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 static 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     _PyString_Resize(&rv, count);
 162     return rv;
 163 }
 164
 165 static PyObject *
 166 lad_write(lad_t *self, PyObject *args)
 167 {
 168     char *cp;
 169     int rv, size;
 170     fd_set write_set_fds;
 171     struct timeval tv;
 172     int select_retval;
 173
 174     if (!PyArg_ParseTuple(args, "s#:write", &cp, &size))
 175         return NULL;
 176
 177     /* use select to wait for audio device to be available */
 178     FD_ZERO(&write_set_fds);
 179     FD_SET(self->x_fd, &write_set_fds);
 180     tv.tv_sec = 4; /* timeout values */
 181     tv.tv_usec = 0;
 182
 183     while (size > 0) {
 184       select_retval = select(self->x_fd+1, NULL, &write_set_fds, NULL, &tv);
 185       tv.tv_sec = 1; tv.tv_usec = 0; /* willing to wait this long next time*/
 186       if (select_retval) {
 187         if ((rv = write(self->x_fd, cp, size)) == -1) {
 188           if (errno != EAGAIN) {
 189             PyErr_SetFromErrno(LinuxAudioError);
 190             return NULL;
 191           } else {
 192             errno = 0; /* EAGAIN: buffer is full, try again */
 193           }
 194         } else {
 195           self->x_ocount += rv;
 196           size -= rv;
 197           cp += rv;
 198         }
 199       } else {
 200         /* printf("Not able to write to linux audio device within %ld seconds\n", tv.tv_sec); */
 201         PyErr_SetFromErrno(LinuxAudioError);
 202         return NULL;
 203       }
 204     }
 205     Py_INCREF(Py_None);
 206     return Py_None;
 207 }
 208
 209 static PyObject *
 210 lad_close(lad_t *self, PyObject *args)
 211 {
 212     if (!PyArg_ParseTuple(args, ":close"))
 213         return NULL;
 214
 215     if (self->x_fd >= 0) {
 216         close(self->x_fd);
 217         self->x_fd = -1;
 218     }
 219     Py_INCREF(Py_None);
 220     return Py_None;
 221 }
 222
 223 static PyObject *
 224 lad_fileno(lad_t *self, PyObject *args)
 225 {
 226     if (!PyArg_ParseTuple(args, ":fileno"))
 227         return NULL;
 228     return PyInt_FromLong(self->x_fd);
 229 }
 230
 231 static PyObject *
 232 lad_setparameters(lad_t *self, PyObject *args)
 233 {
 234     int rate, ssize, nchannels, n, fmt, emulate=0;
 235
 236     if (!PyArg_ParseTuple(args, "iiii|i:setparameters",
 237                           &rate, &ssize, &nchannels, &fmt, &emulate))
 238         return NULL;
 239
 240     if (rate < 0) {
 241         PyErr_Format(PyExc_ValueError, "expected rate >= 0, not %d",
 242                      rate);
 243         return NULL;
 244     }
 245     if (ssize < 0) {
 246         PyErr_Format(PyExc_ValueError, "expected sample size >= 0, not %d",
 247                      ssize);
 248         return NULL;
 249     }
 250     if (nchannels != 1 && nchannels != 2) {
 251         PyErr_Format(PyExc_ValueError, "nchannels must be 1 or 2, not %d",
 252                      nchannels);
 253         return NULL;
 254     }
 255
 256     for (n = 0; n < n_audio_types; n++)
 257         if (fmt == audio_types[n].a_fmt)
 258             break;
 259     if (n == n_audio_types) {
 260         PyErr_Format(PyExc_ValueError, "unknown audio encoding: %d", fmt);
 261         return NULL;
 262     }
 263     if (audio_types[n].a_bps != ssize) {
 264         PyErr_Format(PyExc_ValueError,
 265                      "for %s, expected sample size %d, not %d",
 266                      audio_types[n].a_name, audio_types[n].a_bps, ssize);
 267         return NULL;
 268     }
 269
 270     if (emulate == 0) {
 271         if ((self->x_afmts & audio_types[n].a_fmt) == 0) {
 272             PyErr_Format(PyExc_ValueError,
 273                          "%s format not supported by device",
 274                          audio_types[n].a_name);
