static void vport_print(ScmObj obj, ScmPort *port, ScmWriteContext *ctx)
{
Scm_Printf(port, "#<%A%s %A %p>",
Scm__InternalClassName(Scm_ClassOf(obj)),
SCM_PORT_CLOSED_P(obj)? "(closed)" : "",
Scm_PortName(SCM_PORT(obj)),
obj);
}
ScmObj Scm_PortSeekUnsafe(ScmPort *p, ScmObj off, int whence)
#endif
{
VMDECL;
SHORTCUT(p, return Scm_PortSeekUnsafe(p, off, whence));
if (SCM_PORT_CLOSED_P(p)) {
Scm_PortError(p, SCM_PORT_ERROR_CLOSED,
"attempt to seek on closed port: %S", p);
}
off_t r = (off_t)-1;
off_t o = Scm_IntegerToOffset(off);
int is_telling = (whence == SEEK_CUR && o == 0);
LOCK(p);
off_t pending = port_pending_bytes(p);
if (!is_telling) {
/* Unless we're telling, we discard pending bytes. */
p->scrcnt = 0;
p->ungotten = SCM_CHAR_INVALID;
/* ... and adjust offset, when it's relative. */
if (whence == SEEK_CUR) o -= pending;
}
switch (SCM_PORT_TYPE(p)) {
case SCM_PORT_FILE:
/* NB: we might be able to skip calling seeker if we keep the
# of bytes read or write so far, but such count may be off
when the port has been experienced an error condition. */
/* NB: the following doesn't work if we have bidirectional port.
In such case we need to keep whether the last call of buffer
handling routine was input or output. */
if (!p->src.buf.seeker) break;
if (is_telling) {
SAFE_CALL(p, r = p->src.buf.seeker(p, 0, SEEK_CUR));
if (SCM_PORT_DIR(p)&SCM_PORT_INPUT) {
r -= (off_t)(p->src.buf.end - p->src.buf.current);
} else {
r += (off_t)(p->src.buf.current - p->src.buf.buffer);
}
} else {
/* NB: possible optimization: the specified position is within
the current buffer, we can avoid calling seeker. */
if (SCM_PORT_DIR(p)&SCM_PORT_INPUT) {
char *c = p->src.buf.current; /* save current ptr */
if (whence == SEEK_CUR) {
o -= (off_t)(p->src.buf.end - c);
}
p->src.buf.current = p->src.buf.end; /* invalidate buffer */
SAFE_CALL(p, r = p->src.buf.seeker(p, o, whence));
if (r == (off_t)-1) {
/* This may happend if seeker somehow gave up */
p->src.buf.current = c;
}
} else {
SAFE_CALL(p, bufport_flush(p, 0, TRUE));
SAFE_CALL(p, r = p->src.buf.seeker(p, o, whence));
}
}
break;
case SCM_PORT_ISTR:
r = SEEK_ISTR(p, o, whence, is_telling);
break;
case SCM_PORT_OSTR:
if (is_telling) {
r = (off_t)Scm_DStringSize(&(p->src.ostr));
} else {
/* Not supported yet */
r = (off_t)-1;
}
break;
case SCM_PORT_PROC:
if (p->src.vt.Seek) {
SAFE_CALL(p, r = p->src.vt.Seek(p, o, whence));
}
break;
}
UNLOCK(p);
if (r == (off_t)-1) return SCM_FALSE;
if (is_telling) r -= pending;
return Scm_OffsetToInteger(r);
}
