kc3-lang/SDL/src/joystick/linux/SDL_sysjoystick.c

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• Hash : 0e45984f
  Author :
  Date : 2015-06-21T17:33:46
  

  Fixed crash if initialization of EGL failed but was tried again later. The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly uninitialized data structure if loading the library first failed. A later try to use EGL then skipped initialization and assumed it was previously successful because the data structure now already existed. This led to at least one crash in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was dereferenced to make a call to eglBindAPI().

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• src/joystick/linux/SDL_sysjoystick.c

• /*
    Simple DirectMedia Layer
    Copyright (C) 1997-2015 Sam Lantinga <slouken@libsdl.org>
  
    This software is provided 'as-is', without any express or implied
    warranty.  In no event will the authors be held liable for any damages
    arising from the use of this software.
  
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely, subject to the following restrictions:
  
    1. The origin of this software must not be misrepresented; you must not
       claim that you wrote the original software. If you use this software
       in a product, an acknowledgment in the product documentation would be
       appreciated but is not required.
    2. Altered source versions must be plainly marked as such, and must not be
       misrepresented as being the original software.
    3. This notice may not be removed or altered from any source distribution.
  */
  #include "../../SDL_internal.h"
  
  #ifdef SDL_JOYSTICK_LINUX
  
  #ifndef SDL_INPUT_LINUXEV
  #error SDL now requires a Linux 2.4+ kernel with /dev/input/event support.
  #endif
  
  /* This is the Linux implementation of the SDL joystick API */
  
  #include <sys/stat.h>
  #include <unistd.h>
  #include <fcntl.h>
  #include <sys/ioctl.h>
  #include <limits.h>             /* For the definition of PATH_MAX */
  #include <linux/joystick.h>
  
  #include "SDL_assert.h"
  #include "SDL_joystick.h"
  #include "SDL_endian.h"
  #include "../SDL_sysjoystick.h"
  #include "../SDL_joystick_c.h"
  #include "SDL_sysjoystick_c.h"
  
  /* !!! FIXME: move this somewhere else. */
  #if !SDL_EVENTS_DISABLED
  #include "../../events/SDL_events_c.h"
  #endif
  
  /* This isn't defined in older Linux kernel headers */
  #ifndef SYN_DROPPED
  #define SYN_DROPPED 3
  #endif
  
  #include "../../core/linux/SDL_udev.h"
  
  static int MaybeAddDevice(const char *path);
  #if SDL_USE_LIBUDEV
  static int MaybeRemoveDevice(const char *path);
  void joystick_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath);
  #endif /* SDL_USE_LIBUDEV */
  
  
  /* A linked list of available joysticks */
  typedef struct SDL_joylist_item
  {
      int device_instance;
      char *path;   /* "/dev/input/event2" or whatever */
      char *name;   /* "SideWinder 3D Pro" or whatever */
      SDL_JoystickGUID guid;
      dev_t devnum;
      struct joystick_hwdata *hwdata;
      struct SDL_joylist_item *next;
  } SDL_joylist_item;
  
  static SDL_joylist_item *SDL_joylist = NULL;
  static SDL_joylist_item *SDL_joylist_tail = NULL;
  static int numjoysticks = 0;
  static int instance_counter = 0;
  
  #define test_bit(nr, addr) \
      (((1UL << ((nr) % (sizeof(long) * 8))) & ((addr)[(nr) / (sizeof(long) * 8)])) != 0)
  #define NBITS(x) ((((x)-1)/(sizeof(long) * 8))+1)
  
  static int
  IsJoystick(int fd, char *namebuf, const size_t namebuflen, SDL_JoystickGUID *guid)
  {
      struct input_id inpid;
      Uint16 *guid16 = (Uint16 *) ((char *) &guid->data);
  
