1 /* $NetBSD: refill.c,v 1.7 1997/07/13 20:15:22 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)refill.c 8.1 (Berkeley) 6/4/93"; 43 #else 44 __RCSID("$NetBSD: refill.c,v 1.7 1997/07/13 20:15:22 christos Exp $"); 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include <errno.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include "local.h" 52 53 static int lflush __P((FILE *)); 54 55 static int 56 lflush(fp) 57 FILE *fp; 58 { 59 60 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 61 return (__sflush(fp)); 62 return (0); 63 } 64 65 /* 66 * Refill a stdio buffer. 67 * Return EOF on eof or error, 0 otherwise. 68 */ 69 int 70 __srefill(fp) 71 register FILE *fp; 72 { 73 74 /* make sure stdio is set up */ 75 if (!__sdidinit) 76 __sinit(); 77 78 fp->_r = 0; /* largely a convenience for callers */ 79 80 /* SysV does not make this test; take it out for compatibility */ 81 if (fp->_flags & __SEOF) 82 return (EOF); 83 84 /* if not already reading, have to be reading and writing */ 85 if ((fp->_flags & __SRD) == 0) { 86 if ((fp->_flags & __SRW) == 0) { 87 errno = EBADF; 88 return (EOF); 89 } 90 /* switch to reading */ 91 if (fp->_flags & __SWR) { 92 if (__sflush(fp)) 93 return (EOF); 94 fp->_flags &= ~__SWR; 95 fp->_w = 0; 96 fp->_lbfsize = 0; 97 } 98 fp->_flags |= __SRD; 99 } else { 100 /* 101 * We were reading. If there is an ungetc buffer, 102 * we must have been reading from that. Drop it, 103 * restoring the previous buffer (if any). If there 104 * is anything in that buffer, return. 105 */ 106 if (HASUB(fp)) { 107 FREEUB(fp); 108 if ((fp->_r = fp->_ur) != 0) { 109 fp->_p = fp->_up; 110 return (0); 111 } 112 } 113 } 114 115 if (fp->_bf._base == NULL) 116 __smakebuf(fp); 117 118 /* 119 * Before reading from a line buffered or unbuffered file, 120 * flush all line buffered output files, per the ANSI C 121 * standard. 122 */ 123 if (fp->_flags & (__SLBF|__SNBF)) 124 (void) _fwalk(lflush); 125 fp->_p = fp->_bf._base; 126 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 127 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 128 if (fp->_r <= 0) { 129 if (fp->_r == 0) 130 fp->_flags |= __SEOF; 131 else { 132 fp->_r = 0; 133 fp->_flags |= __SERR; 134 } 135 return (EOF); 136 } 137 return (0); 138 } 139