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SDL_events.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2011 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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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
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
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#include "SDL_config.h"
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/* General event handling code for SDL */
#include "SDL.h"
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#include "SDL_events.h"
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#include "SDL_syswm.h"
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#include "SDL_thread.h"
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#include "SDL_events_c.h"
#include "../timer/SDL_timer_c.h"
#if !SDL_JOYSTICK_DISABLED
#include "../joystick/SDL_joystick_c.h"
#endif
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#include "../video/SDL_sysvideo.h"
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/* Public data -- the event filter */
SDL_EventFilter SDL_EventOK = NULL;
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void *SDL_EventOKParam;
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typedef struct SDL_EventWatcher {
SDL_EventFilter callback;
void *userdata;
struct SDL_EventWatcher *next;
} SDL_EventWatcher;
static SDL_EventWatcher *SDL_event_watchers = NULL;
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typedef struct {
Uint32 bits[8];
} SDL_DisabledEventBlock;
static SDL_DisabledEventBlock *SDL_disabled_events[256];
static Uint32 SDL_userevents = SDL_USEREVENT;
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/* Private data -- event queue */
#define MAXEVENTS 128
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static struct
{
SDL_mutex *lock;
int active;
int head;
int tail;
SDL_Event event[MAXEVENTS];
int wmmsg_next;
struct SDL_SysWMmsg wmmsg[MAXEVENTS];
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} SDL_EventQ;
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static __inline__ SDL_bool
SDL_ShouldPollJoystick()
{
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#if !SDL_JOYSTICK_DISABLED
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if (SDL_numjoysticks &&
(!SDL_disabled_events[SDL_JOYAXISMOTION >> 8] ||
SDL_JoystickEventState(SDL_QUERY))) {
return SDL_TRUE;
}
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#endif
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return SDL_FALSE;
}
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/* Public functions */
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void
SDL_StopEventLoop(void)
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{
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int i;
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if (SDL_EventQ.lock) {
SDL_DestroyMutex(SDL_EventQ.lock);
SDL_EventQ.lock = NULL;
}
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/* Clean out EventQ */
SDL_EventQ.head = 0;
SDL_EventQ.tail = 0;
SDL_EventQ.wmmsg_next = 0;
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/* Clear disabled event state */
for (i = 0; i < SDL_arraysize(SDL_disabled_events); ++i) {
if (SDL_disabled_events[i]) {
SDL_free(SDL_disabled_events[i]);
SDL_disabled_events[i] = NULL;
}
}
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while (SDL_event_watchers) {
SDL_EventWatcher *tmp = SDL_event_watchers;
SDL_event_watchers = tmp->next;
SDL_free(tmp);
}
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}
/* This function (and associated calls) may be called more than once */
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int
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SDL_StartEventLoop(void)
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{
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/* Clean out the event queue */
SDL_EventQ.lock = NULL;
SDL_StopEventLoop();
/* No filter to start with, process most event types */
SDL_EventOK = NULL;
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SDL_EventState(SDL_SYSWMEVENT, SDL_DISABLE);
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/* Create the lock and set ourselves active */
#if !SDL_THREADS_DISABLED
SDL_EventQ.lock = SDL_CreateMutex();
if (SDL_EventQ.lock == NULL) {
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return (-1);
}
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#endif /* !SDL_THREADS_DISABLED */
SDL_EventQ.active = 1;
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return (0);
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}
/* Add an event to the event queue -- called with the queue locked */
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static int
SDL_AddEvent(SDL_Event * event)
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{
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int tail, added;
tail = (SDL_EventQ.tail + 1) % MAXEVENTS;
if (tail == SDL_EventQ.head) {
/* Overflow, drop event */
added = 0;
} else {
SDL_EventQ.event[SDL_EventQ.tail] = *event;
if (event->type == SDL_SYSWMEVENT) {
/* Note that it's possible to lose an event */
int next = SDL_EventQ.wmmsg_next;
SDL_EventQ.wmmsg[next] = *event->syswm.msg;
SDL_EventQ.event[SDL_EventQ.tail].syswm.msg =
&SDL_EventQ.wmmsg[next];
SDL_EventQ.wmmsg_next = (next + 1) % MAXEVENTS;
}
SDL_EventQ.tail = tail;
added = 1;
}
return (added);
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}
/* Cut an event, and return the next valid spot, or the tail */
