1 /*
2 http://code.google.com/p/inferno-os/source/browse/libbio/binit.c
3
4 Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
5 Revisions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com). All rights reserved.
6
7 Permission is hereby granted, free of charge, to any person obtaining a copy
8 of this software and associated documentation files (the "Software"), to deal
9 in the Software without restriction, including without limitation the rights
10 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 copies of the Software, and to permit persons to whom the Software is
12 furnished to do so, subject to the following conditions:
13
14 The above copyright notice and this permission notice shall be included in
15 all copies or substantial portions of the Software.
16
17 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23 THE SOFTWARE.
24 */
25
26 #include <u.h>
27 #include <libc.h>
28 #include <bio.h>
29
30 enum
31 {
32 MAXBUFS = 20
33 };
34
35 static Biobuf* wbufs[MAXBUFS];
36 static int atexitflag;
37
38 static
39 void
40 batexit(void)
41 {
42 Biobuf *bp;
43 int i;
44
45 for(i=0; i<MAXBUFS; i++) {
46 bp = wbufs[i];
47 if(bp != 0) {
48 wbufs[i] = 0;
49 Bflush(bp);
50 }
51 }
52 }
53
54 static
55 void
56 deinstall(Biobuf *bp)
57 {
58 int i;
59
60 for(i=0; i<MAXBUFS; i++)
61 if(wbufs[i] == bp)
62 wbufs[i] = 0;
63 }
64
65 static
66 void
67 install(Biobuf *bp)
68 {
69 int i;
70
71 deinstall(bp);
72 for(i=0; i<MAXBUFS; i++)
73 if(wbufs[i] == 0) {
74 wbufs[i] = bp;
75 break;
76 }
77 if(atexitflag == 0) {
78 atexitflag = 1;
79 atexit(batexit);
80 }
81 }
82
83 int
84 Binits(Biobuf *bp, int f, int mode, unsigned char *p, int size)
85 {
86
87 p += Bungetsize; /* make room for Bungets */
88 size -= Bungetsize;
89
90 switch(mode&~(ORCLOSE|OTRUNC)) {
91 default:
92 fprint(2, "Bopen: unknown mode %d\n", mode);
93 return Beof;
94
95 case OREAD:
96 bp->state = Bractive;
97 bp->ocount = 0;
98 break;
99
100 case OWRITE:
101 install(bp);
102 bp->state = Bwactive;
103 bp->ocount = -size;
104 break;
105 }
106 bp->bbuf = p;
107 bp->ebuf = p+size;
108 bp->bsize = size;
109 bp->icount = 0;
110 bp->gbuf = bp->ebuf;
111 bp->fid = f;
112 bp->flag = 0;
113 bp->rdline = 0;
114 bp->offset = 0;
115 bp->runesize = 0;
116 return 0;
117 }
118
119
120 int
121 Binit(Biobuf *bp, int f, int mode)
122 {
123 return Binits(bp, f, mode, bp->b, sizeof(bp->b));
124 }
125
126 Biobuf*
127 Bfdopen(int f, int mode)
128 {
129 Biobuf *bp;
130
131 bp = malloc(sizeof(Biobuf));
132 if(bp == 0)
133 return 0;
134 Binits(bp, f, mode, bp->b, sizeof(bp->b));
135 bp->flag = Bmagic;
136 return bp;
137 }
138
139 Biobuf*
140 Bopen(char *name, int mode)
141 {
142 Biobuf *bp;
143 int f;
144
145 switch(mode&~(ORCLOSE|OTRUNC)) {
146 default:
147 fprint(2, "Bopen: unknown mode %d\n", mode);
148 return 0;
149
150 case OREAD:
151 f = open(name, OREAD);
152 if(f < 0)
153 return 0;
154 break;
155
156 case OWRITE:
157 f = create(name, OWRITE|OTRUNC, 0666);
158 if(f < 0)
159 return 0;
160 }
161 bp = Bfdopen(f, mode);
162 if(bp == 0)
163 close(f);
164 return bp;
165 }
166
167 int
168 Bterm(Biobuf *bp)
169 {
170
171 deinstall(bp);
172 Bflush(bp);
173 if(bp->flag == Bmagic) {
174 bp->flag = 0;
175 close(bp->fid);
176 free(bp);
177 }
178 return 0;
179 }