C++ snd_ctl_open函数代码示例

INT32 PORT_GetPortMixerCount() {
    INT32 mixerCount;
    int card;
    char devname[16];
    int err;
    snd_ctl_t *handle;
    snd_ctl_card_info_t* info;

    TRACE0("> PORT_GetPortMixerCount\n");

    initAlsaSupport();

    snd_ctl_card_info_malloc(&info);
    card = -1;
    mixerCount = 0;
    if (snd_card_next(&card) >= 0) {
        while (card >= 0) {
            sprintf(devname, ALSA_HARDWARE_CARD, card);
            TRACE1("PORT_GetPortMixerCount: Opening alsa device \"%s\"...\n", devname);
            err = snd_ctl_open(&handle, devname, 0);
            if (err < 0) {
                ERROR2("ERROR: snd_ctl_open, card=%d: %s\n", card, snd_strerror(err));
            } else {
                mixerCount++;
                snd_ctl_close(handle);
            }
            if (snd_card_next(&card) < 0) {
                break;
            }
        }
    }
    snd_ctl_card_info_free(info);
    TRACE0("< PORT_GetPortMixerCount\n");
    return mixerCount;
}

INT32 PORT_GetPortMixerDescription(INT32 mixerIndex, PortMixerDescription* description) {
    snd_ctl_t* handle;
    snd_ctl_card_info_t* card_info;
    char devname[16];
    int err;
    char buffer[100];

    TRACE0("> PORT_GetPortMixerDescription\n");
    snd_ctl_card_info_malloc(&card_info);

    sprintf(devname, ALSA_HARDWARE_CARD, (int) mixerIndex);
    TRACE1("Opening alsa device \"%s\"...\n", devname);
    err = snd_ctl_open(&handle, devname, 0);
    if (err < 0) {
        ERROR2("ERROR: snd_ctl_open, card=%d: %s\n", (int) mixerIndex, snd_strerror(err));
        return FALSE;
    }
    err = snd_ctl_card_info(handle, card_info);
    if (err < 0) {
        ERROR2("ERROR: snd_ctl_card_info, card=%d: %s\n", (int) mixerIndex, snd_strerror(err));
    }
    strncpy(description->name, snd_ctl_card_info_get_id(card_info), PORT_STRING_LENGTH - 1);
    sprintf(buffer, " [%s]", devname);
    strncat(description->name, buffer, PORT_STRING_LENGTH - 1 - strlen(description->name));
    strncpy(description->vendor, "ALSA (http://www.alsa-project.org)", PORT_STRING_LENGTH - 1);
    strncpy(description->description, snd_ctl_card_info_get_name(card_info), PORT_STRING_LENGTH - 1);
    strncat(description->description, ", ", PORT_STRING_LENGTH - 1 - strlen(description->description));
    strncat(description->description, snd_ctl_card_info_get_mixername(card_info), PORT_STRING_LENGTH - 1 - strlen(description->description));
    getALSAVersion(description->version, PORT_STRING_LENGTH - 1);

    snd_ctl_close(handle);
    snd_ctl_card_info_free(card_info);
    TRACE0("< PORT_GetPortMixerDescription\n");
    return TRUE;
}

/*----------------------------------------------------------------------------
** ALSA_AddUserSpecifiedDevice
**  Add a device given from the registry
*/
static int ALSA_AddUserSpecifiedDevice(const char *ctlname, const char *pcmname)
{
    int rc;
    int okay = 0;
    snd_ctl_t *ctl = NULL;
    snd_pcm_t *pcm = NULL;

    if (ctlname)
    {
        rc = snd_ctl_open(&ctl, ctlname, SND_CTL_NONBLOCK);
        if (rc < 0)
            ctl = NULL;
    }

    rc = snd_pcm_open(&pcm, pcmname, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
    if (rc >= 0)
    {
        ALSA_AddPlaybackDevice(ctl, pcm, pcmname, FALSE);
        okay++;
        snd_pcm_close(pcm);
    }

    rc = snd_pcm_open(&pcm, pcmname, SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK);
    if (rc >= 0)
    {
        ALSA_AddCaptureDevice(ctl, pcm, pcmname, FALSE);
        okay++;
        snd_pcm_close(pcm);
    }

    if (ctl)
        snd_ctl_close(ctl);

    return (okay == 0);
}

    std::vector<String> AudioOutputDeviceAlsa::ParameterCard::PossibilitiesAsString(std::map<String,String> Parameters) {
        int err;
        std::vector<String> CardNames;

