gcc-4.3.1/libjava/classpath/native/jni/gtk-peer/gtkpeer.c - toolchain/gcc - Git at Google

 /* gtkpeer.c -- Some GTK peer specific helper functions
    Copyright (C) 2007 Free Software Foundation, Inc.

 This file is part of GNU Classpath.

 GNU Classpath is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2, or (at your option)
 any later version.

 GNU Classpath 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
 General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with GNU Classpath; see the file COPYING.  If not, write to the
 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 02110-1301 USA.

 Linking this library statically or dynamically with other modules is
 making a combined work based on this library.  Thus, the terms and
 conditions of the GNU General Public License cover the whole
 combination.

 As a special exception, the copyright holders of this library give you
 permission to link this library with independent modules to produce an
 executable, regardless of the license terms of these independent
 modules, and to copy and distribute the resulting executable under
 terms of your choice, provided that you also meet, for each linked
 independent module, the terms and conditions of the license of that
 module.  An independent module is a module which is not derived from
 or based on this library.  If you modify this library, you may extend
 this exception to your version of the library, but you are not
 obligated to do so.  If you do not wish to do so, delete this
 exception statement from your version. */

 #include "gtkpeer.h"
 #include "jni.h"

 /**
  * The Pointer class.
  */
 static jclass pointerClass;

 /**
  * The Pointer constructor.
  */
 static jmethodID pointerConstructorMID;

 /**
  * The field ID of the data field in the Pointer class.
  */
 static jfieldID pointerDataFID;

 /**
  * The field ID of the widget field in the GtkGenericPeer class.
  */
 static jfieldID widgetFID;

 /**
  * The field ID of the globalRef field in the GtkGenericPeer class.
  */
 static jfieldID globalRefFID;

 /**
  * The field ID of the display field in the GdkGraphicsEnvironment class.
  */
 static jfieldID displayFID;

 /**
  * The field ID of the screen field in the GdkScreenGraphicsDevice class.
  */
 static jfieldID screenFID;

 /**
  * The field ID of the nativeFont field in GdkFontPeer.
  */
 static jfieldID fontFID;

 /**
  * The field ID of the nativeDecoder field in GdkPixbufDecoder.
  */
 static jfieldID pixbufLoaderFID;

 /**
  * Initializes the IDs of the Pointer* classes.
  *
  * @param env the JNI environment
  */
 void gtkpeer_init_pointer_IDs(JNIEnv* env)
 {
 #if SIZEOF_VOID_P == 8
   pointerClass = (*env)->FindClass (env, "gnu/classpath/Pointer64");
   if (pointerClass != NULL)
     {
       pointerClass = (*env)->NewGlobalRef (env, pointerClass);
       pointerDataFID = (*env)->GetFieldID (env, pointerClass, "data", "J");
       pointerConstructorMID = (*env)->GetMethodID (env, pointerClass, "<init>",
 						   "(J)V");
     }
 #else
 #if SIZEOF_VOID_P == 4
   pointerClass = (*env)->FindClass(env, "gnu/classpath/Pointer32");
   pointerDataFID = (*env)->GetFieldID(env, pointerClass, "data", "I");

   /* Find the Pointer32 constructor. */
   pointerConstructorMID = (*env)->GetMethodID(env, pointerClass, "<init>",
                                               "(I)V");
 #else
 #error "Pointer size is not supported."
 #endif /* SIZEOF_VOID_P == 4 */
 #endif /* SIZEOF_VOID_P == 8 */
 }

 /**
  * Initializes the field IDs for the widget reference.
  *
  * @param env the JNI environment
  */
 void gtkpeer_init_widget_IDs(JNIEnv *env)
 {
   jclass cls;

   /* Find the widget field ID in GtkGenericPeer. */
   cls = (*env)->FindClass(env, "gnu/java/awt/peer/gtk/GtkGenericPeer");
   widgetFID = (*env)->GetFieldID(env, cls, "widget",
                                  "Lgnu/classpath/Pointer;");

   /* Find the globalRef field in GtkGenericPeer. */
   globalRefFID = (*env)->GetFieldID(env, cls, "globalRef",
                                  "Lgnu/classpath/Pointer;");
 }

 /**
  * Stores the GTK widget reference in the GtkGenericPeer object.
  *
  * @param env the JNI environment
  * @param peer the actual peer object
  * @param widget the widget reference to store
  */
 void gtkpeer_set_widget(JNIEnv *env, jobject peer, void *widget)
 {
   jobject obj;

