view src/joystick/os2/SDL_sysjoystick.c @ 4165:3b8ac3d311a2 SDL-1.2

Hello. This patch provides basic support for video on the Sony PS3 Linux framebuffer. Scaling, format-conversion, and drawing is done from the SPEs, so there is little performance impact to PPE applications. This is by no means production quality code, but it is a very good start and a good example of how to use the PS3's hardware capabilities to accelerate video playback on the box. The driver has been verified to work with ffplay, mplayer and xine. This piece of software has been developed at the IBM R&D Lab in Boeblingen, Germany and is now returned to the community. Enjoy ! Signed-off-by: D.Herrendoerfer < d.herrendoerfer [at] de [dot] ibm [dot] com >
author Sam Lantinga <slouken@libsdl.org>
date Thu, 02 Apr 2009 04:06:55 +0000
parents a1b03ba2fcd0
children
line wrap: on
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 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
    Lesser General Public License for more details.

    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

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#ifdef SDL_JOYSTICK_OS2

/* OS/2 Joystick driver, contributed by Daniel Caetano */

#include <mem.h>

#define INCL_DOSDEVICES
#define INCL_DOSDEVIOCTL
#define INCL_DOSMEMMGR
#include <os2.h>
#include "joyos2.h"

#include "SDL_joystick.h"
#include "SDL_events.h"
#include "../SDL_sysjoystick.h"
#include "../SDL_joystick_c.h"

HFILE hJoyPort = NULL;		/* Joystick GAME$ Port Address */
#define MAX_JOYSTICKS	2	/* Maximum of two joysticks */
#define MAX_AXES	4			/* each joystick can have up to 4 axes */
#define MAX_BUTTONS	8		/* 8 buttons */
#define MAX_HATS	0			/* 0 hats - OS/2 doesn't support it */
#define MAX_BALLS	0			/* and 0 balls - OS/2 doesn't support it */
#define AXIS_MIN -32768		/* minimum value for axes coordinate */
#define AXIS_MAX 32767		/* maximum value for axes coordinate */
#define MAX_JOYNAME	128	/* Joystick name may have 128 characters */
/* limit axes to 256 possible positions to filter out noise */
#define JOY_AXIS_THRESHOLD (((AXIS_MAX)-(AXIS_MIN))/256)
/* Calc Button Flag for buttons A to D */
#define JOY_BUTTON_FLAG(n) (1<<n)

/* Joystick data... hold information about detected devices */
typedef struct SYS_JoyData_s
{
Sint8					id;								// Device ID
char					szDeviceName[MAX_JOYNAME];	// Device Name
char					axes;								// Number of axes
char					buttons;							// Number of buttons
char					hats;								// Number of buttons
char					balls;							// Number of buttons
int					axes_min[MAX_AXES];			// minimum callibration value for axes
int					axes_med[MAX_AXES];			// medium callibration value for axes
int					axes_max[MAX_AXES];			// maximum callibration value for axes
int					buttoncalc[4];					// Used for buttons 5, 6, 7 and 8.
} SYS_JoyData_t, *SYS_JoyData_p;

SYS_JoyData_t SYS_JoyData[MAX_JOYSTICKS];


/* Structure used to convert data from OS/2 driver format to SDL format */
struct joystick_hwdata
{
Sint8					id;
struct _transaxes
	{
	int offset;					/* Center Offset */
	float scale1;				/* Center to left/up Scale */
	float scale2;				/* Center to right/down Scale */
	} transaxes[MAX_AXES];
};

/* Structure used to get values from Joystick Environment Variable */
struct _joycfg
{
char	name[MAX_JOYNAME];
unsigned int	axes;
unsigned int	buttons;
unsigned int	hats;
unsigned int	balls;
};

/* OS/2 Implementation Function Prototypes */
APIRET joyPortOpen(HFILE * hGame);
void joyPortClose(HFILE * hGame);
int joyGetData(char *joyenv, char *name, char stopchar, size_t maxchars);
int joyGetEnv(struct _joycfg * joydata);