        // iterate through all cards
        int card_index = -1;
        while (snd_card_next(&card_index) >= 0 && card_index >= 0) {
            String hw_name = "hw:" + ToString(card_index);
            snd_ctl_t* hCardCtrl;
            if ((err = snd_ctl_open(&hCardCtrl, hw_name.c_str(), 0)) < 0) {
                std::cerr << "AudioOutputDeviceAlsa: Cannot open sound control for card " << card_index << " - " << snd_strerror(err) << std::endl;
                continue;
            }

            // iterate through all devices of that card
            int device_index = -1;
            while (!snd_ctl_pcm_next_device(hCardCtrl, &device_index) && device_index >= 0) {
                String name = ToString(card_index) + "," + ToString(device_index);
                //dmsg(1,("[possibility:%s]", name.c_str()));
                CardNames.push_back(name);
            }

            snd_ctl_close(hCardCtrl);
        }

        return CardNames;
    }

static const char* search_device(void)
{
	int card, err;
	snd_hwdep_info_t* info;

	snd_hwdep_info_alloca(&info);
	card = -1;
	while (snd_card_next(&card) >= 0 && card >= 0) {
		char ctl_name[20];
		snd_ctl_t* ctl;
		int device;

		sprintf(ctl_name, "hw:CARD=%d", card);
		err = snd_ctl_open(&ctl, ctl_name, SND_CTL_NONBLOCK);
		if (err < 0)
			continue;
		device = -1;
		while (snd_ctl_hwdep_next_device(ctl, &device) >= 0 && device >= 0) {
			snd_hwdep_info_set_device(info, device);
			err = snd_ctl_hwdep_info(ctl, info);
			if (err >= 0 && snd_hwdep_info_get_iface(info) == SND_HWDEP_IFACE_SB_RC) {
				static char name[36];

				sprintf(name, "hw:CARD=%d,DEV=%d", card, device);
				snd_ctl_close(ctl);
				return name;
			}
		}
		snd_ctl_close(ctl);
	}
	return NULL;
}

void scan_cycle(alsa_rawmidi_t *midi)
{
    int card = -1, err;
    scan_t scan;
    midi_port_t **ports;

    //debug_log("scan: cleanup");
    scan_cleanup(midi);

    scan.midi = midi;
    scan.iterator = &midi->scan.ports;
    snd_rawmidi_info_alloca(&scan.info);

    //debug_log("scan: rescan");
    while ((err = snd_card_next(&card))>=0 && card>=0) {
        char name[32];
        snprintf(name, sizeof(name), "hw:%d", card);
        if ((err = snd_ctl_open(&scan.ctl, name, SND_CTL_NONBLOCK))>=0) {
            scan_card(&scan);
            snd_ctl_close(scan.ctl);
        } else
            alsa_error("scan: snd_ctl_open", err);
    }

    // delayed open to workaround alsa<1.0.14 bug (can't open more than 1 subdevice if ctl is opened).
    ports = &midi->scan.ports;
    while (*ports) {
        midi_port_t *port = *ports;
        if (port->state == PORT_CREATED)
            ports = scan_port_open(midi, ports);
        else
            ports = &port->next;
    }
}

static int open_ctl(snd_use_case_mgr_t *uc_mgr,
		    snd_ctl_t **ctl,
		    const char *ctl_dev)
{
	int err;

