xref: /illumos-gate/usr/src/lib/libc/port/stdio/fread.c (revision 7257d1b4)
17c478bd9Sstevel@tonic-gate /*
27c478bd9Sstevel@tonic-gate  * CDDL HEADER START
37c478bd9Sstevel@tonic-gate  *
47c478bd9Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*7257d1b4Sraf  * Common Development and Distribution License (the "License").
6*7257d1b4Sraf  * You may not use this file except in compliance with the License.
77c478bd9Sstevel@tonic-gate  *
87c478bd9Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
97c478bd9Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
107c478bd9Sstevel@tonic-gate  * See the License for the specific language governing permissions
117c478bd9Sstevel@tonic-gate  * and limitations under the License.
127c478bd9Sstevel@tonic-gate  *
137c478bd9Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
147c478bd9Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
157c478bd9Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
167c478bd9Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
177c478bd9Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
187c478bd9Sstevel@tonic-gate  *
197c478bd9Sstevel@tonic-gate  * CDDL HEADER END
207c478bd9Sstevel@tonic-gate  */
21*7257d1b4Sraf 
227c478bd9Sstevel@tonic-gate /*
23*7257d1b4Sraf  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
247c478bd9Sstevel@tonic-gate  * Use is subject to license terms.
257c478bd9Sstevel@tonic-gate  */
267c478bd9Sstevel@tonic-gate 
277c478bd9Sstevel@tonic-gate /*	Copyright (c) 1988 AT&T	*/
287c478bd9Sstevel@tonic-gate /*	  All Rights Reserved  	*/
297c478bd9Sstevel@tonic-gate 
30*7257d1b4Sraf #pragma ident	"%Z%%M%	%I%	%E% SMI"
317c478bd9Sstevel@tonic-gate 
32*7257d1b4Sraf #include "lint.h"
337c478bd9Sstevel@tonic-gate #include "file64.h"
347c478bd9Sstevel@tonic-gate #include "mtlib.h"
357c478bd9Sstevel@tonic-gate #include <stdio.h>
367c478bd9Sstevel@tonic-gate #include <stddef.h>
377c478bd9Sstevel@tonic-gate #include <values.h>
387c478bd9Sstevel@tonic-gate #include <memory.h>
397c478bd9Sstevel@tonic-gate #include <thread.h>
407c478bd9Sstevel@tonic-gate #include <synch.h>
417c478bd9Sstevel@tonic-gate #include <errno.h>
427c478bd9Sstevel@tonic-gate #include <sys/types.h>
437c478bd9Sstevel@tonic-gate #include "stdiom.h"
447c478bd9Sstevel@tonic-gate #include "mse.h"
457c478bd9Sstevel@tonic-gate 
467c478bd9Sstevel@tonic-gate size_t
fread(void * ptr,size_t size,size_t count,FILE * iop)477c478bd9Sstevel@tonic-gate fread(void *ptr, size_t size, size_t count, FILE *iop)
487c478bd9Sstevel@tonic-gate {
497c478bd9Sstevel@tonic-gate 	ssize_t s;
507c478bd9Sstevel@tonic-gate 	int c;
517c478bd9Sstevel@tonic-gate 	char *dptr = (char *)ptr;
527c478bd9Sstevel@tonic-gate 	rmutex_t *lk;
537c478bd9Sstevel@tonic-gate 
547c478bd9Sstevel@tonic-gate 	FLOCKFILE(lk, iop);
557c478bd9Sstevel@tonic-gate 
567c478bd9Sstevel@tonic-gate 	_SET_ORIENTATION_BYTE(iop);
577c478bd9Sstevel@tonic-gate 
587c478bd9Sstevel@tonic-gate 	/* is it a readable stream */
597c478bd9Sstevel@tonic-gate 	if (!(iop->_flag & (_IOREAD | _IORW))) {
607c478bd9Sstevel@tonic-gate 		iop->_flag |= _IOERR;
617c478bd9Sstevel@tonic-gate 		errno = EBADF;
627c478bd9Sstevel@tonic-gate 		FUNLOCKFILE(lk);
637c478bd9Sstevel@tonic-gate 		return (0);
647c478bd9Sstevel@tonic-gate 	}
657c478bd9Sstevel@tonic-gate 
667c478bd9Sstevel@tonic-gate 	if (iop->_flag & _IOEOF) {
677c478bd9Sstevel@tonic-gate 		FUNLOCKFILE(lk);
687c478bd9Sstevel@tonic-gate 		return (0);
697c478bd9Sstevel@tonic-gate 	}
707c478bd9Sstevel@tonic-gate 
717c478bd9Sstevel@tonic-gate 	/* These checks are here to avoid the multiply */
727c478bd9Sstevel@tonic-gate 	if (count == 1)
737c478bd9Sstevel@tonic-gate 		s = size;
747c478bd9Sstevel@tonic-gate 	else if (size == 1)
757c478bd9Sstevel@tonic-gate 		s = count;
767c478bd9Sstevel@tonic-gate 	else
777c478bd9Sstevel@tonic-gate 		s = size * count;
787c478bd9Sstevel@tonic-gate 
797c478bd9Sstevel@tonic-gate 	while (s > 0) {
807c478bd9Sstevel@tonic-gate 		if (iop->_cnt < s) {
817c478bd9Sstevel@tonic-gate 			if (iop->_cnt > 0) {
827c478bd9Sstevel@tonic-gate 				(void) memcpy((void*)dptr, iop->_ptr,
837c478bd9Sstevel@tonic-gate 				    iop->_cnt);
847c478bd9Sstevel@tonic-gate 				dptr += iop->_cnt;
857c478bd9Sstevel@tonic-gate 				s -= iop->_cnt;
867c478bd9Sstevel@tonic-gate 			}
877c478bd9Sstevel@tonic-gate 			/*
887c478bd9Sstevel@tonic-gate 			 * filbuf clobbers _cnt & _ptr,
897c478bd9Sstevel@tonic-gate 			 * so don't waste time setting them.
