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 *basedev = NULL;
  83     char *mode = NULL;
  84
  85     /* Two ways to call linuxaudiodev.open():
  86          open(device, mode) (for consistency with builtin open())
  87          open(mode)         (for backwards compatibility)
  88        because the *first* argument is optional, parsing args is
  89        a wee bit tricky. */
  90     if (!PyArg_ParseTuple(arg, "s|s:open", &basedev, &mode))
  91        return NULL;
  92     if (mode == NULL) {                 /* only one arg supplied */
  93        mode = basedev;
  94        basedev = NULL;
  95     }
  96
  97     if (strcmp(mode, "r") == 0)
  98         imode = O_RDONLY;
  99     else if (strcmp(mode, "w") == 0)
 100         imode = O_WRONLY;
 101     else {
 102         PyErr_SetString(LinuxAudioError, "mode should be 'r' or 'w'");
 103         return NULL;
 104     }
 105
 106     /* Open the correct device.  The base device name comes from the
 107      * AUDIODEV environment variable first, then /dev/dsp.  The
 108      * control device tacks "ctl" onto the base device name.
 109      *
 110      * Note that the only difference between /dev/audio and /dev/dsp
 111      * is that the former uses logarithmic mu-law encoding and the
 112      * latter uses 8-bit unsigned encoding.
 113      */
 114
 115     if (basedev == NULL) {              /* called with one arg */
 116        basedev = getenv("AUDIODEV");
 117        if (basedev == NULL)             /* $AUDIODEV not set */
 118           basedev = "/dev/dsp";
 119     }
 120
 121     if ((fd = open(basedev, imode)) == -1) {
 122         PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
 123         return NULL;
 124     }
 125     if (imode == O_WRONLY && ioctl(fd, SNDCTL_DSP_NONBLOCK, NULL) == -1) {
 126         PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
 127         return NULL;
 128     }
 129     if (ioctl(fd, SNDCTL_DSP_GETFMTS, &afmts) == -1) {
 130         PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
 131         return NULL;
 132     }
 133     /* Create and initialize the object */
 134     if ((xp = PyObject_New(lad_t, &Ladtype)) == NULL) {
 135         close(fd);
 136         return NULL;
 137     }
 138     xp->x_fd = fd;
 139     xp->x_mode = imode;
 140     xp->x_icount = xp->x_ocount = 0;
 141     xp->x_afmts  = afmts;
 142     return xp;
 143 }
 144
 145 static void
 146 lad_dealloc(lad_t *xp)
 147 {
 148     /* if already closed, don't reclose it */
 149     if (xp->x_fd != -1)
 150         close(xp->x_fd);
 151     PyObject_Del(xp);
 152 }
 153
 154 static PyObject *
 155 lad_read(lad_t *self, PyObject *args)
 156 {
 157     int size, count;
 158     char *cp;
 159     PyObject *rv;
 160
 161     if (!PyArg_ParseTuple(args, "i:read", &size))
 162         return NULL;
 163     rv = PyString_FromStringAndSize(NULL, size);
 164     if (rv == NULL)
 165         return NULL;
 166     cp = PyString_AS_STRING(rv);
 167     if ((count = read(self->x_fd, cp, size)) < 0) {
 168         PyErr_SetFromErrno(LinuxAudioError);
 169         Py_DECREF(rv);
 170         return NULL;
 171     }
 172     self->x_icount += count;
 173     _PyString_Resize(&rv, count);
 174     return rv;
 175 }
 176
 177 static PyObject *
 178 lad_write(lad_t *self, PyObject *args)
 179 {
 180     char *cp;
 181     int rv, size;
 182     fd_set write_set_fds;
