foo.cxx

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/*
DON'T EDIT THIS FILE BY HAND, IT IS GENERATED 
BY THE SCRIPT SndPcmGen.pl FROM
alsa-lib/test/latency.c
SndPcm.cxx.in.head
SndPcm.cxx.in.tail
SndPcm.hxx.in.head
SndPcm.hxx.in.tail
*/

/*
 * Copyright (c) 2001-2004 MUSIC TECHNOLOGY GROUP (MTG)
 *                         UNIVERSITAT POMPEU FABRA
 *
 *
 * 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
 *
 */

#include "SndPcm.hxx"
#include <stdarg.h>

#include <stdarg.h>

void SndPcm::cat_error(const char* fmt,...)
{
        int len = strlen(error_str);
        int rem = 1024 - len;
        if (rem>0) {
                va_list ap;
                va_start(ap,fmt);
                vsnprintf(error_str+len,rem,fmt,ap);
                va_end(ap);
        }
}

        
SndPcm::SndPcm(int irate,int ichannels,int ilatency,
        const char* pdevice,const char* cdevice)
{
        format = SND_PCM_FORMAT_S16_LE;
        rate = irate;
        channels = ichannels;
        latency_min = ilatency;
        latency_max = ilatency*2;
        block = 0;
        tick_time = 0;
        tick_time_ok = 0;
        error_str[0]=0;
        int err;

        if ((err = snd_pcm_open(&phandle, pdevice, SND_PCM_STREAM_PLAYBACK, block ? 0 : SND_PCM_NONBLOCK)) < 0) {
                cat_error("SndPcm::SndPcm(...): Playback open error: %s\n", snd_strerror(err));
                throw SndPcmError(error_str);
        }
        if ((err = snd_pcm_open(&chandle, cdevice, SND_PCM_STREAM_CAPTURE, block ? 0 : SND_PCM_NONBLOCK)) < 0) {
                cat_error("SndPcm::SndPcm(...): Record open error: %s\n", snd_strerror(err));
                throw SndPcmError(error_str);
        }

        latency = latency_min - 4;
        if (setparams(phandle, chandle, &latency) < 0)
                throw SndPcmError(error_str);
}                       

SndPcm::~SndPcm()
{
        snd_pcm_hw_free(phandle);
        snd_pcm_hw_free(chandle);
        snd_pcm_close(phandle);
        snd_pcm_close(chandle);
}

void SndPcm::Start(void)
{
        int err;
        char buffer[1024];
        
        int nSilentBlockSamples = snd_pcm_bytes_to_samples(chandle,1024);
        int nSilentBlockFrames = snd_pcm_bytes_to_frames(chandle,1024);
        
        if ((err = snd_pcm_link(chandle, phandle)) < 0) {
                cat_error("Streams link error: %s\n", snd_strerror(err));
                throw SndPcmError(error_str);
        }
        if (snd_pcm_format_set_silence(format, buffer, nSilentBlockSamples) < 0) {
                cat_error("silence error\n");
                throw SndPcmError(error_str);
        }
        int n = latency*2; /* write two silent buffers */
        while (n)
        {
                int m = n;
                if (m>nSilentBlockFrames) m = nSilentBlockFrames;
                if (writebuf(phandle, buffer, m) < 0) {
                        cat_error("write error\n");
                        throw SndPcmError(error_str);
                }
                n -= m;
        }

        if ((err = snd_pcm_start(chandle)) < 0) {
                cat_error("Go error: %s\n", snd_strerror(err));
                throw SndPcmError(error_str);
        }
}

void SndPcm::Stop(void)
{
        snd_pcm_drop(chandle);
        snd_pcm_nonblock(phandle, 0);
        snd_pcm_drain(phandle);
        snd_pcm_nonblock(phandle, !block ? 1 : 0);
        snd_pcm_unlink(chandle);
}

void SndPcm::RecoverXRun(short* data)
{
        int err;
        