   /* Fetch the widget field object. */
   obj = (*env)->GetObjectField(env, peer, widgetFID);
   if (obj == NULL)
     {
       /* Create if necessary. */
 #if SIZEOF_VOID_P == 8
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jlong) widget);
 #else
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jint) widget);
 #endif
       (*env)->SetObjectField(env, peer, widgetFID, obj);
     }
   else
     {
 #if SIZEOF_VOID_P == 8
       (*env)->SetLongField(env, obj, pointerDataFID, (jlong) widget);
 #else
       (*env)->SetIntField(env, obj, pointerDataFID, (jint) widget);
 #endif
     }
 }

 /**
  * Retrieves the GTK widget reference from a GtkGenericPeer object.
  *
  * @param env the JNI environment
  * @param peer the actual peer object
  *
  * @return the widget reference
  */
 void* gtkpeer_get_widget(JNIEnv *env, jobject peer)
 {
   jobject obj;
   void *widget;

   /* Fetch the widget field from the peer object. */
   obj = (*env)->GetObjectField(env, peer, widgetFID);

   /* Fetch actual widget pointer. */
 #if SIZEOF_VOID_P == 8
   widget = (void*) (*env)->GetLongField(env, obj, pointerDataFID);
 #else
   widget = (void*) (*env)->GetIntField(env, obj, pointerDataFID);
 #endif
   return widget;
 }


 /**
  * Stores the global JNI reference of a peer inside the peer.
  *
  * @param env the JNI environment
  * @param peer the peer object
  */
 void gtkpeer_set_global_ref(JNIEnv *env, jobject peer)
 {
   jobject obj;
   void* globalRef;

   /* Create global reference. */
   globalRef = (*env)->NewGlobalRef(env, peer);

   /* Fetch the globalRef field object. */
   obj = (*env)->GetObjectField(env, peer, globalRefFID);
   if (obj == NULL)
     {
       /* Create if necessary. */
 #if SIZEOF_VOID_P == 8
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jlong) globalRef);
 #else
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jint) globalRef);
 #endif
       (*env)->SetObjectField(env, peer, globalRefFID, obj);
     }
   else
     {
 #if SIZEOF_VOID_P == 8
       (*env)->SetLongField(env, obj, pointerDataFID, (jlong) globalRef);
 #else
       (*env)->SetIntField(env, obj, pointerDataFID, (jint) globalRef);
 #endif
     }
 }

 /**
  * Retrieves the global reference from a peer.
  *
  * @param env the JNI environment
  * @param peer the peer object
  *
  * @return the global reference
  */
 void* gtkpeer_get_global_ref(JNIEnv *env, jobject peer)
 {
   jobject obj;
   void *globalRef;

   /* Fetch the globalRef field from the peer object. */
   obj = (*env)->GetObjectField(env, peer, globalRefFID);

   /* Fetch actual globalRef pointer. */
 #if SIZEOF_VOID_P == 8
   globalRef = (void*) (*env)->GetLongField(env, obj, pointerDataFID);
 #else
   globalRef = (void*) (*env)->GetIntField(env, obj, pointerDataFID);
 #endif
   return globalRef;
 }

 /**
  * Deletes the global reference of a peer. This is necessary in order to
  * allow the peer to be garbage collected.
  *
  * @param env the JNI environment
  * @param peer the peer object.
  */
 void gtkpeer_del_global_ref(JNIEnv* env, jobject peer)
 {
   jobject obj;
   void *globalRef;

   /* Fetch the globalRef field from the peer object. */
   obj = (*env)->GetObjectField(env, peer, globalRefFID);

   /* Fetch actual globalRef pointer. */
 #if SIZEOF_VOID_P == 8
   globalRef = (void*) (*env)->GetLongField(env, obj, pointerDataFID);
 #else
   globalRef = (void*) (*env)->GetIntField(env, obj, pointerDataFID);
 #endif
   (*env)->DeleteGlobalRef(env, globalRef);
 }

 /**
  * Initializes the fieldIDs for the display and screen fields.
  *
  * @param env the JNI environment
  */
 void gtkpeer_init_display_IDs(JNIEnv* env)
 {
   jclass cls;

   /* Find the display field ID in GdkGraphicsEnvironment. */
   cls = (*env)->FindClass(env, "gnu/java/awt/peer/gtk/GdkGraphicsEnvironment");
   displayFID = (*env)->GetFieldID(env, cls, "display",
                                   "Lgnu/classpath/Pointer;");
 }

