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