| 1 | /* An fseeko() function that, together with fflush(), is POSIX compliant.
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| 2 | Copyright (C) 2007-2022 Free Software Foundation, Inc.
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| 3 |
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| 4 | This file is free software: you can redistribute it and/or modify
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| 5 | it under the terms of the GNU Lesser General Public License as
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| 6 | published by the Free Software Foundation; either version 2.1 of the
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| 7 | License, or (at your option) any later version.
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| 8 |
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| 9 | This file is distributed in the hope that it will be useful,
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 12 | GNU Lesser General Public License for more details.
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| 13 |
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| 14 | You should have received a copy of the GNU Lesser General Public License
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| 15 | along with this program. If not, see <https://www.gnu.org/licenses/>. */
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| 16 |
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| 17 | #include <config.h>
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| 18 |
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| 19 | /* Specification. */
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| 20 | #include <stdio.h>
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| 21 |
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| 22 | /* Get off_t, lseek, _POSIX_VERSION. */
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| 23 | #include <unistd.h>
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| 24 |
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| 25 | #include "stdio-impl.h"
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| 26 |
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| 27 | int
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| 28 | fseeko (FILE *fp, off_t offset, int whence)
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| 29 | #undef fseeko
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| 30 | #if !HAVE_FSEEKO
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| 31 | # undef fseek
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| 32 | # define fseeko fseek
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| 33 | #endif
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| 34 | #if _GL_WINDOWS_64_BIT_OFF_T
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| 35 | # undef fseeko
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| 36 | # if HAVE__FSEEKI64 && HAVE_DECL__FSEEKI64 /* msvc, mingw since msvcrt8.0, mingw64 */
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| 37 | # define fseeko _fseeki64
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| 38 | # else /* mingw before msvcrt8.0 */
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| 39 | # define fseeko fseeko64
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| 40 | # endif
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| 41 | #endif
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| 42 | {
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| 43 | #if LSEEK_PIPE_BROKEN
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| 44 | /* mingw gives bogus answers rather than failure on non-seekable files. */
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| 45 | if (lseek (fileno (fp), 0, SEEK_CUR) == -1)
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| 46 | return EOF;
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| 47 | #endif
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| 48 |
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| 49 | /* These tests are based on fpurge.c. */
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| 50 | #if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
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| 51 | /* GNU libc, BeOS, Haiku, Linux libc5 */
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| 52 | if (fp->_IO_read_end == fp->_IO_read_ptr
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| 53 | && fp->_IO_write_ptr == fp->_IO_write_base
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| 54 | && fp->_IO_save_base == NULL)
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| 55 | #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
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| 56 | /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
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| 57 | # if defined __SL64 && defined __SCLE /* Cygwin */
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| 58 | if ((fp->_flags & __SL64) == 0)
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| 59 | {
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| 60 | /* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit
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| 61 | mode; but has an fseeko that requires 64-bit mode. */
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| 62 | FILE *tmp = fopen ("/dev/null", "r");
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| 63 | if (!tmp)
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| 64 | return -1;
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| 65 | fp->_flags |= __SL64;
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| 66 | fp->_seek64 = tmp->_seek64;
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| 67 | fclose (tmp);
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| 68 | }
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| 69 | # endif
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| 70 | if (fp_->_p == fp_->_bf._base
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| 71 | && fp_->_r == 0
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| 72 | && fp_->_w == ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
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| 73 | ? fp_->_bf._size
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| 74 | : 0)
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| 75 | && fp_ub._base == NULL)
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| 76 | #elif defined __EMX__ /* emx+gcc */
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| 77 | if (fp->_ptr == fp->_buffer
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| 78 | && fp->_rcount == 0
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| 79 | && fp->_wcount == 0
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| 80 | && fp->_ungetc_count == 0)
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| 81 | #elif defined __minix /* Minix */
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| 82 | if (fp_->_ptr == fp_->_buf
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| 83 | && (fp_->_ptr == NULL || fp_->_count == 0))
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| 84 | #elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
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| 85 | if (fp_->_ptr == fp_->_base