 /**
  * Sets the native display pointer in the GdkGraphicsEnvironment object.
  *
  * @param env the JNI environment
  * @param graphicsenv the GdkGraphicsEnvironment object
  * @param display the native display pointer
  */
 void gtkpeer_set_display(JNIEnv* env, jobject graphicsenv, void* display)
 {
   jobject obj;

   /* Fetch the display field object. */
   obj = (*env)->GetObjectField(env, graphicsenv, displayFID);
   if (obj == NULL)
     {
       /* Create if necessary. */
 #if SIZEOF_VOID_P == 8
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jlong) display);
 #else
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jint) display);
 #endif
       (*env)->SetObjectField(env, graphicsenv, displayFID, obj);
     }
   else
     {
 #if SIZEOF_VOID_P == 8
       (*env)->SetLongField(env, obj, pointerDataFID, (jlong) display);
 #else
       (*env)->SetIntField(env, obj, pointerDataFID, (jint) display);
 #endif
     }
 }

 /**
  * Fetches the native display pointer from the GdkGraphicsEnvironment object.
  *
  * @param env the JNI environment
  * @param graphicsenv the GdkGraphicsEnvironment object
  *
  * @return the native display pointer
  */
 void* gtkpeer_get_display(JNIEnv* env, jobject graphicsenv)
 {
   jobject obj;
   void *display;

   /* Fetch the display field from the peer object. */
   obj = (*env)->GetObjectField(env, graphicsenv, displayFID);

   /* Fetch actual display pointer. */
 #if SIZEOF_VOID_P == 8
   display = (void*) (*env)->GetLongField(env, obj, pointerDataFID);
 #else
   display = (void*) (*env)->GetIntField(env, obj, pointerDataFID);
 #endif
   return display;
 }

 /**
  * Initializes the fieldIDs for the screen field.
  *
  * @param env the JNI environment
  */
 void gtkpeer_init_screen_IDs(JNIEnv* env)
 {
   jclass cls;

   /* Find the display field ID in GdkScreenGraphicsDevice. */
   cls = (*env)->FindClass(env,
                           "gnu/java/awt/peer/gtk/GdkScreenGraphicsDevice");
   screenFID = (*env)->GetFieldID(env, cls, "screen",
                                  "Lgnu/classpath/Pointer;");
 }

 /**
  * Sets the native screen in the GdkScreenGraphicsDevice object.
  *
  * @param env the JNI environment
  * @param screen_graphics_device the GdkScreenGraphicsDevice object
  * @param ptr the native screen pointer
  */
 void gtkpeer_set_screen(JNIEnv* env, jobject screen_graphics_device,
                         void* ptr)
 {
   jobject obj;

   /* Fetch the screen field object. */
   obj = (*env)->GetObjectField(env, screen_graphics_device, screenFID);
   if (obj == NULL)
     {
       /* Create if necessary. */
 #if SIZEOF_VOID_P == 8
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jlong) ptr);
 #else
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jint) ptr);
 #endif
       (*env)->SetObjectField(env, screen_graphics_device, screenFID, obj);
     }
   else
     {
 #if SIZEOF_VOID_P == 8
       (*env)->SetLongField(env, obj, pointerDataFID, (jlong) ptr);
 #else
       (*env)->SetIntField(env, obj, pointerDataFID, (jint) ptr);
 #endif
     }
 }

 /**
  * Fetches the native screen pointer from the GdkScreenGraphicsDevice object.
  *
  * @param env the JNI environment
  * @param screen_graphics_device the GdkScreenGraphicsDevice object
  *
  * @return the native screen pointer
  */
 void* gtkpeer_get_screen(JNIEnv* env, jobject screen_graphics_device)
 {
   jobject obj;
   void *screen;

   /* Fetch the display field from the peer object. */
   obj = (*env)->GetObjectField(env, screen_graphics_device, screenFID);

   /* Fetch actual display pointer. */
 #if SIZEOF_VOID_P == 8
   screen = (void*) (*env)->GetLongField(env, obj, pointerDataFID);
 #else
   screen = (void*) (*env)->GetIntField(env, obj, pointerDataFID);
 #endif
   return screen;
 }

 /**
  * Initializes the field IDs for fonts.
  *
  * @param env the JNI environment
  */
 void gtkpeer_init_font_IDs(JNIEnv* env)
 {
   jclass cls;