/************************************************************************/
/* Function to scan the system for joysticks.									*/
/* This function should set SDL_numjoysticks to the number of available	*/
/* joysticks.  Joystick 0 should be the system default joystick.			*/
/* It should return 0, or -1 on an unrecoverable fatal error.				*/
/************************************************************************/
int SDL_SYS_JoystickInit(void)
{
APIRET rc;											/* Generic OS/2 return code */
GAME_PORT_STRUCT	stJoyStatus;				/* Joystick Status Structure */
GAME_PARM_STRUCT	stGameParms;				/* Joystick Parameter Structure */
GAME_CALIB_STRUCT	stGameCalib;				/* Calibration Struct */
ULONG ulDataLen;									/* Size of data */
ULONG ulLastTick;						/* Tick Counter for timing operations */
Uint8 maxdevs;										/* Maximum number of devices */
Uint8 numdevs;										/* Number of present devices */
Uint8 maxbut;										/* Maximum number of buttons... */
Uint8 i;												/* Temporary Count Vars */
Uint8 ucNewJoystickMask;										/* Mask for Joystick Detection */
struct _joycfg joycfg;							/* Joy Configuration from envvar */


/* Get Max Number of Devices */
rc = joyPortOpen(&hJoyPort); /* Open GAME$ port */
if (rc != 0) return 0;	/* Cannot open... report no joystick */
ulDataLen = sizeof(stGameParms);
rc = DosDevIOCtl(hJoyPort, IOCTL_CAT_USER, GAME_GET_PARMS,
	NULL, 0, NULL, &stGameParms, ulDataLen, &ulDataLen); /* Ask device info */
if (rc != 0)
	{
	joyPortClose(&hJoyPort);
	SDL_SetError("Could not read joystick port.");
	return -1;
	}
if (stGameParms.useA != 0) maxdevs++;
if (stGameParms.useB != 0) maxdevs++;
if ( maxdevs > MAX_JOYSTICKS ) maxdevs = MAX_JOYSTICKS;

/* Defines min/max axes values (callibration) */
ulDataLen = sizeof(stGameCalib);
rc = DosDevIOCtl(hJoyPort, IOCTL_CAT_USER, GAME_GET_CALIB,
	NULL, 0, NULL, &stGameCalib, ulDataLen, &ulDataLen);
if (rc != 0)
	{
	joyPortClose(&hJoyPort);
	SDL_SetError("Could not read callibration data.");
	return -1;
	}

/* Determine how many joysticks are active */
numdevs = 0;	/* Points no device */
ucNewJoystickMask = 0x0F;	/* read all 4 joystick axis */
ulDataLen = sizeof(ucNewJoystickMask);
rc = DosDevIOCtl(hJoyPort, IOCTL_CAT_USER, GAME_PORT_RESET,
		&ucNewJoystickMask, ulDataLen, &ulDataLen, NULL, 0, NULL);
if (rc == 0)
	{
	ulDataLen = sizeof(stJoyStatus);
	rc = DosDevIOCtl(hJoyPort, IOCTL_CAT_USER, GAME_PORT_GET,
		NULL, 0, NULL, &stJoyStatus, ulDataLen, &ulDataLen);
	if (rc != 0)
		{
		joyPortClose(&hJoyPort);
		SDL_SetError("Could not call joystick port.");
		return -1;
		}
	ulLastTick = stJoyStatus.ulJs_Ticks;
	while (stJoyStatus.ulJs_Ticks == ulLastTick)
		{
		rc = DosDevIOCtl(hJoyPort, IOCTL_CAT_USER, GAME_PORT_GET,
			NULL, 0, NULL, &stJoyStatus, ulDataLen, &ulDataLen);
		}
	if ((stJoyStatus.ucJs_JoyStickMask & 0x03) > 0) numdevs++;
	if (((stJoyStatus.ucJs_JoyStickMask >> 2) & 0x03) > 0) numdevs++;
	}

if (numdevs>maxdevs) numdevs=maxdevs;