        snd_pcm_drop(chandle);
        snd_pcm_drop(phandle);

        putchar('.');

        latency = latency_min - 4;
        if (setparams(phandle, chandle, &latency) < 0)
                throw SndPcmError(error_str);

        if (writebuf(phandle,(char*) data, latency) < 0) {
                cat_error("write error\n");
                throw SndPcmError(error_str);
        }
        if (writebuf(phandle,(char*) data, latency) < 0) {
                cat_error("write error\n");
                throw SndPcmError(error_str);
        }

        if ((err = snd_pcm_start(chandle)) < 0) {
                cat_error("Go error: %s\n", snd_strerror(err));
                throw SndPcmError(error_str);
        }

}


void SndPcm::Poll(void)
{
        snd_pcm_wait(chandle, 1000);
}
/*
 * The functions which follow are taken from the latency test included
 * in the ALSA source distribution, with the following copyright note:
 *
 *  Latency test program
 *
 *     Author: Jaroslav Kysela <perex@suse.cz>
 *
 *     Author of bandpass filter sweep effect:
 *             Maarten de Boer <mdeboer@iua.upf.es>
 *
 *  This small demo program can be used for measuring latency between
 *  capture and playback. This latency is measured from driver (diff when
 *  playback and capture was started). Scheduler is set to SCHED_RR.
 *
 *
 *   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
 *
 */
int SndPcm::setparams_stream(snd_pcm_t *handle,
                     snd_pcm_hw_params_t *params,
                     const char *id)
{
        int err;

        err = snd_pcm_hw_params_any(handle, params);
        if (err < 0) {
                cat_error("Broken configuration for %s PCM: no configurations available: %s\n", snd_strerror(err), id);
                return err;
        }
        err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
        if (err < 0) {
                cat_error("Access type not available for %s: %s\n", id, snd_strerror(err));
                return err;
        }
        err = snd_pcm_hw_params_set_format(handle, params, format);
        if (err < 0) {
                cat_error("Sample format not available for %s: %s\n", id, snd_strerror(err));
                return err;
        }
        err = snd_pcm_hw_params_set_channels(handle, params, channels);
        if (err < 0) {
                cat_error("Channels count (%i) not available for %s: %s\n", channels, id, snd_strerror(err));
                return err;
        }
        err = snd_pcm_hw_params_set_rate_near(handle, params, rate, 0);
        if (err < 0) {
                cat_error("Rate %iHz not available for %s: %s\n", rate, id, snd_strerror(err));
                return err;
        }
        if (err != rate) {
                cat_error("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err);
                return -EINVAL;
        }
        return 0;
}

int SndPcm::setparams_bufsize(snd_pcm_t *handle,
                      snd_pcm_hw_params_t *params,
                      snd_pcm_hw_params_t *tparams,
                      snd_pcm_uframes_t bufsize,
                      const char *id)
{
        int err;
        snd_pcm_uframes_t periodsize;

        snd_pcm_hw_params_copy(params, tparams);
        err = snd_pcm_hw_params_set_buffer_size_near(handle, params, bufsize * 2);
        if (err < 0) {
                cat_error("Unable to set buffer size %li for %s: %s\n", bufsize * 2, id, snd_strerror(err));
                return err;
        }
        periodsize = snd_pcm_hw_params_get_buffer_size(params) / 2;
        err = snd_pcm_hw_params_set_period_size_near(handle, params, periodsize, 0);
        if (err < 0) {
                cat_error("Unable to set period size %li for %s: %s\n", periodsize, id, snd_strerror(err));
                return err;
        }
        return 0;
}

int SndPcm::setparams_set(snd_pcm_t *handle,
                  snd_pcm_hw_params_t *params,
                  snd_pcm_sw_params_t *swparams,
                  const char *id)
{
        int err, val, sleep_min = 0;