/* -- called with the queue locked */
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static int
SDL_CutEvent(int spot)
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{
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if (spot == SDL_EventQ.head) {
SDL_EventQ.head = (SDL_EventQ.head + 1) % MAXEVENTS;
return (SDL_EventQ.head);
} else if ((spot + 1) % MAXEVENTS == SDL_EventQ.tail) {
SDL_EventQ.tail = spot;
return (SDL_EventQ.tail);
} else
/* We cut the middle -- shift everything over */
{
int here, next;
/* This can probably be optimized with SDL_memcpy() -- careful! */
if (--SDL_EventQ.tail < 0) {
SDL_EventQ.tail = MAXEVENTS - 1;
}
for (here = spot; here != SDL_EventQ.tail; here = next) {
next = (here + 1) % MAXEVENTS;
SDL_EventQ.event[here] = SDL_EventQ.event[next];
}
return (spot);
}
/* NOTREACHED */
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}
/* Lock the event queue, take a peep at it, and unlock it */
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int
SDL_PeepEvents(SDL_Event * events, int numevents, SDL_eventaction action,
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Uint32 minType, Uint32 maxType)
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{
int i, used;
/* Don't look after we've quit */
if (!SDL_EventQ.active) {
return (-1);
}
/* Lock the event queue */
used = 0;
if (SDL_mutexP(SDL_EventQ.lock) == 0) {
if (action == SDL_ADDEVENT) {
for (i = 0; i < numevents; ++i) {
used += SDL_AddEvent(&events[i]);
}
} else {
SDL_Event tmpevent;
int spot;
/* If 'events' is NULL, just see if they exist */
if (events == NULL) {
action = SDL_PEEKEVENT;
numevents = 1;
events = &tmpevent;
}
spot = SDL_EventQ.head;
while ((used < numevents) && (spot != SDL_EventQ.tail)) {
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Uint32 type = SDL_EventQ.event[spot].type;
if (minType <= type && type <= maxType) {
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events[used++] = SDL_EventQ.event[spot];
if (action == SDL_GETEVENT) {
spot = SDL_CutEvent(spot);
} else {
spot = (spot + 1) % MAXEVENTS;
}
} else {
spot = (spot + 1) % MAXEVENTS;
}
}
}
SDL_mutexV(SDL_EventQ.lock);
} else {
SDL_SetError("Couldn't lock event queue");
used = -1;
}
return (used);
}
SDL_bool
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SDL_HasEvent(Uint32 type)
{
return (SDL_PeepEvents(NULL, 0, SDL_PEEKEVENT, type, type) > 0);
}
SDL_bool
SDL_HasEvents(Uint32 minType, Uint32 maxType)
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{
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return (SDL_PeepEvents(NULL, 0, SDL_PEEKEVENT, minType, maxType) > 0);
}
void
SDL_FlushEvent(Uint32 type)
{
SDL_FlushEvents(type, type);
}
void
SDL_FlushEvents(Uint32 minType, Uint32 maxType)
{
/* Don't look after we've quit */
if (!SDL_EventQ.active) {
return;
}
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/* Make sure the events are current */
SDL_PumpEvents();
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/* Lock the event queue */
if (SDL_mutexP(SDL_EventQ.lock) == 0) {
int spot = SDL_EventQ.head;
while (spot != SDL_EventQ.tail) {
Uint32 type = SDL_EventQ.event[spot].type;
if (minType <= type && type <= maxType) {
spot = SDL_CutEvent(spot);
} else {
spot = (spot + 1) % MAXEVENTS;
}
}
SDL_mutexV(SDL_EventQ.lock);
}
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}
/* Run the system dependent event loops */
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void
SDL_PumpEvents(void)
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{
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SDL_VideoDevice *_this = SDL_GetVideoDevice();
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/* Get events from the video subsystem */
if (_this) {
_this->PumpEvents(_this);
}
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#if !SDL_JOYSTICK_DISABLED
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/* Check for joystick state change */
if (SDL_ShouldPollJoystick()) {
SDL_JoystickUpdate();
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}
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#endif
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}
/* Public functions */
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int
SDL_PollEvent(SDL_Event * event)
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{
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return SDL_WaitEventTimeout(event, 0);
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}
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int
SDL_WaitEvent(SDL_Event * event)
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{
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return SDL_WaitEventTimeout(event, -1);
}
int
SDL_WaitEventTimeout(SDL_Event * event, int timeout)
{
Uint32 expiration = 0;
if (timeout > 0)
expiration = SDL_GetTicks() + timeout;
for (;;) {
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SDL_PumpEvents();
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switch (SDL_PeepEvents(event, 1, SDL_GETEVENT, SDL_FIRSTEVENT, SDL_LASTEVENT)) {
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case -1:
return 0;
case 1:
return 1;
case 0:
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if (timeout == 0) {
/* Polling and no events, just return */
return 0;
}
if (timeout > 0 && ((int) (SDL_GetTicks() - expiration) >= 0)) {
/* Timeout expired and no events */
return 0;
}
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SDL_Delay(10);
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break;
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}
}
