Modules/linuxaudiodev.c

   1 /* Hey Emacs, this is -*-C-*-
   2  ******************************************************************************
   3  * linuxaudiodev.c -- Linux audio device for python.
   4  *
   5  * Author          : Peter Bosch
   6  * Created On      : Thu Mar  2 21:10:33 2000
   7  * Status          : Unknown, Use with caution!
   8  *
   9  * Unless other notices are present in any part of this file
  10  * explicitly claiming copyrights for other people and/or
  11  * organizations, the contents of this file is fully copyright
  12  * (C) 2000 Peter Bosch, all rights reserved.
  13  ******************************************************************************
  14  */
  15
  16 #include "Python.h"
  17 #include "structmember.h"
  18
  19 #ifdef HAVE_FCNTL_H
  20 #include <fcntl.h>
  21 #else
  22 #define O_RDONLY 00
  23 #define O_WRONLY 01
  24 #endif
  25
  26
  27 #include <sys/ioctl.h>
  28 #if defined(linux)
  29 #include <linux/soundcard.h>
  30
  31 typedef unsigned long uint32_t;
  32
  33 #elif defined(__FreeBSD__)
  34 #include <machine/soundcard.h>
  35
  36 #ifndef SNDCTL_DSP_CHANNELS
  37 #define SNDCTL_DSP_CHANNELS SOUND_PCM_WRITE_CHANNELS
  38 #endif
  39
  40 #endif
  41
  42 typedef struct {
  43     PyObject_HEAD;
  44     int         x_fd;           /* The open file */
  45     int         x_mode;           /* file mode */
  46     int         x_icount;       /* Input count */
  47     int         x_ocount;       /* Output count */
  48     uint32_t    x_afmts;        /* Audio formats supported by hardware*/
  49 } lad_t;
  50
  51 /* XXX several format defined in soundcard.h are not supported,
  52    including _NE (native endian) options and S32 options
  53 */
  54
  55 static struct {
  56     int         a_bps;
  57     uint32_t    a_fmt;
  58     char       *a_name;
  59 } audio_types[] = {
  60     {  8,       AFMT_MU_LAW, "logarithmic mu-law 8-bit audio" },
  61     {  8,       AFMT_A_LAW,  "logarithmic A-law 8-bit audio" },
  62     {  8,       AFMT_U8,     "linear unsigned 8-bit audio" },
  63     {  8,       AFMT_S8,     "linear signed 8-bit audio" },
  64     { 16,       AFMT_U16_BE, "linear unsigned 16-bit big-endian audio" },
  65     { 16,       AFMT_U16_LE, "linear unsigned 16-bit little-endian audio" },
  66     { 16,       AFMT_S16_BE, "linear signed 16-bit big-endian audio" },
  67     { 16,       AFMT_S16_LE, "linear signed 16-bit little-endian audio" },
  68     { 16,       AFMT_S16_NE, "linear signed 16-bit native-endian audio" },
  69 };
  70
  71 static int n_audio_types = sizeof(audio_types) / sizeof(audio_types[0]);
  72
  73 staticforward PyTypeObject Ladtype;
  74
  75 static PyObject *LinuxAudioError;
  76
  77 static lad_t *
  78 newladobject(PyObject *arg)
  79 {
  80     lad_t *xp;
  81     int fd, afmts, imode;
  82     char *mode;
  83     char *basedev;
  84
  85     /* Check arg for r/w/rw */
  86     if (!PyArg_ParseTuple(arg, "s:open", &mode)) return NULL;
  87     if (strcmp(mode, "r") == 0)
  88         imode = O_RDONLY;
  89     else if (strcmp(mode, "w") == 0)
  90         imode = O_WRONLY;
  91     else {
  92         PyErr_SetString(LinuxAudioError, "mode should be 'r' or 'w'");
  93         return NULL;
  94     }
  95
  96     /* Open the correct device.  The base device name comes from the
  97      * AUDIODEV environment variable first, then /dev/dsp.  The
  98      * control device tacks "ctl" onto the base device name.
