/***
*write.c - write to a file handle
*
* Copyright (c) 1989-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _write() - write to a file handle
*
*Revision History:
* 06-14-89 PHG Module created, based on asm version
* 03-13-90 GJF Made calling type _CALLTYPE2 (for now), added #include
* <cruntime.h>, fixed compiler warnings 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
* 10-01-90 GJF New-style function declarators.
* 12-04-90 GJF Appended Win32 version onto source with #ifdef-s.
* Should come back latter and do a better merge.
* 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
* 12-28-90 SRW Added cast of void * to char * for Mips C Compiler
* 01-17-91 GJF ANSI naming.
* 02-25-91 MHL Adapt to ReadFile/WriteFile changes (_WIN32_)
* 04-09-91 PNT Added _MAC_ conditional
* 07-18-91 GJF Removed unreferenced local variable from _write_lk
* routine [_WIN32_].
* 10-24-91 GJF Added LPDWORD casts to make MIPS compiler happy.
* ASSUMES THAT sizeof(int) == sizeof(DWORD).
* 02-13-92 GJF Replaced _nfile by _nhandle for Win32.
* 02-15-92 GJF Increased BUF_SIZE and simplified LF translation code
* for Win32.
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
* 09-06-94 CFW Remove Cruiser support.
* 09-06-94 CFW Replace MTHREAD with _MT.
* 12-03-94 SKS Clean up OS/2 references
* 01-04-95 GJF _WIN32_ -> _WIN32
* 02-15-95 GJF Appended Mac version of source file (somewhat cleaned
* up), with appropriate #ifdef-s.
* 06-12-95 GJF Changed _osfile[] and _osfhnd[] to _osfile() and
* _osfhnd(), which reference __pioinfo[].
* 06-27-95 GJF Added check that the file handle is open.
* 07-09-96 GJF Replaced defined(_WIN32) with !defined(_MAC) and
* defined(_M_M68K) || defined(_M_MPPC) with
* defined(_MAC). Also, detab-ed and cleaned up the
* format a bit.
* 12-30-97 GJF Exception-safe locking.
* 03-03-98 RKP Forced number of bytes written to always be an int
* 05-17-99 PML Remove all Macintosh support.
* 11-10-99 GB Replaced lseek for lseeki64 so as to able to append
* files longer than 4GB
*
*******************************************************************************/
#include <cruntime.h>
#include <oscalls.h>
#include <io.h>
#include <errno.h>
#include <msdos.h>
#include <mtdll.h>
#include <stdlib.h>
#include <string.h>
#include <internal.h>
#define BUF_SIZE 1025 /* size of LF translation buffer */
#define LF '\n' /* line feed */
#define CR '\r' /* carriage return */
#define CTRLZ 26 /* ctrl-z */
/***
*int _write(fh, buf, cnt) - write bytes to a file handle
*
*Purpose:
* Writes count bytes from the buffer to the handle specified.
* If the file was opened in text mode, each LF is translated to
* CR-LF. This does not affect the return value. In text
* mode ^Z indicates end of file.
*
* Multi-thread notes:
* (1) _write() - Locks/unlocks file handle
* _write_lk() - Does NOT lock/unlock file handle
*
*Entry:
* int fh - file handle to write to
* char *buf - buffer to write from
* unsigned int cnt - number of bytes to write
*
*Exit:
* returns number of bytes actually written.
* This may be less than cnt, for example, if out of disk space.
* returns -1 (and set errno) if fails.
