void filebuf::init()
{
_fb._offset = 0;
_link_in();
_fb._fileno = -1;
}
filebuf* filebuf::open(const char *filename, const char *mode)
{
if (is_open())
return NULL;
int oflags = 0, omode;
int read_write;
int oprot = 0666;
switch (*mode++) {
case 'r':
omode = O_RDONLY;
read_write = _S_NO_WRITES;
break;
case 'w':
omode = O_WRONLY;
oflags = O_CREAT|O_TRUNC;
read_write = _S_NO_READS;
break;
case 'a':
omode = O_WRONLY;
oflags = O_CREAT|O_APPEND;
read_write = _S_NO_READS|_S_IS_APPENDING;
break;
default:
errno = EINVAL;
return NULL;
}
if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+')) {
omode = O_RDWR;
read_write = 0;
}
int fdesc = ::open(filename, omode|oflags, oprot);
if (fdesc < 0)
return NULL;
_fb._fileno = fdesc;
xsetflags(read_write, _S_NO_READS+_S_NO_WRITES+_S_IS_APPENDING);
if (read_write & _S_IS_APPENDING)
if (seekoff(0, ios::end) == EOF)
return NULL;
_link_in();
return this;
}
filebuf* filebuf::open(const char *filename, ios::openmode mode, int prot)
{
if (is_open())
return NULL;
int posix_mode;
int read_write;
if (mode & ios::app)
mode |= ios::out;
if ((mode & (ios::in|ios::out)) == (ios::in|ios::out)) {
posix_mode = O_RDWR;
read_write = 0;
}
else if (mode & ios::out)
posix_mode = O_WRONLY, read_write = _S_NO_READS;
else if (mode & (int)ios::in)
posix_mode = O_RDONLY, read_write = _S_NO_WRITES;
else
posix_mode = 0, read_write = _S_NO_READS+_S_NO_WRITES;
if ((mode & (int)ios::trunc) || mode == (int)ios::out)
posix_mode |= O_TRUNC;
if (mode & ios::app)
posix_mode |= O_APPEND, read_write |= _S_IS_APPENDING;
if (!(mode & (int)ios::nocreate) && mode != ios::in)
posix_mode |= O_CREAT;
if (mode & (int)ios::noreplace)
posix_mode |= O_EXCL;
int fd = ::open(filename, posix_mode, prot);
if (fd < 0)
return NULL;
_fb._fileno = fd;
xsetflags(read_write, _S_NO_READS+_S_NO_WRITES+_S_IS_APPENDING);
if (mode & (ios::ate|ios::app)) {
if (seekoff(0, ios::end) == EOF)
return NULL;
}
_link_in();
return this;
}
filebuf* filebuf::open(const char *filename, const char *mode)
{
// fdopen in stdio need this.
if (is_open()) {
// file is open. we cannot open a new file
if (filename) {
errno = EINVAL;
return NULL;
}
}
else {
// file is not open. we have to open a new file
if (filename == NULL) {
errno = EINVAL;
return NULL;
}
}
int oflags = 0, omode;
int read_write;
int oprot = 0666;
switch (*mode++) {
case 'r':
omode = O_RDONLY;
read_write = _S_NO_WRITES;
break;
case 'w':
omode = O_WRONLY;
oflags = O_CREAT|O_TRUNC;
read_write = _S_NO_READS;
break;
case 'a':
omode = O_WRONLY;
oflags = O_CREAT|O_APPEND;
read_write = _S_NO_READS|_S_IS_APPENDING;
break;
default:
errno = EINVAL;
return NULL;
}
if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+')) {
omode = O_RDWR;
read_write &= _S_IS_APPENDING;
}
xsetflags(read_write, _S_NO_READS+_S_NO_WRITES+_S_IS_APPENDING);
if (filename) {
int fdesc = ::open(filename, omode|oflags, oprot);
if (fdesc < 0) return NULL;
_fb._fileno = fdesc;
if (read_write & _S_IS_APPENDING)
if (seekoff(0, ios::end) == EOF && errno != ESPIPE)
return NULL;
}
else {
// Get old status flag.
int status_flag = ::fcntl (_fb._fileno, F_GETFL);
if (status_flag < 0) return NULL;
// We should only do O_APPEND.
#if 0
// We cannot change the access mode for an open file descriptor.
if ((status_flag & O_ACCMODE) != omode) {
errno = EINVAL;
return NULL;
}
#endif
// Get new status flag.
oflags &= O_APPEND;
// check if we need to change the status flag.
if ((status_flag & O_APPEND) != oflags) {
// Set new status flag.
status_flag = (status_flag & ~O_APPEND) | oflags;
if (::fcntl (_fb._fileno, F_SETFL, status_flag) < 0)
return NULL;
}
// Seek off to the current file position.
_fb._offset = -1;
if (seekoff(0, ios::cur) == EOF)
if (errno != ESPIPE) return NULL;
else _fb._offset = 0;
}
_link_in();
return this;
}
filebuf* filebuf::open(const char *filename, ios::openmode mode, int prot)
{
// fdopen in stdio need this.
if (is_open()) {
// file is open. we cannot open a new file
if (filename) {
errno = EINVAL;
return NULL;
}
}
else {
// file is not open. we have to open a new file
if (filename == NULL) {
errno = EINVAL;
return NULL;
}
}
int posix_mode;
int read_write;
if (mode & ios::app)
mode |= ios::out;
if ((mode & (ios::in|ios::out)) == (ios::in|ios::out)) {
posix_mode = O_RDWR;
read_write = 0;
}
else if (mode & ios::out)
posix_mode = O_WRONLY, read_write = _S_NO_READS;
else if (mode & (int)ios::in)
posix_mode = O_RDONLY, read_write = _S_NO_WRITES;
else
posix_mode = 0, read_write = _S_NO_READS+_S_NO_WRITES;
if ((mode & (int)ios::trunc) || mode == (int)ios::out)
posix_mode |= O_TRUNC;
if (mode & ios::app)
posix_mode |= O_APPEND, read_write |= _S_IS_APPENDING;
if (!(mode & (int)ios::nocreate) && mode != ios::in)
posix_mode |= O_CREAT;
if (mode & (int)ios::noreplace)
posix_mode |= O_EXCL;
xsetflags(read_write, _S_NO_READS+_S_NO_WRITES+_S_IS_APPENDING);
if (filename) {
int fd = ::open(filename, posix_mode, prot);
if (fd < 0) return NULL;
_fb._fileno = fd;
if (mode & (ios::ate|ios::app)) {
if (seekoff(0, ios::end) == EOF && errno != ESPIPE)
return NULL;
}
}
else {
// Get old status flag.
int status_flag = ::fcntl (_fb._fileno, F_GETFL);
if (status_flag < 0) return NULL;
// We should only do O_APPEND.
#if 0
// Get new access mode.
int new_access_mode = posix_mode & (O_RDWR | O_WRONLY | O_RDONLY);
// We cannot change the access mode for an open file descriptor.
if ((status_flag & O_ACCMODE) != new_access_mode) {
errno = EINVAL;
return NULL;
}
#endif
// Get new status flag.
posix_mode &= O_APPEND;
// check if we need to change the status flag.
if ((status_flag & O_APPEND) != posix_mode) {
// Set new status flag.
status_flag = (status_flag & ~O_APPEND) | posix_mode;
if (::fcntl (_fb._fileno, F_SETFL, status_flag) < 0)
return NULL;
}
// Seek off to the current file position.
_fb._offset = -1;
if (seekoff(0, ios::cur) == EOF)
if (errno != ESPIPE) return NULL;
else _fb._offset = 0;
}
_link_in();
return this;
}