   /* Find the nativeFont field ID in GdkFontPeer. */
   cls = (*env)->FindClass(env, "gnu/java/awt/peer/gtk/GdkFontPeer");
   fontFID = (*env)->GetFieldID(env, cls, "nativeFont",
                                "Lgnu/classpath/Pointer;");
 }

 /**
  * Sets the native font in the nativeFont field in GdkFontPeer.
  *
  * @param env the JNI environment
  * @param font_peer the font peer object
  * @param font the actual native font reference
  */
 void gtkpeer_set_font(JNIEnv* env, jobject font_peer, void* font)
 {
   jobject obj;

   /* Fetch the nativeFont field object. */
   obj = (*env)->GetObjectField(env, font_peer, fontFID);
   if (obj == NULL)
     {
       /* Create if necessary. */
 #if SIZEOF_VOID_P == 8
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jlong) font);
 #else
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jint) font);
 #endif
       (*env)->SetObjectField(env, font_peer, fontFID, obj);
     }
   else
     {
 #if SIZEOF_VOID_P == 8
       (*env)->SetLongField(env, obj, pointerDataFID, (jlong) font);
 #else
       (*env)->SetIntField(env, obj, pointerDataFID, (jint) font);
 #endif
     }
 }

 /**
  * Fetches the native font reference from the GdkFontPeer object.
  *
  * @param env the JNI environment
  * @param font_peer the font peer object
  *
  * @return the native font structure
  */
 void* gtkpeer_get_font(JNIEnv* env, jobject font_peer)
 {
   jobject obj;
   void *font;

   /* Fetch the nativeFont field from the peer object. */
   obj = (*env)->GetObjectField(env, font_peer, fontFID);

   /* Fetch actual font pointer. */
 #if SIZEOF_VOID_P == 8
   font = (void*) (*env)->GetLongField(env, obj, pointerDataFID);
 #else
   font = (void*) (*env)->GetIntField(env, obj, pointerDataFID);
 #endif
   return font;
 }

 /**
  * Initializes the field IDs for pixbuf decoder.
  *
  * @param env the JNI environment
  */
 void gtkpeer_init_pixbuf_IDs(JNIEnv* env)
 {
   jclass cls;

   /* Find the nativeFont field ID in GdkFontPeer. */
   cls = (*env)->FindClass(env, "gnu/java/awt/peer/gtk/GdkPixbufDecoder");
   pixbufLoaderFID = (*env)->GetFieldID(env, cls, "nativeDecoder",
                                        "Lgnu/classpath/Pointer;");
 }

 /**
  * Sets the native font in the nativeFont field in GdkFontPeer.
  *
  * @param env the JNI environment
  * @param pixbuf_dec the pixbuf decoder object
  * @param pixbuf_loader the native pixbuf loader
  */
 void gtkpeer_set_pixbuf_loader(JNIEnv* env, jobject pixbuf_dec,
                                void* pixbuf_loader)
 {
   jobject obj;

   /* Fetch the nativeDecoder field object. */
   obj = (*env)->GetObjectField(env, pixbuf_dec, pixbufLoaderFID);
   if (obj == NULL)
     {
       /* Create if necessary. */
 #if SIZEOF_VOID_P == 8
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jlong) pixbuf_loader);
 #else
       obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
                               (jint) pixbuf_loader);
 #endif
       (*env)->SetObjectField(env, pixbuf_dec, pixbufLoaderFID, obj);
     }
   else
     {
 #if SIZEOF_VOID_P == 8
       (*env)->SetLongField(env, obj, pointerDataFID, (jlong) pixbuf_loader);
 #else
       (*env)->SetIntField(env, obj, pointerDataFID, (jint) pixbuf_loader);
 #endif
     }
 }

 /**
  * Fetches the native pixbuf loader reference from the GdkPixbufDecoder object.
  *
  * @param env the JNI environment
  * @param pixbuf_dec the pixbuf decoder object
  *
  * @return the native pixbuf loader
  */
 void* gtkpeer_get_pixbuf_loader(JNIEnv* env, jobject pixbuf_dec)
 {
   jobject obj;
   void *loader;

   /* Fetch the nativeFont field from the peer object. */
   obj = (*env)->GetObjectField(env, pixbuf_dec, pixbufLoaderFID);

   /* Fetch actual font pointer. */
 #if SIZEOF_VOID_P == 8
   loader = (void*) (*env)->GetLongField(env, obj, pointerDataFID);
 #else
   loader = (void*) (*env)->GetIntField(env, obj, pointerDataFID);
 #endif
   return loader;
 }
	/* gtkpeer.c -- Some GTK peer specific helper functions
	Copyright (C) 2007 Free Software Foundation, Inc.