        err = snd_pcm_hw_params(handle, params);
        if (err < 0) {
                cat_error("Unable to set hw params for %s: %s\n", id, snd_strerror(err));
                return err;
        }
        err = snd_pcm_sw_params_current(handle, swparams);
        if (err < 0) {
                cat_error("Unable to determine current swparams for %s: %s\n", id, snd_strerror(err));
                return err;
        }
        err = snd_pcm_sw_params_set_start_threshold(handle, swparams, 0x7fffffff);
        if (err < 0) {
                cat_error("Unable to set start threshold mode for %s: %s\n", id, snd_strerror(err));
                return err;
        }
        tick_time_ok = 0;
        if (tick_time > 0) {
                int time, ttime;
                time = snd_pcm_hw_params_get_period_time(params, NULL);
                ttime = snd_pcm_hw_params_get_tick_time(params, NULL);
                if (time < ttime) {
                        cat_error("Skipping to set minimal sleep: period time < tick time\n");
                } else if (ttime <= 0) {
                        cat_error("Skipping to set minimal sleep: tick time <= 0 (%i)\n", ttime);
                } else {
                        sleep_min = tick_time / ttime;
                        if (sleep_min <= 0)
                                sleep_min = 1;
                        err = snd_pcm_sw_params_set_sleep_min(handle, swparams, sleep_min);
                        if (err < 0) {
                                cat_error("Unable to set minimal sleep %i for %s: %s\n", sleep_min, id, snd_strerror(err));
                                return err;
                        }
                        tick_time_ok = sleep_min * ttime;
                }
        }
        val = !block ? 4 : snd_pcm_hw_params_get_period_size(params, NULL);
        if (tick_time_ok > 0)
                val = 16;
        val = snd_pcm_hw_params_get_period_size(params, NULL);
        err = snd_pcm_sw_params_set_avail_min(handle, swparams, val);
        if (err < 0) {
                cat_error("Unable to set avail min for %s: %s\n", id, snd_strerror(err));
                return err;
        }
        val = !block ? 4 : 1;
        err = snd_pcm_sw_params_set_xfer_align(handle, swparams, val);
        if (err < 0) {
                cat_error("Unable to set transfer align for %s: %s\n", id, snd_strerror(err));
                return err;
        }
        err = snd_pcm_sw_params(handle, swparams);
        if (err < 0) {
                cat_error("Unable to set sw params for %s: %s\n", id, snd_strerror(err));
                return err;
        }
        return 0;
}

int SndPcm::setparams(snd_pcm_t *phandle, snd_pcm_t *chandle, int *bufsize)
{
        int err, last_bufsize = *bufsize;
        snd_pcm_hw_params_t *pt_params, *ct_params;     /* templates with rate, format and channels */
        snd_pcm_hw_params_t *p_params, *c_params;
        snd_pcm_sw_params_t *p_swparams, *c_swparams;
        snd_pcm_sframes_t size;

        snd_pcm_hw_params_alloca(&p_params);
        snd_pcm_hw_params_alloca(&c_params);
        snd_pcm_hw_params_alloca(&pt_params);
        snd_pcm_hw_params_alloca(&ct_params);
        snd_pcm_sw_params_alloca(&p_swparams);
        snd_pcm_sw_params_alloca(&c_swparams);
        if ((err = setparams_stream(phandle, pt_params, "playback")) < 0) {
                cat_error("Unable to set parameters for playback stream: %s\n", snd_strerror(err));
                return -1;;
        }
        if ((err = setparams_stream(chandle, ct_params, "capture")) < 0) {
                cat_error("Unable to set parameters for playback stream: %s\n", snd_strerror(err));
                return -1;;
        }

