/****************************************************************************
*
* qasample.c
*
* Copyright (c) 1991-1992 Microsoft Corporation. All Rights Reserved.
*
*
* Sample MCI Device Driver
*
* Internal representation of sample device
*
***************************************************************************/
/* This module contains the complete representation of a simple device
* which has mode and position and plays at one speed using the system
* clock to keep track of time.
*
* the APIs listed in QASAMPLE.H are used to manipulate the device -
* they all have the prefix 'qs'.
*/
#include <windows.h>
#include "qasample.h"
#define QS_VALID_DEVICE(n) ((n) >= 0 && (n) < QS_MAX_DEVICES)
#define QS_MAX_DEVICES 4
/* media length in milliseconds (60 seconds) */
#define QS_MEDIA_LENGTH 120000L
struct {
BOOL fInUse;
WORD nMode;
DWORD dwPosition; /* in milliseconds */
DWORD dwTimeStartedPlaying; /* in milliseconds */
int nTimerStop;
DWORD dwToPosition; /* position to play to */
} DeviceData[QS_MAX_DEVICES];
/****************************************************************************
* @doc INTERNAL
*
* @api BOOL | qsOpen | Open a sample device.
*
* @parm int | nDevice | Device number to open.
*
* @rdesc TRUE on success, FALSE on failure (device in use or invalid
* device number).
***************************************************************************/
BOOL qsOpen(int nDevice)
{
if (!QS_VALID_DEVICE(nDevice))
return FALSE;
if (DeviceData[nDevice].fInUse)
return FALSE;
DeviceData[nDevice].fInUse = TRUE;
DeviceData[nDevice].dwPosition = 0L;
DeviceData[nDevice].nMode = QS_STOPPED;
return TRUE;
}
/****************************************************************************
* @doc INTERNAL
*
* @api BOOL | qsClose | Close a sample device.
*
* @parm int | nDevice | Device number to close.
*
* @rdesc TRUE on success, FALSE on failure (invalid device number).
***************************************************************************/
BOOL qsClose(int nDevice)
{
if (!QS_VALID_DEVICE(nDevice))
return FALSE;
DeviceData[nDevice].fInUse = FALSE;
return TRUE;
}
/****************************************************************************
* @doc INTERNAL
*
* @api DWORD | qsCurrentPosition | Calculate current device position based on
* system time if playing or from the static position.
*
* @parm int | nDevice | Channel to get position of.
*
* @rdesc The current position.
***************************************************************************/
DWORD qsCurrentPosition(int nDevice)
{
/* if the device is currently playing */
/* update the current position based on the current system time */
if (DeviceData[nDevice].nMode == QS_PLAYING) {
DWORD dwSystemTime = GetCurrentTime ();
DeviceData[nDevice].dwPosition =
dwSystemTime -
DeviceData[nDevice].dwTimeStartedPlaying +
DeviceData[nDevice].dwPosition;
DeviceData[nDevice].dwTimeStartedPlaying = dwSystemTime;
/* if the device has passed the to position */
if (DeviceData[nDevice].dwPosition >=
DeviceData[nDevice].dwToPosition) {
/* stop the device at the to position */
DeviceData[nDevice].nMode = QS_STOPPED;
DeviceData[nDevice].dwPosition = DeviceData[nDevice].dwToPosition;
}
}
return DeviceData[nDevice].dwPosition;
}
/****************************************************************************
* @doc INTERNAL
*
* @api BOOL | qsStop | Stop the sample device.
*
* @parm int | nDevice | Device number to use.
*
* @rdesc Returns TRUE on success, and FALSE if device number is invalid.
***************************************************************************/
BOOL qsStop(int nDevice)
{
if (DeviceData[nDevice].nMode == QS_PLAYING)
DeviceData[nDevice].dwPosition = qsCurrentPosition (nDevice);
DeviceData[nDevice].nMode = QS_STOPPED;
return TRUE;
}
/****************************************************************************
* @doc INTERNAL
*
* @api BOOL | qsPause | Pause the sample device.
*
* @parm int | nDevice | Device number to use.