	This file is part of GNU Classpath.

	GNU Classpath is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2, or (at your option)
	any later version.

	GNU Classpath 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
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with GNU Classpath; see the file COPYING. If not, write to the
	Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	02110-1301 USA.

	Linking this library statically or dynamically with other modules is
	making a combined work based on this library. Thus, the terms and
	conditions of the GNU General Public License cover the whole
	combination.

	As a special exception, the copyright holders of this library give you
	permission to link this library with independent modules to produce an
	executable, regardless of the license terms of these independent
	modules, and to copy and distribute the resulting executable under
	terms of your choice, provided that you also meet, for each linked
	independent module, the terms and conditions of the license of that
	module. An independent module is a module which is not derived from
	or based on this library. If you modify this library, you may extend
	this exception to your version of the library, but you are not
	obligated to do so. If you do not wish to do so, delete this
	exception statement from your version. */

	#include "gtkpeer.h"
	#include "jni.h"

	/**
	* The Pointer class.
	*/
	static jclass pointerClass;

	/**
	* The Pointer constructor.
	*/
	static jmethodID pointerConstructorMID;

	/**
	* The field ID of the data field in the Pointer class.
	*/
	static jfieldID pointerDataFID;

	/**
	* The field ID of the widget field in the GtkGenericPeer class.
	*/
	static jfieldID widgetFID;

	/**
	* The field ID of the globalRef field in the GtkGenericPeer class.
	*/
	static jfieldID globalRefFID;

	/**
	* The field ID of the display field in the GdkGraphicsEnvironment class.
	*/
	static jfieldID displayFID;

	/**
	* The field ID of the screen field in the GdkScreenGraphicsDevice class.
	*/
	static jfieldID screenFID;

	/**
	* The field ID of the nativeFont field in GdkFontPeer.
	*/
	static jfieldID fontFID;

	/**
	* The field ID of the nativeDecoder field in GdkPixbufDecoder.
	*/
	static jfieldID pixbufLoaderFID;

	/**
	* Initializes the IDs of the Pointer* classes.
	*
	* @param env the JNI environment
	*/
	void gtkpeer_init_pointer_IDs(JNIEnv* env)
	{
	#if SIZEOF_VOID_P == 8
	pointerClass = (*env)->FindClass (env, "gnu/classpath/Pointer64");
	if (pointerClass != NULL)
	{
	pointerClass = (*env)->NewGlobalRef (env, pointerClass);
	pointerDataFID = (*env)->GetFieldID (env, pointerClass, "data", "J");
	pointerConstructorMID = (*env)->GetMethodID (env, pointerClass, "<init>",
	"(J)V");
	}
	#else
	#if SIZEOF_VOID_P == 4
	pointerClass = (*env)->FindClass(env, "gnu/classpath/Pointer32");
	pointerDataFID = (*env)->GetFieldID(env, pointerClass, "data", "I");

	/* Find the Pointer32 constructor. */
	pointerConstructorMID = (*env)->GetMethodID(env, pointerClass, "<init>",
	"(I)V");
	#else
	#error "Pointer size is not supported."
	#endif /* SIZEOF_VOID_P == 4 */
	#endif /* SIZEOF_VOID_P == 8 */
	}

	/**
	* Initializes the field IDs for the widget reference.
	*
	* @param env the JNI environment
	*/
	void gtkpeer_init_widget_IDs(JNIEnv *env)
	{
	jclass cls;

	/* Find the widget field ID in GtkGenericPeer. */
	cls = (*env)->FindClass(env, "gnu/java/awt/peer/gtk/GtkGenericPeer");
	widgetFID = (*env)->GetFieldID(env, cls, "widget",
	"Lgnu/classpath/Pointer;");

	/* Find the globalRef field in GtkGenericPeer. */
	globalRefFID = (*env)->GetFieldID(env, cls, "globalRef",
	"Lgnu/classpath/Pointer;");
	}

	/**
	* Stores the GTK widget reference in the GtkGenericPeer object.
	*
	* @param env the JNI environment
	* @param peer the actual peer object
	* @param widget the widget reference to store
	*/
	void gtkpeer_set_widget(JNIEnv env, jobject peer, void widget)
	{
	jobject obj;

