188 lines
4.4 KiB
C
188 lines
4.4 KiB
C
/***
|
|
*lseek.c - OS/2 change file position
|
|
*
|
|
* Copyright (c) 1989-1992, Microsoft Corporation. All rights reserved.
|
|
*
|
|
*Purpose:
|
|
* defines _lseek() - move the file pointer
|
|
*
|
|
*Revision History:
|
|
* 06-20-89 PHG Module created, based on asm version
|
|
* 03-12-90 GJF Made calling type _CALLTYPE2 (for now), added #include
|
|
* <cruntime.h> and fixed the copyright. Also, cleaned up
|
|
* the formatting a bit.
|
|
* 04-03-90 GJF Now _CALLTYPE1.
|
|
* 07-24-90 SBM Removed '32' from API names
|
|
* 08-14-90 SBM Compiles cleanly with -W3
|
|
* 09-28-90 GJF New-style function declarators.
|
|
* 12-04-90 GJF Appended Win32 version with #ifdef-s. It's probably
|
|
* worth coming back and doing a more complete merge later
|
|
* (much later).
|
|
* 12-04-90 SRW Changed to include <oscalls.h> instead of <doscalls.h>
|
|
* 12-06-90 SRW Changed to use _osfile and _osfhnd instead of _osfinfo
|
|
* 01-16-91 GJF ANSI naming.
|
|
* 02-07-91 SRW Changed to call _get_osfhandle [_WIN32_]
|
|
* 04-09-91 PNT Added _MAC_ conditional
|
|
* 02-13-92 GJF Replaced _nfile by _nhandle for Win32.
|
|
*
|
|
*******************************************************************************/
|
|
|
|
#include <cruntime.h>
|
|
#include <oscalls.h>
|
|
#include <os2dll.h>
|
|
#include <io.h>
|
|
#include <internal.h>
|
|
#include <stdlib.h>
|
|
#include <errno.h>
|
|
#include <msdos.h>
|
|
#include <stdio.h>
|
|
|
|
/***
|
|
*long _lseek(fh,pos,mthd) - move the file pointer
|
|
*
|
|
*Purpose:
|
|
* Moves the file pointer associated with fh to a new position.
|
|
* The new position is pos bytes (pos may be negative) away
|
|
* from the origin specified by mthd.
|
|
*
|
|
* If mthd == SEEK_SET, the origin in the beginning of file
|
|
* If mthd == SEEK_CUR, the origin is the current file pointer position
|
|
* If mthd == SEEK_END, the origin is the end of the file
|
|
*
|
|
* Multi-thread:
|
|
* _lseek() = locks/unlocks the file
|
|
* _lseek_lk() = does NOT lock/unlock the file (it is assumed that
|
|
* the caller has the aquired the file lock,if needed).
|
|
*
|
|
*Entry:
|
|
* int fh - file handle to move file pointer on
|
|
* long pos - position to move to, relative to origin
|
|
* int mthd - specifies the origin pos is relative to (see above)
|
|
*
|
|
*Exit:
|
|
* returns the offset, in bytes, of the new position from the beginning
|
|
* of the file.
|
|
* returns -1L (and sets errno) if fails.
|
|
* Note that seeking beyond the end of the file is not an error.
|
|
* (although seeking before the beginning is.)
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
|
|
#ifdef MTHREAD
|
|
|
|
/* define locking/validating lseek */
|
|
long _CALLTYPE1 _lseek (
|
|
int fh,
|
|
long pos,
|
|
int mthd
|
|
)
|
|
{
|
|
int r;
|
|
|
|
/* validate fh */
|
|
#ifdef _WIN32_
|
|
if ( (unsigned)fh >= (unsigned)_nhandle ) {
|
|
#else
|
|
if ((unsigned)fh >= (unsigned)_nfile) {
|
|
#endif
|
|
/* bad file handle */
|
|
errno = EBADF;
|
|
_doserrno = 0; /* not OS/2 error */
|
|
return -1;
|
|
}
|
|
|
|
_lock_fh(fh); /* lock file handle */
|
|
r = _lseek_lk(fh, pos, mthd); /* seek */
|
|
_unlock_fh(fh); /* unlock file handle */
|
|
|
|
return r;
|
|
}
|
|
|
|
/* define core _lseek -- doesn't lock or validate fh */
|
|
long _CALLTYPE1 _lseek_lk (
|
|
int fh,
|
|
long pos,
|
|
int mthd
|
|
)
|
|
{
|
|
ULONG newpos; /* new file position */
|
|
ULONG dosretval; /* OS/2 return value */
|
|
|
|
#else
|
|
|
|
/* define normal _lseek */
|
|
long _CALLTYPE1 _lseek (
|
|
int fh,
|
|
long pos,
|
|
int mthd
|
|
)
|
|
{
|
|
ULONG newpos; /* new file position */
|
|
ULONG dosretval; /* OS/2 return value */
|
|
|
|
/* validate fh */
|
|
#ifdef _WIN32_
|
|
if ( (unsigned)fh >= (unsigned)_nhandle ) {
|
|
#else
|
|
if ((unsigned)fh >= (unsigned)_nfile) {
|
|
#endif
|
|
/* bad file handle */
|
|
errno = EBADF;
|
|
_doserrno = 0; /* not OS/2 error */
|
|
return -1;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* tell OS/2 to seek */
|
|
|
|
#ifdef _CRUISER_
|
|
|
|
#if SEEK_SET != FILE_BEGIN || SEEK_CUR != FILE_CURRENT || SEEK_END != FILE_END
|
|
#error Xenix and OS/2 seek constants not compatible
|
|
#endif
|
|
|
|
dosretval = DOSSETFILEPTR(fh, pos, mthd, &newpos);
|
|
|
|
#else /* ndef _CRUISER_ */
|
|
|
|
#ifdef _WIN32_
|
|
|
|
#if SEEK_SET != FILE_BEGIN || SEEK_CUR != FILE_CURRENT || SEEK_END != FILE_END
|
|
#error Xenix and Win32 seek constants not compatible
|
|
#endif
|
|
|
|
if ((newpos = SetFilePointer((HANDLE)_get_osfhandle(fh),
|
|
pos, NULL, mthd)) == -1)
|
|
dosretval = GetLastError();
|
|
else
|
|
dosretval = 0;
|
|
|
|
#else /* ndef _WIN32_ */
|
|
|
|
#ifdef _MAC_
|
|
|
|
TBD();
|
|
|
|
#else /* ndef _MAC_ */
|
|
|
|
#error ERROR - ONLY CRUISER, WIN32, OR MAC TARGET SUPPORTED!
|
|
|
|
#endif /* _MAC_ */
|
|
|
|
#endif /* _WIN32_ */
|
|
|
|
#endif /* _CRUISER_ */
|
|
|
|
if (dosretval) {
|
|
/* OS/2 error */
|
|
_dosmaperr(dosretval);
|
|
return -1;
|
|
}
|
|
|
|
_osfile[fh] &= ~FEOFLAG; /* clear the ctrl-z flag on the file */
|
|
return newpos; /* return */
|
|
}
|