1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 1986 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate /*      Copyright (c) 1984 AT&T */
28*0Sstevel@tonic-gate /*        All Rights Reserved   */
29*0Sstevel@tonic-gate 
30*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 3.11 */
31*0Sstevel@tonic-gate 
32*0Sstevel@tonic-gate /*LINTLIBRARY*/
33*0Sstevel@tonic-gate /*
34*0Sstevel@tonic-gate  * This version reads directly from the buffer rather than looping on getc.
35*0Sstevel@tonic-gate  * Ptr args aren't checked for NULL because the program would be a
36*0Sstevel@tonic-gate  * catastrophic mess anyway.  Better to abort than just to return NULL.
37*0Sstevel@tonic-gate  */
38*0Sstevel@tonic-gate #include <stdio.h>
39*0Sstevel@tonic-gate #include "stdiom.h"
40*0Sstevel@tonic-gate 
41*0Sstevel@tonic-gate #define MIN(x, y)	(x < y ? x : y)
42*0Sstevel@tonic-gate 
43*0Sstevel@tonic-gate extern int _filbuf();
44*0Sstevel@tonic-gate extern _bufsync();
45*0Sstevel@tonic-gate extern char *memcpy();
46*0Sstevel@tonic-gate 
47*0Sstevel@tonic-gate int
48*0Sstevel@tonic-gate fread(ptr, size, count, iop)
49*0Sstevel@tonic-gate char *ptr;
50*0Sstevel@tonic-gate int size, count;
51*0Sstevel@tonic-gate register FILE *iop;
52*0Sstevel@tonic-gate {
53*0Sstevel@tonic-gate 	register unsigned int nleft;
54*0Sstevel@tonic-gate 	register int n;
55*0Sstevel@tonic-gate 
56*0Sstevel@tonic-gate 	if (size <= 0 || count <= 0) return 0;
57*0Sstevel@tonic-gate 	nleft = count * size;
58*0Sstevel@tonic-gate 
59*0Sstevel@tonic-gate 	/* Put characters in the buffer */
60*0Sstevel@tonic-gate 	/* note that the meaning of n when just starting this loop is
61*0Sstevel@tonic-gate 	   irrelevant.  It is defined in the loop */
62*0Sstevel@tonic-gate 	for ( ; ; ) {
63*0Sstevel@tonic-gate 		if (iop->_cnt <= 0) { /* empty buffer */
64*0Sstevel@tonic-gate 			if (_filbuf(iop) == EOF)
65*0Sstevel@tonic-gate 				return (count - (nleft + size - 1)/size);
66*0Sstevel@tonic-gate 			iop->_ptr--;
67*0Sstevel@tonic-gate 			iop->_cnt++;
68*0Sstevel@tonic-gate 		}
69*0Sstevel@tonic-gate 		n = MIN(nleft, iop->_cnt);
70*0Sstevel@tonic-gate 		ptr = memcpy(ptr, (char *) iop->_ptr, n) + n;
71*0Sstevel@tonic-gate 		iop->_cnt -= n;
72*0Sstevel@tonic-gate 		iop->_ptr += n;
73*0Sstevel@tonic-gate 		_BUFSYNC(iop);
74*0Sstevel@tonic-gate 		if ((nleft -= n) == 0)
75*0Sstevel@tonic-gate 			return (count);
76*0Sstevel@tonic-gate 	}
77*0Sstevel@tonic-gate }
78