* Replace the fixed size extended_joystick structure with a variably sized one

inside BJoystick.
* Add joystick_module_info flag to communicate support for variably sized reads.
* The variably sized data structure is set up to describe either the actual
  amount of data, when variably sized reads are supported by the driver, or it
  is set up so that it exactly matches the data layout of the extended_joystick
  structure. This allows us to support both as input data, while only needing to
  care about a single format inside BJoystick. Convenience pointers allow the
  data to be retrieved without additional overhead or extra logic.
* Add some sanity checks and ensure some boundaries when dealing reading data
  from the variably sized structure (as there might not be any buttons, hats,
  axis at all now).
* Ensure that the extended_joystick structure doesn't change in size due to
  padding by making it _PACKED (it wasn't padded though).

This is still supposed to work exactly as before. However, it opens up the
possibility to actually support arbitrary controllers with arbitrary axis, hat
and button counts. It therefore allows to actually deliver what the BJoystick
API was designed to handle all along.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@41885 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/device/Joystick.h

@@ -103,7 +103,8 @@ friend class _BJoystickTweaker;
 			int				fFD;
 			BList*			fDevices;
 			_joystick_info*	fJoystickInfo;
-			BList*			fExtendedJoystick;
+			BList*			fJoystickData;
+
 			uint32          _reserved_Joystick_[10];
 };
 

headers/private/device/JoystickPrivate.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2011 Michael Lotz <[email protected]>
+ * Distributed under the terms of the MIT license.
+ */
+#ifndef _JOYSTICK_PRIVATE_H
+#define _JOYSTICK_PRIVATE_H
+
+#include <SupportDefs.h>
+
+typedef struct _variable_joystick {
+	uint32		axis_count;
+	uint32		hat_count;
+	uint32		button_blocks;
+
+	// these pointers all point into the data section
+	bigtime_t *	timestamp;
+	uint32 *	buttons;
+	int16 *		axes;
+	uint8 *		hats;
+
+	size_t		data_size;
+	uint8 *		data;
+} variable_joystick;
+
+#endif // _JOYSTICK_PRIVATE_H

headers/private/device/joystick_driver.h

@@ -39,13 +39,14 @@ typedef struct _extended_joystick {
 	uint32		buttons;		/* lsb to msb, 1 == on */
 	int16		axes[MAX_AXES];	/* -32768 to 32767, X, Y, Z, U, V, W */
 	uint8		hats[MAX_HATS];	/* 0 through 8 (1 == N, 3 == E, 5 == S, 7 == W) */
-} extended_joystick;
+} _PACKED extended_joystick;
 
 #define MAX_CONFIG_SIZE 100
 
 enum {	/* flags for joystick module info */
 	js_flag_force_feedback = 0x1,
-	js_flag_force_feedback_directional = 0x2
+	js_flag_force_feedback_directional = 0x2,
+	js_flag_variable_size_reads = 0x4
 };
 
 typedef struct _joystick_module_info {