fread.c - vx32 - Local 9vx git repository for patches.
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fread.c (2978B)
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1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char rcsid[] = "$OpenBSD: fread.c,v 1.2 1996/08/19 08:32:44 tholo Exp $";
39 #endif /* LIBC_SCCS and not lint */
40
41 #include <stdio.h>
42 #include <string.h>
43 #include "local.h"
44
45 size_t
46 fread(buf, size, count, fp)
47 void *buf;
48 size_t size, count;
49 register FILE *fp;
50 {
51 register size_t resid;
52 register char *p;
53 register int r;
54 size_t total;
55
56 /*
57 * The ANSI standard requires a return value of 0 for a count
58 * or a size of 0. Peculiarily, it imposes no such requirements
59 * on fwrite; it only requires fread to be broken.
60 */
61 if ((resid = count * size) == 0)
62 return (0);
63 if (fp->_r < 0)
64 fp->_r = 0;
65 total = resid;
66 p = buf;
67 while (resid > (r = fp->_r)) {
68 (void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
69 fp->_p += r;
70 /* fp->_r = 0 ... done in __srefill */
71 p += r;
72 resid -= r;
73 if (__srefill(fp)) {
74 /* no more input: return partial result */
75 return ((total - resid) / size);
76 }
77 }
78 (void)memcpy((void *)p, (void *)fp->_p, resid);
79 fp->_r -= resid;
80 fp->_p += resid;
81 return (count);
82 }