  #if !SDL_USE_LIBUDEV
      /* When udev is enabled we only get joystick devices here, so there's no need to test them */
      unsigned long evbit[NBITS(EV_MAX)] = { 0 };
      unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
      unsigned long absbit[NBITS(ABS_MAX)] = { 0 };
  
      if ((ioctl(fd, EVIOCGBIT(0, sizeof(evbit)), evbit) < 0) ||
          (ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) < 0) ||
          (ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) < 0)) {
          return (0);
      }
  
      if (!(test_bit(EV_KEY, evbit) && test_bit(EV_ABS, evbit) &&
            test_bit(ABS_X, absbit) && test_bit(ABS_Y, absbit))) {
          return 0;
      }
  #endif
  
      if (ioctl(fd, EVIOCGNAME(namebuflen), namebuf) < 0) {
          return 0;
      }
  
      if (ioctl(fd, EVIOCGID, &inpid) < 0) {
          return 0;
      }
  
  #ifdef DEBUG_JOYSTICK
      printf("Joystick: %s, bustype = %d, vendor = 0x%x, product = 0x%x, version = %d\n", namebuf, inpid.bustype, inpid.vendor, inpid.product, inpid.version);
  #endif
  
      SDL_memset(guid->data, 0, sizeof(guid->data));
  
      /* We only need 16 bits for each of these; space them out to fill 128. */
      /* Byteswap so devices get same GUID on little/big endian platforms. */
      *(guid16++) = SDL_SwapLE16(inpid.bustype);
      *(guid16++) = 0;
  
      if (inpid.vendor && inpid.product && inpid.version) {
          *(guid16++) = SDL_SwapLE16(inpid.vendor);
          *(guid16++) = 0;
          *(guid16++) = SDL_SwapLE16(inpid.product);
          *(guid16++) = 0;
          *(guid16++) = SDL_SwapLE16(inpid.version);
          *(guid16++) = 0;
      } else {
          SDL_strlcpy((char*)guid16, namebuf, sizeof(guid->data) - 4);
      }
  
      return 1;
  }
  
  #if SDL_USE_LIBUDEV
  void joystick_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath)
  {
      if (devpath == NULL) {
          return;
      }
  
      switch (udev_type) {
          case SDL_UDEV_DEVICEADDED:
              if (!(udev_class & SDL_UDEV_DEVICE_JOYSTICK)) {
                  return;
              }
              MaybeAddDevice(devpath);
              break;
              
          case SDL_UDEV_DEVICEREMOVED:
              MaybeRemoveDevice(devpath);
              break;
              
          default:
              break;
      }
      
  }
  #endif /* SDL_USE_LIBUDEV */
  
  
  /* !!! FIXME: I would love to dump this code and use libudev instead. */
  static int
  MaybeAddDevice(const char *path)
  {
      struct stat sb;
      int fd = -1;
      int isstick = 0;
      char namebuf[128];
      SDL_JoystickGUID guid;
      SDL_joylist_item *item;
  #if !SDL_EVENTS_DISABLED
      SDL_Event event;
  #endif
  
      if (path == NULL) {
          return -1;
      }
  
      if (stat(path, &sb) == -1) {
          return -1;
      }
  
      /* Check to make sure it's not already in list. */
      for (item = SDL_joylist; item != NULL; item = item->next) {
          if (sb.st_rdev == item->devnum) {
              return -1;  /* already have this one */
          }
      }
  
      fd = open(path, O_RDONLY, 0);
      if (fd < 0) {
          return -1;
      }
  
  #ifdef DEBUG_INPUT_EVENTS
      printf("Checking %s\n", path);
  #endif
  
      isstick = IsJoystick(fd, namebuf, sizeof (namebuf), &guid);
      close(fd);
      if (!isstick) {
          return -1;
      }
  
      item = (SDL_joylist_item *) SDL_malloc(sizeof (SDL_joylist_item));
      if (item == NULL) {
          return -1;
      }
  
      SDL_zerop(item);
      item->devnum = sb.st_rdev;
      item->path = SDL_strdup(path);
      item->name = SDL_strdup(namebuf);
      item->guid = guid;
  
      if ( (item->path == NULL) || (item->name == NULL) ) {
           SDL_free(item->path);
           SDL_free(item->name);
           SDL_free(item);
           return -1;
      }
  
      item->device_instance = instance_counter++;
      if (SDL_joylist_tail == NULL) {
          SDL_joylist = SDL_joylist_tail = item;
      } else {
          SDL_joylist_tail->next = item;
          SDL_joylist_tail = item;
      }
  
