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