma incomplete Ndbcache
+*/
+
+enum
+{
+	Ndbalen=	32,	/* max attribute length */
+	Ndbvlen=	64,	/* max value length */
+};
+
+/*
+ *  the database
+ */
+struct Ndb
+{
+	Ndb		*next;
+
+	Biobuf	b;		/* buffered input file */
+
+	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;			/* value(s) */
+	Ndbtuple	*entry;			/* next tuple in this entry */
+	Ndbtuple	*line;			/* next tuple on this line */
+	ulong		ptr;			/* (for the application - starts 0) */
+	char		valbuf[Ndbvlen];	/* initial allocation for value */
+};
+
+/*
+ *  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)&0xFF; (a)[1] = ((v)>>8)&0xFF; (a)[2] = ((v)>>16)&0xFF; }
+#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)&0xFF; (a)[1] = ((v)>>8)&0xFF; (a)[2] = ((v)>>16)&0xFF; (a)[3] = ((v)>>24)&0xFF; }
+#define NDBGETUL(a) ((a)[0] | ((a)[1]<<8) | ((a)[2]<<16) | ((a)[3]<<24))
+
+#define NDB_IPlen 16
+
+Ndbtuple*	csgetval(char*, char*, char*, char*, char*);
+char*		csgetvalue(char*, char*, char*, char*, Ndbtuple**);
+Ndbtuple*	csipinfo(char*, char*, char*, char**, int);
+Ndbtuple*	dnsquery(char*, char*, char*);
+char*		ipattr(char*);
+Ndb*		ndbcat(Ndb*, Ndb*);
+int		ndbchanged(Ndb*);
+void		ndbclose(Ndb*);
+Ndbtuple*	ndbconcatenate(Ndbtuple*, Ndbtuple*);
+Ndbtuple*	ndbdiscard(Ndbtuple*, Ndbtuple*);
+void		ndbfree(Ndbtuple*);
+Ndbtuple*	ndbgetipaddr(Ndb*, char*);
+Ndbtuple*	ndbgetval(Ndb*, Ndbs*, char*, char*, char*, char*);
+char*		ndbgetvalue(Ndb*, Ndbs*, char*, char*, char*, Ndbtuple**);
+Ndbtuple*	ndbfindattr(Ndbtuple*, Ndbtuple*, char*);
+ulong		ndbhash(char*, int);
+Ndbtuple*	ndbipinfo(Ndb*, char*, char*, char**, int);
+Ndbtuple*	ndblookval(Ndbtuple*, Ndbtuple*, char*, char*);
+Ndbtuple*	ndbnew(char*, char*);
+Ndb*		ndbopen(char*);
+Ndbtuple*	ndbparse(Ndb*);
+int		ndbreopen(Ndb*);
+Ndbtuple*	ndbreorder(Ndbtuple*, Ndbtuple*);
+Ndbtuple*	ndbsearch(Ndb*, Ndbs*, char*, char*);
+long		ndbseek(Ndb*, long);
+void		ndbsetval(Ndbtuple*, char*, int);
+Ndbtuple*	ndbsnext(Ndbs*, char*, char*);
+Ndbtuple*	ndbsubstitute(Ndbtuple*, Ndbtuple*, Ndbtuple*);