/* If *any* joystick was detected... Let's configure SDL for them */
if (numdevs > 0)
	{
	/* Verify if it is a "user defined" joystick */
	if (joyGetEnv(&joycfg))
		{
		GAME_3POS_STRUCT * axis[4];
		axis[0] = &stGameCalib.Ax;
		axis[1] = &stGameCalib.Ay;
		axis[2] = &stGameCalib.Bx;
		axis[3] = &stGameCalib.By;
		/* Say it has one device only (user defined is always one device only) */
		numdevs = 1;
		/* Define Device 0 as... */
		SYS_JoyData[0].id=0;
		/* Define Number of Axes... up to 4 */
		if (joycfg.axes>MAX_AXES) joycfg.axes = MAX_AXES;
		SYS_JoyData[0].axes = joycfg.axes;
		/* Define number of buttons... 8 if 2 axes, 6 if 3 axes and 4 if 4 axes */
		maxbut = MAX_BUTTONS;
		if (joycfg.axes>2) maxbut-=((joycfg.axes-2)<<1); /* MAX_BUTTONS - 2*(axes-2) */
		if (joycfg.buttons > maxbut) joycfg.buttons = maxbut;
		SYS_JoyData[0].buttons = joycfg.buttons;
		/* Define number of hats */
		if (joycfg.hats > MAX_HATS) joycfg.hats = MAX_HATS;
		SYS_JoyData[0].hats = joycfg.hats;
		/* Define number of balls */
		if (joycfg.balls > MAX_BALLS) joycfg.balls = MAX_BALLS;
		SYS_JoyData[0].balls = joycfg.balls;
		/* Initialize Axes Callibration Values */
		for (i=0; i<joycfg.axes; i++)
			{
			SYS_JoyData[0].axes_min[i] = axis[i]->lower;
			SYS_JoyData[0].axes_med[i] = axis[i]->centre;
			SYS_JoyData[0].axes_max[i] = axis[i]->upper;
			}
		/* Initialize Buttons 5 to 8 structures */
		if (joycfg.buttons>=5) SYS_JoyData[0].buttoncalc[0]=((axis[2]->lower+axis[3]->centre)>>1);
		if (joycfg.buttons>=6) SYS_JoyData[0].buttoncalc[1]=((axis[3]->lower+axis[3]->centre)>>1);
		if (joycfg.buttons>=7) SYS_JoyData[0].buttoncalc[2]=((axis[2]->upper+axis[3]->centre)>>1);
		if (joycfg.buttons>=8) SYS_JoyData[0].buttoncalc[3]=((axis[3]->upper+axis[3]->centre)>>1);
		/* Intialize Joystick Name */
		SDL_strlcpy (SYS_JoyData[0].szDeviceName,joycfg.name, SDL_arraysize(SYS_JoyData[0].szDeviceName));
		}
	/* Default Init ... autoconfig */
	else
		{
		/* if two devices were detected... configure as Joy1 4 axis and Joy2 2 axis */
		if (numdevs==2)
			{
			/* Define Device 0 as 4 axes, 4 buttons */
			SYS_JoyData[0].id=0;
			SYS_JoyData[0].axes = 4;
			SYS_JoyData[0].buttons = 4;
			SYS_JoyData[0].hats = 0;
			SYS_JoyData[0].balls = 0;
			SYS_JoyData[0].axes_min[0] = stGameCalib.Ax.lower;
			SYS_JoyData[0].axes_med[0] = stGameCalib.Ax.centre;
			SYS_JoyData[0].axes_max[0] = stGameCalib.Ax.upper;
			SYS_JoyData[0].axes_min[1] = stGameCalib.Ay.lower;