 183     struct timeval tv;
 184     int select_retval;
 185
 186     if (!PyArg_ParseTuple(args, "s#:write", &cp, &size))
 187         return NULL;
 188
 189     /* use select to wait for audio device to be available */
 190     FD_ZERO(&write_set_fds);
 191     FD_SET(self->x_fd, &write_set_fds);
 192     tv.tv_sec = 4; /* timeout values */
 193     tv.tv_usec = 0;
 194
 195     while (size > 0) {
 196       select_retval = select(self->x_fd+1, NULL, &write_set_fds, NULL, &tv);
 197       tv.tv_sec = 1; tv.tv_usec = 0; /* willing to wait this long next time*/
 198       if (select_retval) {
 199         if ((rv = write(self->x_fd, cp, size)) == -1) {
 200           if (errno != EAGAIN) {
 201             PyErr_SetFromErrno(LinuxAudioError);
 202             return NULL;
 203           } else {
 204             errno = 0; /* EAGAIN: buffer is full, try again */
 205           }
 206         } else {
 207           self->x_ocount += rv;
 208           size -= rv;
 209           cp += rv;
 210         }
 211       } else {
 212         /* printf("Not able to write to linux audio device within %ld seconds\n", tv.tv_sec); */
 213         PyErr_SetFromErrno(LinuxAudioError);
 214         return NULL;
 215       }
 216     }
 217     Py_INCREF(Py_None);
 218     return Py_None;
 219 }
 220
 221 static PyObject *
 222 lad_close(lad_t *self, PyObject *unused)
 223 {
 224     if (self->x_fd >= 0) {
 225         close(self->x_fd);
 226         self->x_fd = -1;
 227     }
 228     Py_RETURN_NONE;
 229 }
 230
 231 static PyObject *
 232 lad_fileno(lad_t *self, PyObject *unused)
 233 {
 234     return PyInt_FromLong(self->x_fd);
 235 }
 236
 237 static PyObject *
 238 lad_setparameters(lad_t *self, PyObject *args)
 239 {
 240     int rate, ssize, nchannels, n, fmt, emulate=0;
 241
 242     if (!PyArg_ParseTuple(args, "iiii|i:setparameters",
 243                           &rate, &ssize, &nchannels, &fmt, &emulate))
 244         return NULL;
 245
 246     if (rate < 0) {
 247         PyErr_Format(PyExc_ValueError, "expected rate >= 0, not %d",
 248                      rate);
 249         return NULL;
 250     }
 251     if (ssize < 0) {
 252         PyErr_Format(PyExc_ValueError, "expected sample size >= 0, not %d",
 253                      ssize);
 254         return NULL;
 255     }
 256     if (nchannels != 1 && nchannels != 2) {
 257         PyErr_Format(PyExc_ValueError, "nchannels must be 1 or 2, not %d",
 258                      nchannels);
 259         return NULL;
 260     }
 261
 262     for (n = 0; n < n_audio_types; n++)
 263         if (fmt == audio_types[n].a_fmt)
 264             break;
 265     if (n == n_audio_types) {
 266         PyErr_Format(PyExc_ValueError, "unknown audio encoding: %d", fmt);
 267         return NULL;
 268     }
 269     if (audio_types[n].a_bps != ssize) {
 270         PyErr_Format(PyExc_ValueError,
 271                      "for %s, expected sample size %d, not %d",
 272                      audio_types[n].a_name, audio_types[n].a_bps, ssize);
 273         return NULL;
 274     }
 275
 276     if (emulate == 0) {
 277         if ((self->x_afmts & audio_types[n].a_fmt) == 0) {
 278             PyErr_Format(PyExc_ValueError,
 279                          "%s format not supported by device",
 280                          audio_types[n].a_name);
 281             return NULL;
 282         }
 283     }
 284     if (ioctl(self->x_fd, SNDCTL_DSP_SETFMT,