      /* Need to increment the joystick count before we post the event */
      ++numjoysticks;
  
      /* !!! FIXME: Move this to an SDL_PrivateJoyDeviceAdded() function? */
  #if !SDL_EVENTS_DISABLED
      event.type = SDL_JOYDEVICEADDED;
  
      if (SDL_GetEventState(event.type) == SDL_ENABLE) {
          event.jdevice.which = (numjoysticks - 1);
          if ( (SDL_EventOK == NULL) ||
               (*SDL_EventOK) (SDL_EventOKParam, &event) ) {
              SDL_PushEvent(&event);
          }
      }
  #endif /* !SDL_EVENTS_DISABLED */
  
      return numjoysticks;
  }
  
  #if SDL_USE_LIBUDEV
  /* !!! FIXME: I would love to dump this code and use libudev instead. */
  static int
  MaybeRemoveDevice(const char *path)
  {
      SDL_joylist_item *item;
      SDL_joylist_item *prev = NULL;
  #if !SDL_EVENTS_DISABLED
      SDL_Event event;
  #endif
  
      if (path == NULL) {
          return -1;
      }
  
      for (item = SDL_joylist; item != NULL; item = item->next) {
          /* found it, remove it. */
          if (SDL_strcmp(path, item->path) == 0) {
              const int retval = item->device_instance;
              if (item->hwdata) {
                  item->hwdata->item = NULL;
              }
              if (prev != NULL) {
                  prev->next = item->next;
              } else {
                  SDL_assert(SDL_joylist == item);
                  SDL_joylist = item->next;
              }
              if (item == SDL_joylist_tail) {
                  SDL_joylist_tail = prev;
              }
  
              /* Need to decrement the joystick count before we post the event */
              --numjoysticks;
  
              /* !!! FIXME: Move this to an SDL_PrivateJoyDeviceRemoved() function? */
  #if !SDL_EVENTS_DISABLED
              event.type = SDL_JOYDEVICEREMOVED;
  
              if (SDL_GetEventState(event.type) == SDL_ENABLE) {
                  event.jdevice.which = item->device_instance;
                  if ( (SDL_EventOK == NULL) ||
                       (*SDL_EventOK) (SDL_EventOKParam, &event) ) {
                      SDL_PushEvent(&event);
                  }
              }
  #endif /* !SDL_EVENTS_DISABLED */
  
              SDL_free(item->path);
              SDL_free(item->name);
              SDL_free(item);
              return retval;
          }
          prev = item;
      }
  
      return -1;
  }
  #endif
  
  static int
  JoystickInitWithoutUdev(void)
  {
      int i;
      char path[PATH_MAX];
  
      /* !!! FIXME: only finds sticks if they're called /dev/input/event[0..31] */
      /* !!! FIXME:  we could at least readdir() through /dev/input...? */
      /* !!! FIXME:  (or delete this and rely on libudev?) */
      for (i = 0; i < 32; i++) {
          SDL_snprintf(path, SDL_arraysize(path), "/dev/input/event%d", i);
          MaybeAddDevice(path);
      }
  
      return numjoysticks;
  }
  
  
  #if SDL_USE_LIBUDEV
  static int
  JoystickInitWithUdev(void)
  {
      if (SDL_UDEV_Init() < 0) {
          return SDL_SetError("Could not initialize UDEV");
      }
  
      /* Set up the udev callback */
      if (SDL_UDEV_AddCallback(joystick_udev_callback) < 0) {
          SDL_UDEV_Quit();
          return SDL_SetError("Could not set up joystick <-> udev callback");
      }
      
      /* Force a scan to build the initial device list */
      SDL_UDEV_Scan();
  
      return numjoysticks;
  }
  #endif
  
  int
  SDL_SYS_JoystickInit(void)
  {
      /* First see if the user specified one or more joysticks to use */
      if (SDL_getenv("SDL_JOYSTICK_DEVICE") != NULL) {
          char *envcopy, *envpath, *delim;
          envcopy = SDL_strdup(SDL_getenv("SDL_JOYSTICK_DEVICE"));
          envpath = envcopy;
          while (envpath != NULL) {
              delim = SDL_strchr(envpath, ':');
              if (delim != NULL) {
                  *delim++ = '\0';
              }
              MaybeAddDevice(envpath);
              envpath = delim;
          }
          SDL_free(envcopy);
      }
  
