1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)fread.c 8.2 (Berkeley) 12/11/93"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include "namespace.h" 44 #include <stdio.h> 45 #include <string.h> 46 #include "un-namespace.h" 47 #include "local.h" 48 #include "libc_private.h" 49 50 /* 51 * MT-safe version 52 */ 53 54 size_t 55 fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp) 56 { 57 int ret; 58 59 FLOCKFILE(fp); 60 ret = __fread(buf, size, count, fp); 61 FUNLOCKFILE(fp); 62 return (ret); 63 } 64 65 size_t 66 __fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp) 67 { 68 size_t resid; 69 char *p; 70 int r; 71 size_t total; 72 73 /* 74 * The ANSI standard requires a return value of 0 for a count 75 * or a size of 0. Peculiarily, it imposes no such requirements 76 * on fwrite; it only requires fread to be broken. 77 */ 78 if ((resid = count * size) == 0) 79 return (0); 80 ORIENT(fp, -1); 81 if (fp->_r < 0) 82 fp->_r = 0; 83 total = resid; 84 p = buf; 85 while (resid > (r = fp->_r)) { 86 (void)memcpy((void *)p, (void *)fp->_p, (size_t)r); 87 fp->_p += r; 88 /* fp->_r = 0 ... done in __srefill */ 89 p += r; 90 resid -= r; 91 if (__srefill(fp)) { 92 /* no more input: return partial result */ 93 return ((total - resid) / size); 94 } 95 } 96 (void)memcpy((void *)p, (void *)fp->_p, resid); 97 fp->_r -= resid; 98 fp->_p += resid; 99 return (count); 100 } 101