			SYS_JoyData[0].axes_med[1] = stGameCalib.Ay.centre;
			SYS_JoyData[0].axes_max[1] = stGameCalib.Ay.upper;
			SYS_JoyData[0].axes_min[2] = stGameCalib.Bx.lower;
			SYS_JoyData[0].axes_med[2] = stGameCalib.Bx.centre;
			SYS_JoyData[0].axes_max[2] = stGameCalib.Bx.upper;
			SYS_JoyData[0].axes_min[3] = stGameCalib.By.lower;
			SYS_JoyData[0].axes_med[3] = stGameCalib.By.centre;
			SYS_JoyData[0].axes_max[3] = stGameCalib.By.upper;
			/* Define Device 1 as 2 axes, 2 buttons */
			SYS_JoyData[1].id=1;
			SYS_JoyData[1].axes = 2;
			SYS_JoyData[1].buttons = 2;
			SYS_JoyData[1].hats = 0;
			SYS_JoyData[1].balls = 0;
			SYS_JoyData[1].axes_min[0] = stGameCalib.Bx.lower;
			SYS_JoyData[1].axes_med[0] = stGameCalib.Bx.centre;
			SYS_JoyData[1].axes_max[0] = stGameCalib.Bx.upper;
			SYS_JoyData[1].axes_min[1] = stGameCalib.By.lower;
			SYS_JoyData[1].axes_med[1] = stGameCalib.By.centre;
			SYS_JoyData[1].axes_max[1] = stGameCalib.By.upper;
			}
		/* One joystick only? */
		else
			{
			/* If it is joystick A... */
			if ((stJoyStatus.ucJs_JoyStickMask & 0x03) > 0)
				{
				/* Define Device 0 as 2 axes, 4 buttons */
				SYS_JoyData[0].id=0;
				SYS_JoyData[0].axes = 2;
				SYS_JoyData[0].buttons = 4;
				SYS_JoyData[0].hats = 0;
				SYS_JoyData[0].balls = 0;
				SYS_JoyData[0].axes_min[0] = stGameCalib.Ax.lower;
				SYS_JoyData[0].axes_med[0] = stGameCalib.Ax.centre;
				SYS_JoyData[0].axes_max[0] = stGameCalib.Ax.upper;
				SYS_JoyData[0].axes_min[1] = stGameCalib.Ay.lower;
				SYS_JoyData[0].axes_med[1] = stGameCalib.Ay.centre;
				SYS_JoyData[0].axes_max[1] = stGameCalib.Ay.upper;
				}
			/* If not, it is joystick B */
			else
				{
				/* Define Device 1 as 2 axes, 2 buttons */
				SYS_JoyData[0].id=1;
				SYS_JoyData[0].axes = 2;
				SYS_JoyData[0].buttons = 2;
				SYS_JoyData[0].hats = 0;
				SYS_JoyData[0].balls = 0;
				SYS_JoyData[0].axes_min[0] = stGameCalib.Bx.lower;
				SYS_JoyData[0].axes_med[0] = stGameCalib.Bx.centre;
				SYS_JoyData[0].axes_max[0] = stGameCalib.Bx.upper;
				SYS_JoyData[0].axes_min[1] = stGameCalib.By.lower;
				SYS_JoyData[0].axes_med[1] = stGameCalib.By.centre;
				SYS_JoyData[0].axes_max[1] = stGameCalib.By.upper;
				}
			}
		/* Hack to define Joystick Port Names */
		if ( numdevs > maxdevs ) numdevs = maxdevs;
		for (i=0; i<numdevs; i++)
                  SDL_snprintf (SYS_JoyData[i].szDeviceName, SDL_arraysize(SYS_JoyData[i].szDeviceName), "Default Joystick %c", 'A'+SYS_JoyData[i].id);