907c478bd9Sstevel@tonic-gate 			 */
917c478bd9Sstevel@tonic-gate 			if ((c = __filbuf(iop)) == EOF)
927c478bd9Sstevel@tonic-gate 				break;
937c478bd9Sstevel@tonic-gate 			*dptr++ = (char)c;
947c478bd9Sstevel@tonic-gate 			s--;
957c478bd9Sstevel@tonic-gate 		}
967c478bd9Sstevel@tonic-gate 		if (iop->_cnt >= s) {
977c478bd9Sstevel@tonic-gate 			char *tmp = (char *)iop->_ptr;
987c478bd9Sstevel@tonic-gate 			switch (s) {
997c478bd9Sstevel@tonic-gate 			case 8:
1007c478bd9Sstevel@tonic-gate 				*dptr++ = *tmp++;
1017c478bd9Sstevel@tonic-gate 				/*FALLTHRU*/
1027c478bd9Sstevel@tonic-gate 			case 7:
1037c478bd9Sstevel@tonic-gate 				*dptr++ = *tmp++;
1047c478bd9Sstevel@tonic-gate 				/*FALLTHRU*/
1057c478bd9Sstevel@tonic-gate 			case 6:
1067c478bd9Sstevel@tonic-gate 				*dptr++ = *tmp++;
1077c478bd9Sstevel@tonic-gate 				/*FALLTHRU*/
1087c478bd9Sstevel@tonic-gate 			case 5:
1097c478bd9Sstevel@tonic-gate 				*dptr++ = *tmp++;
1107c478bd9Sstevel@tonic-gate 				/*FALLTHRU*/
1117c478bd9Sstevel@tonic-gate 			case 4:
1127c478bd9Sstevel@tonic-gate 				*dptr++ = *tmp++;
1137c478bd9Sstevel@tonic-gate 				/*FALLTHRU*/
1147c478bd9Sstevel@tonic-gate 			case 3:
1157c478bd9Sstevel@tonic-gate 				*dptr++ = *tmp++;
1167c478bd9Sstevel@tonic-gate 				/*FALLTHRU*/
1177c478bd9Sstevel@tonic-gate 			case 2:
1187c478bd9Sstevel@tonic-gate 				*dptr++ = *tmp++;
1197c478bd9Sstevel@tonic-gate 				/*FALLTHRU*/
1207c478bd9Sstevel@tonic-gate 			case 1:
1217c478bd9Sstevel@tonic-gate 				*dptr++ = *tmp++;
1227c478bd9Sstevel@tonic-gate 				break;
1237c478bd9Sstevel@tonic-gate 			default:
1247c478bd9Sstevel@tonic-gate 				(void) memcpy((void*)dptr, iop->_ptr,
1257c478bd9Sstevel@tonic-gate 				    (size_t)s);
1267c478bd9Sstevel@tonic-gate 			}
1277c478bd9Sstevel@tonic-gate 			iop->_ptr += s;
1287c478bd9Sstevel@tonic-gate 			iop->_cnt -= s;
1297c478bd9Sstevel@tonic-gate 			FUNLOCKFILE(lk);
1307c478bd9Sstevel@tonic-gate 			return (count);
1317c478bd9Sstevel@tonic-gate 		}
1327c478bd9Sstevel@tonic-gate 	}
1337c478bd9Sstevel@tonic-gate 	FUNLOCKFILE(lk);
1347c478bd9Sstevel@tonic-gate 	return (size != 0 ? count - ((s + size - 1) / size) : 0);
1357c478bd9Sstevel@tonic-gate }
136