1 /* $OpenBSD: fread.c,v 1.11 2009/11/21 09:53:44 guenther Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <stdio.h> 35 #include <string.h> 36 #include "local.h" 37 38 size_t 39 fread(void *buf, size_t size, size_t count, FILE *fp) 40 { 41 size_t resid; 42 char *p; 43 int r; 44 size_t total; 45 46 /* 47 * ANSI and SUSv2 require a return value of 0 if size or count are 0. 48 */ 49 if ((resid = count * size) == 0) 50 return (0); 51 FLOCKFILE(fp); 52 _SET_ORIENTATION(fp, -1); 53 if (fp->_r < 0) 54 fp->_r = 0; 55 total = resid; 56 p = buf; 57 while (resid > (r = fp->_r)) { 58 (void)memcpy((void *)p, (void *)fp->_p, (size_t)r); 59 fp->_p += r; 60 /* fp->_r = 0 ... done in __srefill */ 61 p += r; 62 resid -= r; 63 if (__srefill(fp)) { 64 /* no more input: return partial result */ 65 FUNLOCKFILE(fp); 66 return ((total - resid) / size); 67 } 68 } 69 (void)memcpy((void *)p, (void *)fp->_p, resid); 70 fp->_r -= resid; 71 fp->_p += resid; 72 FUNLOCKFILE(fp); 73 return (count); 74 } 75