cdesktopenv/cde/programs/dtinfo/DtMmdb/utility/filebuf.C

301 lines
6.4 KiB
C

/*
* CDE - Common Desktop Environment
*
* Copyright (c) 1993-2012, The Open Group. All rights reserved.
*
* These libraries and programs are free software; you can
* redistribute them and/or modify them under the terms of the GNU
* Lesser General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* These libraries and programs are distributed in the hope that
* they will be useful, but WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with these libraries and programs; if not, write
* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
* Floor, Boston, MA 02110-1301 USA
*/
/* $XConsortium: filebuf.C /main/9 1996/10/04 10:44:52 drk $ */
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#if !defined(hpux) && !defined(__linux__) && !defined(CSRG_BASED) && !defined(sun)
#include <sysent.h>
#endif
#include <fcntl.h>
#include <string.h>
#include "utility/c_filebuf.h"
#include <sys/stat.h>
filebuf::~filebuf()
{
close();
delete _name;
}
/////////////////////////////////////////////
// only current_pos is used.
/////////////////////////////////////////////
filebuf::filebuf(int __fd) :
_fd(__fd), _prev_action(-1), _name(0),
current_pos(0), new_pos(0), default_new_pos(0)
{
_mode = 0;
struct stat statbuf;
if ( fstat(_fd, &statbuf ) == 0 ) {
if ( BIT_TEST( statbuf.st_mode, S_IRUSR) )
_mode |= ios::in;
if ( BIT_TEST( statbuf.st_mode, S_IWUSR) )
_mode |= ios::out;
} else {
_mode = 0;
}
}
filebuf::filebuf(const char* name, int mode, int protect) :
_fd(-1), _prev_action(-1), _name(strdup(name)),
current_pos(0), new_pos(0), default_new_pos(0)
{
open(name, mode, protect);
}
int filebuf::open(const char* name, int mode, int protect)
{
if ( _fd != -1 &&
_name && strcmp(name, _name) == 0 &&
mode == _mode
)
return 0;
close();
delete _name; _name = strdup(name);
_mode = mode;
int flag = 0;
if ( BIT_TEST(mode, ios::app) || BIT_TEST(mode, ios::out) ) {
if ( BIT_TEST(mode, ios::in) )
flag |= O_RDWR;
else
flag |= O_WRONLY;
} else {
if ( BIT_TEST(mode, ios::in) )
flag |= O_RDONLY;
}
if ( BIT_TEST(mode, ios::trunc) ||
(
BIT_TEST(mode, ios::trunc) &&
!(BIT_TEST(mode, ios::in)||BIT_TEST(mode, ios::app))
)
)
flag |= O_TRUNC;
//fprintf(stderr, "flag=%x\n", flag);
_fd = ::open(name, flag);
if ( _fd < 0 ) {
//fprintf(stderr, "use O_CREAT\n");
flag |= O_CREAT;
_fd = ::open(name, flag, protect);
}
if ( _fd >= 0 ) {
//fprintf(stderr, "filebuf::open OK, name = %s, fd = %d, this = %d\n", name, _fd, (void*)this);
return 0;
} else
return EOF;
}
int filebuf::close()
{
if ( _prev_action == streambuf::PUT )
flush();
::close(_fd);
_fd = -1;
return 0;
}
int filebuf::is_open()
{
return (_fd>=0) ? 1 : 0;
}
void filebuf::notify(int action_t)
{
if ( _prev_action == -1 ) {
_prev_action = action_t;
} else
if ( _prev_action != action_t )
_notify(action_t);
}
void filebuf::_notify(int action_t)
{
switch ( action_t ) {
case streambuf::GET:
//////////////////////////////////////////////////////////////
// previous action was PUT. Now calculate the number of chars
// that have been put and write them out.
//
// Note: put_ptr always starts at base. And at this time,
// get_ptr == base.
//
//////////////////////////////////////////////////////////////
overflow();
break;
case streambuf::PUT:
//////////////////////////////////////////////////////////////
// previous action was a GET.
//
// Note: get_ptr always starts at base.
//
//////////////////////////////////////////////////////////////
empty_buffer();
break;
default:
return;
}
_prev_action = action_t;
}
int filebuf::_write(char* ptr, int size)
{
//fprintf(stderr, "_write() size = %d, fd = %d\n", size, _fd);
int _written_size = ::write(_fd, ptr, size);
if ( _written_size != size ) {
//fprintf(stderr, "fwrite only writes %d bytes\n.", size - _written_size);
return EOF;
}
return _written_size;
}
int filebuf::overflow()
{
// write to the file if possible and clean the buffer
if ( !BIT_TEST(_mode, ios::out) && !BIT_TEST(_mode, ios::app) )
return EOF;
if ( _size == 0 ) return 0;
if ( BIT_TEST(_mode, ios::app) ) {
if ( _seek(0L, SEEK_END) != 0 ) return EOF;
} else
if ( _seek() != 0 ) return EOF;
int ok;
if ( get_ptr + _size <= end ) {
ok = _write(get_ptr, _size);
} else {
int l = end - get_ptr;
ok = _write(get_ptr, l);
if ( ok != EOF )
ok = _write(base, _size - l);
}
if ( ok == EOF ) return EOF;
current_pos += _size;
empty_buffer();
return ok;
}
int filebuf::underflow()
{
// get more from the file if possible
if ( !BIT_TEST(_mode, ios::in) )
return EOF;
if ( _seek() != 0 ) return EOF;
_size = ::read(_fd, base, _capacity);
//fprintf(stderr, "read in _underflow() this = %d, _size = %d, current_pos = %d, fd = %d\n", (void*)this, _size, current_pos, _fd);
if (_size <=0)
return EOF;
else {
get_ptr = base;
put_ptr = base + _size;
}
current_pos += _size;
return 0;
}
int filebuf::_seek()
{
//fprintf(stderr, "_seek() [1] current_pos= %d\n", current_pos);
if ( ::lseek(_fd, current_pos, SEEK_SET) == -1 ) {
fprintf(stderr, "lseek failed. current_pos= %ld\n", current_pos);
return EOF;
} else
return 0;
}
int filebuf::_seek(streampos pos, int whence)
{
//fprintf(stderr, "_seek() [2]: pos= %d, whence=%d\n", pos, whence);
current_pos = pos;
if ( ::lseek(_fd, pos, whence) == -1 ) {
fprintf(stderr, "lseek failed. pos= %ld, whence=%d\n", pos, whence);
return EOF;
} else
return 0;
}
int filebuf::seekg(long delta)
{
if ( _prev_action == streambuf::PUT )
overflow();
else
empty_buffer();
current_pos = delta;
return 0;
}
int filebuf::flush()
{
if ( overflow() == EOF )
return EOF;
if ( ::fsync(_fd) != 0 )
return EOF;
else
return 0;
}