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
|
/* backpage.c
*/
/* This software is copyrighted as detailed in the LICENSE file. */
#include "EXTERN.h"
#include "common.h"
#include "intrp.h"
#include "util2.h"
#include "final.h"
#include "INTERN.h"
#include "backpage.h"
ART_LINE maxindx = -1;
void
backpage_init()
{
char* varyname;
varyname = filexp(VARYNAME);
close(creat(varyname,0600));
varyfd = open(varyname,2);
UNLINK(varyname);
if (varyfd < 0) {
printf(cantopen,varyname) FLUSH;
sig_catcher(0);
}
}
/* virtual array read */
ART_POS
vrdary(indx)
ART_LINE indx;
{
int subindx;
long offset;
#ifdef DEBUG
if (indx > maxindx) {
printf("vrdary(%ld) > %ld\n",(long)indx, (long)maxindx) FLUSH;
return 0;
}
#endif
if (indx < 0)
return 0;
subindx = indx % VARYSIZE;
offset = (indx - subindx) * sizeof(varybuf[0]);
if (offset != oldoffset) {
if (oldoffset >= 0) {
#ifndef lint
(void)lseek(varyfd,oldoffset,0);
write(varyfd, (char*)varybuf,sizeof(varybuf));
#endif /* lint */
}
#ifndef lint
(void)lseek(varyfd,offset,0);
read(varyfd,(char*)varybuf,sizeof(varybuf));
#endif /* lint */
oldoffset = offset;
}
return varybuf[subindx];
}
/* write to virtual array */
void
vwtary(indx,newvalue)
ART_LINE indx;
ART_POS newvalue;
{
int subindx;
long offset;
#ifdef DEBUG
if (indx < 0)
printf("vwtary(%ld)\n",(long)indx) FLUSH;
if (!indx)
maxindx = 0;
if (indx > maxindx) {
if (indx != maxindx + 1)
printf("indx skipped %d-%d\n",maxindx+1,indx-1) FLUSH;
maxindx = indx;
}
#endif
subindx = indx % VARYSIZE;
offset = (indx - subindx) * sizeof(varybuf[0]);
if (offset != oldoffset) {
if (oldoffset >= 0) {
#ifndef lint
(void)lseek(varyfd,oldoffset,0);
write(varyfd,(char*)varybuf,sizeof(varybuf));
#endif /* lint */
}
#ifndef lint
(void)lseek(varyfd,offset,0);
read(varyfd,(char*)varybuf,sizeof(varybuf));
#endif /* lint */
oldoffset = offset;
}
varybuf[subindx] = newvalue;
}
|
