1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * 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 /*static char *sccsid = "from: @(#)refill.c 5.3 (Berkeley) 2/24/91";*/ 39 static char *rcsid = "$Id: refill.c,v 1.3 1993/08/26 00:47:16 jtc Exp $"; 40 #endif /* LIBC_SCCS and not lint */ 41 42 #include <errno.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include "local.h" 46 47 static 48 lflush(fp) 49 FILE *fp; 50 { 51 52 if ((fp->_flags & (__SLBF|__SWR)) == __SLBF|__SWR) 53 return (__sflush(fp)); 54 return (0); 55 } 56 57 /* 58 * Refill a stdio buffer. 59 * Return EOF on eof or error, 0 otherwise. 60 */ 61 __srefill(fp) 62 register FILE *fp; 63 { 64 65 /* make sure stdio is set up */ 66 if (!__sdidinit) 67 __sinit(); 68 69 fp->_r = 0; /* largely a convenience for callers */ 70 71 /* SysV does not make this test; take it out for compatibility */ 72 if (fp->_flags & __SEOF) 73 return (EOF); 74 75 /* if not already reading, have to be reading and writing */ 76 if ((fp->_flags & __SRD) == 0) { 77 if ((fp->_flags & __SRW) == 0) { 78 errno = EBADF; 79 return (EOF); 80 } 81 /* switch to reading */ 82 if (fp->_flags & __SWR) { 83 if (__sflush(fp)) 84 return (EOF); 85 fp->_flags &= ~__SWR; 86 fp->_w = 0; 87 fp->_lbfsize = 0; 88 } 89 fp->_flags |= __SRD; 90 } else { 91 /* 92 * We were reading. If there is an ungetc buffer, 93 * we must have been reading from that. Drop it, 94 * restoring the previous buffer (if any). If there 95 * is anything in that buffer, return. 96 */ 97 if (HASUB(fp)) { 98 FREEUB(fp); 99 if ((fp->_r = fp->_ur) != 0) { 100 fp->_p = fp->_up; 101 return (0); 102 } 103 } 104 } 105 106 if (fp->_bf._base == NULL) 107 __smakebuf(fp); 108 109 /* 110 * Before reading from a line buffered or unbuffered file, 111 * flush all line buffered output files, per the ANSI C 112 * standard. 113 */ 114 if (fp->_flags & (__SLBF|__SNBF)) 115 (void) _fwalk(lflush); 116 fp->_p = fp->_bf._base; 117 fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); 118 fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ 119 if (fp->_r <= 0) { 120 if (fp->_r == 0) 121 fp->_flags |= __SEOF; 122 else { 123 fp->_r = 0; 124 fp->_flags |= __SERR; 125 } 126 return (EOF); 127 } 128 return (0); 129 } 130