pa_linux_alsa.c

一个开源的sip源代码

/*
 * $Id: pa_linux_alsa.c 1196 2007-04-23 20:46:56Z aknudsen $
 * PortAudio Portable Real-Time Audio Library
 * Latest Version at: http://www.portaudio.com
 * ALSA implementation by Joshua Haberman and Arve Knudsen
 *
 * Copyright (c) 2002 Joshua Haberman <[e-mail]>
 * Copyright (c) 2005-2006 Arve Knudsen <[e-mail]>
 *
 * Based on the Open Source API proposed by Ross Bencina
 * Copyright (c) 1999-2002 Ross Bencina, Phil Burk
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * The text above constitutes the entire PortAudio license; however, 
 * the PortAudio community also makes the following non-binding requests:
 *
 * Any person wishing to distribute modifications to the Software is
 * requested to send the modifications to the original developer so that
 * they can be incorporated into the canonical version. It is also 
 * requested that these non-binding requests be included along with the 
 * license above.
 */

/**
 @file
 @ingroup hostapi_src
*/

#define ALSA_PCM_NEW_HW_PARAMS_API
#define ALSA_PCM_NEW_SW_PARAMS_API
#include <alsa/asoundlib.h>
#undef ALSA_PCM_NEW_HW_PARAMS_API
#undef ALSA_PCM_NEW_SW_PARAMS_API

#include <sys/poll.h>
#include <string.h> /* strlen() */
#include <limits.h>
#include <math.h>
#include <pthread.h>
#include <signal.h>
#include <time.h>
#include <sys/mman.h>
#include <signal.h> /* For sig_atomic_t */

#include "portaudio.h"
#include "pa_util.h"
#include "pa_unix_util.h"
#include "pa_allocation.h"
#include "pa_hostapi.h"
#include "pa_stream.h"
#include "pa_cpuload.h"
#include "pa_process.h"
#include "pa_endianness.h"

#include "pa_linux_alsa.h"

/* Check return value of ALSA function, and map it to PaError */
#define ENSURE_(expr, code) \
    do { \
        if( UNLIKELY( (aErr_ = (expr)) < 0 ) ) \
        { \
            /* PaUtil_SetLastHostErrorInfo should only be used in the main thread */ \
            if( (code) == paUnanticipatedHostError && pthread_equal( pthread_self(), paUnixMainThread) ) \
            { \
                PaUtil_SetLastHostErrorInfo( paALSA, aErr_, snd_strerror( aErr_ ) ); \
            } \
            PaUtil_DebugPrint( "Expression '" #expr "' failed in '" __FILE__ "', line: " STRINGIZE( __LINE__ ) "\n" ); \
            if( (code) == paUnanticipatedHostError ) \
                PA_DEBUG(( "Host error description: %s\n", snd_strerror( aErr_ ) )); \
            result = (code); \
            goto error; \
        } \
    } while( 0 );

#define ASSERT_CALL_(expr, success) \
    aErr_ = (expr); \
    assert( success == aErr_ );

static int aErr_;               /* Used with ENSURE_ */

typedef enum
{
    StreamDirection_In,
    StreamDirection_Out
} StreamDirection;

typedef struct
{
    PaSampleFormat hostSampleFormat;
    unsigned long framesPerBuffer;
    int numUserChannels, numHostChannels;
    int userInterleaved, hostInterleaved;
    PaDeviceIndex device;     /* Keep the device index */

    snd_pcm_t *pcm;
    snd_pcm_uframes_t bufferSize;
    snd_pcm_format_t nativeFormat;
    unsigned int nfds;
    int ready;  /* Marked ready from poll */
    void **userBuffers;
    snd_pcm_uframes_t offset;
    StreamDirection streamDir;

    snd_pcm_channel_area_t *channelAreas;  /* Needed for channel adaption */
} PaAlsaStreamComponent;

/* Implementation specific stream structure */
typedef struct PaAlsaStream
{
    PaUtilStreamRepresentation streamRepresentation;
    PaUtilCpuLoadMeasurer cpuLoadMeasurer;
    PaUtilBufferProcessor bufferProcessor;
    PaUnixThread thread;

    unsigned long framesPerUserBuffer, maxFramesPerHostBuffer;

    int primeBuffers;
    int callbackMode;              /* bool: are we running in callback mode? */
    int pcmsSynced;	            /* Have we successfully synced pcms */
    int rtSched;

