111 lines
3.5 KiB
C
111 lines
3.5 KiB
C
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/***
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*flength.c - find length of a file
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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 _filelength() - find the length of a file
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*
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*Revision History:
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* 10-22-84 RN initial version
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* 10-27-87 JCR Multi-thread support; also, cleaned up code to save
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* an lseek() in some cases.
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* 12-11-87 JCR Added "_LOAD_DS" to declaration
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* 05-25-88 PHG Merged DLL and normal versions
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* 03-12-90 GJF Replaced _LOAD_DS with _CALLTYPE1, added #include
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* <cruntime.h>, removed #include <register.h> and fixed
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* the copyright. Also, cleaned up the formatting a bit.
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* 07-23-90 SBM Removed #include <assertm.h>
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* 09-28-90 GJF New-style function declarator.
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* 12-04-90 GJF Improved range check of file handle. Also, replaced
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* numeric values with symbolic constants for seek
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* methods.
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* 01-16-91 GJF ANSI naming.
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* 02-13-92 GJF Replaced _nfile by _nhandle for Win32.
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* 04-06-93 SKS Replace _CRTAPI* with __cdecl
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* 01-04-95 GJF _WIN32_ -> _WIN32
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* 02-15-95 GJF Appended Mac version of source file (somewhat cleaned
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* up), with appropriate #ifdef-s.
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* 06-27-95 GJF Added check that the file handle is open.
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* 07-08-96 GJF Replaced defined(_WIN32) with !defined(_MAC), and
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* defined(_M_M68K) || defined(_M_MPPC) with
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* defined(_MAC). Removed obsolete REG1 macro. Also,
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* detab-ed and cleaned up the format a bit.
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* 12-19-97 GJF Exception-safe locking.
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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 <errno.h>
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#include <io.h>
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#include <internal.h>
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#include <msdos.h>
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#include <mtdll.h>
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#include <stddef.h>
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#include <stdlib.h>
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/***
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*long _filelength(filedes) - find length of a file
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*
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*Purpose:
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* Returns the length in bytes of the specified file.
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*
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*Entry:
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* int filedes - handle referring to file to find length of
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*
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*Exit:
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* returns length of file in bytes
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* returns -1L if fails
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*
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*Exceptions:
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*
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*******************************************************************************/
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long __cdecl _filelength (
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int filedes
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)
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{
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long length;
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long here;
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if ( ((unsigned)filedes >= (unsigned)_nhandle) ||
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!(_osfile(filedes) & FOPEN) )
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{
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errno = EBADF;
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_doserrno = 0L; /* not an OS error */
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return(-1L);
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}
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#ifdef _MT
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_lock_fh(filedes);
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__try {
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if ( _osfile(filedes) & FOPEN ) {
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#endif /* _MT */
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/* Seek to end to get length of file. */
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if ( (here = _lseek_lk(filedes, 0L, SEEK_CUR)) == -1L )
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length = -1L; /* return error */
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else {
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length = _lseek_lk(filedes, 0L, SEEK_END);
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if ( here != length )
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_lseek_lk(filedes, here, SEEK_SET);
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}
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#ifdef _MT
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}
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else {
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errno = EBADF;
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_doserrno = 0L;
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length = -1L;
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}
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}
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__finally {
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_unlock_fh(filedes);
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}
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#endif /* _MT */
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return(length);
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}
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