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*);