*
* @rdesc Returns TRUE on success, and FALSE if device number is invalid.
***************************************************************************/
BOOL qsPause(int nDevice)
{
if (DeviceData[nDevice].nMode == QS_PLAYING)
DeviceData[nDevice].dwPosition = qsCurrentPosition (nDevice);
DeviceData[nDevice].nMode = QS_PAUSED;
return TRUE;
}
/****************************************************************************
* @doc INTERNAL
*
* @api BOOL | qsPlay | Play the sample device.
*
* @parm int | nDevice | Device number to use.
*
* @parm DWORD | dwFrom | From position.
*
* @parm DWORD | dwTo | To position.
*
* @rdesc Returns TRUE on success, and FALSE if device number is invalid.
***************************************************************************/
BOOL qsPlay(int nDevice, DWORD dwFrom, DWORD dwTo)
{
if (!QS_VALID_DEVICE(nDevice))
return FALSE;
if (!DeviceData[nDevice].fInUse)
return FALSE;
if (dwFrom > dwTo)
return FALSE;
DeviceData[nDevice].dwPosition = dwFrom;
if (dwFrom == dwTo)
return TRUE;
DeviceData[nDevice].nMode = QS_PLAYING;
DeviceData[nDevice].dwToPosition = dwTo;
DeviceData[nDevice].dwTimeStartedPlaying = GetCurrentTime();
return TRUE;
}
/****************************************************************************
* @doc INTERNAL
*
* @api BOOL | qsSeek | Seek on the sample device.
*
* @parm int | nDevice | Device number to use.
*
* @parm DWORD | dwTo | To position.
*
* @rdesc Returns TRUE on success, and FALSE if device number is invalid.
***************************************************************************/
BOOL qsSeek(int nDevice, DWORD dwTo)
{
if (!QS_VALID_DEVICE(nDevice))
return FALSE;
if (!DeviceData[nDevice].fInUse)
return FALSE;
DeviceData[nDevice].dwPosition = dwTo;
DeviceData[nDevice].nMode = QS_STOPPED;
return TRUE;
}
/****************************************************************************
* @doc INTERNAL
*
* @api BOOL | qsInfo | Dump all information about the device.
*
* @parm int | nDevice | Device number to use.
*
* @parm LPQS_INFO | lpInfo | Structure to hold data.
*
* @rdesc Returns TRUE on success, and FALSE if device number is invalid.
***************************************************************************/
BOOL qsInfo(int nDevice, LPQS_INFO lpInfo)
{
if (!QS_VALID_DEVICE(nDevice))
return FALSE;
if (lpInfo == NULL)
return FALSE;
/* if the device is currently playing */
/* calculate the current position based on the current time */
if (DeviceData[nDevice].nMode == QS_PLAYING)
lpInfo->dwPosition = qsCurrentPosition (nDevice);
/* else device is not playing */
/* so current position is static */
else
lpInfo->dwPosition = DeviceData[nDevice].dwPosition;
lpInfo->nMode = DeviceData[nDevice].nMode;
lpInfo->dwLength = QS_MEDIA_LENGTH;
return TRUE;
}
/****************************************************************************
* @doc INTERNAL
*
* @api int | qsCurrentMode | Return the current mode of the device.
*
* @parm int | nDevice | Device number to use.
*
* @rdesc Returns mode.
***************************************************************************/
int qsCurrentMode(int nDevice)
{
if (!QS_VALID_DEVICE(nDevice))
return FALSE;
/* if the device is currently playing */
/* recalculate the mode to see if the device has stopped */
if (DeviceData[nDevice].nMode == QS_PLAYING)
qsCurrentPosition (nDevice);
return DeviceData[nDevice].nMode;
}
/****************************************************************************
* @doc INTERNAL
*
* @api DWORD | qsMediaLength | Return the media length.
*
* @parm int | nDevice | Device number to use.
*
* @rdesc Returns media length, or 0 on error.
***************************************************************************/
DWORD qsMediaLength(int nDevice)
{
if (!QS_VALID_DEVICE(nDevice))
return 0;
return QS_MEDIA_LENGTH;
}
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