scoutos / prex-0.9.0 / usr / lib / libc / stdio / refill.c @ 03e9c04a
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| 1 | 03e9c04a | Brad Neuman | /*-
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| 2 | * Copyright (c) 1990, 1993
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| 3 | * The Regents of the University of California. All rights reserved.
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| 4 | *
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| 5 | * This code is derived from software contributed to Berkeley by
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| 6 | * Chris Torek.
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| 7 | *
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| 8 | * Redistribution and use in source and binary forms, with or without
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| 9 | * modification, are permitted provided that the following conditions
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| 10 | * are met:
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| 11 | * 1. Redistributions of source code must retain the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer.
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| 13 | * 2. Redistributions in binary form must reproduce the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer in the
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| 15 | * documentation and/or other materials provided with the distribution.
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| 16 | * 3. Neither the name of the University nor the names of its contributors
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| 17 | * may be used to endorse or promote products derived from this software
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| 18 | * without specific prior written permission.
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| 19 | *
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| 20 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 30 | * SUCH DAMAGE.
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| 31 | */
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| 32 | |||
| 33 | #include <errno.h> |
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| 34 | #include <stdio.h> |
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| 35 | #include <stdlib.h> |
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| 36 | #include "local.h" |
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| 37 | |||
| 38 | static int |
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| 39 | lflush(FILE *fp) |
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| 40 | {
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| 41 | |||
| 42 | if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
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| 43 | return (__sflush(fp));
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| 44 | return (0); |
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| 45 | } |
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| 46 | |||
| 47 | /*
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| 48 | * Refill a stdio buffer.
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| 49 | * Return EOF on eof or error, 0 otherwise.
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| 50 | */
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| 51 | int
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| 52 | __srefill(fp) |
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| 53 | FILE *fp; |
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| 54 | {
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| 55 | |||
| 56 | /* make sure stdio is set up */
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| 57 | if (!__sdidinit)
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| 58 | __sinit(); |
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| 59 | |||
| 60 | fp->_r = 0; /* largely a convenience for callers */ |
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| 61 | |||
| 62 | /* SysV does not make this test; take it out for compatibility */
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| 63 | if (fp->_flags & __SEOF)
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| 64 | return (EOF); |
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| 65 | |||
| 66 | /* if not already reading, have to be reading and writing */
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| 67 | if ((fp->_flags & __SRD) == 0) { |
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| 68 | if ((fp->_flags & __SRW) == 0) { |
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| 69 | errno = EBADF; |
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| 70 | return (EOF); |
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| 71 | } |
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| 72 | /* switch to reading */
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| 73 | if (fp->_flags & __SWR) {
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| 74 | if (__sflush(fp))
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| 75 | return (EOF); |
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| 76 | fp->_flags &= ~__SWR; |
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| 77 | fp->_w = 0;
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| 78 | } |
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| 79 | fp->_flags |= __SRD; |
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| 80 | } else {
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| 81 | /*
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| 82 | * We were reading. If there is an ungetc buffer,
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| 83 | * we must have been reading from that. Drop it,
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| 84 | * restoring the previous buffer (if any). If there
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| 85 | * is anything in that buffer, return.
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| 86 | */
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| 87 | if (HASUB(fp)) {
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| 88 | FREEUB(fp); |
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| 89 | if ((fp->_r = fp->_ur) != 0) { |
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| 90 | fp->_p = fp->_up; |
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| 91 | return (0); |
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| 92 | } |
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| 93 | } |
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| 94 | } |
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| 95 | |||
| 96 | if (fp->_bf._base == NULL) |
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| 97 | __smakebuf(fp); |
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| 98 | |||
| 99 | /*
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| 100 | * Before reading from a line buffered or unbuffered file,
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| 101 | * flush all line buffered output files, per the ANSI C
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| 102 | * standard.
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| 103 | */
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| 104 | if (fp->_flags & (__SLBF|__SNBF))
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| 105 | (void) _fwalk(lflush);
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| 106 | fp->_p = fp->_bf._base; |
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| 107 | fp->_r = __sread(fp, (char *)fp->_p, fp->_bf._size);
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| 108 | if (fp->_r <= 0) { |
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| 109 | if (fp->_r == 0) |
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| 110 | fp->_flags |= __SEOF; |
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| 111 | else {
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| 112 | fp->_r = 0;
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| 113 | fp->_flags |= __SERR; |
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| 114 | } |
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| 115 | return (EOF); |
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| 116 | } |
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| 117 | return (0); |
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| 118 | } |