Audio module for Linux, contributed by Peter Bosch.

Careful, this has had zero testing (except by Peter)!

Modules/linuxaudio.c

+/* Hey Emacs, this is -*-C-*- 
+ ******************************************************************************
+ * linuxaudiodev.c -- Linux audio device for python.
+ * 
+ * Author          : Peter Bosch
+ * Created On      : Thu Mar  2 21:10:33 2000
+ * Last Modified By: Peter Bosch
+ * Last Modified On: Fri Mar 24 11:27:00 2000
+ * Status          : Unknown, Use with caution!
+ * 
+ * Unless other notices are present in any part of this file
+ * explicitly claiming copyrights for other people and/or 
+ * organizations, the contents of this file is fully copyright 
+ * (C) 2000 Peter Bosch, all rights reserved.
+ ******************************************************************************
+ */
+
+#include "Python.h"
+#include "structmember.h"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+
+#include <stropts.h>
+#include <sys/ioctl.h>
+#include <linux/soundcard.h>
+
+typedef unsigned long uint32_t;
+
+typedef struct {
+  PyObject_HEAD;
+  int		x_fd;		/* The open file */
+  int		x_icount;	/* Input count */
+  int		x_ocount;	/* Output count */
+  uint32_t	x_afmts;	/* Supported audio formats */
+} lad_t;
+
+static struct {
+  int		a_bps;
+  uint32_t	a_fmt;
+} audio_types[] = {
+  {  8, 	AFMT_MU_LAW },
+  {  8,		AFMT_U8 },
+  {  8, 	AFMT_S8 },
+  { 16, 	AFMT_U16_BE },
+  { 16, 	AFMT_U16_LE },
+  { 16, 	AFMT_S16_BE },
+  { 16, 	AFMT_S16_LE },
+};
+
+
+staticforward PyTypeObject Ladtype;
+
+static PyObject *LinuxAudioError;
+
+static lad_t *
+newladobject(PyObject *arg)
+{
+  lad_t *xp;
+  int fd, afmts, imode;
+  char *mode;
+  char *basedev;
+  char *ctldev;
+  char *opendev;
+
+  /* Check arg for r/w/rw */
+  if (!PyArg_ParseTuple(arg, "s", &mode)) return NULL;
+  if (strcmp(mode, "r") == 0)
+    imode = 0;
+  else if (strcmp(mode, "w") == 0)
+    imode = 1;
+  else {
+    PyErr_SetString(LinuxAudioError, "Mode should be one of 'r', or 'w'");
+    return NULL;
+  }
+	
+  /* Open the correct device.  The base device name comes from the
+   * AUDIODEV environment variable first, then /dev/audio.  The
+   * control device tacks "ctl" onto the base device name.
+   */
+  basedev = getenv("AUDIODEV");
+  if (!basedev)
+    basedev = "/dev/dsp";
+
+  if ((fd = open(basedev, imode)) < 0) {
+    PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
+    return NULL;
+  }
+
+  if (imode) {
+    if (ioctl(fd, SNDCTL_DSP_NONBLOCK, NULL) < 0) {
+      PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
+      return NULL;
+    }
+  }
+
+  if (ioctl(fd, SNDCTL_DSP_GETFMTS, &afmts) < 0) {
+    PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
+    return NULL;
+  }
+
+  /* Create and initialize the object */
+  if ((xp = PyObject_NEW(lad_t, &Ladtype)) == NULL) {
+    close(fd);
+    return NULL;
+  }
+  xp->x_fd     = fd;
+  xp->x_icount = xp->x_ocount = 0;
+  xp->x_afmts  = afmts;
+  return xp;
+}
+
+static void
+lad_dealloc(lad_t *xp)
+{
+  close(xp->x_fd);
+  PyMem_DEL(xp);
+}
+
+static PyObject *
+lad_read(lad_t *self, PyObject *args)
+{
+  int size, count;
+  char *cp;
+  PyObject *rv;
+	
+  if (!PyArg_ParseTuple(args, "i", &size)) return NULL;
+  rv = PyString_FromStringAndSize(NULL, size);
+  if (rv == NULL) return NULL;
+
+  if (!(cp = PyString_AsString(rv))) {
+    Py_DECREF(rv);
+    return NULL;
+  }
+
+  if ((count = read(self->x_fd, cp, size)) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    Py_DECREF(rv);
+    return NULL;
+  }
+
+  self->x_icount += count;
+  return rv;
+}
+
+static PyObject *
+lad_write(lad_t *self, PyObject *args)
+{
+  char *cp;
+  int rv, size;
+	
+  if (!PyArg_ParseTuple(args, "s#", &cp, &size)) return NULL;
+
+  while (size > 0) {
+    if ((rv = write(self->x_fd, cp, size)) < 0) {
+      PyErr_SetFromErrno(LinuxAudioError);
+      return NULL;
+    }
+    self->x_ocount += rv;
+    size           -= rv;
