projects / unix-history / blame
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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 | * %sccs.include.redist.c% | |
| 9 | */ | |
| 10 | ||
| 11 | #if defined(LIBC_SCCS) && !defined(lint) | |
| cb631443 | 12 | static char sccsid[] = "@(#)refill.c 5.3 (Berkeley) %G%"; |
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13 | #endif /* LIBC_SCCS and not lint */ |
| 14 | ||
| 15 | #include <errno.h> | |
| 16 | #include <stdio.h> | |
| cb631443 | 17 | #include <stdlib.h> |
| c9be6cfe KB |
18 | #include "local.h" |
| 19 | ||
| 20 | static | |
| 21 | lflush(fp) | |
| 22 | FILE *fp; | |
| 23 | { | |
| 24 | ||
| 25 | if ((fp->_flags & (__SLBF|__SWR)) == __SLBF|__SWR) | |
| 5b2b97c1 | 26 | return (__sflush(fp)); |
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27 | return (0); |
| 28 | } | |
| 29 | ||
| 30 | /* | |
| 31 | * Refill a stdio buffer. | |
| 32 | * Return EOF on eof or error, 0 otherwise. | |
| 33 | */ | |
| 34 | __srefill(fp) | |
| 35 | register FILE *fp; | |
| 36 | { | |
| 37 | ||
| 38 | /* make sure stdio is set up */ | |
| 39 | if (!__sdidinit) | |
| 40 | __sinit(); | |
| 41 | ||
| 42 | fp->_r = 0; /* largely a convenience for callers */ | |
| 43 | ||
| 44 | /* SysV does not make this test; take it out for compatibility */ | |
| 45 | if (fp->_flags & __SEOF) | |
| 46 | return (EOF); | |
| 47 | ||
| 48 | /* if not already reading, have to be reading and writing */ | |
| 49 | if ((fp->_flags & __SRD) == 0) { | |
| 50 | if ((fp->_flags & __SRW) == 0) { | |
| 51 | errno = EBADF; | |
| 52 | return (EOF); | |
| 53 | } | |
| 54 | /* switch to reading */ | |
| 55 | if (fp->_flags & __SWR) { | |
| 5b2b97c1 | 56 | if (__sflush(fp)) |
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57 | return (EOF); |
| 58 | fp->_flags &= ~__SWR; | |
| 59 | fp->_w = 0; | |
| 60 | fp->_lbfsize = 0; | |
| 61 | } | |
| 62 | fp->_flags |= __SRD; | |
| 63 | } else { | |
| 64 | /* | |
| 65 | * We were reading. If there is an ungetc buffer, | |
| 66 | * we must have been reading from that. Drop it, | |
| 67 | * restoring the previous buffer (if any). If there | |
| 68 | * is anything in that buffer, return. | |
| 69 | */ | |
| 70 | if (HASUB(fp)) { | |
| 71 | FREEUB(fp); | |
| 72 | if ((fp->_r = fp->_ur) != 0) { | |
| 73 | fp->_p = fp->_up; | |
| 74 | return (0); | |
| 75 | } | |
| 76 | } | |
| 77 | } | |
| 78 | ||
| 79 | if (fp->_bf._base == NULL) | |
| 80 | __smakebuf(fp); | |
| 81 | ||
| 82 | /* | |
| 83 | * Before reading from a line buffered or unbuffered file, | |
| 84 | * flush all line buffered output files, per the ANSI C | |
| 85 | * standard. | |
| 86 | */ | |
| 87 | if (fp->_flags & (__SLBF|__SNBF)) | |
| 88 | (void) _fwalk(lflush); | |
| 89 | fp->_p = fp->_bf._base; | |
| 90 | fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size); | |
| 91 | fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ | |
| 92 | if (fp->_r <= 0) { | |
| 93 | if (fp->_r == 0) | |
| 94 | fp->_flags |= __SEOF; | |
| 95 | else { | |
| 96 | fp->_r = 0; | |
| 97 | fp->_flags |= __SERR; | |
| 98 | } | |
| 99 | return (EOF); | |
| 100 | } | |
| 101 | return (0); | |
| 102 | } |