1 #include "lib9.h"
2 #include <bio.h>
3
4 enum
5 {
6 MAXBUFS = 20
7 };
8
9 static Biobuf* wbufs[MAXBUFS];
10 static int atexitflag;
11
12 static
13 void
batexit(void)14 batexit(void)
15 {
16 Biobuf *bp;
17 int i;
18
19 for(i=0; i<nelem(wbufs); i++) {
20 bp = wbufs[i];
21 if(bp != 0) {
22 wbufs[i] = 0;
23 Bflush(bp);
24 }
25 }
26 }
27
28 static
29 void
deinstall(Biobuf * bp)30 deinstall(Biobuf *bp)
31 {
32 int i;
33
34 for(i=0; i<nelem(wbufs); i++)
35 if(wbufs[i] == bp)
36 wbufs[i] = 0;
37 }
38
39 static
40 void
install(Biobuf * bp)41 install(Biobuf *bp)
42 {
43 int i;
44
45 deinstall(bp);
46 for(i=0; i<nelem(wbufs); i++)
47 if(wbufs[i] == 0) {
48 wbufs[i] = bp;
49 break;
50 }
51 if(atexitflag == 0) {
52 atexitflag = 1;
53 atexit(batexit);
54 }
55 }
56
57 int
Binits(Biobuf * bp,int f,int mode,uchar * p,int size)58 Binits(Biobuf *bp, int f, int mode, uchar *p, int size)
59 {
60
61 p += Bungetsize; /* make room for Bungets */
62 size -= Bungetsize;
63
64 switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
65 default:
66 fprint(2, "Bopen: unknown mode %d\n", mode);
67 return Beof;
68
69 case OREAD:
70 bp->state = Bractive;
71 bp->ocount = 0;
72 break;
73
74 case OWRITE:
75 install(bp);
76 bp->state = Bwactive;
77 bp->ocount = -size;
78 break;
79 }
80 bp->bbuf = p;
81 bp->ebuf = p+size;
82 bp->bsize = size;
83 bp->icount = 0;
84 bp->gbuf = bp->ebuf;
85 bp->fid = f;
86 bp->flag = 0;
87 bp->rdline = 0;
88 bp->offset = 0;
89 bp->runesize = 0;
90 return 0;
91 }
92
93
94 int
Binit(Biobuf * bp,int f,int mode)95 Binit(Biobuf *bp, int f, int mode)
96 {
97 return Binits(bp, f, mode, bp->b, sizeof(bp->b));
98 }
99
100 Biobuf*
Bopen(char * name,int mode)101 Bopen(char *name, int mode)
102 {
103 Biobuf *bp;
104 int f;
105
106 switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
107 default:
108 fprint(2, "Bopen: unknown mode %d\n", mode);
109 return 0;
110
111 case OREAD:
112 f = open(name, OREAD);
113 break;
114
115 case OWRITE:
116 f = create(name, mode, 0666);
117 break;
118 }
119 if(f < 0)
120 return 0;
121 bp = malloc(sizeof(Biobuf));
122 if(bp == nil)
123 return 0;
124 Binits(bp, f, mode, bp->b, sizeof(bp->b));
125 bp->flag = Bmagic;
126 return bp;
127 }
128
129 int
Bterm(Biobuf * bp)130 Bterm(Biobuf *bp)
131 {
132 int r;
133
134 deinstall(bp);
135 r = Bflush(bp);
136 if(bp->flag == Bmagic) {
137 bp->flag = 0;
138 close(bp->fid);
139 bp->fid = -1; /* prevent accidents */
140 free(bp);
141 }
142 /* otherwise opened with Binit(s) */
143 return r;
144 }
145