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 * @(#)fread.c 8.2 (Berkeley) 12/11/93 33 * $FreeBSD: src/lib/libc/stdio/fread.c,v 1.15 2008/12/01 14:33:34 ru Exp $ 34 * $DragonFly: src/lib/libc/stdio/fread.c,v 1.8 2005/12/20 00:21:53 davidxu Exp $ 35 */ 36 37 #include "namespace.h" 38 #include <stdio.h> 39 #include <string.h> 40 #include "un-namespace.h" 41 #include "local.h" 42 #include "libc_private.h" 43 #include "priv_stdio.h" 44 45 /* 46 * MT-safe version 47 */ 48 49 size_t 50 fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp) 51 { 52 size_t ret; 53 54 FLOCKFILE(fp); 55 ret = __fread(buf, size, count, fp); 56 FUNLOCKFILE(fp); 57 return (ret); 58 } 59 60 size_t 61 __fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp) 62 { 63 size_t resid; 64 char *p; 65 int r; 66 size_t total; 67 68 /* 69 * The ANSI standard requires a return value of 0 for a count 70 * or a size of 0. Peculiarily, it imposes no such requirements 71 * on fwrite; it only requires fread to be broken. 72 */ 73 if ((resid = count * size) == 0) 74 return (0); 75 ORIENT(fp, -1); 76 if (fp->pub._r < 0) 77 fp->pub._r = 0; 78 total = resid; 79 p = buf; 80 while (resid > (r = fp->pub._r)) { 81 memcpy((void *)p, (void *)fp->pub._p, (size_t)r); 82 fp->pub._p += r; 83 /* fp->pub._r = 0 ... done in __srefill */ 84 p += r; 85 resid -= r; 86 if (__srefill(fp)) { 87 /* no more input: return partial result */ 88 return ((total - resid) / size); 89 } 90 } 91 memcpy((void *)p, (void *)fp->pub._p, resid); 92 fp->pub._r -= resid; 93 fp->pub._p += resid; 94 return (count); 95 } 96