xref: /csrg-svn/usr.sbin/sendmail/src/stab.c (revision 4319)
1 # include "sendmail.h"
2 
3 static char SccsId[] = "@(#)stab.c	3.8	09/06/81";
4 
5 /*
6 **  STAB -- manage the symbol table
7 **
8 **	Parameters:
9 **		name -- the name to be looked up or inserted.
10 **		type -- the type of symbol.
11 **		op -- what to do:
12 **			ST_ENTER -- enter the name if not
13 **				already present.
14 **			ST_FIND -- find it only.
15 **
16 **	Returns:
17 **		pointer to a STAB entry for this name.
18 **		NULL if not found and not entered.
19 **
20 **	Side Effects:
21 **		can update the symbol table.
22 */
23 
24 # define STABSIZE	400
25 
26 static STAB	*SymTab[STABSIZE];
27 
28 STAB *
29 stab(name, type, op)
30 	char *name;
31 	int type;
32 	int op;
33 {
34 	register STAB *s;
35 	register STAB **ps;
36 	extern bool sameword();
37 	register int hfunc;
38 	register char *p;
39 	extern char lower();
40 
41 # ifdef DEBUG
42 	if (Debug > 4)
43 		printf("STAB: %s %d ", name, type);
44 # endif DEBUG
45 
46 	/*
47 	**  Compute the hashing function
48 	**
49 	**	We could probably do better....
50 	*/
51 
52 	hfunc = type;
53 	for (p = name; *p != '\0'; p++)
54 		hfunc = ((hfunc << 7) | lower(*p)) % STABSIZE;
55 
56 # ifdef DEBUG
57 	if (Debug > 15)
58 		printf("(hfunc=%d) ", hfunc);
59 # endif DEBUG
60 
61 	ps = &SymTab[hfunc];
62 	while ((s = *ps) != NULL && (!sameword(name, s->s_name) || s->s_type != type))
63 	{
64 		ps = &s->s_next;
65 		s = s->s_next;
66 	}
67 
68 	/*
69 	**  Dispose of the entry.
70 	*/
71 
72 	if (s != NULL || op == ST_FIND)
73 	{
74 # ifdef DEBUG
75 		if (Debug > 4)
76 		{
77 			if (s == NULL)
78 				printf("not found\n");
79 			else
80 				printf("type %d val %x\n", s->s_type, s->s_class);
81 		}
82 # endif DEBUG
83 		return (s);
84 	}
85 
86 	/*
87 	**  Make a new entry and link it in.
88 	*/
89 
90 # ifdef DEBUG
91 	if (Debug > 4)
92 		printf("entered\n");
93 # endif DEBUG
94 
95 	/* make new entry */
96 	s = (STAB *) xalloc(sizeof *s);
97 	clear((char *) s, sizeof *s);
98 	s->s_name = newstr(name);
99 	makelower(s->s_name);
100 	s->s_type = type;
101 
102 	/* link it in */
103 	*ps = s;
104 
105 	return (s);
106 }
107