                }
	}
/* Return the number of devices found */
return(numdevs);
}


/***********************************************************/
/* Function to get the device-dependent name of a joystick */
/***********************************************************/
const char *SDL_SYS_JoystickName(int index)
{
/* No need to verify if device exists, already done in upper layer */
return(SYS_JoyData[index].szDeviceName);
}



/******************************************************************************/
/* Function to open a joystick for use.													*/
/* The joystick to open is specified by the index field of the joystick.		*/
/* 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 index;		/* Index shortcut for index in joystick structure */
int i;			/* Generic Counter */

/* allocate memory for system specific hardware data */
joystick->hwdata = (struct joystick_hwdata *) SDL_malloc(sizeof(*joystick->hwdata));
if (joystick->hwdata == NULL)
	{
	SDL_OutOfMemory();
	return(-1);
	}
/* Reset Hardware Data */
SDL_memset(joystick->hwdata, 0, sizeof(*joystick->hwdata));

/* ShortCut Pointer */
index = joystick->index;
/* Define offsets and scales for all axes */
joystick->hwdata->id = SYS_JoyData[index].id;
for ( i = 0; i < MAX_AXES; ++i )
	{
	if ( (i<2) || i < SYS_JoyData[index].axes )
		{
		joystick->hwdata->transaxes[i].offset = ((AXIS_MAX + AXIS_MIN)>>1) - SYS_JoyData[index].axes_med[i];
		//joystick->hwdata->transaxes[i].scale = (float)((AXIS_MAX - AXIS_MIN)/(SYS_JoyData[index].axes_max[i]-SYS_JoyData[index].axes_min[i]));
		joystick->hwdata->transaxes[i].scale1 = (float)abs((AXIS_MIN/SYS_JoyData[index].axes_min[i]));
		joystick->hwdata->transaxes[i].scale2 = (float)abs((AXIS_MAX/SYS_JoyData[index].axes_max[i]));
		}
	else
		{
		joystick->hwdata->transaxes[i].offset = 0;
		//joystick->hwdata->transaxes[i].scale = 1.0; /* Just in case */
		joystick->hwdata->transaxes[i].scale1 = 1.0; /* Just in case */
		joystick->hwdata->transaxes[i].scale2 = 1.0; /* Just in case */
		}
	}

/* fill nbuttons, naxes, and nhats fields */
joystick->nbuttons = SYS_JoyData[index].buttons;
joystick->naxes = SYS_JoyData[index].axes;
/* joystick->nhats = SYS_JoyData[index].hats; */
joystick->nhats = 0; /* No support for hats at this time */
/* joystick->nballs = SYS_JoyData[index].balls; */
joystick->nballs = 0; /* No support for balls at this time */
return 0;
}



/***************************************************************************/
/* Function to update the state of a joystick - called as a device poll.	*/
/* This function shouldn't update the joystick structure directly,			*/
/* but instead should call SDL_PrivateJoystick*() to deliver events			*/
/* and update joystick device state.													*/
/***************************************************************************/
void SDL_SYS_JoystickUpdate(SDL_Joystick *joystick)
{
APIRET rc;									/* Generic OS/2 return code */
int index;									/* index shortcurt to joystick index */
int i;										/* Generic counter */
int normbut;								/* Number of buttons reported by joystick */
int corr;									/* Correction for button names */
Sint16 value, change;					/* Values used to update axis values */
struct _transaxes *transaxes;			/* Shortcut for Correction structure */
Uint32 pos[MAX_AXES];					/* Vector to inform the Axis status */
ULONG ulDataLen;							/* Size of data */
GAME_STATUS_STRUCT stGameStatus;		/* Joystick Status Structure */

ulDataLen = sizeof(stGameStatus);
rc = DosDevIOCtl(hJoyPort, IOCTL_CAT_USER, GAME_GET_STATUS,
	NULL, 0, NULL, &stGameStatus, ulDataLen, &ulDataLen);
if (rc != 0)
	{
	SDL_SetError("Could not read joystick status.");
	return; /* Could not read data */
	}

/* Shortcut pointer */
index = joystick->index;
/* joystick motion events */

if (SYS_JoyData[index].id == 0)
	{
	pos[0] = stGameStatus.curdata.A.x;
	pos[1] = stGameStatus.curdata.A.y;
	if (SYS_JoyData[index].axes >= 3)	pos[2] = stGameStatus.curdata.B.x;
	else pos[2]=0;
	if (SYS_JoyData[index].axes >= 4)	pos[3] = stGameStatus.curdata.B.y;
	else pos[3]=0;
	pos[4]=0;	/* OS/2 basic drivers do not support more than 4 axes joysticks */
	pos[5]=0;
	}
else if (SYS_JoyData[index].id == 1)
	{
	pos[0] = stGameStatus.curdata.B.x;
	pos[1] = stGameStatus.curdata.B.y;
	pos[2]=0;
	pos[3]=0;
	pos[4]=0;
	pos[5]=0;
	}

