227 lines
8 KiB
C
227 lines
8 KiB
C
/***
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*_filbuf.c - fill buffer and get character
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*
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* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* defines _filbuf() - fill buffer and read first character, allocate
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* buffer if there is none. Used from getc().
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* defines _filwbuf() - fill buffer and read first wide character, allocate
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* buffer if there is none. Used from getwc().
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*
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*Revision History:
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* 09-01-83 RN initial version
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* 06-26-85 TC added code to handle variable length buffers
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* 04-16-87 JCR added _IOUNGETC support
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* 08-04-87 JCR added _getbuff routine
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* 09-28-87 JCR Corrected _iob2 indexing (now uses _iob_index() macro).
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* 11-06-87 JCR Multi-thread support; also, split _getbuf() off
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* 12-11-87 JCR Added "_LOAD_DS" to declaration
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* 01-11-88 JCR Merged mthread version into normal code
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* 01-13-88 SKS Changed bogus "_fileno_lk" to "fileno"
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* 03-04-88 JCR Read() return value must be considered unsigned, not
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* signed
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* 06-06-88 JCR Optimized _iob2 references
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* 06-13-88 JCR Use near pointer to reference _iob[] entries
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* 08-25-88 GJF Don't use FP_OFF() macro for the 386
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* 06-20-89 PHG Re-activate C version, propogated fixes
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* 08-28-89 JCR Removed _NEAR_ for 386
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* 02-15-90 GJF _iob[], _iob2[] merge. Also, fixed copyright and
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* alignment.
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* 03-16-90 GJF Replaced cdecl _LOAD_DS with _CALLTYPE1, added #include
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* <cruntime.h> and removed #include <register.h>. Also,
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* removed some leftover 16-bit support.
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* 03-27-90 GJF Added #include <io.h>.
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* 07-23-90 SBM Replaced <assertm.h> by <assert.h>
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* 10-03-90 GJF New-style function declarator.
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* 01-22-91 GJF ANSI naming.
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* 03-27-92 DJM POSIX support.
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* 08-26-92 GJF Include unistd.h for POSIX build.
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* 04-06-93 SKS Replace _CRTAPI* with __cdecl
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* 04-26-93 CFW Wide char enable.
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* 05-06-93 CFW Optimize wide char conversion.
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* 05-24-93 GJF Detect small buffer size (_SMALL_BUFSIZ) resulting
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* from fseek call on read-access-only stream and
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* restore the larger size (_INTERNAL_BUFSIZ) for the
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* next _filbuf call.
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* 06-22-93 GJF Check _IOSETVBUF (new) before changing buffer size.
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* 11-05-93 GJF Merged with NT SDK version (picked up _NTSUBSET_
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* stuff).
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* 10-17-94 BWT Move wchar.h to non-POSIX build (ino_t definitions conflict)
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* 02-06-94 CFW assert -> _ASSERTE.
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* 02-16-95 GJF Appended Mac version of source file (somewhat cleaned
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* up), with appropriate #ifdef-s.
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* 06-12-95 GJF Replaced _osfile[] with _osfile() (macro referencing
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* field in ioinfo struct).
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* 07-27-95 GJF Replaced _osfile() with _osfile_safe().
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* 12-07-95 SKS Fix misspelling of _NTSUBSET_ (final _ was missing)
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* 05-17-99 PML Remove all Macintosh support.
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*
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*******************************************************************************/
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#include <cruntime.h>
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#include <stdio.h>
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#include <file2.h>
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#include <io.h>
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#include <dbgint.h>
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#include <malloc.h>
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#include <internal.h>
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#ifdef _POSIX_
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#include <unistd.h>
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#include <errno.h>
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#else
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#include <msdos.h>
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#include <wchar.h>
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#endif
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#ifdef _MT
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#include <mtdll.h>
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#endif
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#include <tchar.h>
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#ifndef _UNICODE
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/***
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*int _filbuf(stream) - fill buffer and get first character
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*
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*Purpose:
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* get a buffer if the file doesn't have one, read into it, return first
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* char. try to get a buffer, if a user buffer is not assigned. called
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* only from getc; intended for use only within library. assume no input
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* stream is to remain unbuffered when memory is available unless it is
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* marked _IONBF. at worst, give it a single char buffer. the need for a
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* buffer, no matter how small, becomes evident when we consider the
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* ungetc's necessary in scanf
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*
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* [NOTE: Multi-thread - _filbuf() assumes that the caller has aquired
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* the stream lock, if needed.]