	/* Fetch the widget field object. */
	obj = (*env)->GetObjectField(env, peer, widgetFID);
	if (obj == NULL)
	{
	/* Create if necessary. */
	#if SIZEOF_VOID_P == 8
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jlong) widget);
	#else
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jint) widget);
	#endif
	(*env)->SetObjectField(env, peer, widgetFID, obj);
	}
	else
	{
	#if SIZEOF_VOID_P == 8
	(*env)->SetLongField(env, obj, pointerDataFID, (jlong) widget);
	#else
	(*env)->SetIntField(env, obj, pointerDataFID, (jint) widget);
	#endif
	}
	}

	/**
	* Retrieves the GTK widget reference from a GtkGenericPeer object.
	*
	* @param env the JNI environment
	* @param peer the actual peer object
	*
	* @return the widget reference
	*/
	void* gtkpeer_get_widget(JNIEnv *env, jobject peer)
	{
	jobject obj;
	void *widget;

	/* Fetch the widget field from the peer object. */
	obj = (*env)->GetObjectField(env, peer, widgetFID);

	/* Fetch actual widget pointer. */
	#if SIZEOF_VOID_P == 8
	widget = (void) (env)->GetLongField(env, obj, pointerDataFID);
	#else
	widget = (void) (env)->GetIntField(env, obj, pointerDataFID);
	#endif
	return widget;
	}


	/**
	* Stores the global JNI reference of a peer inside the peer.
	*
	* @param env the JNI environment
	* @param peer the peer object
	*/
	void gtkpeer_set_global_ref(JNIEnv *env, jobject peer)
	{
	jobject obj;
	void* globalRef;

	/* Create global reference. */
	globalRef = (*env)->NewGlobalRef(env, peer);

	/* Fetch the globalRef field object. */
	obj = (*env)->GetObjectField(env, peer, globalRefFID);
	if (obj == NULL)
	{
	/* Create if necessary. */
	#if SIZEOF_VOID_P == 8
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jlong) globalRef);
	#else
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jint) globalRef);
	#endif
	(*env)->SetObjectField(env, peer, globalRefFID, obj);
	}
	else
	{
	#if SIZEOF_VOID_P == 8
	(*env)->SetLongField(env, obj, pointerDataFID, (jlong) globalRef);
	#else
	(*env)->SetIntField(env, obj, pointerDataFID, (jint) globalRef);
	#endif
	}
	}

	/**
	* Retrieves the global reference from a peer.
	*
	* @param env the JNI environment
	* @param peer the peer object
	*
	* @return the global reference
	*/
	void* gtkpeer_get_global_ref(JNIEnv *env, jobject peer)
	{
	jobject obj;
	void *globalRef;

	/* Fetch the globalRef field from the peer object. */
	obj = (*env)->GetObjectField(env, peer, globalRefFID);

	/* Fetch actual globalRef pointer. */
	#if SIZEOF_VOID_P == 8
	globalRef = (void) (env)->GetLongField(env, obj, pointerDataFID);
	#else
	globalRef = (void) (env)->GetIntField(env, obj, pointerDataFID);
	#endif
	return globalRef;
	}

	/**
	* Deletes the global reference of a peer. This is necessary in order to
	* allow the peer to be garbage collected.
	*
	* @param env the JNI environment
	* @param peer the peer object.
	*/
	void gtkpeer_del_global_ref(JNIEnv* env, jobject peer)
	{
	jobject obj;
	void *globalRef;

	/* Fetch the globalRef field from the peer object. */
	obj = (*env)->GetObjectField(env, peer, globalRefFID);

	/* Fetch actual globalRef pointer. */
	#if SIZEOF_VOID_P == 8
	globalRef = (void) (env)->GetLongField(env, obj, pointerDataFID);
	#else
	globalRef = (void) (env)->GetIntField(env, obj, pointerDataFID);
	#endif
	(*env)->DeleteGlobalRef(env, globalRef);
	}

	/**
	* Initializes the fieldIDs for the display and screen fields.
	*
	* @param env the JNI environment
	*/
	void gtkpeer_init_display_IDs(JNIEnv* env)
	{
	jclass cls;

	/* Find the display field ID in GdkGraphicsEnvironment. */
	cls = (*env)->FindClass(env, "gnu/java/awt/peer/gtk/GdkGraphicsEnvironment");
	displayFID = (*env)->GetFieldID(env, cls, "display",
	"Lgnu/classpath/Pointer;");
	}

