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279 lines
10 KiB
279 lines
10 KiB
/***
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*write.c - write to a file handle
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*
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* Copyright (c) 1989-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* defines _write() - write to a file handle
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*
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*Revision History:
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* 06-14-89 PHG Module created, based on asm version
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* 03-13-90 GJF Made calling type _CALLTYPE2 (for now), added #include
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* <cruntime.h>, fixed compiler warnings and fixed the
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* copyright. Also, cleaned up the formatting a bit.
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* 04-03-90 GJF Now _CALLTYPE1.
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* 07-24-90 SBM Removed '32' from API names
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* 08-14-90 SBM Compiles cleanly with -W3
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* 10-01-90 GJF New-style function declarators.
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* 12-04-90 GJF Appended Win32 version onto source with #ifdef-s.
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* Should come back latter and do a better merge.
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* 12-04-90 SRW Changed to include <oscalls.h> instead of <doscalls.h>
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* 12-06-90 SRW Changed to use _osfile and _osfhnd instead of _osfinfo
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* 12-28-90 SRW Added _CRUISER_ conditional around check_stack pragma
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* 12-28-90 SRW Added cast of void * to char * for Mips C Compiler
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* 01-17-91 GJF ANSI naming.
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* 02-25-91 MHL Adapt to ReadFile/WriteFile changes (_WIN32_)
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* 04-09-91 PNT Added _MAC_ conditional
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* 07-18-91 GJF Removed unreferenced local variable from _write_lk
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* routine [_WIN32_].
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* 10-24-91 GJF Added LPDWORD casts to make MIPS compiler happy.
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* ASSUMES THAT sizeof(int) == sizeof(DWORD).
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* 02-13-92 GJF Replaced _nfile by _nhandle for Win32.
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* 02-15-92 GJF Increased BUF_SIZE and simplified LF translation code
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* for Win32.
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* 04-06-93 SKS Replace _CRTAPI* with __cdecl
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* 09-06-94 CFW Remove Cruiser support.
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* 09-06-94 CFW Replace MTHREAD with _MT.
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* 12-03-94 SKS Clean up OS/2 references
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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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* 06-12-95 GJF Changed _osfile[] and _osfhnd[] to _osfile() and
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* _osfhnd(), which reference __pioinfo[].
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* 06-27-95 GJF Added check that the file handle is open.
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* 07-09-96 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). Also, detab-ed and cleaned up the
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* format a bit.
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* 12-30-97 GJF Exception-safe locking.
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* 03-03-98 RKP Forced number of bytes written to always be an int
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* 05-17-99 PML Remove all Macintosh support.
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* 11-10-99 GB Replaced lseek for lseeki64 so as to able to append
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* files longer than 4GB
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*
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*******************************************************************************/
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#include <cruntime.h>
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#include <oscalls.h>
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#include <io.h>
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#include <errno.h>
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#include <msdos.h>
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#include <mtdll.h>
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#include <stdlib.h>
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#include <string.h>
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#include <internal.h>
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#define BUF_SIZE 1025 /* size of LF translation buffer */
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#define LF '\n' /* line feed */
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#define CR '\r' /* carriage return */
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#define CTRLZ 26 /* ctrl-z */
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/***
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*int _write(fh, buf, cnt) - write bytes to a file handle
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*
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*Purpose:
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* Writes count bytes from the buffer to the handle specified.
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* If the file was opened in text mode, each LF is translated to
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* CR-LF. This does not affect the return value. In text
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* mode ^Z indicates end of file.
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*
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* Multi-thread notes:
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* (1) _write() - Locks/unlocks file handle
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* _write_lk() - Does NOT lock/unlock file handle
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*
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*Entry:
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* int fh - file handle to write to
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* char *buf - buffer to write from
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* unsigned int cnt - number of bytes to write
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*
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*Exit:
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* returns number of bytes actually written.
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* This may be less than cnt, for example, if out of disk space.
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* returns -1 (and set errno) if fails.