 285               &audio_types[n].a_fmt) == -1) {
 286         PyErr_SetFromErrno(LinuxAudioError);
 287         return NULL;
 288     }
 289     if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, &nchannels) == -1) {
 290         PyErr_SetFromErrno(LinuxAudioError);
 291         return NULL;
 292     }
 293     if (ioctl(self->x_fd, SNDCTL_DSP_SPEED, &rate) == -1) {
 294         PyErr_SetFromErrno(LinuxAudioError);
 295         return NULL;
 296     }
 297
 298     Py_INCREF(Py_None);
 299     return Py_None;
 300 }
 301
 302 static int
 303 _ssize(lad_t *self, int *nchannels, int *ssize)
 304 {
 305     int fmt;
 306
 307     fmt = 0;
 308     if (ioctl(self->x_fd, SNDCTL_DSP_SETFMT, &fmt) < 0)
 309         return -errno;
 310
 311     switch (fmt) {
 312     case AFMT_MU_LAW:
 313     case AFMT_A_LAW:
 314     case AFMT_U8:
 315     case AFMT_S8:
 316         *ssize = sizeof(char);
 317         break;
 318     case AFMT_S16_LE:
 319     case AFMT_S16_BE:
 320     case AFMT_U16_LE:
 321     case AFMT_U16_BE:
 322         *ssize = sizeof(short);
 323         break;
 324     case AFMT_MPEG:
 325     case AFMT_IMA_ADPCM:
 326     default:
 327         return -EOPNOTSUPP;
 328     }
 329     if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, nchannels) < 0)
 330         return -errno;
 331     return 0;
 332 }
 333
 334
 335 /* bufsize returns the size of the hardware audio buffer in number
 336    of samples */
 337 static PyObject *
 338 lad_bufsize(lad_t *self, PyObject *unused)
 339 {
 340     audio_buf_info ai;
 341     int nchannels=0, ssize=0;
 342
 343     if (_ssize(self, &nchannels, &ssize) < 0 || !ssize || !nchannels) {
 344         PyErr_SetFromErrno(LinuxAudioError);
 345         return NULL;
 346     }
 347     if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
 348         PyErr_SetFromErrno(LinuxAudioError);
 349         return NULL;
 350     }
 351     return PyInt_FromLong((ai.fragstotal * ai.fragsize) / (nchannels * ssize));
 352 }
 353
 354 /* obufcount returns the number of samples that are available in the
 355    hardware for playing */
 356 static PyObject *
 357 lad_obufcount(lad_t *self, PyObject *unused)
 358 {
 359     audio_buf_info ai;
 360     int nchannels=0, ssize=0;
 361
 362     if (_ssize(self, &nchannels, &ssize) < 0 || !ssize || !nchannels) {
 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 *unused)
 378 {
 379     audio_buf_info ai;
 380     int nchannels=0, ssize=0;
 381
 382     if (_ssize(self, &nchannels, &ssize) < 0 || !ssize || !nchannels) {
 383         PyErr_SetFromErrno(LinuxAudioError);
 384         return NULL;
 385     }
 386     if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
 387         PyErr_SetFromErrno(LinuxAudioError);
 388         return NULL;
 389     }
 390     return PyInt_FromLong(ai.bytes / (ssize * nchannels));
 391 }
 392
 393 /* Flush the device */
 394 static PyObject *
 395 lad_flush(lad_t *self, PyObject *unused)
 396 {
 397     if (ioctl(self->x_fd, SNDCTL_DSP_SYNC, NULL) == -1) {
 398         PyErr_SetFromErrno(LinuxAudioError);
 399         return NULL;
 400     }
 401     Py_RETURN_NONE;
 402 }
 403
 404 static PyObject *
 405 lad_getptr(lad_t *self, PyObject *unused)
 406 {
 407     count_info info;
 408     int req;
 409
 410     if (self->x_mode == O_RDONLY)
 411         req = SNDCTL_DSP_GETIPTR;
 412     else
