Annotation of prex-old/usr/lib/libc/stdio/refill.c, Revision 1.1.1.1
1.1 nbrk 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. Neither the name of the University nor the names of its contributors
17: * may be used to endorse or promote products derived from this software
18: * without specific prior written permission.
19: *
20: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30: * SUCH DAMAGE.
31: */
32:
33: #include <errno.h>
34: #include <stdio.h>
35: #include <stdlib.h>
36: #include "local.h"
37:
38: static int
39: lflush(FILE *fp)
40: {
41:
42: if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
43: return (__sflush(fp));
44: return (0);
45: }
46:
47: /*
48: * Refill a stdio buffer.
49: * Return EOF on eof or error, 0 otherwise.
50: */
51: int
52: __srefill(fp)
53: FILE *fp;
54: {
55:
56: /* make sure stdio is set up */
57: if (!__sdidinit)
58: __sinit();
59:
60: fp->_r = 0; /* largely a convenience for callers */
61:
62: /* SysV does not make this test; take it out for compatibility */
63: if (fp->_flags & __SEOF)
64: return (EOF);
65:
66: /* if not already reading, have to be reading and writing */
67: if ((fp->_flags & __SRD) == 0) {
68: if ((fp->_flags & __SRW) == 0) {
69: errno = EBADF;
70: return (EOF);
71: }
72: /* switch to reading */
73: if (fp->_flags & __SWR) {
74: if (__sflush(fp))
75: return (EOF);
76: fp->_flags &= ~__SWR;
77: fp->_w = 0;
78: }
79: fp->_flags |= __SRD;
80: } else {
81: /*
82: * We were reading. If there is an ungetc buffer,
83: * we must have been reading from that. Drop it,
84: * restoring the previous buffer (if any). If there
85: * is anything in that buffer, return.
86: */
87: if (HASUB(fp)) {
88: FREEUB(fp);
89: if ((fp->_r = fp->_ur) != 0) {
90: fp->_p = fp->_up;
91: return (0);
92: }
93: }
94: }
95:
96: if (fp->_bf._base == NULL)
97: __smakebuf(fp);
98:
99: /*
100: * Before reading from a line buffered or unbuffered file,
101: * flush all line buffered output files, per the ANSI C
102: * standard.
103: */
104: if (fp->_flags & (__SLBF|__SNBF))
105: (void) _fwalk(lflush);
106: fp->_p = fp->_bf._base;
107: fp->_r = __sread(fp, (char *)fp->_p, fp->_bf._size);
108: if (fp->_r <= 0) {
109: if (fp->_r == 0)
110: fp->_flags |= __SEOF;
111: else {
112: fp->_r = 0;
113: fp->_flags |= __SERR;
114: }
115: return (EOF);
116: }
117: return (0);
118: }
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