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