 275             return NULL;
 276         }
 277     }
 278     if (ioctl(self->x_fd, SNDCTL_DSP_SETFMT,
 279               &audio_types[n].a_fmt) == -1) {
 280         PyErr_SetFromErrno(LinuxAudioError);
 281         return NULL;
 282     }
 283     if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, &nchannels) == -1) {
 284         PyErr_SetFromErrno(LinuxAudioError);
 285         return NULL;
 286     }
 287     if (ioctl(self->x_fd, SNDCTL_DSP_SPEED, &rate) == -1) {
 288         PyErr_SetFromErrno(LinuxAudioError);
 289         return NULL;
 290     }
 291
 292     Py_INCREF(Py_None);
 293     return Py_None;
 294 }
 295
 296 static int
 297 _ssize(lad_t *self, int *nchannels, int *ssize)
 298 {
 299     int fmt;
 300
 301     fmt = 0;
 302     if (ioctl(self->x_fd, SNDCTL_DSP_SETFMT, &fmt) < 0)
 303         return -errno;
 304
 305     switch (fmt) {
 306     case AFMT_MU_LAW:
 307     case AFMT_A_LAW:
 308     case AFMT_U8:
 309     case AFMT_S8:
 310         *ssize = sizeof(char);
 311         break;
 312     case AFMT_S16_LE:
 313     case AFMT_S16_BE:
 314     case AFMT_U16_LE:
 315     case AFMT_U16_BE:
 316         *ssize = sizeof(short);
 317         break;
 318     case AFMT_MPEG:
 319     case AFMT_IMA_ADPCM:
 320     default:
 321         return -EOPNOTSUPP;
 322     }
 323     *nchannels = 0;
 324     if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, nchannels) < 0)
 325         return -errno;
 326     return 0;
 327 }
 328
 329
 330 /* bufsize returns the size of the hardware audio buffer in number
 331    of samples */
 332 static PyObject *
 333 lad_bufsize(lad_t *self, PyObject *args)
 334 {
 335     audio_buf_info ai;
 336     int nchannels, ssize;
 337
 338     if (!PyArg_ParseTuple(args, ":bufsize")) return NULL;
 339
 340     if (_ssize(self, &nchannels, &ssize) < 0) {
 341         PyErr_SetFromErrno(LinuxAudioError);
 342         return NULL;
 343     }
 344     if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
 345         PyErr_SetFromErrno(LinuxAudioError);
 346         return NULL;
 347     }
 348     return PyInt_FromLong((ai.fragstotal * ai.fragsize) / (nchannels * ssize));
 349 }
 350
 351 /* obufcount returns the number of samples that are available in the
 352    hardware for playing */
 353 static PyObject *
 354 lad_obufcount(lad_t *self, PyObject *args)
 355 {
 356     audio_buf_info ai;
 357     int nchannels, ssize;
 358
 359     if (!PyArg_ParseTuple(args, ":obufcount"))
 360         return NULL;
 361
 362     if (_ssize(self, &nchannels, &ssize) < 0) {
 363         PyErr_SetFromErrno(LinuxAudioError);
 364         return NULL;
 365     }
 366     if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
 367         PyErr_SetFromErrno(LinuxAudioError);
 368         return NULL;
 369     }
 370     return PyInt_FromLong((ai.fragstotal * ai.fragsize - ai.bytes) /
 371                           (ssize * nchannels));
 372 }
 373
 374 /* obufcount returns the number of samples that can be played without
 375    blocking */
 376 static PyObject *
 377 lad_obuffree(lad_t *self, PyObject *args)
 378 {
 379     audio_buf_info ai;
 380     int nchannels, ssize;
 381
 382     if (!PyArg_ParseTuple(args, ":obuffree"))
 383         return NULL;
 384
 385     if (_ssize(self, &nchannels, &ssize) < 0) {
 386         PyErr_SetFromErrno(LinuxAudioError);
 387         return NULL;
 388     }
 389     if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
 390         PyErr_SetFromErrno(LinuxAudioError);
 391         return NULL;
 392     }
 393     return PyInt_FromLong(ai.bytes / (ssize * nchannels));
 394 }
 395
 396 /* Flush the device */
 397 static PyObject *
 398 lad_flush(lad_t *self, PyObject *args)
 399 {
 400     if (!PyArg_ParseTuple(args, ":flush")) return NULL;
 401
 402     if (ioctl(self->x_fd, SNDCTL_DSP_SYNC, NULL) == -1) {
