1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 1986 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1984 AT&T */ 28 /* All Rights Reserved */ 29 30 #pragma ident "%Z%%M% %I% %E% SMI" 31 32 /*LINTLIBRARY*/ 33 /* 34 * This version reads directly from the buffer rather than looping on getc. 35 * Ptr args aren't checked for NULL because the program would be a 36 * catastrophic mess anyway. Better to abort than just to return NULL. 37 */ 38 #include <stdio.h> 39 #include "stdiom.h" 40 #include <memory.h> 41 42 #define MIN(x, y) (x < y ? x : y) 43 44 extern int _filbuf(); 45 46 int 47 fread(char *ptr, int size, int count, FILE *iop) 48 { 49 unsigned int nleft; 50 int n; 51 52 if (size <= 0 || count <= 0) return 0; 53 nleft = count * size; 54 55 /* Put characters in the buffer */ 56 /* note that the meaning of n when just starting this loop is 57 irrelevant. It is defined in the loop */ 58 for ( ; ; ) { 59 if (iop->_cnt <= 0) { /* empty buffer */ 60 if (_filbuf(iop) == EOF) 61 return (count - (nleft + size - 1)/size); 62 iop->_ptr--; 63 iop->_cnt++; 64 } 65 n = MIN(nleft, iop->_cnt); 66 ptr = memcpy(ptr, (char *) iop->_ptr, n) + n; 67 iop->_cnt -= n; 68 iop->_ptr += n; 69 _BUFSYNC(iop); 70 if ((nleft -= n) == 0) 71 return (count); 72 } 73 } 74