  #if SDL_USE_LIBUDEV
      return JoystickInitWithUdev();
  #endif
  
      return JoystickInitWithoutUdev();
  }
  
  int SDL_SYS_NumJoysticks()
  {
      return numjoysticks;
  }
  
  void SDL_SYS_JoystickDetect()
  {
  #if SDL_USE_LIBUDEV
      SDL_UDEV_Poll();
  #endif
      
  }
  
  static SDL_joylist_item *
  JoystickByDevIndex(int device_index)
  {
      SDL_joylist_item *item = SDL_joylist;
  
      if ((device_index < 0) || (device_index >= numjoysticks)) {
          return NULL;
      }
  
      while (device_index > 0) {
          SDL_assert(item != NULL);
          device_index--;
          item = item->next;
      }
  
      return item;
  }
  
  /* Function to get the device-dependent name of a joystick */
  const char *
  SDL_SYS_JoystickNameForDeviceIndex(int device_index)
  {
      return JoystickByDevIndex(device_index)->name;
  }
  
  /* Function to perform the mapping from device index to the instance id for this index */
  SDL_JoystickID SDL_SYS_GetInstanceIdOfDeviceIndex(int device_index)
  {
      return JoystickByDevIndex(device_index)->device_instance;
  }
  
  static int
  allocate_hatdata(SDL_Joystick * joystick)
  {
      int i;
  
      joystick->hwdata->hats =
          (struct hwdata_hat *) SDL_malloc(joystick->nhats *
                                           sizeof(struct hwdata_hat));
      if (joystick->hwdata->hats == NULL) {
          return (-1);
      }
      for (i = 0; i < joystick->nhats; ++i) {
          joystick->hwdata->hats[i].axis[0] = 1;
          joystick->hwdata->hats[i].axis[1] = 1;
      }
      return (0);
  }
  
  static int
  allocate_balldata(SDL_Joystick * joystick)
  {
      int i;
  
      joystick->hwdata->balls =
          (struct hwdata_ball *) SDL_malloc(joystick->nballs *
                                            sizeof(struct hwdata_ball));
      if (joystick->hwdata->balls == NULL) {
          return (-1);
      }
      for (i = 0; i < joystick->nballs; ++i) {
          joystick->hwdata->balls[i].axis[0] = 0;
          joystick->hwdata->balls[i].axis[1] = 0;
      }
      return (0);
  }
  
  static void
  ConfigJoystick(SDL_Joystick * joystick, int fd)
  {
      int i, t;
      unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
      unsigned long absbit[NBITS(ABS_MAX)] = { 0 };
      unsigned long relbit[NBITS(REL_MAX)] = { 0 };
  
      /* See if this device uses the new unified event API */
      if ((ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) >= 0) &&
          (ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) >= 0) &&
          (ioctl(fd, EVIOCGBIT(EV_REL, sizeof(relbit)), relbit) >= 0)) {
  
          /* Get the number of buttons, axes, and other thingamajigs */
          for (i = BTN_JOYSTICK; i < KEY_MAX; ++i) {
              if (test_bit(i, keybit)) {
  #ifdef DEBUG_INPUT_EVENTS
                  printf("Joystick has button: 0x%x\n", i);
  #endif
                  joystick->hwdata->key_map[i - BTN_MISC] = joystick->nbuttons;
                  ++joystick->nbuttons;
              }
          }
          for (i = BTN_MISC; i < BTN_JOYSTICK; ++i) {
              if (test_bit(i, keybit)) {
  #ifdef DEBUG_INPUT_EVENTS
                  printf("Joystick has button: 0x%x\n", i);
  #endif
                  joystick->hwdata->key_map[i - BTN_MISC] = joystick->nbuttons;
                  ++joystick->nbuttons;
              }
          }
          for (i = 0; i < ABS_MAX; ++i) {
              /* Skip hats */
              if (i == ABS_HAT0X) {
                  i = ABS_HAT3Y;
                  continue;
              }
              if (test_bit(i, absbit)) {
                  struct input_absinfo absinfo;
  