/* Corrects the movements using the callibration */
transaxes = joystick->hwdata->transaxes;
for (i = 0; i < joystick->naxes; i++)
	{
	value = pos[i] + transaxes[i].offset;
	if (value<0)
		{
		value*=transaxes[i].scale1;
		if (value>0) value = AXIS_MIN;
		}
	else
		{
		value*=transaxes[i].scale2;
		if (value<0) value = AXIS_MAX;
		}
	change = (value - joystick->axes[i]);
	if ( (change < -JOY_AXIS_THRESHOLD) || (change > JOY_AXIS_THRESHOLD) )
		{
		SDL_PrivateJoystickAxis(joystick, (Uint8)i, (Sint16)value);
		}
	}

/* joystick button A to D events */
if (SYS_JoyData[index].id == 1) corr = 2;
else corr = 0;
normbut=4;	/* Number of normal buttons */
if (joystick->nbuttons<normbut) normbut = joystick->nbuttons;
for ( i = corr; (i-corr) < normbut; ++i )
	{
	/*
		Button A: 1110 0000
		Button B: 1101 0000
		Button C: 1011 0000
		Button D: 0111 0000
	*/
	if ( (~stGameStatus.curdata.butMask)>>4 & JOY_BUTTON_FLAG(i) )
		{
		if ( ! joystick->buttons[i-corr] )
			{
			SDL_PrivateJoystickButton(joystick, (Uint8)(i-corr), SDL_PRESSED);
			}
		}
	else
		{
		if ( joystick->buttons[i-corr] )
			{
			SDL_PrivateJoystickButton(joystick, (Uint8)(i-corr), SDL_RELEASED);
			}
		}
	}

/* Joystick button E to H buttons */
	/*
		Button E: Axis 2 X Left
		Button F: Axis 2 Y Up
		Button G: Axis 2 X Right
		Button H: Axis 2 Y Down
	*/
if (joystick->nbuttons>=5)
	{
	if (stGameStatus.curdata.B.x < SYS_JoyData[index].buttoncalc[0]) SDL_PrivateJoystickButton(joystick, (Uint8)4, SDL_PRESSED);
	else SDL_PrivateJoystickButton(joystick, (Uint8)4, SDL_RELEASED);
	}
if (joystick->nbuttons>=6)
	{
	if (stGameStatus.curdata.B.y < SYS_JoyData[index].buttoncalc[1]) SDL_PrivateJoystickButton(joystick, (Uint8)5, SDL_PRESSED);
	else SDL_PrivateJoystickButton(joystick, (Uint8)5, SDL_RELEASED);
	}
if (joystick->nbuttons>=7)
	{
	if (stGameStatus.curdata.B.x > SYS_JoyData[index].buttoncalc[2]) SDL_PrivateJoystickButton(joystick, (Uint8)6, SDL_PRESSED);
	else SDL_PrivateJoystickButton(joystick, (Uint8)6, SDL_RELEASED);
	}
if (joystick->nbuttons>=8)
	{
	if (stGameStatus.curdata.B.y > SYS_JoyData[index].buttoncalc[3]) SDL_PrivateJoystickButton(joystick, (Uint8)7, SDL_PRESSED);
	else SDL_PrivateJoystickButton(joystick, (Uint8)7, SDL_RELEASED);
	}

/* joystick hat events */
/* Not Supported under OS/2 */
/* joystick ball events */
/* Not Supported under OS/2 */
}



/******************************************/
/* Function to close a joystick after use */
/******************************************/
void SDL_SYS_JoystickClose(SDL_Joystick *joystick)
{
if (joystick->hwdata != NULL)
	{
	/* free system specific hardware data */
	SDL_free(joystick->hwdata);
	}
}



/********************************************************************/
/* Function to perform any system-specific joystick related cleanup */
/********************************************************************/
void SDL_SYS_JoystickQuit(void)
{
joyPortClose(&hJoyPort);
}



/************************/
/************************/
/* OS/2 Implementations */
/************************/
/************************/


/*****************************************/
/* Open Joystick Port, if not opened yet */
/*****************************************/
APIRET joyPortOpen(HFILE * hGame)
{
APIRET		rc;				/* Generic Return Code */
ULONG			ulAction;		/* ? */
ULONG			ulVersion;		/* Version of joystick driver */
ULONG			ulDataLen;		/* Size of version data */

