qmmixer.cpp

可以播放MP3,wma等文件格式的播放器

/* qmmixer.cpp
 *
 * $Id: qmmixer.cpp,v 1.18.2.2 2002/10/19 14:50:10 kyllingstad Exp $
 *
 * Apollo sound player: http://www.apolloplayer.org
 * Copyright(C) 2000-2002 Apollo Team.  See CREDITS file.
 *
 * This program 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
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The GNU General Public License is also available online at:
 *
 * http://www.gnu.org/copyleft/gpl.html
 */

#include "qmmixer.h"

#include <fcntl.h>
#include <iostream>
#include <math.h>
#include <qglobal.h>

#include "qmmainwindow.h"
#include "message.h"

#ifdef USING_QT3
	#ifdef Q_WS_X11
		#include <sys/ioctl.h>
		#ifdef Q_OS_LINUX
			#include <linux/soundcard.h>
		#else
			#include <sys/soundcard.h>
		#endif
	#endif
#else
	#ifdef _WS_X11_
		#include <sys/ioctl.h>
		#ifdef LINUX
			#include <linux/soundcard.h>
		#else
			#include <sys/soundcard.h>
		#endif
	#endif
#endif // USING_QT3

QmAutoPtr<QmMixer> QmMixer::s_pInstance;

/*!
  \file qmmixer.cpp
  Interface to mixer to control volume
*/

/*!
  \class QmMixer qmmixer.h
  \brief Provides functionality to control the mixer.

  This class is used to adjust the volume of the mixer.  This class is
  currently UNIX specific.
*/


/*!
  Constructs a new mixer control.  Set \a logarithmic to
  true to enable logarithmic volume control.  If set to
  false (default), linear volume control will be used.

  The choice is given because some sound cards do not
  seem to support the logarithmic control.  Logarithmic
  control may give a more pleasant result for controlling
  the volume, though, as a linear control may not \e
  sound linear, i.e. 50% of the volume in linear mode
  may seem like 30% of the volume.
*/

QmMixer::QmMixer(
	bool logarithmic)
	: m_UseLog(logarithmic), m_Step(10)
{
	m_MixerFd = open("/dev/mixer", O_RDWR);

	if(m_MixerFd == -1)
	{
		QmMainWindow::mainwin->statusUpdate(new Message(Message::Error,"Can't open mixer"));
		// do exception or something
	}
}


/*!
  Destroys the mixer and closes the device.
*/

QmMixer::~QmMixer()
{
	// For some reason, closing the mixer devices gives core dump.
	// Sample mixer programs doesn't seem to close the mixer fd.
	//	close(m_MixerFd);
}

QmMixer*
QmMixer::instance()
{
	if (QmMixer::s_pInstance.get() == 0)
		s_pInstance.reset(new QmMixer());

	return reinterpret_cast<QmMixer *>(QmMixer::s_pInstance.get());
}


/*!
  Reads the current volume of PCM from the mixer device.
 */

int
QmMixer::volume() const
{
	int vol = 0;
	int res = -1;
    static int errors;
    if (errors > 3) {
        QmMainWindow::mainwin->statusUpdate(new Message(Message::Error,
            "Can't read volume, have given up! Is your soundcard properly configured?"));
        return 10;
    }

#ifndef _WS_WIN_
	res = ioctl(m_MixerFd, MIXER_READ(SOUND_MIXER_PCM), &vol);
#endif

	if(res == -1)
	{
		if (errors++ < 3) 
            QmMainWindow::mainwin->statusUpdate(new Message(Message::Error,
                "Can't read volume - is your sound card properly configured?"));
        else
            QmMainWindow::mainwin->statusUpdate(new Message(Message::Error,
                "Can't read volume - giving up!"));

        return 10;
	}

	// Least significant byte is left channel volume.  Next byte is right channel volume.
	// The upper 16 bits are undefined.  For mono devices, only the left channel is used.

//	int left = vol & 0x7f;
//	int right = (vol >> 8) & 0x7f;
//	cout << " left channel is: " << left << endl
//		 << "right channel is: " << right << endl;

	// Since we don't offer individual left/right volume control, we'll simply use
	// the left channel (as this is also used for mono devices) as the volume, and
	// set the right channel to the same value.
	return vol & 0x7f;
}

int
QmMixer::balance() const
{
	int vol, res, bal = 0;
#ifndef _WS_WIN_
	res = ioctl(m_MixerFd, MIXER_READ(SOUND_MIXER_PCM), &vol);
#endif

	if (res != -1) {
		int left = vol & 0x7f;
		int right = (vol >> 8) & 0x7f;
		if (left == 0)
			left = 1;
		if (right == 0)
			right = 1;
		
		if (right > left)
			bal = -100 + ((right * 100) / left);
		else if (left > right)
			bal = 100 - ((left * 100) / right);
		else
			bal = 0;
	}
	return bal;
}



/*!
  Sets the PCM volume of the mixer device to \a v.
 */

void
QmMixer::setVolume(
	int v)
{
    static int errors = 0;
    if (errors > 3) {
        QmMainWindow::mainwin->statusUpdate(new Message(Message::Error,
            "Can't set volume, have given up! Is your soundcard properly configured?"));
        return;
    }
    
        
	if(v == 0)
		v = 1;
	
	// Use same volume for left and right channels

	if(m_UseLog)
		v = (int)floor((log10((double)v) * 50.0 + 0.5));
	
	int vol;
	vol = ((v << 8) & 0x7f00) | (v & 0x007f);
	int res = -1;

#ifndef _WS_WIN_
	res = ioctl(m_MixerFd, MIXER_WRITE(SOUND_MIXER_PCM), &vol);
#endif

	if(res == -1)
	{
		if (errors++ < 3) 
            QmMainWindow::mainwin->statusUpdate(new Message(Message::Error,
                "Can't set volume - is your sound card properly configured?"));
        else
            QmMainWindow::mainwin->statusUpdate(new Message(Message::Error,
                "Can't set volume - giving up!"));
	}
}