    /* the callback thread uses these to poll the sound device(s), waiting
     * for data to be ready/available */
    struct pollfd* pfds;
    int pollTimeout;

    /* Used in communication between threads */
    volatile sig_atomic_t callback_finished; /* bool: are we in the "callback finished" state? */
    volatile sig_atomic_t callbackAbort;    /* Drop frames? */
    volatile sig_atomic_t isActive;         /* Is stream in active state? (Between StartStream and StopStream || !paContinue) */
    PaUnixMutex stateMtx;                   /* Used to synchronize access to stream state */

    int neverDropInput;

    PaTime underrun;
    PaTime overrun;

    PaAlsaStreamComponent capture, playback;
}
PaAlsaStream;

/* PaAlsaHostApiRepresentation - host api datastructure specific to this implementation */

typedef struct PaAlsaHostApiRepresentation
{
    PaUtilHostApiRepresentation baseHostApiRep;
    PaUtilStreamInterface callbackStreamInterface;
    PaUtilStreamInterface blockingStreamInterface;

    PaUtilAllocationGroup *allocations;

    PaHostApiIndex hostApiIndex;
}
PaAlsaHostApiRepresentation;

typedef struct PaAlsaDeviceInfo
{
    PaDeviceInfo baseDeviceInfo;
    char *alsaName;
    int isPlug;
    int minInputChannels;
    int minOutputChannels;
}
PaAlsaDeviceInfo;

/* prototypes for functions declared in this file */

static void Terminate( struct PaUtilHostApiRepresentation *hostApi );
static PaError IsFormatSupported( struct PaUtilHostApiRepresentation *hostApi,
                                  const PaStreamParameters *inputParameters,
                                  const PaStreamParameters *outputParameters,
                                  double sampleRate );
static PaError OpenStream( struct PaUtilHostApiRepresentation *hostApi,
                           PaStream** s,
                           const PaStreamParameters *inputParameters,
                           const PaStreamParameters *outputParameters,
                           double sampleRate,
                           unsigned long framesPerBuffer,
                           PaStreamFlags streamFlags,
                           PaStreamCallback *callback,
                           void *userData );
static PaError CloseStream( PaStream* stream );
static PaError StartStream( PaStream *stream );
static PaError StopStream( PaStream *stream );
static PaError AbortStream( PaStream *stream );
static PaError IsStreamStopped( PaStream *s );
static PaError IsStreamActive( PaStream *stream );
static PaTime GetStreamTime( PaStream *stream );
static double GetStreamCpuLoad( PaStream* stream );
static PaError BuildDeviceList( PaAlsaHostApiRepresentation *hostApi );
static int SetApproximateSampleRate( snd_pcm_t *pcm, snd_pcm_hw_params_t *hwParams, double sampleRate );
static int GetExactSampleRate( snd_pcm_hw_params_t *hwParams, double *sampleRate );

/* Callback prototypes */
static void *CallbackThreadFunc( void *userData );

/* Blocking prototypes */
static signed long GetStreamReadAvailable( PaStream* s );
static signed long GetStreamWriteAvailable( PaStream* s );
static PaError ReadStream( PaStream* stream, void *buffer, unsigned long frames );
static PaError WriteStream( PaStream* stream, const void *buffer, unsigned long frames );


static const PaAlsaDeviceInfo *GetDeviceInfo( const PaUtilHostApiRepresentation *hostApi, int device )
{
    return (const PaAlsaDeviceInfo *)hostApi->deviceInfos[device];
}

static void AlsaErrorHandler(const char *file, int line, const char *function, int err, const char *fmt, ...)
{
}

PaError PaAlsa_Initialize( PaUtilHostApiRepresentation **hostApi, PaHostApiIndex hostApiIndex )
{
    PaError result = paNoError;
    PaAlsaHostApiRepresentation *alsaHostApi = NULL;

    PA_UNLESS( alsaHostApi = (PaAlsaHostApiRepresentation*) PaUtil_AllocateMemory(
                sizeof(PaAlsaHostApiRepresentation) ), paInsufficientMemory );
    PA_UNLESS( alsaHostApi->allocations = PaUtil_CreateAllocationGroup(), paInsufficientMemory );
    alsaHostApi->hostApiIndex = hostApiIndex;