	/* FIXME: add a list of ctl devices to uc_mgr structure and
           cache accesses for multiple opened ctl devices */
	if (uc_mgr->ctl_dev != NULL && strcmp(ctl_dev, uc_mgr->ctl_dev) == 0) {
		*ctl = uc_mgr->ctl;
		return 0;
	}
	if (uc_mgr->ctl_dev) {
		free(uc_mgr->ctl_dev);
		uc_mgr->ctl_dev = NULL;
		snd_ctl_close(uc_mgr->ctl);
		uc_mgr->ctl = NULL;
	
	}
	err = snd_ctl_open(ctl, ctl_dev, 0);
	if (err < 0)
		return err;
	uc_mgr->ctl_dev = strdup(ctl_dev);
	if (uc_mgr->ctl_dev == NULL) {
		snd_ctl_close(*ctl);
		return -ENOMEM;
	}
	uc_mgr->ctl = *ctl;
	return 0;
}

static int cards(lua_State *lstate) {
	snd_ctl_t *handle;
	int ret, card, ord;
	char buf[32];
	snd_ctl_card_info_t *info;
	snd_ctl_card_info_alloca(&info);
	ord = 1;
	card = -1;
	lua_newtable(lstate);
	while (1) {
		if ((snd_card_next(&card) < 0) || (card < 0)) break;
		sprintf(buf, "hw:%d", card);
		if ((ret = snd_ctl_open(&handle, buf, 0)) < 0) {
			logmsg("control open: %s\n", snd_strerror(ret));
			continue;
			}
		if ((ret = snd_ctl_card_info(handle, info)) < 0) {
			logmsg("control info: %s\n", snd_strerror(ret));
			continue;
			}
		lua_pushinteger(lstate, ord++);
		lua_newtable(lstate);
		set_string(lstate, "dev", buf);
		set_string(lstate, "name",
				snd_ctl_card_info_get_name(info));
		lua_settable(lstate, -3);
		snd_ctl_close(handle);
		//view_card(buf);
		}
	return 1;
	}

/**
 * Partly based on get_cards function in alsamixer.
 * This gets all alsa cards and fills the global
 * GSList 'cards'.
 * The list always starts with the 'default' card.
 */
static void
get_cards(void)
{
    int err, num;
    snd_ctl_card_info_t *info;
    snd_ctl_t *ctl;
    char buf[10];
    struct acard *cur_card, *default_card;

    if (cards != NULL)
        g_slist_free_full(cards, card_free);

    cards = NULL;

    default_card = g_malloc(sizeof(struct acard));
    default_card->name = g_strdup("(default)");
    default_card->dev = g_strdup("default");
    default_card->channels = get_channels("default");

    cards = g_slist_append(cards, default_card);

    // don't need to free this as it's alloca'd
    snd_ctl_card_info_alloca(&info);
    num = -1;
    for (;;) {
        err = snd_card_next(&num);
        if (err < 0) {
            report_error("Can't get sounds cards: %s", snd_strerror(err));
            return;
        }
        if (num < 0)
            break;
        sprintf(buf, "hw:%d", num);
        if (snd_ctl_open(&ctl, buf, 0) < 0)
            continue;
        err = snd_ctl_card_info(ctl, info);
        snd_ctl_close(ctl);
        if (err < 0)
            continue;
        cur_card = g_malloc(sizeof(struct acard));
        cur_card->name = g_strdup(snd_ctl_card_info_get_name(info));
        sprintf(buf, "hw:%d", num);
        cur_card->dev = g_strdup(buf);
        cur_card->channels = get_channels(buf);
        cards = g_slist_append(cards, cur_card);
    }
#ifdef DEBUG
    GSList *tmp = cards;
    if (tmp) {
        printf("------ Card list ------\n");
        while (tmp) {
            struct acard *c = tmp->data;
            printf("\t%s\t%s\t%s\n", c->dev, c->name,
                   c->channels ? "" : "No chann");
            tmp = tmp->next;
        }
        printf("-----------------------\n");
    }
#endif
}

void audio_set_default_levels() {
  int err;
  snd_ctl_t *ctl;
  snd_ctl_elem_value_t *val;

  snd_ctl_elem_value_alloca(&val);

  if (snd_ctl_open(&ctl, ALSA_DEVICE, 0)) {
    fprintf(stderr, "can't open audio device");
    return;
  }

