#include <stdio.h>
#include <alsa/asoundlib.h>

#define ENABLE_SETPARAMS_RATE 1
#define ENABLE_SETPARAMS_PERIOD 2

/* neither set_rate_min() nor set_period_size_near() is ok (but trivial) */
//#define ENABLE_SETPARAMS 0

/* only set_rate_min() is ok */
//#define ENABLE_SETPARAMS  ENABLE_SETPARAMS_RATE

/* only set_period_size_near() is ok as well */
//#define ENABLE_SETPARAMS  ENABLE_SETPARAMS_PERIOD

/* both set_rate_min() and set_period_size_near() -> CRASH */
#define ENABLE_SETPARAMS  ENABLE_SETPARAMS_RATE | ENABLE_SETPARAMS_PERIOD

int pcm_configure(snd_pcm_t *pcm) {
  unsigned int rate=44100;
  snd_pcm_uframes_t uframes = 64;

  snd_pcm_hw_params_t* hw_params;
  int err;

  snd_pcm_hw_params_alloca(&hw_params);
  err = snd_pcm_hw_params_any(pcm, hw_params);
  if(err<0){fprintf(stderr, "snd_pcm_hw_params_any failed: %s\n",  snd_strerror(err));return err;}

#if ENABLE_SETPARAMS & 1
  err = snd_pcm_hw_params_set_rate_min(pcm, hw_params, &rate, 0);
  if(err<0){fprintf(stderr, "snd_pcm_hw_params_set_rate_min failed: %s\n",  snd_strerror(err));return err;}
#endif

#if ENABLE_SETPARAMS & 2
  err = snd_pcm_hw_params_set_period_size_near(pcm, hw_params, &uframes, 0);
  if(err<0){fprintf(stderr, "snd_pcm_hw_params_set_period_size failed: %s\n",  snd_strerror(err));return err;}
#endif

  err = snd_pcm_hw_params(pcm, hw_params);
  if(err<0){fprintf(stderr, "snd_pcm_hw_params failed: %s\n",  snd_strerror(err));return err;}

  printf("configuring device succeeded\n");
  return 0;
}

void pcm_open(char*name) {
 int err=0;
 snd_pcm_t *pcmIn=0, *pcmOut=0;

  printf("trying to open '%s' as CAPTURE\n", name);
  err = snd_pcm_open(&pcmIn, name, SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK);
  if(err<0){fprintf(stderr, "snd_pcm_open(CAPTURE) failed: %s\n",  snd_strerror(err));goto closeit;}
  err=snd_pcm_nonblock(pcmIn, 1);
  if(err<0){fprintf(stderr, "snd_pcm_nonblock failed: %s\n",  snd_strerror(err));goto closeit;}
  pcm_configure(pcmIn);
  fprintf(stderr, "CAPTURE configured\n");

  printf("trying to open '%s' as PLAYBACK\n", name);
  err = snd_pcm_open(&pcmOut, name, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  if(err<0){fprintf(stderr, "snd_pcm_open(PLAYBACK) failed: %s\n",  snd_strerror(err));goto closeit;}
  err=snd_pcm_nonblock(pcmOut, 1);
  if(err<0){fprintf(stderr, "snd_pcm_nonblock failed: %s\n",  snd_strerror(err));goto closeit;}
  pcm_configure(pcmOut);
  fprintf(stderr, "PLAYBACK configured\n");

 closeit:
  if(pcmIn)snd_pcm_close(pcmIn);
  if(pcmOut)snd_pcm_close(pcmOut);
}


int main(int argc, char**argv) {
  int i=0;
  if(argc>1) {
    for(i=1; i<argc; i++) {
      pcm_open(argv[i]);
    }
  } else {
      pcm_open("hw:0");
      pcm_open("plughw:0");
  }
  fprintf(stderr, "bye bye\n");
  return 0;
}