                  if (ioctl(fd, EVIOCGABS(i), &absinfo) < 0) {
                      continue;
                  }
  #ifdef DEBUG_INPUT_EVENTS
                  printf("Joystick has absolute axis: 0x%.2x\n", i);
                  printf("Values = { %d, %d, %d, %d, %d }\n",
                         absinfo.value, absinfo.minimum, absinfo.maximum,
                         absinfo.fuzz, absinfo.flat);
  #endif /* DEBUG_INPUT_EVENTS */
                  joystick->hwdata->abs_map[i] = joystick->naxes;
                  if (absinfo.minimum == absinfo.maximum) {
                      joystick->hwdata->abs_correct[i].used = 0;
                  } else {
                      joystick->hwdata->abs_correct[i].used = 1;
                      joystick->hwdata->abs_correct[i].coef[0] =
                          (absinfo.maximum + absinfo.minimum) - 2 * absinfo.flat;
                      joystick->hwdata->abs_correct[i].coef[1] =
                          (absinfo.maximum + absinfo.minimum) + 2 * absinfo.flat;
                      t = ((absinfo.maximum - absinfo.minimum) - 4 * absinfo.flat);
                      if (t != 0) {
                          joystick->hwdata->abs_correct[i].coef[2] =
                              (1 << 28) / t;
                      } else {
                          joystick->hwdata->abs_correct[i].coef[2] = 0;
                      }
                  }
                  ++joystick->naxes;
              }
          }
          for (i = ABS_HAT0X; i <= ABS_HAT3Y; i += 2) {
              if (test_bit(i, absbit) || test_bit(i + 1, absbit)) {
                  struct input_absinfo absinfo;
  
                  if (ioctl(fd, EVIOCGABS(i), &absinfo) < 0) {
                      continue;
                  }
  #ifdef DEBUG_INPUT_EVENTS
                  printf("Joystick has hat %d\n", (i - ABS_HAT0X) / 2);
                  printf("Values = { %d, %d, %d, %d, %d }\n",
                         absinfo.value, absinfo.minimum, absinfo.maximum,
                         absinfo.fuzz, absinfo.flat);
  #endif /* DEBUG_INPUT_EVENTS */
                  ++joystick->nhats;
              }
          }
          if (test_bit(REL_X, relbit) || test_bit(REL_Y, relbit)) {
              ++joystick->nballs;
          }
  
          /* Allocate data to keep track of these thingamajigs */
          if (joystick->nhats > 0) {
              if (allocate_hatdata(joystick) < 0) {
                  joystick->nhats = 0;
              }
          }
          if (joystick->nballs > 0) {
              if (allocate_balldata(joystick) < 0) {
                  joystick->nballs = 0;
              }
          }
      }
  }
  
  
  /* Function to open a joystick for use.
     The joystick to open is specified by the device index.
     This should fill the nbuttons and naxes fields of the joystick structure.
     It returns 0, or -1 if there is an error.
   */
  int
  SDL_SYS_JoystickOpen(SDL_Joystick * joystick, int device_index)
  {
      SDL_joylist_item *item = JoystickByDevIndex(device_index);
      char *fname = NULL;
      int fd = -1;
  
      if (item == NULL) {
          return SDL_SetError("No such device");
      }
  
      fname = item->path;
      fd = open(fname, O_RDONLY, 0);
      if (fd < 0) {
          return SDL_SetError("Unable to open %s", fname);
      }
  
      joystick->instance_id = item->device_instance;
      joystick->hwdata = (struct joystick_hwdata *)
          SDL_malloc(sizeof(*joystick->hwdata));
      if (joystick->hwdata == NULL) {
          close(fd);
          return SDL_OutOfMemory();
      }
      SDL_memset(joystick->hwdata, 0, sizeof(*joystick->hwdata));
      joystick->hwdata->item = item;
      joystick->hwdata->guid = item->guid;
      joystick->hwdata->fd = fd;
      joystick->hwdata->fname = SDL_strdup(item->path);
      if (joystick->hwdata->fname == NULL) {
          SDL_free(joystick->hwdata);
          joystick->hwdata = NULL;
          close(fd);
          return SDL_OutOfMemory();
      }
  