*
*Exceptions:
*
*******************************************************************************/
#ifdef _MT
/* define normal version that locks/unlocks, validates fh */
int __cdecl _write (
int fh,
const void *buf,
unsigned cnt
)
{
int r; /* return value */
/* validate handle */
if ( ((unsigned)fh >= (unsigned)_nhandle) ||
!(_osfile(fh) & FOPEN) )
{
/* out of range -- return error */
errno = EBADF;
_doserrno = 0; /* not o.s. error */
return -1;
}
_lock_fh(fh); /* lock file */
__try {
if ( _osfile(fh) & FOPEN )
r = _write_lk(fh, buf, cnt); /* write bytes */
else {
errno = EBADF;
_doserrno = 0; /* not o.s. error */
r = -1;
}
}
__finally {
_unlock_fh(fh); /* unlock file */
}
return r;
}
/* now define version that doesn't lock/unlock, validate fh */
int __cdecl _write_lk (
int fh,
const void *buf,
unsigned cnt
)
{
int lfcount; /* count of line feeds */
int charcount; /* count of chars written so far */
int written; /* count of chars written on this write */
ULONG dosretval; /* o.s. return value */
char ch; /* current character */
char *p, *q; /* pointers into buf and lfbuf resp. */
char lfbuf[BUF_SIZE]; /* lf translation buffer */
#else
/* now define normal version */
int __cdecl _write (
int fh,
const void *buf,
unsigned cnt
)
{
int lfcount; /* count of line feeds */
int charcount; /* count of chars written so far */
int written; /* count of chars written on this write */
ULONG dosretval; /* o.s. return value */
char ch; /* current character */
char *p, *q; /* pointers into buf and lfbuf resp. */
char lfbuf[BUF_SIZE]; /* lf translation buffer */
/* validate handle */
if ( ((unsigned)fh >= (unsigned)_nhandle) ||
!(_osfile(fh) & FOPEN) )
{
/* out of range -- return error */
errno = EBADF;
_doserrno = 0; /* not o.s. error */
return -1;
}
#endif
lfcount = charcount = 0; /* nothing written yet */
if (cnt == 0)
return 0; /* nothing to do */
if (_osfile(fh) & FAPPEND) {
/* appending - seek to end of file; ignore error, because maybe
file doesn't allow seeking */
#if _INTEGRAL_MAX_BITS >= 64 /*IFSTRIP=IGN*/
(void)_lseeki64_lk(fh, 0, FILE_END);
#else
(void)_lseek_lk(fh, 0, FILE_END);
#endif
}
/* check for text mode with LF's in the buffer */
if ( _osfile(fh) & FTEXT ) {
/* text mode, translate LF's to CR/LF's on output */
p = (char *)buf; /* start at beginning of buffer */
dosretval = 0; /* no OS error yet */
while ( (unsigned)(p - (char *)buf) < cnt ) {
q = lfbuf; /* start at beginning of lfbuf */
/* fill the lf buf, except maybe last char */
while ( q - lfbuf < BUF_SIZE - 1 &&
(unsigned)(p - (char *)buf) < cnt ) {
ch = *p++;
if ( ch == LF ) {
++lfcount;
*q++ = CR;
}
*q++ = ch;
}
/* write the lf buf and update total */
if ( WriteFile( (HANDLE)_osfhnd(fh),
lfbuf,
(int)(q - lfbuf),
(LPDWORD)&written,
NULL) )
{
charcount += written;
if (written < q - lfbuf)
break;
}
else {
dosretval = GetLastError();
break;
}
}
}
else {
/* binary mode, no translation */
if ( WriteFile( (HANDLE)_osfhnd(fh),
(LPVOID)buf,
cnt,
(LPDWORD)&written,
NULL) )
{
dosretval = 0;
charcount = written;
}
else
dosretval = GetLastError();
}
if (charcount == 0) {
/* If nothing was written, first check if an o.s. error,
otherwise we return -1 and set errno to ENOSPC,
unless a device and first char was CTRL-Z */
if (dosretval != 0) {
/* o.s. error happened, map error */
if (dosretval == ERROR_ACCESS_DENIED) {
/* wrong read/write mode should return EBADF, not
EACCES */
errno = EBADF;
_doserrno = dosretval;
}
else
_dosmaperr(dosretval);
return -1;
}
else if ((_osfile(fh) & FDEV) && *(char *)buf == CTRLZ)
return 0;
else {
errno = ENOSPC;
_doserrno = 0; /* no o.s. error */
return -1;
}
}
else
/* return adjusted bytes written */
return charcount - lfcount;
}