  /* unmute microphone */
  snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
  snd_ctl_elem_value_set_name(val, "Mic Capture Switch");
  snd_ctl_elem_value_set_integer(val, 0, 1);
  err = snd_ctl_elem_write(ctl, val);
  if (err)
    fprintf(stderr, "can't unmute microphone: %s\n", snd_strerror(err));

  /* unmute speaker */
  snd_ctl_elem_value_clear(val);
  snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
  snd_ctl_elem_value_set_name(val, "Speaker Playback Switch");
  snd_ctl_elem_value_set_integer(val, 0, 1);
  err = snd_ctl_elem_write(ctl, val);
  if (err)
    fprintf(stderr, "can't unmute speaker: %s\n", snd_strerror(err));

  /* set mic volume */
  snd_ctl_elem_value_clear(val);
  snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
  snd_ctl_elem_value_set_name(val, "Mic Capture Volume");
  snd_ctl_elem_value_set_integer(val, 0, DEFAULT_MIC_VOL);
  err = snd_ctl_elem_write(ctl, val);
  if (err)
    fprintf(stderr, "can't set microphone volume: %s\n", snd_strerror(err));

  /* set speaker volume */
  snd_ctl_elem_value_clear(val);
  snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
  snd_ctl_elem_value_set_name(val, "Speaker Playback Volume");
  snd_ctl_elem_value_set_integer(val, 0, DEFAULT_SPKR_VOL);
  snd_ctl_elem_value_set_integer(val, 1, DEFAULT_SPKR_VOL);
  err = snd_ctl_elem_write(ctl, val);
  if (err)
    fprintf(stderr, "can't set speaker volume: %s\n", snd_strerror(err));

  /* set capture source */
  snd_ctl_elem_value_clear(val);
  snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
  snd_ctl_elem_value_set_name(val, "PCM Capture Source");
  snd_ctl_elem_value_set_integer(val, 0, 0);
  err = snd_ctl_elem_write(ctl, val);
  if (err)
    fprintf(stderr, "can't set capture source: %s\n", snd_strerror(err));

  snd_ctl_close(ctl);
}

int main(int argc, char **argv)
{
   register int  err;
   int           cardNum;

   // Start with first card
   cardNum = -1;

   for (;;)
   {
      snd_ctl_t *cardHandle;

      // Get next sound card's card number. When "cardNum" == -1, then ALSA
      // fetches the first card
      if ((err = snd_card_next(&cardNum)) < 0)
      {
         printf("Can't get the next card number: %s\n", snd_strerror(err));
         break;
      }

      // No more cards? ALSA sets "cardNum" to -1 if so
      if (cardNum < 0) break;

      // Open this card's control interface. We specify only the card number -- not
      // any device nor sub-device too
      {
      char   str[64];

      sprintf(str, "hw:%i", cardNum);
      if ((err = snd_ctl_open(&cardHandle, str, 0)) < 0)
      {
         printf("Can't open card %i: %s\n", cardNum, snd_strerror(err));
         continue;
      }
      }

      {
      snd_ctl_card_info_t *cardInfo;

      // We need to get a snd_ctl_card_info_t. Just alloc it on the stack
      snd_ctl_card_info_alloca(&cardInfo);

      // Tell ALSA to fill in our snd_ctl_card_info_t with info about this card
      if ((err = snd_ctl_card_info(cardHandle, cardInfo)) < 0)
         printf("Can't get info for card %i: %s\n", cardNum, snd_strerror(err));
      else
         printf("Card %i = %s\n", cardNum, snd_ctl_card_info_get_name(cardInfo));
      }