      SDL_assert(item->hwdata == NULL);
      item->hwdata = joystick->hwdata;
  
      /* Set the joystick to non-blocking read mode */
      fcntl(fd, F_SETFL, O_NONBLOCK);
  
      /* Get the number of buttons and axes on the joystick */
      ConfigJoystick(joystick, fd);
  
      /* mark joystick as fresh and ready */
      joystick->hwdata->fresh = 1;
  
      return (0);
  }
  
  /* Function to determine if this joystick is attached to the system right now */
  SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
  {
      return joystick->hwdata->item != NULL;
  }
  
  static SDL_INLINE void
  HandleHat(SDL_Joystick * stick, Uint8 hat, int axis, int value)
  {
      struct hwdata_hat *the_hat;
      const Uint8 position_map[3][3] = {
          {SDL_HAT_LEFTUP, SDL_HAT_UP, SDL_HAT_RIGHTUP},
          {SDL_HAT_LEFT, SDL_HAT_CENTERED, SDL_HAT_RIGHT},
          {SDL_HAT_LEFTDOWN, SDL_HAT_DOWN, SDL_HAT_RIGHTDOWN}
      };
  
      the_hat = &stick->hwdata->hats[hat];
      if (value < 0) {
          value = 0;
      } else if (value == 0) {
          value = 1;
      } else if (value > 0) {
          value = 2;
      }
      if (value != the_hat->axis[axis]) {
          the_hat->axis[axis] = value;
          SDL_PrivateJoystickHat(stick, hat,
                                 position_map[the_hat->
                                              axis[1]][the_hat->axis[0]]);
      }
  }
  
  static SDL_INLINE void
  HandleBall(SDL_Joystick * stick, Uint8 ball, int axis, int value)
  {
      stick->hwdata->balls[ball].axis[axis] += value;
  }
  
  
  static SDL_INLINE int
  AxisCorrect(SDL_Joystick * joystick, int which, int value)
  {
      struct axis_correct *correct;
  
      correct = &joystick->hwdata->abs_correct[which];
      if (correct->used) {
          value *= 2;
          if (value > correct->coef[0]) {
              if (value < correct->coef[1]) {
                  return 0;
              }
              value -= correct->coef[1];
          } else {
              value -= correct->coef[0];
          }
          value *= correct->coef[2];
          value >>= 13;
      }
  
      /* Clamp and return */
      if (value < -32768)
          return -32768;
      if (value > 32767)
          return 32767;
  
      return value;
  }
  
  static SDL_INLINE void
  PollAllValues(SDL_Joystick * joystick)
  {
      struct input_absinfo absinfo;
      int a, b = 0;
  
      /* Poll all axis */
      for (a = ABS_X; b < ABS_MAX; a++) {
          switch (a) {
          case ABS_HAT0X:
          case ABS_HAT0Y:
          case ABS_HAT1X:
          case ABS_HAT1Y:
          case ABS_HAT2X:
          case ABS_HAT2Y:
          case ABS_HAT3X:
          case ABS_HAT3Y:
              /* ingore hats */
              break;
          default:
              if (joystick->hwdata->abs_correct[b].used) {
                  if (ioctl(joystick->hwdata->fd, EVIOCGABS(a), &absinfo) >= 0) {
                      absinfo.value = AxisCorrect(joystick, b, absinfo.value);
  
  #ifdef DEBUG_INPUT_EVENTS
                      printf("Joystick : Re-read Axis %d (%d) val= %d\n",
                          joystick->hwdata->abs_map[b], a, absinfo.value);
  #endif
                      SDL_PrivateJoystickAxis(joystick,
                              joystick->hwdata->abs_map[b],
                              absinfo.value);
                  }
              }
              b++;
          }
      }
  }
  
  static SDL_INLINE void
  HandleInputEvents(SDL_Joystick * joystick)
  {
      struct input_event events[32];
      int i, len;
      int code;
  
      if (joystick->hwdata->fresh) {
          PollAllValues(joystick);
          joystick->hwdata->fresh = 0;
      }
  
