1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 1986 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1984 AT&T */
28 /* All Rights Reserved */
29
30 #pragma ident "%Z%%M% %I% %E% SMI"
31
32 /*LINTLIBRARY*/
33 /*
34 * This version reads directly from the buffer rather than looping on getc.
35 * Ptr args aren't checked for NULL because the program would be a
36 * catastrophic mess anyway. Better to abort than just to return NULL.
37 */
38 #include <stdio.h>
39 #include "stdiom.h"
40 #include <memory.h>
41
42 #define MIN(x, y) (x < y ? x : y)
43
44 extern int _filbuf();
45
46 int
fread(char * ptr,int size,int count,FILE * iop)47 fread(char *ptr, int size, int count, FILE *iop)
48 {
49 unsigned int nleft;
50 int n;
51
52 if (size <= 0 || count <= 0) return 0;
53 nleft = count * size;
54
55 /* Put characters in the buffer */
56 /* note that the meaning of n when just starting this loop is
57 irrelevant. It is defined in the loop */
58 for ( ; ; ) {
59 if (iop->_cnt <= 0) { /* empty buffer */
60 if (_filbuf(iop) == EOF)
61 return (count - (nleft + size - 1)/size);
62 iop->_ptr--;
63 iop->_cnt++;
64 }
65 n = MIN(nleft, iop->_cnt);
66 ptr = memcpy(ptr, (char *) iop->_ptr, n) + n;
67 iop->_cnt -= n;
68 iop->_ptr += n;
69 _BUFSYNC(iop);
70 if ((nleft -= n) == 0)
71 return (count);
72 }
73 }
74