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1.1 root 1: #include "defs"
2:
3: #ifdef HASHEDTABLE
4: /* Basic symbol table maintainer. Action depends on t:
5: t = -1 Remove name from table
6: t = 0 Put name in table if not there. Copy name string
7: t = 1 Find name in table if there, otherwise return 0.
8: t = 2 Put name in table if not there. Do not copy name
9: */
10:
11: struct stentry *hashtab[MAXEFLNAMES+1];
12: struct stentry **hashend = hashtab+MAXEFLNAMES+1;
13:
14: #define NEXT(x) (++x<hashend ? x : hashtab )
15:
16: struct stentry *name(s,t)
17: char *s;
18: int t;
19: {
20: int hash;
21: register struct stentry *p, **hp;
22: char *copys();
23:
24: hash = hashfunct(s);
25:
26: for(hp = hashtab + hash; (p = *hp) ; hp = NEXT(hp) )
27: if(hash==p->hashval && equals(s,p->namep))
28: switch(t)
29: {
30: case -1:
31: cfree(p->namep);
32: cfree(p);
33: delhash(hp);
34: --neflnames;
35: return(0);
36:
37: case 0:
38: case 1:
39: case 2:
40: return(p);
41:
42: default:
43: fatal("name: illegal argument");
44: }
45:
46: /* not in table */
47: switch(t)
48: {
49: case -1:
50: fatal1("cannot delete nonexistent name %s from symbol table", s);
51:
52: case 1:
53: return(0);
54:
55: case 0:
56: case 2:
57: if(++neflnames >= MAXEFLNAMES)
58: fatal("hash table full");
59:
60: *hp = p = ALLOC(stentry);
61: p->namep = (t==0 ? copys(s) : s);
62: p->hashval = hash;
63: return(p);
64:
65: default:
66: fatal("illegal call to name");
67: } return 0;
68: }
69:
70:
71:
72: hashfunct(s)
73: register char *s;
74: {
75: register int h;
76:
77: h = 0;
78: while(*s)
79: h += *s++;
80:
81: return( h % (MAXEFLNAMES+1) );
82: }
83:
84:
85: delhash(hp)
86: struct stentry **hp;
87: {
88: struct stentry **hq, **hvp;
89:
90: for ( ; ; )
91: {
92: *hp = 0;
93: hq = hp;
94: for(hp = NEXT(hp) ; *hp &&
95: ( (hq < (hvp = hashtab + (*hp)->hashval) && hvp<=hp)
96: || (hp<hq && hq<hvp) || (hvp<=hp && hp<hq) ) ;
97: hp = NEXT(hp) )
98: ;
99: if(*hp == 0)
100: return;
101: *hq = *hp;
102: }
103: }
104: #endif
105:
106: #ifndef HASHEDTABLE
107: /* Basic symbol table maintainer. Action depends on t:
108: t = -1 Remove name from table
109: t = 0 Put name in table if not there. Copy name string
110: t = 1 Find name in table if there, otherwise return 0.
111: t = 2 Put name in table if not there. Do not copy name
112: *!!/
113:
114: struct stentry *hashtab[MAXEFLNAMES];
115: struct stentry **hashend hashtab;
116:
117: name(s,t)
118: char *s;
119: int t;
120: {
121: int hash;
122: register struct stentry *p, **hp;
123: char *copys();
124:
125: hash = hashfunct(s);
126:
127: for(hp = hashtab ; hp<hashend ; ++hp)
128: if( (p = *hp) && hash==p->hashval && equals(s,p->namep))
129: switch(t)
130: {
131: case -1:
132: cfree(p->namep);
133: cfree(p);
134: *hp = 0;
135: return(0);
136:
137: case 0:
138: case 1:
139: case 2:
140: return(p);
141:
142: default:
143: fatal("name: illegal argument");
144: }
145:
146: /* not in table *!!/
147: switch(t)
148: {
149: case -1:
150: fatal1("cannot delete nonexistent name %s from symbol table", s);
151:
152: case 1:
153: return(0);
154:
155: case 0:
156: case 2:
157: /* look for an empty slot *!!/
158: for(hp = hashtab ; hp<hashend && *hp!=0 ; ++hp)
159: ;
160:
161: if(hp == hashend)
162: if(++neflnames >= MAXEFLNAMES)
163: fatal("hash table full");
164: else ++hashend;
165:
166: *hp = p = ALLOC(stentry);
167: p->namep = (t==0 ? copys(s) : s);
168: p->hashval = hash;
169: return(p);
170:
171: default:
172: fatal("illegal call to name");
173: }
174: }
175:
176:
177:
178: hashfunct(s)
179: register char *s;
180: {
181: register int h;
182:
183: h = 0;
184: while(*s)
185: h = *s++;
186:
187: return(h);
188: }
189: */
190: #endif
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