      // Close the card's control interface after we're done with it
      snd_ctl_close(cardHandle);
   }

   // ALSA allocates some mem to load its config file when we call some of the
   // above functions. Now that we're done getting the info, let's tell ALSA
   // to unload the info and free up that mem
   snd_config_update_free_global();
}

static char *ListAvailableDevices( demux_t *p_demux, bool b_probe )
{
    snd_ctl_card_info_t *p_info = NULL;
    snd_ctl_card_info_alloca( &p_info );

    snd_pcm_info_t *p_pcminfo = NULL;
    snd_pcm_info_alloca( &p_pcminfo );

    if( !b_probe )
        msg_Dbg( p_demux, "Available alsa capture devices:" );
    int i_card = -1;
    while( !snd_card_next( &i_card ) && i_card >= 0 )
    {
        char psz_devname[10];
        snprintf( psz_devname, 10, "hw:%d", i_card );

        snd_ctl_t *p_ctl = NULL;
        if( snd_ctl_open( &p_ctl, psz_devname, 0 ) < 0 ) continue;

        snd_ctl_card_info( p_ctl, p_info );
        if( !b_probe )
            msg_Dbg( p_demux, "  %s (%s)",
                     snd_ctl_card_info_get_id( p_info ),
                     snd_ctl_card_info_get_name( p_info ) );

        int i_dev = -1;
        while( !snd_ctl_pcm_next_device( p_ctl, &i_dev ) && i_dev >= 0 )
        {
            snd_pcm_info_set_device( p_pcminfo, i_dev );
            snd_pcm_info_set_subdevice( p_pcminfo, 0 );
            snd_pcm_info_set_stream( p_pcminfo, SND_PCM_STREAM_CAPTURE );
            if( snd_ctl_pcm_info( p_ctl, p_pcminfo ) < 0 ) continue;

            if( !b_probe )
                msg_Dbg( p_demux, "    hw:%d,%d : %s (%s)", i_card, i_dev,
                         snd_pcm_info_get_id( p_pcminfo ),
                         snd_pcm_info_get_name( p_pcminfo ) );
            else
            {
                char *psz_device;
                if( asprintf( &psz_device, "hw:%d,%d", i_card, i_dev ) > 0 )
                {
                    if( ProbeAudioDevAlsa( p_demux, psz_device ) )
                    {
                        snd_ctl_close( p_ctl );
                        return psz_device;
                    }
                    else
                        free( psz_device );
                }
            }
        }

        snd_ctl_close( p_ctl );
    }
    return NULL;
}

bool MainWindowImpl::FindRadioshark(string& device)
{
	int card = -1;
	int dev = -1;
	
	snd_ctl_t *handle = NULL;
	snd_ctl_card_info_t *info = NULL;
	snd_pcm_info_t *pcminfo = NULL;
	snd_pcm_stream_t stream = SND_PCM_STREAM_CAPTURE;
	char card_id[32];
	char *name = NULL;

	snd_ctl_card_info_alloca (&info);
	snd_pcm_info_alloca (&pcminfo);

	if (snd_card_next (&card) < 0 || card < 0)
	{
		return false;
	}
	while(card >= 0)
	{
		snprintf (card_id, 32, "hw:%d", card);
		if (snd_ctl_open (&handle, card_id, 0) == 0)
		{
			snd_ctl_card_info (handle, info);
			while (1)
			{
				snd_ctl_pcm_next_device (handle, &dev);
				if (dev < 0){
					break;
				}
				snd_pcm_info_set_device (pcminfo, dev);
				snd_pcm_info_set_subdevice (pcminfo, 0);
				snd_pcm_info_set_stream (pcminfo, stream);
	