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| 86 | && (fp_->_ptr == NULL || fp_->_cnt == 0))
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| 87 | #elif defined __UCLIBC__ /* uClibc */
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| 88 | if (((fp->__modeflags & __FLAG_WRITING) == 0
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| 89 | || fp->__bufpos == fp->__bufstart)
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| 90 | && ((fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) == 0
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| 91 | || fp->__bufpos == fp->__bufread))
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| 92 | #elif defined __QNX__ /* QNX */
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| 93 | if ((fp->_Mode & 0x2000 /* _MWRITE */ ? fp->_Next == fp->_Buf : fp->_Next == fp->_Rend)
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| 94 | && fp->_Rback == fp->_Back + sizeof (fp->_Back)
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| 95 | && fp->_Rsave == NULL)
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| 96 | #elif defined __MINT__ /* Atari FreeMiNT */
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| 97 | if (fp->__bufp == fp->__buffer
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| 98 | && fp->__get_limit == fp->__bufp
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| 99 | && fp->__put_limit == fp->__bufp
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| 100 | && !fp->__pushed_back)
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| 101 | #elif defined EPLAN9 /* Plan9 */
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| 102 | if (fp->rp == fp->buf
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| 103 | && fp->wp == fp->buf)
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| 104 | #elif FUNC_FFLUSH_STDIN < 0 && 200809 <= _POSIX_VERSION
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| 105 | /* Cross-compiling to some other system advertising conformance to
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| 106 | POSIX.1-2008 or later. Assume fseeko and fflush work as advertised.
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| 107 | If this assumption is incorrect, please report the bug to
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| 108 | bug-gnulib. */
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| 109 | if (0)
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| 110 | #else
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| 111 | #error "Please port gnulib fseeko.c to your platform! Look at the code in fseeko.c, then report this to bug-gnulib."
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| 112 | #endif
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| 113 | {
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| 114 | /* We get here when an fflush() call immediately preceded this one (or
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| 115 | if ftell() has created buffers but no I/O has occurred on a
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| 116 | newly-opened stream). We know there are no buffers. */
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| 117 | off_t pos = lseek (fileno (fp), offset, whence);
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| 118 | if (pos == -1)
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| 119 | {
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| 120 | #if defined __sferror || defined __DragonFly__ || defined __ANDROID__
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| 121 | /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
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| 122 | fp_->_flags &= ~__SOFF;
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| 123 | #endif
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| 124 | return -1;
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| 125 | }
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| 126 |
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| 127 | #if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
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| 128 | /* GNU libc, BeOS, Haiku, Linux libc5 */
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| 129 | fp->_flags &= ~_IO_EOF_SEEN;
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| 130 | fp->_offset = pos;
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| 131 | #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
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| 132 | /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
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| 133 | # if defined __CYGWIN__ || (defined __NetBSD__ && __NetBSD_Version__ >= 600000000) || defined __minix
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| 134 | /* fp_->_offset is typed as an integer. */
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| 135 | fp_->_offset = pos;
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| 136 | # else
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| 137 | /* fp_->_offset is an fpos_t. */
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| 138 | {
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| 139 | /* Use a union, since on NetBSD, the compilation flags
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| 140 | determine whether fpos_t is typedef'd to off_t or a struct
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| 141 | containing a single off_t member. */
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| 142 | union
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| 143 | {
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| 144 | fpos_t f;
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| 145 | off_t o;
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| 146 | } u;
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| 147 | u.o = pos;
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| 148 | fp_->_offset = u.f;
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| 149 | }
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| 150 | # endif
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| 151 | fp_->_flags |= __SOFF;
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| 152 | fp_->_flags &= ~__SEOF;
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| 153 | #elif defined __EMX__ /* emx+gcc */
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| 154 | fp->_flags &= ~_IOEOF;
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| 155 | #elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
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| 156 | fp_->_flag &= ~_IOEOF;
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| 157 | #elif defined __MINT__ /* Atari FreeMiNT */
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| 158 | fp->__offset = pos;
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| 159 | fp->__eof = 0;
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| 160 | #endif
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| 161 | return 0;
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| 162 | }
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| 163 | return fseeko (fp, offset, whence);
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| 164 | }
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