      __again:
        if (last_bufsize == *bufsize)
                *bufsize += 4;
        last_bufsize = *bufsize;
        if (*bufsize > latency_max)
                return -1;
        if ((err = setparams_bufsize(phandle, p_params, pt_params, *bufsize, "playback")) < 0) {
                cat_error("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
                return -1;;
        }
        if ((err = setparams_bufsize(chandle, c_params, ct_params, *bufsize, "capture")) < 0) {
                cat_error("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
                return -1;;
        }

        size = snd_pcm_hw_params_get_period_size(p_params, NULL);
        if (size > *bufsize)
                *bufsize = size;
        size = snd_pcm_hw_params_get_period_size(c_params, NULL);
        if (size > *bufsize)
                *bufsize = size;
        if (snd_pcm_hw_params_get_period_time(p_params, NULL) !=
            snd_pcm_hw_params_get_period_time(c_params, NULL))
                goto __again;
        if (snd_pcm_hw_params_get_period_size(p_params, NULL) * 2 < snd_pcm_hw_params_get_buffer_size(p_params))
                goto __again;
        if (snd_pcm_hw_params_get_period_size(c_params, NULL) * 2 < snd_pcm_hw_params_get_buffer_size(c_params))
                goto __again;

        if ((err = setparams_set(phandle, p_params, p_swparams, "playback")) < 0) {
                cat_error("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
                return -1;;
        }
        if ((err = setparams_set(chandle, c_params, c_swparams, "capture")) < 0) {
                cat_error("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
                return -1;;
        }

        if ((err = snd_pcm_prepare(phandle)) < 0) {
                cat_error("Prepare error: %s\n", snd_strerror(err));
                return -1;;
        }



        fflush(stdout);
        return 0;
}

long SndPcm::readbuf(snd_pcm_t *handle, char *buf, long len)
{
        long r;

        if (!block) {
                do {
                        r = snd_pcm_readi(handle, buf, len);
                } while (r == -EAGAIN);
                if (r > 0) {



                }
                // cat_error("read = %li\n", r);
        } else {
                int frame_bytes = (snd_pcm_format_width(format) / 8) * channels;
                do {
                        r = snd_pcm_readi(handle, buf, len);
                        if (r > 0) {
                                buf += r * frame_bytes;
                                len -= r;



                        }
                        // cat_error("r = %li, len = %li\n", r, len);
                } while (r >= 1 && len > 0);
        }
        // showstat(handle, 0);
        return r;
}

long SndPcm::writebuf(snd_pcm_t *handle, char *buf, long len)
{
        long r;

        while (len > 0) {
                r = snd_pcm_writei(handle, buf, len);
                if (r == -EAGAIN)
                        continue;
                // cat_error("write = %li\n", r);
                if (r < 0)
                        return r;
                // showstat(handle, 0);
                buf += r * 4;
                len -= r;

        }
        return 0;
}

/*
 * Copyright (c) 2001-2002 MUSIC TECHNOLOGY GROUP (MTG)
 *                         UNIVERSITAT POMPEU FABRA
 *
 *
 * 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
 *
 */

#ifdef TESTSNDPCM

#include <sched.h>

void setscheduler(void)
{
        struct sched_param sched_param;

        if (sched_getparam(0, &sched_param) < 0) {
                printf("Scheduler getparam failed...\n");
                return;
        }
        sched_param.sched_priority = sched_get_priority_max(SCHED_RR);
        if (!sched_setscheduler(0, SCHED_RR, &sched_param)) {
                printf("Scheduler set to Round Robin with priority %i...\n", sched_param.sched_priority);
                fflush(stdout);
                return;
        }
        printf("!!!Scheduler set to Round Robin with priority %i FAILED!!!\n", sched_param.sched_priority);
}

main()
{
        short buf[1024];
        try
        {
                SndPcm sndpcm(44099,2,"plughw:0,0","plughw:0,0");
                
                setscheduler();

                sndpcm.Start();
                
                for (int i=0;i<1000;i++)
                {
                        sndpcm.Poll();
                        sndpcm.ReadBuf(buf);
                        sndpcm.WriteBuf(buf);
                }
        }
        catch (SndPcmError e)
        {
                printf(e.str);
        }
}

#endif

---