  99      *
 100      * Note that the only difference between /dev/audio and /dev/dsp
 101      * is that the former uses logarithmic mu-law encoding and the
 102      * latter uses 8-bit unsigned encoding.
 103      */
 104
 105     basedev = getenv("AUDIODEV");
 106     if (!basedev)
 107         basedev = "/dev/dsp";
 108
 109     if ((fd = open(basedev, imode)) == -1) {
 110         PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
 111         return NULL;
 112     }
 113     if (imode == O_WRONLY && ioctl(fd, SNDCTL_DSP_NONBLOCK, NULL) == -1) {
 114         PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
 115         return NULL;
 116     }
 117     if (ioctl(fd, SNDCTL_DSP_GETFMTS, &afmts) == -1) {
 118         PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
 119         return NULL;
 120     }
 121     /* Create and initialize the object */
 122     if ((xp = PyObject_New(lad_t, &Ladtype)) == NULL) {
 123         close(fd);
 124         return NULL;
 125     }
 126     xp->x_fd = fd;
 127     xp->x_mode = imode;
 128     xp->x_icount = xp->x_ocount = 0;
 129     xp->x_afmts  = afmts;
 130     return xp;
 131 }
 132
 133 static void
 134 lad_dealloc(lad_t *xp)
 135 {
 136     /* if already closed, don't reclose it */
 137     if (xp->x_fd != -1)
 138         close(xp->x_fd);
 139     PyObject_Del(xp);
 140 }
 141
 142 static PyObject *
 143 lad_read(lad_t *self, PyObject *args)
 144 {
 145     int size, count;
 146     char *cp;
 147     PyObject *rv;
 148
 149     if (!PyArg_ParseTuple(args, "i:read", &size))
 150         return NULL;
 151     rv = PyString_FromStringAndSize(NULL, size);
 152     if (rv == NULL)
 153         return NULL;
 154     cp = PyString_AS_STRING(rv);
 155     if ((count = read(self->x_fd, cp, size)) < 0) {
 156         PyErr_SetFromErrno(LinuxAudioError);
 157         Py_DECREF(rv);
 158         return NULL;
 159     }
 160     self->x_icount += count;
 161     if (_PyString_Resize(&rv, count) == -1)
 162         return NULL;
 163     return rv;
 164 }
 165
 166 static PyObject *
 167 lad_write(lad_t *self, PyObject *args)
 168 {
 169     char *cp;
 170     int rv, size;
 171     fd_set write_set_fds;
 172     struct timeval tv;
 173     int select_retval;
 174
 175     if (!PyArg_ParseTuple(args, "s#:write", &cp, &size))
 176         return NULL;
 177
 178     /* use select to wait for audio device to be available */
 179     FD_ZERO(&write_set_fds);
 180     FD_SET(self->x_fd, &write_set_fds);
 181     tv.tv_sec = 4; /* timeout values */
 182     tv.tv_usec = 0;
 183
 184     while (size > 0) {
 185       select_retval = select(self->x_fd+1, NULL, &write_set_fds, NULL, &tv);
 186       tv.tv_sec = 1; tv.tv_usec = 0; /* willing to wait this long next time*/
 187       if (select_retval) {
 188         if ((rv = write(self->x_fd, cp, size)) == -1) {
 189           if (errno != EAGAIN) {
 190             PyErr_SetFromErrno(LinuxAudioError);
 191             return NULL;
 192           } else {
 193             errno = 0; /* EAGAIN: buffer is full, try again */
 194           }
 195         } else {
 196           self->x_ocount += rv;
 197           size -= rv;
 198           cp += rv;
 199         }
 200       } else {
 201         /* printf("Not able to write to linux audio device within %ld seconds\n", tv.tv_sec); */