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}
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int
SDL_PushEvent(SDL_Event * event)
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{
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SDL_EventWatcher *curr;
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if (SDL_EventOK && !SDL_EventOK(SDL_EventOKParam, event)) {
return 0;
}
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for (curr = SDL_event_watchers; curr; curr = curr->next) {
curr->callback(curr->userdata, event);
}
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if (SDL_PeepEvents(event, 1, SDL_ADDEVENT, 0, 0) <= 0) {
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return -1;
}
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SDL_GestureProcessEvent(event);
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return 1;
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}
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void
SDL_SetEventFilter(SDL_EventFilter filter, void *userdata)
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{
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SDL_Event bitbucket;
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/* Set filter and discard pending events */
SDL_EventOK = filter;
SDL_EventOKParam = userdata;
while (SDL_PollEvent(&bitbucket) > 0);
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}
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SDL_bool
SDL_GetEventFilter(SDL_EventFilter * filter, void **userdata)
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{
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if (filter) {
*filter = SDL_EventOK;
}
if (userdata) {
*userdata = SDL_EventOKParam;
}
return SDL_EventOK ? SDL_TRUE : SDL_FALSE;
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}
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/* FIXME: This is not thread-safe yet */
void
SDL_AddEventWatch(SDL_EventFilter filter, void *userdata)
{
SDL_EventWatcher *watcher;
watcher = (SDL_EventWatcher *)SDL_malloc(sizeof(*watcher));
if (!watcher) {
/* Uh oh... */
return;
}
watcher->callback = filter;
watcher->userdata = userdata;
watcher->next = SDL_event_watchers;
SDL_event_watchers = watcher;
}
/* FIXME: This is not thread-safe yet */
void
SDL_DelEventWatch(SDL_EventFilter filter, void *userdata)
{
SDL_EventWatcher *prev = NULL;
SDL_EventWatcher *curr;
for (curr = SDL_event_watchers; curr; prev = curr, curr = curr->next) {
if (curr->callback == filter && curr->userdata == userdata) {
if (prev) {
prev->next = curr->next;
} else {
SDL_event_watchers = curr->next;
}
SDL_free(curr);
break;
}
}
}
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void
SDL_FilterEvents(SDL_EventFilter filter, void *userdata)
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{
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if (SDL_mutexP(SDL_EventQ.lock) == 0) {
int spot;
spot = SDL_EventQ.head;
while (spot != SDL_EventQ.tail) {
if (filter(userdata, &SDL_EventQ.event[spot])) {
spot = (spot + 1) % MAXEVENTS;
} else {
spot = SDL_CutEvent(spot);
}
}
}
SDL_mutexV(SDL_EventQ.lock);
}
Uint8
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SDL_EventState(Uint32 type, int state)
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{
Uint8 current_state;
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Uint8 hi = ((type >> 8) & 0xff);
Uint8 lo = (type & 0xff);
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if (SDL_disabled_events[hi] &&
(SDL_disabled_events[hi]->bits[lo/32] & (1 << (lo&31)))) {
current_state = SDL_DISABLE;
} else {
current_state = SDL_ENABLE;
}
if (state != current_state)
{
switch (state) {
case SDL_DISABLE:
/* Disable this event type and discard pending events */
if (!SDL_disabled_events[hi]) {
SDL_disabled_events[hi] = (SDL_DisabledEventBlock*) SDL_calloc(1, sizeof(SDL_DisabledEventBlock));
if (!SDL_disabled_events[hi]) {
/* Out of memory, nothing we can do... */
break;
}
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}
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SDL_disabled_events[hi]->bits[lo/32] |= (1 << (lo&31));
SDL_FlushEvent(type);
break;
case SDL_ENABLE:
SDL_disabled_events[hi]->bits[lo/32] &= ~(1 << (lo&31));
break;
default:
/* Querying state... */
break;
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}
}
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return current_state;
}
Uint32
SDL_RegisterEvents(int numevents)
{
Uint32 event_base;
if (SDL_userevents+numevents <= SDL_LASTEVENT) {
event_base = SDL_userevents;
SDL_userevents += numevents;
} else {
event_base = (Uint32)-1;
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}
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return event_base;
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}
/* This is a generic event handler.
*/
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int
SDL_SendSysWMEvent(SDL_SysWMmsg * message)
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{
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int posted;
posted = 0;
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if (SDL_GetEventState(SDL_SYSWMEVENT) == SDL_ENABLE) {
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SDL_Event event;
SDL_memset(&event, 0, sizeof(event));
event.type = SDL_SYSWMEVENT;
event.syswm.msg = message;
posted = (SDL_PushEvent(&event) > 0);
}
/* Update internal event state */
return (posted);
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}
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/* vi: set ts=4 sw=4 expandtab: */