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/***
*chsize.c - OS/2 change size of a file
*
* Copyright (c) 1985-1992, Microsoft Corporation. All rights reserved.
*
*Purpose:
* contains the _chsize() function - changes the size of a file.
*
*Revision History:
* 03-13-84 RN initial version
* 05-17-86 SKS ported to OS/2
* 07-07-87 JCR Added (_doserrno == 5) check that is in DOS 3.2 version
* 10-29-87 JCR Multi-thread support; also, re-wrote for efficiency
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 05-25-88 PHG Merged DLL and normal versions
* 10-03-88 GJF Changed DOSNEWSIZE to SYSNEWSIZE
* 10-10-88 GJF Made API names match DOSCALLS.H
* 04-13-89 JCR New syscall interface
* 05-25-89 JCR 386 OS/2 calls use '_syscall' calling convention
* 03-12-90 GJF Replaced _LOAD_DS with _CALLTYPE1, added #include
* <cruntime.h>, removed #include <register.h> and fixed
* the copyright. Also, cleaned up the formatting a bit.
* 04-04-90 GJF Added #include <string.h>, removed #include <dos.h>.
* 05-21-90 GJF Fixed stack checking pragma syntax.
* 07-24-90 SBM Replaced <assertm.h> by <assert.h>, removed '32'
* from API names
* 09-28-90 GJF New-style function declarator.
* 12-03-90 GJF Appended Win32 version of the function. It is based
* on the Cruiser version and probably could be merged
* in 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
* 12-28-90 SRW Added _CRUISER_ conditional around check_stack pragma
* 01-16-91 GJF ANSI naming. Also, fixed _chsize_lk parameter decls.
* 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.
* 05-01-92 GJF Fixed embarrassing bug (didn't work for Win32)!
*
*******************************************************************************/
#include <cruntime.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <fcntl.h>
#include <msdos.h>
#include <io.h>
#include <string.h>
#include <oscalls.h>
#include <internal.h>
#include <os2dll.h>
#ifdef _CRUISER_
#pragma check_stack(on) /* turn stack probes on */
#endif /* ndef _CRUISER_ */
/***
*int _chsize(filedes, size) - change size of a file
*
*Purpose:
* Change file size. Assume file is open for writing, or we can't do it.
* The DOS way to do this is to go to the right spot and write 0 bytes. The
* Xenix way to do this is to make a system call. We write '\0' bytes because
* DOS won't do this for you if you lseek beyond eof, though Xenix will.
*
*Entry:
* int filedes - file handle to change size of
* long size - new size of file
*
*Exit:
* return 0 if successful
* returns -1 and sets errno if fails
*
*Exceptions:
*
*******************************************************************************/
#ifdef MTHREAD
/* define normal version that locks/unlocks, validates fh */
int _CALLTYPE1 _chsize (
REG1 int filedes,
long size
)
{
int r; /* return value */
#ifdef _WIN32_
if ( (unsigned)filedes >= (unsigned)_nhandle ) {
#else
if (filedes < 0 || filedes >= _nfile) {
#endif
errno = EBADF;
return(-1);
}
_lock_fh(filedes);
r = _chsize_lk(filedes,size);
_unlock_fh(filedes);
return r;
}
/* now define version that doesn't lock/unlock, validate fh */
int _CALLTYPE1 _chsize_lk (
REG1 int filedes,
long size
)
{
long filend;
long extend;
long place;
int cnt;
char blanks[BUFSIZ];
REG2 char *bl = blanks;
int oldmode;
int retval = 0; /* assume good return */
#else
/* now define normal version */
int _CALLTYPE1 _chsize (
REG1 int filedes,
long size
)
{
long filend;
long extend;
long place;
int cnt;
char blanks[BUFSIZ];
REG2 char *bl = blanks;
int oldmode;
int retval = 0; /* assume good return */
#ifdef _WIN32_
if ( (unsigned)filedes >= (unsigned)_nhandle ) {
#else
if (filedes < 0 || filedes >= _nfile) {
#endif
errno = EBADF;
return(-1);
}
#endif
assert(size >= 0);
/* Get current file position and seek to end */
if ( ((place = _lseek_lk(filedes, 0L, SEEK_CUR)) == -1L) ||
((filend = _lseek_lk(filedes, 0L, SEEK_END)) == -1L) )
return -1;
extend = size - filend;
/* Grow or shrink the file as necessary */
if (extend > 0L) {
/* extending the file */
memset(bl, '\0', BUFSIZ);
oldmode = _setmode_lk(filedes, _O_BINARY);
/* pad out with nulls */
do {
cnt = (extend >= (long)BUFSIZ ) ? BUFSIZ : (int)extend;
if ( ( cnt = _write_lk( filedes, bl, (extend >=
(long)BUFSIZ ) ? BUFSIZ : (int)extend)) == -1 ) {
/* Error on write */
if (_doserrno == ERROR_ACCESS_DENIED)
errno = EACCES;
retval = cnt;
break; /* leave write loop */
}
}
while ((extend -= (long)cnt) > 0L);
_setmode_lk(filedes, oldmode);
/* retval set correctly */
}
else if (extend < 0L) {
/* shortening the file */
#ifdef _CRUISER_
retval = ( DOSSETFILESIZE(filedes, size) ? -1 : 0 );
#else /* ndef _CRUISER_ */
#ifdef _WIN32_
/*
* Set file pointer to new eof...and truncate it there.
*/
_lseek_lk(filedes, size, SEEK_SET);
if ( (retval = SetEndOfFile((HANDLE)_get_osfhandle(filedes)) ?
0 : -1) == -1 ) {
errno = EACCES;
_doserrno = GetLastError();
}
#else /* ndef _WIN32_ */
#ifdef _MAC_
TBD();
#else /* ndef _MAC_ */
#error ERROR - ONLY CRUISER, WIN32, OR MAC TARGET SUPPORTED!
#endif /* _MAC_ */
#endif /* _WIN32_ */
#endif /* _CRUISER_ */
}
/* else */
/* no file change needed */
/* retval = 0; */
/* Common return code */
_lseek_lk(filedes, place, SEEK_SET);
return retval;
}
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