				if (snd_ctl_pcm_info (handle, pcminfo) >= 0)
				{
					snd_card_get_name (card, &name);
					if(strncmp(name,"radioSHARK",32) == 0)
					{void PokeScreensaver(void);
						snd_ctl_close(handle);
						free (name);
						snprintf (card_id, 32, "hw:%d,%d", card,dev);
						device = string(card_id);
						return true;
					}
					free (name);
				}
			}
			snd_ctl_close(handle);
		}
		snd_card_next (&card);
	}
	return false;//didn't find the proper Radioshark card.
}

static void deviceList(int type, vector_DevMap *devmap)
{
    snd_ctl_t* handle;
    snd_pcm_info_t pcminfo;
    int max_cards, card, err, dev;
    DevMap entry;
    char name[1024];
    struct snd_ctl_hw_info info;
    void* temp;

    max_cards = snd_cards();
    if(max_cards < 0)
        return;

    VECTOR_RESERVE(*devmap, max_cards+1);
    VECTOR_RESIZE(*devmap, 0);

    entry.name = strdup(qsaDevice);
    entry.card = 0;
    entry.dev = 0;
    VECTOR_PUSH_BACK(*devmap, entry);

    for(card = 0;card < max_cards;card++)
    {
        if((err=snd_ctl_open(&handle, card)) < 0)
            continue;

        if((err=snd_ctl_hw_info(handle, &info)) < 0)
        {
            snd_ctl_close(handle);
            continue;
        }

        for(dev = 0;dev < (int)info.pcmdevs;dev++)
        {
            if((err=snd_ctl_pcm_info(handle, dev, &pcminfo)) < 0)
                continue;

            if((type==SND_PCM_CHANNEL_PLAYBACK && (pcminfo.flags&SND_PCM_INFO_PLAYBACK)) ||
               (type==SND_PCM_CHANNEL_CAPTURE && (pcminfo.flags&SND_PCM_INFO_CAPTURE)))
            {
                snprintf(name, sizeof(name), "%s [%s] (hw:%d,%d)", info.name, pcminfo.name, card, dev);
                entry.name = strdup(name);
                entry.card = card;
                entry.dev = dev;

                VECTOR_PUSH_BACK(*devmap, entry);
                TRACE("Got device \"%s\", card %d, dev %d\n", name, card, dev);
            }
        }
        snd_ctl_close(handle);
    }
}

std::vector<HwIDPair>
AlsaLayer::getAudioDeviceIndexMap(bool getCapture) const
{
    snd_ctl_t* handle;
    snd_ctl_card_info_t *info;
    snd_pcm_info_t* pcminfo;
    snd_ctl_card_info_alloca(&info);
    snd_pcm_info_alloca(&pcminfo);

    int numCard = -1;

    std::vector<HwIDPair> audioDevice;

    if (snd_card_next(&numCard) < 0 || numCard < 0)
        return audioDevice;

    do {
        std::stringstream ss;
        ss << numCard;
        std::string name = "hw:" + ss.str();

        if (snd_ctl_open(&handle, name.c_str(), 0) == 0) {
            if (snd_ctl_card_info(handle, info) == 0) {
                snd_pcm_info_set_device(pcminfo, 0);
                snd_pcm_info_set_stream(pcminfo, getCapture ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK);

                int err;

                if ((err = snd_ctl_pcm_info(handle, pcminfo)) < 0) {
                    WARN("Cannot get info for %s %s: %s", getCapture ?
                         "capture device" : "playback device", name.c_str(),
                         snd_strerror(err));
                } else {
                    DEBUG("card %i : %s [%s]",
                          numCard,
                          snd_ctl_card_info_get_id(info),
                          snd_ctl_card_info_get_name(info));
                    std::string description = snd_ctl_card_info_get_name(info);
                    description.append(" - ");
                    description.append(snd_pcm_info_get_name(pcminfo));

                    // The number of the sound card is associated with a string description
                    audioDevice.push_back(HwIDPair(numCard, description));
                }
            }

            snd_ctl_close(handle);
        }
    } while (snd_card_next(&numCard) >= 0 && numCard >= 0);


    return audioDevice;
}