 413         req = SNDCTL_DSP_GETOPTR;
 414     if (ioctl(self->x_fd, req, &info) == -1) {
 415         PyErr_SetFromErrno(LinuxAudioError);
 416         return NULL;
 417     }
 418     return Py_BuildValue("iii", info.bytes, info.blocks, info.ptr);
 419 }
 420
 421 static PyMethodDef lad_methods[] = {
 422     { "read",           (PyCFunction)lad_read, METH_VARARGS },
 423     { "write",          (PyCFunction)lad_write, METH_VARARGS },
 424     { "setparameters",  (PyCFunction)lad_setparameters, METH_VARARGS },
 425     { "bufsize",        (PyCFunction)lad_bufsize, METH_VARARGS },
 426     { "obufcount",      (PyCFunction)lad_obufcount, METH_NOARGS },
 427     { "obuffree",       (PyCFunction)lad_obuffree, METH_NOARGS },
 428     { "flush",          (PyCFunction)lad_flush, METH_NOARGS },
 429     { "close",          (PyCFunction)lad_close, METH_NOARGS },
 430     { "fileno",         (PyCFunction)lad_fileno, METH_NOARGS },
 431     { "getptr",         (PyCFunction)lad_getptr, METH_NOARGS },
 432     { NULL,             NULL}           /* sentinel */
 433 };
 434
 435 static PyObject *
 436 lad_getattr(lad_t *xp, char *name)
 437 {
 438     return Py_FindMethod(lad_methods, (PyObject *)xp, name);
 439 }
 440
 441 static PyTypeObject Ladtype = {
 442     PyObject_HEAD_INIT(&PyType_Type)
 443     0,                          /*ob_size*/
 444     "linuxaudiodev.linux_audio_device", /*tp_name*/
 445     sizeof(lad_t),              /*tp_size*/
 446     0,                          /*tp_itemsize*/
 447     /* methods */
 448     (destructor)lad_dealloc,    /*tp_dealloc*/
 449     0,                          /*tp_print*/
 450     (getattrfunc)lad_getattr,   /*tp_getattr*/
 451     0,                          /*tp_setattr*/
 452     0,                          /*tp_compare*/
 453     0,                          /*tp_repr*/
 454 };
 455
 456 static PyObject *
 457 ladopen(PyObject *self, PyObject *args)
 458 {
 459     return (PyObject *)newladobject(args);
 460 }
 461
 462 static PyMethodDef linuxaudiodev_methods[] = {
 463     { "open", ladopen, METH_VARARGS },
 464     { 0, 0 },
 465 };
 466
 467 void
 468 initlinuxaudiodev(void)
 469 {
 470     PyObject *m;
 471
 472     m = Py_InitModule("linuxaudiodev", linuxaudiodev_methods);
 473     if (m == NULL)
 474         return;
 475
 476     LinuxAudioError = PyErr_NewException("linuxaudiodev.error", NULL, NULL);
 477     if (LinuxAudioError)
 478         PyModule_AddObject(m, "error", LinuxAudioError);
 479
 480     if (PyModule_AddIntConstant(m, "AFMT_MU_LAW", (long)AFMT_MU_LAW) == -1)
 481         return;
 482     if (PyModule_AddIntConstant(m, "AFMT_A_LAW", (long)AFMT_A_LAW) == -1)
 483         return;
 484     if (PyModule_AddIntConstant(m, "AFMT_U8", (long)AFMT_U8) == -1)
 485         return;
 486     if (PyModule_AddIntConstant(m, "AFMT_S8", (long)AFMT_S8) == -1)
 487         return;
 488     if (PyModule_AddIntConstant(m, "AFMT_U16_BE", (long)AFMT_U16_BE) == -1)
 489         return;
 490     if (PyModule_AddIntConstant(m, "AFMT_U16_LE", (long)AFMT_U16_LE) == -1)
 491         return;
 492     if (PyModule_AddIntConstant(m, "AFMT_S16_BE", (long)AFMT_S16_BE) == -1)
 493         return;
 494     if (PyModule_AddIntConstant(m, "AFMT_S16_LE", (long)AFMT_S16_LE) == -1)
 495         return;
 496     if (PyModule_AddIntConstant(m, "AFMT_S16_NE", (long)AFMT_S16_NE) == -1)
 497         return;
 498
 499     return;
 500 }