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//
// "$Id$"
//
// Idle routine support for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2008 by Bill Spitzak and others.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems on the following page:
//
// http://www.fltk.org/str.php
//
// Allows you to manage an arbitrary set of idle() callbacks.
// Replaces the older set_idle() call (which is used to implement this)
#include <FL/Fl.H>
struct idle_cb {
void (*cb)(void*);
void* data;
idle_cb *next;
};
// the callbacks are stored linked in a ring. last points at the one
// just called, first at the next to call. last->next == first.
static idle_cb* first;
static idle_cb* last;
static idle_cb* freelist;
static void call_idle() {
idle_cb* p = first;
last = p; first = p->next;
p->cb(p->data); // this may call add_idle() or remove_idle()!
}
/**
Adds a callback function that is called every time by
Fl::wait() and also makes it act as though the timeout is
zero (this makes Fl::wait() return immediately, so if it is
in a loop it is called repeatedly, and thus the idle fucntion is
called repeatedly). The idle function can be used to get background
processing done.
<P>You can have multiple idle callbacks. To remove an idle callback use Fl::remove_idle().
<P>Fl::wait() and Fl::check() call idle callbacks,
but Fl::ready() does not.
<P>The idle callback can call any FLTK functions, including
Fl::wait(), Fl::check(), and Fl::ready().
FLTK will not recursively call the idle callback.
*/
void Fl::add_idle(void (*cb)(void*), void* data) {
idle_cb* p = freelist;
if (p) freelist = p->next;
else p = new idle_cb;
p->cb = cb;
p->data = data;
if (first) {
last->next = p;
last = p;
p->next = first;
} else {
first = last = p;
p->next = p;
set_idle(call_idle);
}
}
/** Returns true if the specified idle callback is currently installed. */
int Fl::has_idle(void (*cb)(void*), void* data) {
idle_cb* p = first;
if (!p) return 0;
for (;; p = p->next) {
if (p->cb == cb && p->data == data) return 1;
if (p==last) return 0;
}
}
/** Removes the specified idle callback, if it is installed. */
void Fl::remove_idle(void (*cb)(void*), void* data) {
idle_cb* p = first;
if (!p) return;
idle_cb* l = last;
for (;; p = p->next) {
if (p->cb == cb && p->data == data) break;
if (p==last) return; // not found
l = p;
}
if (l == p) { // only one
first = last = 0;
set_idle(0);
} else {
last = l;
first = l->next = p->next;
}
p->next = freelist;
freelist = p;
}
//
// End of "$Id$".
//
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