 202         PyErr_SetFromErrno(LinuxAudioError);
 203         return NULL;
 204       }
 205     }
 206     Py_INCREF(Py_None);
 207     return Py_None;
 208 }
 209
 210 static PyObject *
 211 lad_close(lad_t *self, PyObject *args)
 212 {
 213     if (!PyArg_ParseTuple(args, ":close"))
 214         return NULL;
 215
 216     if (self->x_fd >= 0) {
 217         close(self->x_fd);
 218         self->x_fd = -1;
 219     }
 220     Py_INCREF(Py_None);
 221     return Py_None;
 222 }
 223
 224 static PyObject *
 225 lad_fileno(lad_t *self, PyObject *args)
 226 {
 227     if (!PyArg_ParseTuple(args, ":fileno"))
 228         return NULL;
 229     return PyInt_FromLong(self->x_fd);
 230 }
 231
 232 static PyObject *
 233 lad_setparameters(lad_t *self, PyObject *args)
 234 {
 235     int rate, ssize, nchannels, n, fmt, emulate=0;
 236
 237     if (!PyArg_ParseTuple(args, "iiii|i:setparameters",
 238                           &rate, &ssize, &nchannels, &fmt, &emulate))
 239         return NULL;
 240
 241     if (rate < 0) {
 242         PyErr_Format(PyExc_ValueError, "expected rate >= 0, not %d",
 243                      rate);
 244         return NULL;
 245     }
 246     if (ssize < 0) {
 247         PyErr_Format(PyExc_ValueError, "expected sample size >= 0, not %d",
 248                      ssize);
 249         return NULL;
 250     }
 251     if (nchannels != 1 && nchannels != 2) {
 252         PyErr_Format(PyExc_ValueError, "nchannels must be 1 or 2, not %d",
 253                      nchannels);
 254         return NULL;
 255     }
 256
 257     for (n = 0; n < n_audio_types; n++)
 258         if (fmt == audio_types[n].a_fmt)
 259             break;
 260     if (n == n_audio_types) {
 261         PyErr_Format(PyExc_ValueError, "unknown audio encoding: %d", fmt);
 262         return NULL;
 263     }
 264     if (audio_types[n].a_bps != ssize) {
 265         PyErr_Format(PyExc_ValueError,
 266                      "for %s, expected sample size %d, not %d",
 267                      audio_types[n].a_name, audio_types[n].a_bps, ssize);
 268         return NULL;
 269     }
 270
 271     if (emulate == 0) {
 272         if ((self->x_afmts & audio_types[n].a_fmt) == 0) {
 273             PyErr_Format(PyExc_ValueError,
 274                          "%s format not supported by device",
 275                          audio_types[n].a_name);
 276             return NULL;
 277         }
 278     }
 279     if (ioctl(self->x_fd, SNDCTL_DSP_SETFMT,
 280               &audio_types[n].a_fmt) == -1) {
 281         PyErr_SetFromErrno(LinuxAudioError);
 282         return NULL;
 283     }
 284     if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, &nchannels) == -1) {
 285         PyErr_SetFromErrno(LinuxAudioError);
 286         return NULL;
 287     }
 288     if (ioctl(self->x_fd, SNDCTL_DSP_SPEED, &rate) == -1) {
 289         PyErr_SetFromErrno(LinuxAudioError);
 290         return NULL;
 291     }
 292
 293     Py_INCREF(Py_None);
 294     return Py_None;
 295 }
 296
 297 static int
 298 _ssize(lad_t *self, int *nchannels, int *ssize)
 299 {
 300     int fmt;
 301
 302     fmt = 0;
 303     if (ioctl(self->x_fd, SNDCTL_DSP_SETFMT, &fmt) < 0)
 304         return -errno;
 305
 306     switch (fmt) {
 307     case AFMT_MU_LAW:
 308     case AFMT_A_LAW:
 309     case AFMT_U8:
 310     case AFMT_S8:
 311         *ssize = sizeof(char);
 312         break;
 313     case AFMT_S16_LE:
 314     case AFMT_S16_BE:
 315     case AFMT_U16_LE:
 316     case AFMT_U16_BE:
 317         *ssize = sizeof(short);
 318         break;
 319     case AFMT_MPEG:
 320     case AFMT_IMA_ADPCM:
 321     default:
 322         return -EOPNOTSUPP;
 323     }
 324     *nchannels = 0;
 325     if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, nchannels) < 0)
 326         return -errno;
 327     return 0;
 328 }
 329
 330
 331 /* bufsize returns the size of the hardware audio buffer in number
 332    of samples */
 333 static PyObject *
 334 lad_bufsize(lad_t *self, PyObject *args)
 335 {
 336     audio_buf_info ai;
 337     int nchannels, ssize;
 338
 339     if (!PyArg_ParseTuple(args, ":bufsize")) return NULL;
 340
 341     if (_ssize(self, &nchannels, &ssize) < 0) {
 342         PyErr_SetFromErrno(LinuxAudioError);
 343         return NULL;
 344     }
 345     if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
 346         PyErr_SetFromErrno(LinuxAudioError);
 347         return NULL;
 348     }
 349     return PyInt_FromLong((ai.fragstotal * ai.fragsize) / (nchannels * ssize));
 350 }
 351
 352 /* obufcount returns the number of samples that are available in the
 353    hardware for playing */
 354 static PyObject *
 355 lad_obufcount(lad_t *self, PyObject *args)
 356 {
 357     audio_buf_info ai;
 358     int nchannels, ssize;
 359
 360     if (!PyArg_ParseTuple(args, ":obufcount"))
 361         return NULL;
 362
 363     if (_ssize(self, &nchannels, &ssize) < 0) {
 364         PyErr_SetFromErrno(LinuxAudioError);
 365         return NULL;
 366     }
 367     if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
 368         PyErr_SetFromErrno(LinuxAudioError);
 369         return NULL;
 370     }
 371     return PyInt_FromLong((ai.fragstotal * ai.fragsize - ai.bytes) /
 372                           (ssize * nchannels));
 373 }
 374
 375 /* obufcount returns the number of samples that can be played without
 376    blocking */
 377 static PyObject *
 378 lad_obuffree(lad_t *self, PyObject *args)
 379 {
 380     audio_buf_info ai;
 381     int nchannels, ssize;
 382
 383     if (!PyArg_ParseTuple(args, ":obuffree"))
 384         return NULL;
 385
 386     if (_ssize(self, &nchannels, &ssize) < 0) {
 387         PyErr_SetFromErrno(LinuxAudioError);
 388         return NULL;
 389     }
 390     if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
 391         PyErr_SetFromErrno(LinuxAudioError);
 392         return NULL;
 393     }
 394     return PyInt_FromLong(ai.bytes / (ssize * nchannels));
 395 }
 396
 397 /* Flush the device */
 398 static PyObject *
 399 lad_flush(lad_t *self, PyObject *args)
 400 {
 401     if (!PyArg_ParseTuple(args, ":flush")) return NULL;
 402
 403     if (ioctl(self->x_fd, SNDCTL_DSP_SYNC, NULL) == -1) {
 404         PyErr_SetFromErrno(LinuxAudioError);
 405         return NULL;
 406     }
 407     Py_INCREF(Py_None);
 408     return Py_None;
 409 }
 410
 411 static PyObject *
 412 lad_getptr(lad_t *self, PyObject *args)
 413 {
 414     count_info info;
 415     int req;
 416
 417     if (!PyArg_ParseTuple(args, ":getptr"))
 418         return NULL;
 419
 420     if (self->x_mode == O_RDONLY)
 421         req = SNDCTL_DSP_GETIPTR;
 422     else
 423         req = SNDCTL_DSP_GETOPTR;
