[444] | 1 | /* |
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| 2 | * Copyright (c) 1990 The Regents of the University of California. |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms are permitted |
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| 6 | * provided that the above copyright notice and this paragraph are |
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| 7 | * duplicated in all such forms and that any documentation, |
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| 8 | * advertising materials, and other materials related to such |
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| 9 | * distribution and use acknowledge that the software was developed |
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| 10 | * by the University of California, Berkeley. The name of the |
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| 11 | * University may not be used to endorse or promote products derived |
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| 12 | * from this software without specific prior written permission. |
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| 13 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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| 14 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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| 15 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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| 16 | */ |
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| 17 | |
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| 18 | /* |
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| 19 | FUNCTION |
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| 20 | <<ftello64>>---return position in a stream or file |
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| 21 | |
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| 22 | INDEX |
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| 23 | ftello64 |
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| 24 | INDEX |
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| 25 | _ftello64_r |
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| 26 | |
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| 27 | SYNOPSIS |
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| 28 | #include <stdio.h> |
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| 29 | _off64_t ftello64(FILE *<[fp]>); |
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| 30 | _off64_t _ftello64_r(struct _reent *<[ptr]>, FILE *<[fp]>); |
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| 31 | |
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| 32 | DESCRIPTION |
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| 33 | Objects of type <<FILE>> can have a ``position'' that records how much |
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| 34 | of the file your program has already read. Many of the <<stdio>> functions |
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| 35 | depend on this position, and many change it as a side effect. |
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| 36 | |
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| 37 | The result of <<ftello64>> is the current position for a large file |
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| 38 | identified by <[fp]>. If you record this result, you can later |
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| 39 | use it with <<fseeko64>> to return the file to this |
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| 40 | position. The difference between <<ftello>> and <<ftello64>> is that |
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| 41 | <<ftello>> returns <<off_t>> and <<ftello64>> is designed to work |
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| 42 | for large files (>2GB) and returns <<_off64_t>>. |
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| 43 | |
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| 44 | In the current implementation, <<ftello64>> simply uses a character |
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| 45 | count to represent the file position; this is the same number that |
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| 46 | would be recorded by <<fgetpos64>>. |
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| 47 | |
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| 48 | The function exists only if the __LARGE64_FILES flag is defined. |
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| 49 | An error occurs if the <[fp]> was not opened via <<fopen64>>. |
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| 50 | |
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| 51 | RETURNS |
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| 52 | <<ftello64>> returns the file position, if possible. If it cannot do |
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| 53 | this, it returns <<-1>>. Failure occurs on streams that do not support |
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| 54 | positioning or not opened via <<fopen64>>; the global <<errno>> indicates |
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| 55 | this condition with the value <<ESPIPE>>. |
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| 56 | |
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| 57 | PORTABILITY |
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| 58 | <<ftello64>> is a glibc extension. |
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| 59 | |
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| 60 | No supporting OS subroutines are required. |
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| 61 | */ |
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| 62 | |
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| 63 | #if defined(LIBC_SCCS) && !defined(lint) |
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| 64 | static char sccsid[] = "%W% (Berkeley) %G%"; |
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| 65 | #endif /* LIBC_SCCS and not lint */ |
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| 66 | |
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| 67 | /* |
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| 68 | * ftello64: return current offset. |
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| 69 | */ |
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| 70 | |
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| 71 | #include <stdio.h> |
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| 72 | #include <errno.h> |
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| 73 | |
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| 74 | #include "local.h" |
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| 75 | |
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| 76 | #ifdef __LARGE64_FILES |
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| 77 | |
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| 78 | _off64_t |
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| 79 | _ftello64_r (struct _reent *ptr, |
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| 80 | register FILE * fp) |
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| 81 | { |
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| 82 | _fpos64_t pos; |
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| 83 | |
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| 84 | /* Only do 64-bit tell on large file. */ |
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| 85 | if (!(fp->_flags & __SL64)) |
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| 86 | return (_off64_t) _ftello_r (ptr, fp); |
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| 87 | |
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| 88 | /* Ensure stdio is set up. */ |
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| 89 | |
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| 90 | CHECK_INIT (ptr, fp); |
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| 91 | |
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| 92 | _newlib_flockfile_start(fp); |
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| 93 | |
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| 94 | if (fp->_seek64 == NULL) |
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| 95 | { |
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| 96 | ptr->_errno = ESPIPE; |
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| 97 | _newlib_flockfile_exit(fp); |
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| 98 | return (_off64_t) -1; |
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| 99 | } |
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| 100 | |
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| 101 | /* Find offset of underlying I/O object, then adjust for buffered bytes. */ |
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| 102 | if (!(fp->_flags & __SRD) && (fp->_flags & __SWR) && |
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| 103 | fp->_p != NULL && fp->_p - fp->_bf._base > 0 && |
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| 104 | (fp->_flags & __SAPP)) |
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| 105 | { |
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| 106 | pos = fp->_seek64 (ptr, fp->_cookie, (_fpos64_t) 0, SEEK_END); |
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| 107 | if (pos == (_fpos64_t) -1) |
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| 108 | { |
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| 109 | _newlib_flockfile_exit (fp); |
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| 110 | return (_off64_t) -1; |
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| 111 | } |
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| 112 | } |
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| 113 | else if (fp->_flags & __SOFF) |
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| 114 | pos = fp->_offset; |
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| 115 | else |
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| 116 | { |
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| 117 | pos = fp->_seek64 (ptr, fp->_cookie, (_fpos64_t) 0, SEEK_CUR); |
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| 118 | if (pos == (_fpos64_t) -1) |
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| 119 | { |
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| 120 | _newlib_flockfile_exit(fp); |
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| 121 | return (_off64_t) pos; |
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| 122 | } |
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| 123 | } |
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| 124 | if (fp->_flags & __SRD) |
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| 125 | { |
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| 126 | /* |
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| 127 | * Reading. Any unread characters (including |
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| 128 | * those from ungetc) cause the position to be |
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| 129 | * smaller than that in the underlying object. |
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| 130 | */ |
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| 131 | pos -= fp->_r; |
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| 132 | if (HASUB (fp)) |
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| 133 | pos -= fp->_ur; |
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| 134 | } |
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| 135 | else if (fp->_flags & __SWR && fp->_p != NULL) |
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| 136 | { |
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| 137 | /* |
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| 138 | * Writing. Any buffered characters cause the |
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| 139 | * position to be greater than that in the |
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| 140 | * underlying object. |
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| 141 | */ |
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| 142 | pos += fp->_p - fp->_bf._base; |
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| 143 | } |
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| 144 | |
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| 145 | _newlib_flockfile_end(fp); |
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| 146 | return (_off64_t) pos; |
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| 147 | } |
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| 148 | |
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| 149 | #ifndef _REENT_ONLY |
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| 150 | |
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| 151 | _off64_t |
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| 152 | ftello64 (register FILE * fp) |
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| 153 | { |
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| 154 | return _ftello64_r (_REENT, fp); |
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| 155 | } |
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| 156 | |
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| 157 | #endif /* !_REENT_ONLY */ |
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| 158 | |
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| 159 | #endif /* __LARGE64_FILES */ |
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