	/**
	* Sets the native display pointer in the GdkGraphicsEnvironment object.
	*
	* @param env the JNI environment
	* @param graphicsenv the GdkGraphicsEnvironment object
	* @param display the native display pointer
	*/
	void gtkpeer_set_display(JNIEnv* env, jobject graphicsenv, void* display)
	{
	jobject obj;

	/* Fetch the display field object. */
	obj = (*env)->GetObjectField(env, graphicsenv, displayFID);
	if (obj == NULL)
	{
	/* Create if necessary. */
	#if SIZEOF_VOID_P == 8
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jlong) display);
	#else
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jint) display);
	#endif
	(*env)->SetObjectField(env, graphicsenv, displayFID, obj);
	}
	else
	{
	#if SIZEOF_VOID_P == 8
	(*env)->SetLongField(env, obj, pointerDataFID, (jlong) display);
	#else
	(*env)->SetIntField(env, obj, pointerDataFID, (jint) display);
	#endif
	}
	}

	/**
	* Fetches the native display pointer from the GdkGraphicsEnvironment object.
	*
	* @param env the JNI environment
	* @param graphicsenv the GdkGraphicsEnvironment object
	*
	* @return the native display pointer
	*/
	void* gtkpeer_get_display(JNIEnv* env, jobject graphicsenv)
	{
	jobject obj;
	void *display;

	/* Fetch the display field from the peer object. */
	obj = (*env)->GetObjectField(env, graphicsenv, displayFID);

	/* Fetch actual display pointer. */
	#if SIZEOF_VOID_P == 8
	display = (void) (env)->GetLongField(env, obj, pointerDataFID);
	#else
	display = (void) (env)->GetIntField(env, obj, pointerDataFID);
	#endif
	return display;
	}

	/**
	* Initializes the fieldIDs for the screen field.
	*
	* @param env the JNI environment
	*/
	void gtkpeer_init_screen_IDs(JNIEnv* env)
	{
	jclass cls;

	/* Find the display field ID in GdkScreenGraphicsDevice. */
	cls = (*env)->FindClass(env,
	"gnu/java/awt/peer/gtk/GdkScreenGraphicsDevice");
	screenFID = (*env)->GetFieldID(env, cls, "screen",
	"Lgnu/classpath/Pointer;");
	}

	/**
	* Sets the native screen in the GdkScreenGraphicsDevice object.
	*
	* @param env the JNI environment
	* @param screen_graphics_device the GdkScreenGraphicsDevice object
	* @param ptr the native screen pointer
	*/
	void gtkpeer_set_screen(JNIEnv* env, jobject screen_graphics_device,
	void* ptr)
	{
	jobject obj;

	/* Fetch the screen field object. */
	obj = (*env)->GetObjectField(env, screen_graphics_device, screenFID);
	if (obj == NULL)
	{
	/* Create if necessary. */
	#if SIZEOF_VOID_P == 8
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jlong) ptr);
	#else
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jint) ptr);
	#endif
	(*env)->SetObjectField(env, screen_graphics_device, screenFID, obj);
	}
	else
	{
	#if SIZEOF_VOID_P == 8
	(*env)->SetLongField(env, obj, pointerDataFID, (jlong) ptr);
	#else
	(*env)->SetIntField(env, obj, pointerDataFID, (jint) ptr);
	#endif
	}
	}

	/**
	* Fetches the native screen pointer from the GdkScreenGraphicsDevice object.
	*
	* @param env the JNI environment
	* @param screen_graphics_device the GdkScreenGraphicsDevice object
	*
	* @return the native screen pointer
	*/
	void* gtkpeer_get_screen(JNIEnv* env, jobject screen_graphics_device)
	{
	jobject obj;
	void *screen;

	/* Fetch the display field from the peer object. */
	obj = (*env)->GetObjectField(env, screen_graphics_device, screenFID);

	/* Fetch actual display pointer. */
	#if SIZEOF_VOID_P == 8
	screen = (void) (env)->GetLongField(env, obj, pointerDataFID);
	#else
	screen = (void) (env)->GetIntField(env, obj, pointerDataFID);
	#endif
	return screen;
	}

	/**
	* Initializes the field IDs for fonts.
	*
	* @param env the JNI environment
	*/
	void gtkpeer_init_font_IDs(JNIEnv* env)
	{
	jclass cls;

	/* Find the nativeFont field ID in GdkFontPeer. */
	cls = (*env)->FindClass(env, "gnu/java/awt/peer/gtk/GdkFontPeer");
	fontFID = (*env)->GetFieldID(env, cls, "nativeFont",
	"Lgnu/classpath/Pointer;");
	}

