1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/* $OpenBSD: table.c,v 1.11 2005/03/30 17:16:37 deraadt Exp $ */
/*
* dynamic hashed associative table for commands and variables
*/
#include "sh.h"
#define INIT_TBLS 8 /* initial table size (power of 2) */
static void texpand(struct table *, int);
static int tnamecmp(void *, void *);
unsigned int
hash(const char *n)
{
unsigned int h = 0;
while (*n != '\0')
h = 2*h + *n++;
return h * 32821; /* scatter bits */
}
void
tinit(struct table *tp, Area *ap, int tsize)
{
tp->areap = ap;
tp->tbls = NULL;
tp->size = tp->nfree = 0;
if (tsize)
texpand(tp, tsize);
}
static void
texpand(struct table *tp, int nsize)
{
int i;
struct tbl *tblp, **p;
struct tbl **ntblp, **otblp = tp->tbls;
int osize = tp->size;
ntblp = (struct tbl**) alloc(sizeofN(struct tbl *, nsize), tp->areap);
for (i = 0; i < nsize; i++)
ntblp[i] = NULL;
tp->size = nsize;
tp->nfree = 8*nsize/10; /* table can get 80% full */
tp->tbls = ntblp;
if (otblp == NULL)
return;
for (i = 0; i < osize; i++)
if ((tblp = otblp[i]) != NULL) {
if ((tblp->flag&DEFINED)) {
for (p = &ntblp[hash(tblp->name) &
(tp->size-1)]; *p != NULL; p--)
if (p == ntblp) /* wrap */
p += tp->size;
*p = tblp;
tp->nfree--;
} else if (!(tblp->flag & FINUSE)) {
afree((void*)tblp, tp->areap);
}
}
afree((void*)otblp, tp->areap);
}
/* table */
/* name to enter */
/* hash(n) */
struct tbl *
tsearch(struct table *tp, const char *n, unsigned int h)
{
struct tbl **pp, *p;
if (tp->size == 0)
return NULL;
/* search for name in hashed table */
for (pp = &tp->tbls[h & (tp->size-1)]; (p = *pp) != NULL; pp--) {
if (*p->name == *n && strcmp(p->name, n) == 0 &&
(p->flag&DEFINED))
return p;
if (pp == tp->tbls) /* wrap */
pp += tp->size;
}
return NULL;
}
/* table */
/* name to enter */
/* hash(n) */
struct tbl *
tenter(struct table *tp, const char *n, unsigned int h)
{
struct tbl **pp, *p;
int len;
if (tp->size == 0)
texpand(tp, INIT_TBLS);
Search:
/* search for name in hashed table */
for (pp = &tp->tbls[h & (tp->size-1)]; (p = *pp) != NULL; pp--) {
if (*p->name == *n && strcmp(p->name, n) == 0)
return p; /* found */
if (pp == tp->tbls) /* wrap */
pp += tp->size;
}
if (tp->nfree <= 0) { /* too full */
texpand(tp, 2*tp->size);
goto Search;
}
/* create new tbl entry */
len = strlen(n) + 1;
p = (struct tbl *) alloc(offsetof(struct tbl, name[0]) + len,
tp->areap);
p->flag = 0;
p->type = 0;
p->areap = tp->areap;
p->u2.field = 0;
p->u.array = (struct tbl *)0;
memcpy(p->name, n, len);
/* enter in tp->tbls */
tp->nfree--;
*pp = p;
return p;
}
void
tdelete(struct tbl *p)
{
p->flag = 0;
}
void
twalk(struct tstate *ts, struct table *tp)
{
ts->left = tp->size;
ts->next = tp->tbls;
}
struct tbl *
tnext(struct tstate *ts)
{
while (--ts->left >= 0) {
struct tbl *p = *ts->next++;
if (p != NULL && (p->flag&DEFINED))
return p;
}
return NULL;
}
static int
tnamecmp(void *p1, void *p2)
{
return strcmp(((struct tbl *)p1)->name, ((struct tbl *)p2)->name);
}
struct tbl **
tsort(struct table *tp)
{
int i;
struct tbl **p, **sp, **dp;
p = (struct tbl **)alloc(sizeofN(struct tbl *, tp->size+1), ATEMP);
sp = tp->tbls; /* source */
dp = p; /* dest */
for (i = 0; i < tp->size; i++)
if ((*dp = *sp++) != NULL && (((*dp)->flag&DEFINED) ||
((*dp)->flag&ARRAY)))
dp++;
i = dp - p;
qsortp((void**)p, (size_t)i, tnamecmp);
p[i] = NULL;
return p;
}
#ifdef PERF_DEBUG /* performance debugging */
void tprintinfo(struct table *tp);
void
tprintinfo(struct table *tp)
{
struct tbl *te;
char *n;
unsigned int h;
int ncmp;
int totncmp = 0, maxncmp = 0;
int nentries = 0;
struct tstate ts;
shellf("table size %d, nfree %d\n", tp->size, tp->nfree);
shellf(" Ncmp name\n");
twalk(&ts, tp);
while ((te = tnext(&ts))) {
struct tbl **pp, *p;
h = hash(n = te->name);
ncmp = 0;
/* taken from tsearch() and added counter */
for (pp = &tp->tbls[h & (tp->size-1)]; (p = *pp); pp--) {
ncmp++;
if (*p->name == *n && strcmp(p->name, n) == 0 &&
(p->flag&DEFINED))
break; /* return p; */
if (pp == tp->tbls) /* wrap */
pp += tp->size;
}
shellf(" %4d %s\n", ncmp, n);
totncmp += ncmp;
nentries++;
if (ncmp > maxncmp)
maxncmp = ncmp;
}
if (nentries)
shellf(" %d entries, worst ncmp %d, avg ncmp %d.%02d\n",
nentries, maxncmp,
totncmp / nentries,
(totncmp % nentries) * 100 / nentries);
}
#endif /* PERF_DEBUG */
|