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*
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*Exceptions:
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*
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*******************************************************************************/
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#ifdef _MT
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/* define normal version that locks/unlocks, validates fh */
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int __cdecl _write (
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int fh,
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const void *buf,
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unsigned cnt
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)
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{
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int r; /* return value */
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/* validate handle */
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if ( ((unsigned)fh >= (unsigned)_nhandle) ||
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!(_osfile(fh) & FOPEN) )
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{
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/* out of range -- return error */
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errno = EBADF;
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_doserrno = 0; /* not o.s. error */
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return -1;
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}
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_lock_fh(fh); /* lock file */
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__try {
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if ( _osfile(fh) & FOPEN )
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r = _write_lk(fh, buf, cnt); /* write bytes */
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else {
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errno = EBADF;
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_doserrno = 0; /* not o.s. error */
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r = -1;
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}
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}
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__finally {
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_unlock_fh(fh); /* unlock file */
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}
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return r;
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}
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/* now define version that doesn't lock/unlock, validate fh */
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int __cdecl _write_lk (
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int fh,
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const void *buf,
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unsigned cnt
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)
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{
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int lfcount; /* count of line feeds */
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int charcount; /* count of chars written so far */
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int written; /* count of chars written on this write */
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ULONG dosretval; /* o.s. return value */
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char ch; /* current character */
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char *p, *q; /* pointers into buf and lfbuf resp. */
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char lfbuf[BUF_SIZE]; /* lf translation buffer */
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#else
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/* now define normal version */
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int __cdecl _write (
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int fh,
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const void *buf,
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unsigned cnt
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)
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{
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int lfcount; /* count of line feeds */
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int charcount; /* count of chars written so far */
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int written; /* count of chars written on this write */
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ULONG dosretval; /* o.s. return value */
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char ch; /* current character */
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char *p, *q; /* pointers into buf and lfbuf resp. */
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char lfbuf[BUF_SIZE]; /* lf translation buffer */
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/* validate handle */
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if ( ((unsigned)fh >= (unsigned)_nhandle) ||
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!(_osfile(fh) & FOPEN) )
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{
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/* out of range -- return error */
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errno = EBADF;
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_doserrno = 0; /* not o.s. error */
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return -1;
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}
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#endif
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lfcount = charcount = 0; /* nothing written yet */
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if (cnt == 0)
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return 0; /* nothing to do */
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if (_osfile(fh) & FAPPEND) {
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/* appending - seek to end of file; ignore error, because maybe
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file doesn't allow seeking */
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#if _INTEGRAL_MAX_BITS >= 64 /*IFSTRIP=IGN*/
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(void)_lseeki64_lk(fh, 0, FILE_END);
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#else
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(void)_lseek_lk(fh, 0, FILE_END);
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#endif
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}
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/* check for text mode with LF's in the buffer */
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if ( _osfile(fh) & FTEXT ) {
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/* text mode, translate LF's to CR/LF's on output */
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p = (char *)buf; /* start at beginning of buffer */
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dosretval = 0; /* no OS error yet */
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while ( (unsigned)(p - (char *)buf) < cnt ) {
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q = lfbuf; /* start at beginning of lfbuf */
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/* fill the lf buf, except maybe last char */
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while ( q - lfbuf < BUF_SIZE - 1 &&
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(unsigned)(p - (char *)buf) < cnt ) {
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ch = *p++;
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if ( ch == LF ) {
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++lfcount;
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*q++ = CR;
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}
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*q++ = ch;
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}
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/* write the lf buf and update total */
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if ( WriteFile( (HANDLE)_osfhnd(fh),
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lfbuf,
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(int)(q - lfbuf),
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(LPDWORD)&written,
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NULL) )
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{
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charcount += written;
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if (written < q - lfbuf)
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break;
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}
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else {
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dosretval = GetLastError();
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break;
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}
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}
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}
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else {
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/* binary mode, no translation */
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if ( WriteFile( (HANDLE)_osfhnd(fh),
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(LPVOID)buf,
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cnt,
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(LPDWORD)&written,
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NULL) )
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{
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dosretval = 0;
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charcount = written;
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}
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else
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dosretval = GetLastError();
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}
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if (charcount == 0) {
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/* If nothing was written, first check if an o.s. error,
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otherwise we return -1 and set errno to ENOSPC,
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unless a device and first char was CTRL-Z */
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if (dosretval != 0) {
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/* o.s. error happened, map error */
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if (dosretval == ERROR_ACCESS_DENIED) {
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/* wrong read/write mode should return EBADF, not
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EACCES */
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errno = EBADF;
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_doserrno = dosretval;
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}
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else
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_dosmaperr(dosretval);
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return -1;
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}
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else if ((_osfile(fh) & FDEV) && *(char *)buf == CTRLZ)
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return 0;
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else {
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errno = ENOSPC;
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_doserrno = 0; /* no o.s. error */
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return -1;
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}
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}
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else
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/* return adjusted bytes written */
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return charcount - lfcount;
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}
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