 403         PyErr_SetFromErrno(LinuxAudioError);
 404         return NULL;
 405     }
 406     Py_INCREF(Py_None);
 407     return Py_None;
 408 }
 409
 410 static PyObject *
 411 lad_getptr(lad_t *self, PyObject *args)
 412 {
 413     count_info info;
 414     int req;
 415
 416     if (!PyArg_ParseTuple(args, ":getptr"))
 417         return NULL;
 418
 419     if (self->x_mode == O_RDONLY)
 420         req = SNDCTL_DSP_GETIPTR;
 421     else
 422         req = SNDCTL_DSP_GETOPTR;
 423     if (ioctl(self->x_fd, req, &info) == -1) {
 424         PyErr_SetFromErrno(LinuxAudioError);
 425         return NULL;
 426     }
 427     return Py_BuildValue("iii", info.bytes, info.blocks, info.ptr);
 428 }
 429
 430 static PyMethodDef lad_methods[] = {
 431     { "read",           (PyCFunction)lad_read, METH_VARARGS },
 432     { "write",          (PyCFunction)lad_write, METH_VARARGS },
 433     { "setparameters",  (PyCFunction)lad_setparameters, METH_VARARGS },
 434     { "bufsize",        (PyCFunction)lad_bufsize, METH_VARARGS },
 435     { "obufcount",      (PyCFunction)lad_obufcount, METH_VARARGS },
 436     { "obuffree",       (PyCFunction)lad_obuffree, METH_VARARGS },
 437     { "flush",          (PyCFunction)lad_flush, METH_VARARGS },
 438     { "close",          (PyCFunction)lad_close, METH_VARARGS },
 439     { "fileno",         (PyCFunction)lad_fileno, METH_VARARGS },
 440     { "getptr",         (PyCFunction)lad_getptr, METH_VARARGS },
 441     { NULL,             NULL}           /* sentinel */
 442 };
 443
 444 static PyObject *
 445 lad_getattr(lad_t *xp, char *name)
 446 {
 447     return Py_FindMethod(lad_methods, (PyObject *)xp, name);
 448 }
 449
 450 static PyTypeObject Ladtype = {
 451     PyObject_HEAD_INIT(&PyType_Type)
 452     0,                          /*ob_size*/
 453     "linuxaudiodev.linux_audio_device", /*tp_name*/
 454     sizeof(lad_t),              /*tp_size*/
 455     0,                          /*tp_itemsize*/
 456     /* methods */
 457     (destructor)lad_dealloc,    /*tp_dealloc*/
 458     0,                          /*tp_print*/
 459     (getattrfunc)lad_getattr,   /*tp_getattr*/
 460     0,                          /*tp_setattr*/
 461     0,                          /*tp_compare*/
 462     0,                          /*tp_repr*/
 463 };
 464
 465 static PyObject *
 466 ladopen(PyObject *self, PyObject *args)
 467 {
 468     return (PyObject *)newladobject(args);
 469 }
 470
 471 static PyMethodDef linuxaudiodev_methods[] = {
 472     { "open", ladopen, METH_VARARGS },
 473     { 0, 0 },
 474 };
 475
 476 void
 477 initlinuxaudiodev(void)
 478 {
 479     PyObject *m;
 480
 481     m = Py_InitModule("linuxaudiodev", linuxaudiodev_methods);
 482
 483     LinuxAudioError = PyErr_NewException("linuxaudiodev.error", NULL, NULL);
 484     if (LinuxAudioError)
 485         PyModule_AddObject(m, "error", LinuxAudioError);
 486
 487     if (PyModule_AddIntConstant(m, "AFMT_MU_LAW", (long)AFMT_MU_LAW) == -1)
 488         return;
 489     if (PyModule_AddIntConstant(m, "AFMT_A_LAW", (long)AFMT_A_LAW) == -1)
 490         return;
 491     if (PyModule_AddIntConstant(m, "AFMT_U8", (long)AFMT_U8) == -1)
 492         return;
 493     if (PyModule_AddIntConstant(m, "AFMT_S8", (long)AFMT_S8) == -1)
 494         return;
 495     if (PyModule_AddIntConstant(m, "AFMT_U16_BE", (long)AFMT_U16_BE) == -1)
 496         return;
 497     if (PyModule_AddIntConstant(m, "AFMT_U16_LE", (long)AFMT_U16_LE) == -1)
 498         return;
 499     if (PyModule_AddIntConstant(m, "AFMT_S16_BE", (long)AFMT_S16_BE) == -1)
 500         return;
 501     if (PyModule_AddIntConstant(m, "AFMT_S16_LE", (long)AFMT_S16_LE) == -1)
 502         return;
 503     if (PyModule_AddIntConstant(m, "AFMT_S16_NE", (long)AFMT_S16_NE) == -1)
 504         return;
 505
 506     return;
 507 }