      while ((len = read(joystick->hwdata->fd, events, (sizeof events))) > 0) {
          len /= sizeof(events[0]);
          for (i = 0; i < len; ++i) {
              code = events[i].code;
              switch (events[i].type) {
              case EV_KEY:
                  if (code >= BTN_MISC) {
                      code -= BTN_MISC;
                      SDL_PrivateJoystickButton(joystick,
                                                joystick->hwdata->key_map[code],
                                                events[i].value);
                  }
                  break;
              case EV_ABS:
                  switch (code) {
                  case ABS_HAT0X:
                  case ABS_HAT0Y:
                  case ABS_HAT1X:
                  case ABS_HAT1Y:
                  case ABS_HAT2X:
                  case ABS_HAT2Y:
                  case ABS_HAT3X:
                  case ABS_HAT3Y:
                      code -= ABS_HAT0X;
                      HandleHat(joystick, code / 2, code % 2, events[i].value);
                      break;
                  default:
                      events[i].value =
                          AxisCorrect(joystick, code, events[i].value);
                      SDL_PrivateJoystickAxis(joystick,
                                              joystick->hwdata->abs_map[code],
                                              events[i].value);
                      break;
                  }
                  break;
              case EV_REL:
                  switch (code) {
                  case REL_X:
                  case REL_Y:
                      code -= REL_X;
                      HandleBall(joystick, code / 2, code % 2, events[i].value);
                      break;
                  default:
                      break;
                  }
                  break;
              case EV_SYN:
                  switch (code) {
                  case SYN_DROPPED :
  #ifdef DEBUG_INPUT_EVENTS
                      printf("Event SYN_DROPPED detected\n");
  #endif
                      PollAllValues(joystick);
                      break;
                  default:
                      break;
                  }
              default:
                  break;
              }
          }
      }
  }
  
  void
  SDL_SYS_JoystickUpdate(SDL_Joystick * joystick)
  {
      int i;
  
      HandleInputEvents(joystick);
  
      /* Deliver ball motion updates */
      for (i = 0; i < joystick->nballs; ++i) {
          int xrel, yrel;
  
          xrel = joystick->hwdata->balls[i].axis[0];
          yrel = joystick->hwdata->balls[i].axis[1];
          if (xrel || yrel) {
              joystick->hwdata->balls[i].axis[0] = 0;
              joystick->hwdata->balls[i].axis[1] = 0;
              SDL_PrivateJoystickBall(joystick, (Uint8) i, xrel, yrel);
          }
      }
  }
  
  /* Function to close a joystick after use */
  void
  SDL_SYS_JoystickClose(SDL_Joystick * joystick)
  {
      if (joystick->hwdata) {
          close(joystick->hwdata->fd);
          if (joystick->hwdata->item) {
              joystick->hwdata->item->hwdata = NULL;
          }
          SDL_free(joystick->hwdata->hats);
          SDL_free(joystick->hwdata->balls);
          SDL_free(joystick->hwdata->fname);
          SDL_free(joystick->hwdata);
      }
  }
  
  /* Function to perform any system-specific joystick related cleanup */
  void
  SDL_SYS_JoystickQuit(void)
  {
      SDL_joylist_item *item = NULL;
      SDL_joylist_item *next = NULL;
  
      for (item = SDL_joylist; item; item = next) {
          next = item->next;
          SDL_free(item->path);
          SDL_free(item->name);
          SDL_free(item);
      }
  
      SDL_joylist = SDL_joylist_tail = NULL;
  
      numjoysticks = 0;
      instance_counter = 0;
  
  #if SDL_USE_LIBUDEV
      SDL_UDEV_DelCallback(joystick_udev_callback);
      SDL_UDEV_Quit();
  #endif
  }
  
  SDL_JoystickGUID SDL_SYS_JoystickGetDeviceGUID( int device_index )
  {
      return JoystickByDevIndex(device_index)->guid;
  }
  
  SDL_JoystickGUID SDL_SYS_JoystickGetGUID(SDL_Joystick * joystick)
  {
      return joystick->hwdata->guid;
  }
  
  #endif /* SDL_JOYSTICK_LINUX */
  
  /* vi: set ts=4 sw=4 expandtab: */
  

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