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*
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*Entry:
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* FILE *stream - stream to read from
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*
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*Exit:
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* returns first character from buffer (next character to be read)
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* returns EOF if the FILE is actually a string, or not open for reading,
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* or if open for writing or if no more chars to read.
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* all fields in FILE structure may be changed except _file.
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*
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*Exceptions:
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*
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*******************************************************************************/
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int __cdecl _filbuf (
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FILE *str
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)
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#else /* _UNICODE */
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/***
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*int _filwbuf(stream) - fill buffer and get first wide character
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*
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*Purpose:
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* get a buffer if the file doesn't have one, read into it, return first
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* char. try to get a buffer, if a user buffer is not assigned. called
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* only from getc; intended for use only within library. assume no input
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* stream is to remain unbuffered when memory is available unless it is
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* marked _IONBF. at worst, give it a single char buffer. the need for a
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* buffer, no matter how small, becomes evident when we consider the
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* ungetc's necessary in scanf
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*
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* [NOTE: Multi-thread - _filwbuf() assumes that the caller has aquired
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* the stream lock, if needed.]
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*
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*Entry:
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* FILE *stream - stream to read from
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*
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*Exit:
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* returns first wide character from buffer (next character to be read)
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* returns WEOF if the FILE is actually a string, or not open for reading,
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* or if open for writing or if no more chars to read.
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* all fields in FILE structure may be changed except _file.
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*
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*Exceptions:
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*
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*******************************************************************************/
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int __cdecl _filwbuf (
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FILE *str
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)
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#endif /* _UNICODE */
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{
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#ifdef _NTSUBSET_
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return(_TEOF);
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#else /* ndef _NTSUBSET_ */
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REG1 FILE *stream;
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_ASSERTE(str != NULL);
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/* Init pointer to _iob2 entry. */
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stream = str;
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if (!inuse(stream) || stream->_flag & _IOSTRG)
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return(_TEOF);
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if (stream->_flag & _IOWRT) {
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#ifdef _POSIX_
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errno = EBADF;
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#endif
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stream->_flag |= _IOERR;
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return(_TEOF);
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}
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stream->_flag |= _IOREAD;
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/* Get a buffer, if necessary. */
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if (!anybuf(stream))
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_getbuf(stream);
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else
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stream->_ptr = stream->_base;
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#ifdef _POSIX_
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stream->_cnt = read(fileno(stream), stream->_base, stream->_bufsiz);
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#else
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stream->_cnt = _read(_fileno(stream), stream->_base, stream->_bufsiz);
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#endif
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#ifndef _UNICODE
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if ((stream->_cnt == 0) || (stream->_cnt == -1)) {
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#else /* _UNICODE */
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if ((stream->_cnt == 0) || (stream->_cnt == 1) || stream->_cnt == -1) {
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#endif /* _UNICODE */
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stream->_flag |= stream->_cnt ? _IOERR : _IOEOF;
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stream->_cnt = 0;
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return(_TEOF);
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}
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#ifndef _POSIX_
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if ( !(stream->_flag & (_IOWRT|_IORW)) &&
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((_osfile_safe(_fileno(stream)) & (FTEXT|FEOFLAG)) ==
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(FTEXT|FEOFLAG)) )
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stream->_flag |= _IOCTRLZ;
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#endif
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/* Check for small _bufsiz (_SMALL_BUFSIZ). If it is small and
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if it is our buffer, then this must be the first _filbuf after
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an fseek on a read-access-only stream. Restore _bufsiz to its
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larger value (_INTERNAL_BUFSIZ) so that the next _filbuf call,
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if one is made, will fill the whole buffer. */
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if ( (stream->_bufsiz == _SMALL_BUFSIZ) && (stream->_flag &
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_IOMYBUF) && !(stream->_flag & _IOSETVBUF) )
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{
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stream->_bufsiz = _INTERNAL_BUFSIZ;
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}
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#ifndef _UNICODE
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stream->_cnt--;
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return(0xff & *stream->_ptr++);
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#else /* _UNICODE */
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stream->_cnt -= sizeof(wchar_t);
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return (0xffff & *((wchar_t *)(stream->_ptr))++);
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#endif /* _UNICODE */
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#endif /* _NTSUBSET_ */
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}
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