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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27/*	Copyright (c) 1988 AT&T	*/
28/*	  All Rights Reserved  	*/
29
30#pragma ident	"%Z%%M%	%I%	%E% SMI"
31
32#include "lint.h"
33#include "file64.h"
34#include "mtlib.h"
35#include <stdio.h>
36#include <stddef.h>
37#include <values.h>
38#include <memory.h>
39#include <thread.h>
40#include <synch.h>
41#include <errno.h>
42#include <sys/types.h>
43#include "stdiom.h"
44#include "mse.h"
45
46size_t
47fread(void *ptr, size_t size, size_t count, FILE *iop)
48{
49	ssize_t s;
50	int c;
51	char *dptr = (char *)ptr;
52	rmutex_t *lk;
53
54	FLOCKFILE(lk, iop);
55
56	_SET_ORIENTATION_BYTE(iop);
57
58	/* is it a readable stream */
59	if (!(iop->_flag & (_IOREAD | _IORW))) {
60		iop->_flag |= _IOERR;
61		errno = EBADF;
62		FUNLOCKFILE(lk);
63		return (0);
64	}
65
66	if (iop->_flag & _IOEOF) {
67		FUNLOCKFILE(lk);
68		return (0);
69	}
70
71	/* These checks are here to avoid the multiply */
72	if (count == 1)
73		s = size;
74	else if (size == 1)
75		s = count;
76	else
77		s = size * count;
78
79	while (s > 0) {
80		if (iop->_cnt < s) {
81			if (iop->_cnt > 0) {
82				(void) memcpy((void*)dptr, iop->_ptr,
83				    iop->_cnt);
84				dptr += iop->_cnt;
85				s -= iop->_cnt;
86			}
87			/*
88			 * filbuf clobbers _cnt & _ptr,
89			 * so don't waste time setting them.
90			 */
91			if ((c = __filbuf(iop)) == EOF)
92				break;
93			*dptr++ = (char)c;
94			s--;
95		}
96		if (iop->_cnt >= s) {
97			char *tmp = (char *)iop->_ptr;
98			switch (s) {
99			case 8:
100				*dptr++ = *tmp++;
101				/*FALLTHRU*/
102			case 7:
103				*dptr++ = *tmp++;
104				/*FALLTHRU*/
105			case 6:
106				*dptr++ = *tmp++;
107				/*FALLTHRU*/
108			case 5:
109				*dptr++ = *tmp++;
110				/*FALLTHRU*/
111			case 4:
112				*dptr++ = *tmp++;
113				/*FALLTHRU*/
114			case 3:
115				*dptr++ = *tmp++;
116				/*FALLTHRU*/
117			case 2:
118				*dptr++ = *tmp++;
119				/*FALLTHRU*/
120			case 1:
121				*dptr++ = *tmp++;
122				break;
123			default:
124				(void) memcpy((void*)dptr, iop->_ptr,
125				    (size_t)s);
126			}
127			iop->_ptr += s;
128			iop->_cnt -= s;
129			FUNLOCKFILE(lk);
130			return (count);
131		}
132	}
133	FUNLOCKFILE(lk);
134	return (size != 0 ? count - ((s + size - 1) / size) : 0);
135}
136