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