 424     if (ioctl(self->x_fd, req, &info) == -1) {
 425         PyErr_SetFromErrno(LinuxAudioError);
 426         return NULL;
 427     }
 428     return Py_BuildValue("iii", info.bytes, info.blocks, info.ptr);
 429 }
 430
 431 static PyMethodDef lad_methods[] = {
 432     { "read",           (PyCFunction)lad_read, METH_VARARGS },
 433     { "write",          (PyCFunction)lad_write, METH_VARARGS },
 434     { "setparameters",  (PyCFunction)lad_setparameters, METH_VARARGS },
 435     { "bufsize",        (PyCFunction)lad_bufsize, METH_VARARGS },
 436     { "obufcount",      (PyCFunction)lad_obufcount, METH_VARARGS },
 437     { "obuffree",       (PyCFunction)lad_obuffree, METH_VARARGS },
 438     { "flush",          (PyCFunction)lad_flush, METH_VARARGS },
 439     { "close",          (PyCFunction)lad_close, METH_VARARGS },
 440     { "fileno",         (PyCFunction)lad_fileno, METH_VARARGS },
 441     { "getptr",         (PyCFunction)lad_getptr, METH_VARARGS },
 442     { NULL,             NULL}           /* sentinel */
 443 };
 444
 445 static PyObject *
 446 lad_getattr(lad_t *xp, char *name)
 447 {
 448     return Py_FindMethod(lad_methods, (PyObject *)xp, name);
 449 }
 450
 451 static PyTypeObject Ladtype = {
 452     PyObject_HEAD_INIT(&PyType_Type)
 453     0,                          /*ob_size*/
 454     "linuxaudiodev.linux_audio_device", /*tp_name*/
 455     sizeof(lad_t),              /*tp_size*/
 456     0,                          /*tp_itemsize*/
 457     /* methods */
 458     (destructor)lad_dealloc,    /*tp_dealloc*/
 459     0,                          /*tp_print*/
 460     (getattrfunc)lad_getattr,   /*tp_getattr*/
 461     0,                          /*tp_setattr*/
 462     0,                          /*tp_compare*/
 463     0,                          /*tp_repr*/
 464 };
 465
 466 static PyObject *
 467 ladopen(PyObject *self, PyObject *args)
 468 {
 469     return (PyObject *)newladobject(args);
 470 }
 471
 472 static PyMethodDef linuxaudiodev_methods[] = {
 473     { "open", ladopen, METH_VARARGS },
 474     { 0, 0 },
 475 };
 476
 477 void
 478 initlinuxaudiodev(void)
 479 {
 480     PyObject *m;
 481
 482     m = Py_InitModule("linuxaudiodev", linuxaudiodev_methods);
 483
 484     LinuxAudioError = PyErr_NewException("linuxaudiodev.error", NULL, NULL);
 485     if (LinuxAudioError)
 486         PyModule_AddObject(m, "error", LinuxAudioError);
 487
 488     if (PyModule_AddIntConstant(m, "AFMT_MU_LAW", (long)AFMT_MU_LAW) == -1)
 489         return;
 490     if (PyModule_AddIntConstant(m, "AFMT_A_LAW", (long)AFMT_A_LAW) == -1)
 491         return;
 492     if (PyModule_AddIntConstant(m, "AFMT_U8", (long)AFMT_U8) == -1)
 493         return;
 494     if (PyModule_AddIntConstant(m, "AFMT_S8", (long)AFMT_S8) == -1)
 495         return;
 496     if (PyModule_AddIntConstant(m, "AFMT_U16_BE", (long)AFMT_U16_BE) == -1)
 497         return;
 498     if (PyModule_AddIntConstant(m, "AFMT_U16_LE", (long)AFMT_U16_LE) == -1)
 499         return;
 500     if (PyModule_AddIntConstant(m, "AFMT_S16_BE", (long)AFMT_S16_BE) == -1)
 501         return;
 502     if (PyModule_AddIntConstant(m, "AFMT_S16_LE", (long)AFMT_S16_LE) == -1)
 503         return;
 504     if (PyModule_AddIntConstant(m, "AFMT_S16_NE", (long)AFMT_S16_NE) == -1)
 505         return;
 506
 507     return;
 508 }