/*
* Set up a file stream on an OS file. The caller has allocated the
* stream and buffer.
*/
void
file_init_stream(stream *s, FILE *file, const char *fmode, byte *buffer,
uint buffer_size)
{
switch (fmode[0]) {
case 'a':
sappend_file(s, file, buffer, buffer_size);
break;
case 'r':
/* Defeat buffering for terminals. */
{
struct stat rstat;
fstat(fileno(file), &rstat);
sread_file(s, file, buffer,
(S_ISCHR(rstat.st_mode) ? 1 : buffer_size));
}
break;
case 'w':
swrite_file(s, file, buffer, buffer_size);
}
if (fmode[1] == '+')
s->file_modes |= s_mode_read | s_mode_write;
s->save_close = s->procs.close;
s->procs.close = file_close_file;
}
/* Switch a file stream to reading or writing. */
static int
s_fileno_switch(stream * s, bool writing)
{
uint modes = s->file_modes;
int fd = sfileno(s);
long pos;
if (writing) {
if (!(s->file_modes & s_mode_write))
return ERRC;
pos = stell(s);
if_debug2('s', "[s]switch 0x%lx to write at %ld\n",
(ulong) s, pos);
lseek(fd, pos, SEEK_SET); /* pacify OS */
if (modes & s_mode_append) {
sappend_file(s, s->file, s->cbuf, s->cbsize); /* sets position */
} else {
swrite_file(s, s->file, s->cbuf, s->cbsize);
s->position = pos;
}
s->modes = modes;
} else {
if (!(s->file_modes & s_mode_read))
return ERRC;
pos = stell(s);
if_debug2('s', "[s]switch 0x%lx to read at %ld\n",
(ulong) s, pos);
if (sflush(s) < 0)
return ERRC;
lseek(fd, 0L, SEEK_CUR); /* pacify OS */
sread_file(s, s->file, s->cbuf, s->cbsize);
s->modes |= modes & s_mode_append; /* don't lose append info */
s->position = pos;
}
s->file_modes = modes;
return 0;
}
