plan9port

fork of plan9port with libvec, libstr and libsdb
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ndb.h (4400B)

      1 /*
      2 #pragma	src	"/sys/src/libndb"
      3 #pragma	lib	"libndb.a"
      4 */
      5 AUTOLIB(ndb)
      6 
      7 /*
      8  *  this include file requires includes of <u.h> and <bio.h>
      9  */
     10 typedef struct Ndb	Ndb;
     11 typedef struct Ndbtuple	Ndbtuple;
     12 typedef struct Ndbhf	Ndbhf;
     13 typedef struct Ndbs	Ndbs;
     14 typedef struct Ndbcache	Ndbcache;
     15 
     16 /*
     17 #pragma incomplete Ndbhf
     18 #pragma incomplete Ndbcache
     19 */
     20 
     21 enum
     22 {
     23 	Ndbalen=	32,	/* max attribute length */
     24 	Ndbvlen=	64	/* max value length */
     25 };
     26 
     27 /*
     28  *  the database
     29  */
     30 struct Ndb
     31 {
     32 	Ndb		*next;
     33 
     34 	Biobuf	b;		/* buffered input file */
     35 
     36 	ulong		mtime;		/* mtime of db file */
     37 	Qid		qid;		/* qid of db file */
     38 	char		file[128];/* path name of db file */
     39 	ulong		length;		/* length of db file */
     40 
     41 	int		nohash;		/* don't look for hash files */
     42 	Ndbhf		*hf;		/* open hash files */
     43 
     44 	int		ncache;		/* size of tuple cache */
     45 	Ndbcache	*cache;		/* cached entries */
     46 };
     47 
     48 /*
     49  *  a parsed entry, doubly linked
     50  */
     51 struct Ndbtuple
     52 {
     53 	char		attr[Ndbalen];		/* attribute name */
     54 	char		*val;			/* value(s) */
     55 	Ndbtuple	*entry;			/* next tuple in this entry */
     56 	Ndbtuple	*line;			/* next tuple on this line */
     57 	ulong		ptr;			/* (for the application - starts 0) */
     58 	char		valbuf[Ndbvlen];	/* initial allocation for value */
     59 };
     60 
     61 /*
     62  *  each hash file is of the form
     63  *
     64  *		+---------------------------------------+
     65  *		|	mtime of db file (4 bytes)	|
     66  *		+---------------------------------------+
     67  *		|  size of table (in entries - 4 bytes)	|
     68  *		+---------------------------------------+
     69  *		|		hash table		|
     70  *		+---------------------------------------+
     71  *		|		hash chains		|
     72  *		+---------------------------------------+
     73  *
     74  *  hash collisions are resolved using chained entries added to the
     75  *  the end of the hash table.
     76  *
     77  *  Hash entries are of the form
     78  *
     79  *		+-------------------------------+
     80  *		|	offset	(3 bytes) 	|
     81  *		+-------------------------------+
     82  *
     83  *  Chain entries are of the form
     84  *
     85  *		+-------------------------------+
     86  *		|	offset1	(3 bytes) 	|
     87  *		+-------------------------------+
     88  *		|	offset2	(3 bytes) 	|
     89  *		+-------------------------------+
     90  *
     91  *  The top bit of an offset set to 1 indicates a pointer to a hash chain entry.
     92  */
     93 #define NDBULLEN	4		/* unsigned long length in bytes */
     94 #define NDBPLEN		3		/* pointer length in bytes */
     95 #define NDBHLEN		(2*NDBULLEN)	/* hash file header length in bytes */
     96 
     97 /*
     98  *  finger pointing to current point in a search
     99  */
    100 struct Ndbs
    101 {
    102 	Ndb	*db;	/* data base file being searched */
    103 	Ndbhf	*hf;	/* hash file being searched */
    104 	int	type;
    105 	ulong	ptr;	/* current pointer */
    106 	ulong	ptr1;	/* next pointer */
    107 	Ndbtuple *t;	/* last attribute value pair found */
    108 };
    109 
    110 /*
    111  *  bit defs for pointers in hash files
    112  */
    113 #define NDBSPEC 	(1<<23)
    114 #define NDBCHAIN	NDBSPEC		/* points to a collision chain */
    115 #define NDBNAP		(NDBSPEC|1)	/* not a pointer */
    116 
    117 /*
    118  *  macros for packing and unpacking pointers
    119  */
    120 #define NDBPUTP(v,a) { (a)[0] = (v)&0xFF; (a)[1] = ((v)>>8)&0xFF; (a)[2] = ((v)>>16)&0xFF; }
    121 #define NDBGETP(a) ((a)[0] | ((a)[1]<<8) | ((a)[2]<<16))
    122 
    123 /*
    124  *  macros for packing and unpacking unsigned longs
    125  */
    126 #define NDBPUTUL(v,a) { (a)[0] = (v)&0xFF; (a)[1] = ((v)>>8)&0xFF; (a)[2] = ((v)>>16)&0xFF; (a)[3] = ((v)>>24)&0xFF; }
    127 #define NDBGETUL(a) ((a)[0] | ((a)[1]<<8) | ((a)[2]<<16) | ((a)[3]<<24))
    128 
    129 #define NDB_IPlen 16
    130 
    131 Ndbtuple*	csgetval(char*, char*, char*, char*, char*);
    132 char*		csgetvalue(char*, char*, char*, char*, Ndbtuple**);
    133 Ndbtuple*	csipinfo(char*, char*, char*, char**, int);
    134 Ndbtuple*	dnsquery(char*, char*, char*);
    135 char*		ipattr(char*);
    136 Ndb*		ndbcat(Ndb*, Ndb*);
    137 int		ndbchanged(Ndb*);
    138 void		ndbclose(Ndb*);
    139 Ndbtuple*	ndbconcatenate(Ndbtuple*, Ndbtuple*);
    140 Ndbtuple*	ndbdiscard(Ndbtuple*, Ndbtuple*);
    141 void		ndbfree(Ndbtuple*);
    142 Ndbtuple*	ndbgetipaddr(Ndb*, char*);
    143 Ndbtuple*	ndbgetval(Ndb*, Ndbs*, char*, char*, char*, char*);
    144 char*		ndbgetvalue(Ndb*, Ndbs*, char*, char*, char*, Ndbtuple**);
    145 Ndbtuple*	ndbfindattr(Ndbtuple*, Ndbtuple*, char*);
    146 ulong		ndbhash(char*, int);
    147 Ndbtuple*	ndbipinfo(Ndb*, char*, char*, char**, int);
    148 Ndbtuple*	ndblookval(Ndbtuple*, Ndbtuple*, char*, char*);
    149 Ndbtuple*	ndbnew(char*, char*);
    150 Ndb*		ndbopen(char*);
    151 Ndbtuple*	ndbparse(Ndb*);
    152 int		ndbreopen(Ndb*);
    153 Ndbtuple*	ndbreorder(Ndbtuple*, Ndbtuple*);
    154 Ndbtuple*	ndbsearch(Ndb*, Ndbs*, char*, char*);
    155 long		ndbseek(Ndb*, long);
    156 void		ndbsetval(Ndbtuple*, char*, int);
    157 Ndbtuple*	ndbsnext(Ndbs*, char*, char*);
    158 Ndbtuple*	ndbsubstitute(Ndbtuple*, Ndbtuple*, Ndbtuple*);