/* Verifies if joyport is not already open... */
if (*hGame != NULL) return 0;
/* Open GAME$ for read */
rc = DosOpen((PSZ)GAMEPDDNAME, hGame, &ulAction, 0, FILE_READONLY,
	FILE_OPEN, OPEN_ACCESS_READONLY | OPEN_SHARE_DENYNONE, NULL);
if (rc != 0)
	{
	SDL_SetError("Could not open Joystick Port.");
	return -1;
	}
	
/* Get Joystick Driver Version... must be 2.0 or higher */
ulVersion = 0;
ulDataLen = sizeof(ulVersion);
rc = DosDevIOCtl( *hGame, IOCTL_CAT_USER, GAME_GET_VERSION,
	NULL, 0, NULL, &ulVersion, ulDataLen, &ulDataLen);
if (rc != 0)
	{
	joyPortClose(hGame);
	SDL_SetError("Could not get Joystick Driver version.");
	return -1;	
	}
if (ulVersion < GAME_VERSION)
	{
	joyPortClose(hGame);
	SDL_SetError("Driver too old. At least IBM driver version 2.0 required.");
	return -1;
	}
return 0;
}



/****************************/
/* Close JoyPort, if opened */
/****************************/
void joyPortClose(HFILE * hGame)
{
if (*hGame != NULL) DosClose(*hGame);
*hGame = NULL;
}



/***************************/
/* Get SDL Joystick EnvVar */
/***************************/
int joyGetEnv(struct _joycfg * joydata)
{
char *joyenv;				/* Pointer to tested character */
char tempnumber[5];		/* Temporary place to put numeric texts */

joyenv = SDL_getenv("SDL_OS2_JOYSTICK");
if (joyenv == NULL) return 0;
/* Joystick Environment is defined! */
while (*joyenv==' ' && *joyenv!=0) joyenv++; /* jump spaces... */
/* If the string name starts with '... get if fully */
if (*joyenv=='\'') joyenv+=joyGetData(++joyenv,joydata->name,'\'',sizeof(joydata->name));
/* If not, get it until the next space */
else if (*joyenv=='\"') joyenv+=joyGetData(++joyenv,joydata->name,'\"',sizeof(joydata->name));
else joyenv+=joyGetData(joyenv,joydata->name,' ',sizeof(joydata->name));
/* Now get the number of axes */
while (*joyenv==' ' && *joyenv!=0) joyenv++; /* jump spaces... */
joyenv+=joyGetData(joyenv,tempnumber,' ',sizeof(tempnumber));
joydata->axes = atoi(tempnumber);
/* Now get the number of buttons */
while (*joyenv==' ' && *joyenv!=0) joyenv++; /* jump spaces... */
joyenv+=joyGetData(joyenv,tempnumber,' ',sizeof(tempnumber));
joydata->buttons = atoi(tempnumber);
/* Now get the number of hats */
while (*joyenv==' ' && *joyenv!=0) joyenv++; /* jump spaces... */
joyenv+=joyGetData(joyenv,tempnumber,' ',sizeof(tempnumber));
joydata->hats = atoi(tempnumber);
/* Now get the number of balls */
while (*joyenv==' ' && *joyenv!=0) joyenv++; /* jump spaces... */
joyenv+=joyGetData(joyenv,tempnumber,' ',sizeof(tempnumber));
joydata->balls = atoi(tempnumber);
return 1;
}



/************************************************************************/
/* Get a text from in the string starting in joyenv until it finds		*/
/* the stopchar or maxchars is reached. The result is placed in name.	*/
/************************************************************************/
int joyGetData(char *joyenv, char *name, char stopchar, size_t maxchars)
{
char *nameptr;			/* Pointer to the selected character */
int chcnt=0;			/* Count how many characters where copied */

nameptr=name;
while (*joyenv!=stopchar && *joyenv!=0)
	{
	if (nameptr<(name+(maxchars-1)))
		{
		*nameptr = *joyenv; /* Only copy if smaller than maximum */
		nameptr++;
		}
	chcnt++;
	joyenv++;
	}
if (*joyenv==stopchar)
	{
	joyenv++; /* Jump stopchar */
	chcnt++;
	}
*nameptr = 0; /* Mark last byte */
return chcnt;
}

#endif /* SDL_JOYSTICK_OS2 */