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. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)fread.c 8.2 (Berkeley) 12/11/93
33 * $FreeBSD: src/lib/libc/stdio/fread.c,v 1.15 2008/12/01 14:33:34 ru Exp $
34 */
35
36 #include "namespace.h"
37 #include <stdio.h>
38 #include <string.h>
39 #include "un-namespace.h"
40 #include "local.h"
41 #include "libc_private.h"
42
43 /*
44 * MT-safe version
45 */
46
47 size_t
fread(void * __restrict buf,size_t size,size_t count,FILE * __restrict fp)48 fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
49 {
50 size_t ret;
51
52 FLOCKFILE(fp);
53 ret = __fread(buf, size, count, fp);
54 FUNLOCKFILE(fp);
55 return (ret);
56 }
57
58 size_t
__fread(void * __restrict buf,size_t size,size_t count,FILE * __restrict fp)59 __fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
60 {
61 size_t resid;
62 char *p;
63 int r;
64 size_t total;
65
66 /*
67 * The ANSI standard requires a return value of 0 for a count
68 * or a size of 0. Peculiarily, it imposes no such requirements
69 * on fwrite; it only requires fread to be broken.
70 */
71 if ((resid = count * size) == 0)
72 return (0);
73 ORIENT(fp, -1);
74 if (fp->pub._r < 0)
75 fp->pub._r = 0;
76 total = resid;
77 p = buf;
78 while (resid > (r = fp->pub._r)) {
79 memcpy((void *)p, (void *)fp->pub._p, (size_t)r);
80 fp->pub._p += r;
81 /* fp->pub._r = 0 ... done in __srefill */
82 p += r;
83 resid -= r;
84 if (__srefill(fp)) {
85 /* no more input: return partial result */
86 return ((total - resid) / size);
87 }
88 }
89 memcpy((void *)p, (void *)fp->pub._p, resid);
90 fp->pub._r -= resid;
91 fp->pub._p += resid;
92 return (count);
93 }
94
95 __weak_reference(__fread, fread_unlocked);
96