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 #if 0 39 static char sccsid[] = "@(#)refill.c 8.1 (Berkeley) 6/4/93"; 40 #endif 41 static const char rcsid[] = 42 "$Id$"; 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include <errno.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include "local.h" 49 50 static int lflush __P((FILE *)); 51 52 static int 53 lflush(fp) 54 FILE *fp; 55 { 56 57 if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) 58 return (__sflush(fp)); 59 return (0); 60 } 61 62 /* 63 * Refill a stdio buffer. 64 * Return EOF on eof or error, 0 otherwise. 65 */ 66 int 67 __srefill(fp) 68 register FILE *fp; 69 { 70 71 /* make sure stdio is set up */ 72 if (!__sdidinit) 73 __sinit(); 74 75 fp->_r = 0; /* largely a convenience for callers */ 76 77 /* SysV does not make this test; take it out for compatibility */ 78 if (fp->_flags & __SEOF) 79 return (EOF); 80 81 /* if not already reading, have to be reading and writing */ 82 if ((fp->_flags & __SRD) == 0) { 83 if ((fp->_flags & __SRW) == 0) { 84 errno = EBADF; 85 return (EOF); 86 } 87 /* switch to reading */ 88 if (fp->_flags & __SWR) { 89 if (__sflush(fp)) 90 return (EOF); 91 fp->_flags &= ~__SWR; 92 fp->_w = 0; 93 fp->_lbfsize = 0; 94 } 95 fp->_flags |= __SRD; 96 } else { 97 /* 98 * We were reading. If there is an ungetc buffer, 99 * we must have been reading from that. Drop it, 100 * restoring the previous buffer (if any). If there 101 * is anything in that buffer, return. 102 */ 103 if (HASUB(fp)) { 104 FREEUB(fp); 105 if ((fp->_r = fp->_ur) != 0) { 106 fp->_p = fp->_up; 107 return (0); 108 } 109 } 110 } 111 112 if (fp->_bf._base == NULL) 113 __smakebuf(fp); 114 115 /* 116 * Before reading from a line buffered or unbuffered file, 117 * flush all line buffered output files, per the ANSI C 118 * standard. 119 */ 120 if (fp->_flags & (__SLBF|__SNBF)) 121 (void) _fwalk(lflush); 122 fp->_p = fp->_bf._base; 123 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 124 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 125 if (fp->_r <= 0) { 126 if (fp->_r == 0) 127 fp->_flags |= __SEOF; 128 else { 129 fp->_r = 0; 130 fp->_flags |= __SERR; 131 } 132 return (EOF); 133 } 134 return (0); 135 } 136