fvwrite.c revision 1.5 1 /* $NetBSD: fvwrite.c,v 1.5 1996/03/29 23:29:09 jtc Exp $ */
2
3 /*-
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39 #if defined(LIBC_SCCS) && !defined(lint)
40 #if 0
41 static char sccsid[] = "@(#)fvwrite.c 8.1 (Berkeley) 6/4/93";
42 #endif
43 static char rcsid[] = "$NetBSD: fvwrite.c,v 1.5 1996/03/29 23:29:09 jtc Exp $";
44 #endif /* LIBC_SCCS and not lint */
45
46 #include <stdio.h>
47 #include <string.h>
48 #include "local.h"
49 #include "fvwrite.h"
50
51 /*
52 * Write some memory regions. Return zero on success, EOF on error.
53 *
54 * This routine is large and unsightly, but most of the ugliness due
55 * to the three different kinds of output buffering is handled here.
56 */
57 int
58 __sfvwrite(fp, uio)
59 register FILE *fp;
60 register struct __suio *uio;
61 {
62 register size_t len;
63 register char *p;
64 register struct __siov *iov;
65 register int w, s;
66 char *nl;
67 int nlknown, nldist;
68
69 if ((len = uio->uio_resid) == 0)
70 return (0);
71 /* make sure we can write */
72 if (cantwrite(fp))
73 return (EOF);
74
75 #define MIN(a, b) ((a) < (b) ? (a) : (b))
76 #define COPY(n) (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
77
78 iov = uio->uio_iov;
79 p = iov->iov_base;
80 len = iov->iov_len;
81 iov++;
82 #define GETIOV(extra_work) \
83 while (len == 0) { \
84 extra_work; \
85 p = iov->iov_base; \
86 len = iov->iov_len; \
87 iov++; \
88 }
89 if (fp->_flags & __SNBF) {
90 /*
91 * Unbuffered: write up to BUFSIZ bytes at a time.
92 */
93 do {
94 GETIOV(;);
95 w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ));
96 if (w <= 0)
97 goto err;
98 p += w;
99 len -= w;
100 } while ((uio->uio_resid -= w) != 0);
101 } else if ((fp->_flags & __SLBF) == 0) {
102 /*
103 * Fully buffered: fill partially full buffer, if any,
104 * and then flush. If there is no partial buffer, write
105 * one _bf._size byte chunk directly (without copying).
106 *
107 * String output is a special case: write as many bytes
108 * as fit, but pretend we wrote everything. This makes
109 * snprintf() return the number of bytes needed, rather
110 * than the number used, and avoids its write function
111 * (so that the write function can be invalid).
112 */
113 do {
114 GETIOV(;);
115 w = fp->_w;
116 if (fp->_flags & __SSTR) {
117 if (len < w)
118 w = len;
119 COPY(w); /* copy MIN(fp->_w,len), */
120 fp->_w -= w;
121 fp->_p += w;
122 w = len; /* but pretend copied all */
123 } else if (fp->_p > fp->_bf._base && len > w) {
124 /* fill and flush */
125 COPY(w);
126 /* fp->_w -= w; */ /* unneeded */
127 fp->_p += w;
128 if (fflush(fp))
129 goto err;
130 } else if (len >= (w = fp->_bf._size)) {
131 /* write directly */
132 w = (*fp->_write)(fp->_cookie, p, w);
133 if (w <= 0)
134 goto err;
135 } else {
136 /* fill and done */
137 w = len;
138 COPY(w);
139 fp->_w -= w;
140 fp->_p += w;
141 }
142 p += w;
143 len -= w;
144 } while ((uio->uio_resid -= w) != 0);
145 } else {
146 /*
147 * Line buffered: like fully buffered, but we
148 * must check for newlines. Compute the distance
149 * to the first newline (including the newline),
150 * or `infinity' if there is none, then pretend
151 * that the amount to write is MIN(len,nldist).
152 */
153 nlknown = 0;
154 nldist = 0; /* XXX just to keep gcc happy */
155 do {
156 GETIOV(nlknown = 0);
157 if (!nlknown) {
158 nl = memchr((void *)p, '\n', len);
159 nldist = nl ? nl + 1 - p : len + 1;
160 nlknown = 1;
161 }
162 s = MIN(len, nldist);
163 w = fp->_w + fp->_bf._size;
164 if (fp->_p > fp->_bf._base && s > w) {
165 COPY(w);
166 /* fp->_w -= w; */
167 fp->_p += w;
168 if (fflush(fp))
169 goto err;
170 } else if (s >= (w = fp->_bf._size)) {
171 w = (*fp->_write)(fp->_cookie, p, w);
172 if (w <= 0)
173 goto err;
174 } else {
175 w = s;
176 COPY(w);
177 fp->_w -= w;
178 fp->_p += w;
179 }
180 if ((nldist -= w) == 0) {
181 /* copied the newline: flush and forget */
182 if (fflush(fp))
183 goto err;
184 nlknown = 0;
185 }
186 p += w;
187 len -= w;
188 } while ((uio->uio_resid -= w) != 0);
189 }
190 return (0);
191
192 err:
193 fp->_flags |= __SERR;
194 return (EOF);
195 }
196