	/**
	* Sets the native font in the nativeFont field in GdkFontPeer.
	*
	* @param env the JNI environment
	* @param font_peer the font peer object
	* @param font the actual native font reference
	*/
	void gtkpeer_set_font(JNIEnv* env, jobject font_peer, void* font)
	{
	jobject obj;

	/* Fetch the nativeFont field object. */
	obj = (*env)->GetObjectField(env, font_peer, fontFID);
	if (obj == NULL)
	{
	/* Create if necessary. */
	#if SIZEOF_VOID_P == 8
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jlong) font);
	#else
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jint) font);
	#endif
	(*env)->SetObjectField(env, font_peer, fontFID, obj);
	}
	else
	{
	#if SIZEOF_VOID_P == 8
	(*env)->SetLongField(env, obj, pointerDataFID, (jlong) font);
	#else
	(*env)->SetIntField(env, obj, pointerDataFID, (jint) font);
	#endif
	}
	}

	/**
	* Fetches the native font reference from the GdkFontPeer object.
	*
	* @param env the JNI environment
	* @param font_peer the font peer object
	*
	* @return the native font structure
	*/
	void* gtkpeer_get_font(JNIEnv* env, jobject font_peer)
	{
	jobject obj;
	void *font;

	/* Fetch the nativeFont field from the peer object. */
	obj = (*env)->GetObjectField(env, font_peer, fontFID);

	/* Fetch actual font pointer. */
	#if SIZEOF_VOID_P == 8
	font = (void) (env)->GetLongField(env, obj, pointerDataFID);
	#else
	font = (void) (env)->GetIntField(env, obj, pointerDataFID);
	#endif
	return font;
	}

	/**
	* Initializes the field IDs for pixbuf decoder.
	*
	* @param env the JNI environment
	*/
	void gtkpeer_init_pixbuf_IDs(JNIEnv* env)
	{
	jclass cls;

	/* Find the nativeFont field ID in GdkFontPeer. */
	cls = (*env)->FindClass(env, "gnu/java/awt/peer/gtk/GdkPixbufDecoder");
	pixbufLoaderFID = (*env)->GetFieldID(env, cls, "nativeDecoder",
	"Lgnu/classpath/Pointer;");
	}

	/**
	* Sets the native font in the nativeFont field in GdkFontPeer.
	*
	* @param env the JNI environment
	* @param pixbuf_dec the pixbuf decoder object
	* @param pixbuf_loader the native pixbuf loader
	*/
	void gtkpeer_set_pixbuf_loader(JNIEnv* env, jobject pixbuf_dec,
	void* pixbuf_loader)
	{
	jobject obj;

	/* Fetch the nativeDecoder field object. */
	obj = (*env)->GetObjectField(env, pixbuf_dec, pixbufLoaderFID);
	if (obj == NULL)
	{
	/* Create if necessary. */
	#if SIZEOF_VOID_P == 8
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jlong) pixbuf_loader);
	#else
	obj = (*env)->NewObject(env, pointerClass, pointerConstructorMID,
	(jint) pixbuf_loader);
	#endif
	(*env)->SetObjectField(env, pixbuf_dec, pixbufLoaderFID, obj);
	}
	else
	{
	#if SIZEOF_VOID_P == 8
	(*env)->SetLongField(env, obj, pointerDataFID, (jlong) pixbuf_loader);
	#else
	(*env)->SetIntField(env, obj, pointerDataFID, (jint) pixbuf_loader);
	#endif
	}
	}

	/**
	* Fetches the native pixbuf loader reference from the GdkPixbufDecoder object.
	*
	* @param env the JNI environment
	* @param pixbuf_dec the pixbuf decoder object
	*
	* @return the native pixbuf loader
	*/
	void* gtkpeer_get_pixbuf_loader(JNIEnv* env, jobject pixbuf_dec)
	{
	jobject obj;
	void *loader;

	/* Fetch the nativeFont field from the peer object. */
	obj = (*env)->GetObjectField(env, pixbuf_dec, pixbufLoaderFID);

	/* Fetch actual font pointer. */
	#if SIZEOF_VOID_P == 8
	loader = (void) (env)->GetLongField(env, obj, pointerDataFID);
	#else
	loader = (void) (env)->GetIntField(env, obj, pointerDataFID);
	#endif
	return loader;
	}