    *hostApi = (PaUtilHostApiRepresentation*)alsaHostApi;
    (*hostApi)->info.structVersion = 1;
    (*hostApi)->info.type = paALSA;
    (*hostApi)->info.name = "ALSA";

    (*hostApi)->Terminate = Terminate;
    (*hostApi)->OpenStream = OpenStream;
    (*hostApi)->IsFormatSupported = IsFormatSupported;

    ENSURE_( snd_lib_error_set_handler(AlsaErrorHandler), paUnanticipatedHostError );

    PA_ENSURE( BuildDeviceList( alsaHostApi ) );

    PaUtil_InitializeStreamInterface( &alsaHostApi->callbackStreamInterface,
                                      CloseStream, StartStream,
                                      StopStream, AbortStream,
                                      IsStreamStopped, IsStreamActive,
                                      GetStreamTime, GetStreamCpuLoad,
                                      PaUtil_DummyRead, PaUtil_DummyWrite,
                                      PaUtil_DummyGetReadAvailable,
                                      PaUtil_DummyGetWriteAvailable );

    PaUtil_InitializeStreamInterface( &alsaHostApi->blockingStreamInterface,
                                      CloseStream, StartStream,
                                      StopStream, AbortStream,
                                      IsStreamStopped, IsStreamActive,
                                      GetStreamTime, PaUtil_DummyGetCpuLoad,
                                      ReadStream, WriteStream,
                                      GetStreamReadAvailable,
                                      GetStreamWriteAvailable );

    PA_ENSURE( PaUnixThreading_Initialize() );

    return result;

error:
    if( alsaHostApi )
    {
        if( alsaHostApi->allocations )
        {
            PaUtil_FreeAllAllocations( alsaHostApi->allocations );
            PaUtil_DestroyAllocationGroup( alsaHostApi->allocations );
        }

        PaUtil_FreeMemory( alsaHostApi );
    }

    return result;
}

static void Terminate( struct PaUtilHostApiRepresentation *hostApi )
{
    PaAlsaHostApiRepresentation *alsaHostApi = (PaAlsaHostApiRepresentation*)hostApi;

    assert( hostApi );

    if( alsaHostApi->allocations )
    {
        PaUtil_FreeAllAllocations( alsaHostApi->allocations );
        PaUtil_DestroyAllocationGroup( alsaHostApi->allocations );
    }

    PaUtil_FreeMemory( alsaHostApi );
    snd_config_update_free_global();
}

/** Determine max channels and default latencies.
 *
 * This function provides functionality to grope an opened (might be opened for capture or playback) pcm device for 
 * traits like max channels, suitable default latencies and default sample rate. Upon error, max channels is set to zero,
 * and a suitable result returned. The device is closed before returning.
 */
static PaError GropeDevice( snd_pcm_t* pcm, int isPlug, StreamDirection mode, int openBlocking,
        PaAlsaDeviceInfo* devInfo, int* canMmap )
{
    PaError result = paNoError;
    snd_pcm_hw_params_t *hwParams;
    snd_pcm_uframes_t lowLatency = 512, highLatency = 2048;
    unsigned int minChans, maxChans;
    int* minChannels, * maxChannels;
    double * defaultLowLatency, * defaultHighLatency, * defaultSampleRate =
        &devInfo->baseDeviceInfo.defaultSampleRate;
    double defaultSr = *defaultSampleRate;

    assert( pcm );

    if( StreamDirection_In == mode )
    {
        minChannels = &devInfo->minInputChannels;
        maxChannels = &devInfo->baseDeviceInfo.maxInputChannels;
        defaultLowLatency = &devInfo->baseDeviceInfo.defaultLowInputLatency;
        defaultHighLatency = &devInfo->baseDeviceInfo.defaultHighInputLatency;
    }
    else
    {
        minChannels = &devInfo->minOutputChannels;
        maxChannels = &devInfo->baseDeviceInfo.maxOutputChannels;
        defaultLowLatency = &devInfo->baseDeviceInfo.defaultLowOutputLatency;
        defaultHighLatency = &devInfo->baseDeviceInfo.defaultHighOutputLatency;
    }

    ENSURE_( snd_pcm_nonblock( pcm, 0 ), paUnanticipatedHostError );