Annotation of prex/usr/lib/libc/stdio/fread.c, Revision 1.1.1.1
1.1 nbrk 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:
33: #include <stdio.h>
34: #include <string.h>
35: #include "local.h"
36:
37: size_t
38: fread(buf, size, count, fp)
39: void *buf;
40: size_t size, count;
41: FILE *fp;
42: {
43: size_t resid;
44: char *p;
45: int r;
46: size_t total;
47:
48: /*
49: * The ANSI standard requires a return value of 0 for a count
50: * or a size of 0. Peculiarily, it imposes no such requirements
51: * on fwrite; it only requires fread to be broken.
52: */
53: if ((resid = count * size) == 0)
54: return (0);
55: if (fp->_r < 0)
56: fp->_r = 0;
57: total = resid;
58: p = buf;
59: while (resid > (size_t)(r = fp->_r)) {
60: (void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
61: fp->_p += r;
62: /* fp->_r = 0 ... done in __srefill */
63: p += r;
64: resid -= r;
65: if (__srefill(fp)) {
66: /* no more input: return partial result */
67: return ((total - resid) / size);
68: }
69: }
70: (void)memcpy((void *)p, (void *)fp->_p, resid);
71: fp->_r -= resid;
72: fp->_p += resid;
73: return (count);
74: }
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