+    cp             += rv;
+  }
+  Py_INCREF(Py_None);
+  return Py_None;
+}
+
+static PyObject *
+lad_close(lad_t *self, PyObject *args)
+{
+  if (!PyArg_ParseTuple(args, "")) return NULL;
+  if (self->x_fd >= 0) {
+    close(self->x_fd);
+    self->x_fd = -1;
+  }
+  Py_INCREF(Py_None);
+  return Py_None;
+}
+
+static PyObject *
+lad_fileno(lad_t *self, PyObject *args)
+{
+  if (!PyArg_ParseTuple(args, "")) return NULL;
+  return PyInt_FromLong(self->x_fd);
+}
+
+static PyObject *
+lad_setparameters(lad_t *self, PyObject *args)
+{
+  int rate, ssize, nchannels, stereo, n, fmt;
+
+  if (!PyArg_ParseTuple(args, "iiii", &rate, &ssize, &nchannels, &fmt))
+    return NULL;
+  
+  if (rate < 0 || ssize < 0 || (nchannels != 1 && nchannels != 2)) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  if (ioctl(self->x_fd, SOUND_PCM_WRITE_RATE, &rate) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  if (ioctl(self->x_fd, SNDCTL_DSP_SAMPLESIZE, &ssize) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  stereo = (nchannels == 1)? 0: (nchannels == 2)? 1: -1;
+  if (ioctl(self->x_fd, SNDCTL_DSP_STEREO, &stereo) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  for (n = 0; n != sizeof(audio_types) / sizeof(audio_types[0]); n++)
+    if (fmt == audio_types[n].a_fmt)
+      break;
+
+  if (n == sizeof(audio_types) / sizeof(audio_types[0]) ||
+      audio_types[n].a_bps != ssize ||
+      (self->x_afmts & audio_types[n].a_fmt) == 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  if (ioctl(self->x_fd, SNDCTL_DSP_SETFMT, &audio_types[n].a_fmt) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+  
+  Py_INCREF(Py_None);
+  return Py_None;
+}
+
+static int
+_ssize(lad_t *self, int *nchannels, int *ssize)
+{
+  int fmt;
+
+  fmt = 0;
+  if (ioctl(self->x_fd, SNDCTL_DSP_SETFMT, &fmt) < 0) 
+    return -errno;
+
+  switch (fmt) {
+  case AFMT_MU_LAW:
+  case AFMT_A_LAW:
+  case AFMT_U8:
+  case AFMT_S8:
+    *ssize = sizeof(char);
+    break;
+  case AFMT_S16_LE:
+  case AFMT_S16_BE:
+  case AFMT_U16_LE:
+  case AFMT_U16_BE:
+    *ssize = sizeof(short);
+    break;
+  case AFMT_MPEG:
+  case AFMT_IMA_ADPCM:
+  default:
+    return -EOPNOTSUPP;
+  }
+
+  *nchannels = 0;
+  if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, nchannels) < 0)
+    return -errno;
+  return 0;
+}
+
+
+/* bufsize returns the size of the hardware audio buffer in number 
+ of samples */
+static PyObject *
+lad_bufsize(lad_t *self, PyObject *args)
+{
+  audio_buf_info ai;
+  int nchannels, ssize;
+
+  if (!PyArg_ParseTuple(args, "")) return NULL;
+
+  if (_ssize(self, &nchannels, &ssize) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  return PyInt_FromLong((ai.fragstotal * ai.fragsize) / (nchannels * ssize));
+}
+
+/* obufcount returns the number of samples that are available in the 
+   hardware for playing */
+static PyObject *
+lad_obufcount(lad_t *self, PyObject *args)
+{
+  audio_buf_info ai;
+  int nchannels, ssize;
+
+  if (!PyArg_ParseTuple(args, "")) return NULL;
+
+  if (_ssize(self, &nchannels, &ssize) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  return PyInt_FromLong((ai.fragstotal * ai.fragsize - ai.bytes) / 
+			(ssize * nchannels));
+}
+
+/* obufcount returns the number of samples that can be played without
+ blocking */
+static PyObject *
+lad_obuffree(lad_t *self, PyObject *args)
+{
+  audio_buf_info ai;
+  int nchannels, ssize;
+
+  if (!PyArg_ParseTuple(args, "")) return NULL;
+
+  if (_ssize(self, &nchannels, &ssize) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  if (ioctl(self->x_fd, SNDCTL_DSP_GETOSPACE, &ai) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  return PyInt_FromLong(ai.bytes / (ssize * nchannels));
+}
+
+/* Flush the device */
+static PyObject *
+lad_flush(lad_t *self, PyObject *args)
+{
+  if (!PyArg_ParseTuple(args, "")) return NULL;
+
+  if (ioctl(self->x_fd, SNDCTL_DSP_SYNC, NULL) < 0) {
+    PyErr_SetFromErrno(LinuxAudioError);
+    return NULL;
+  }
+
+  Py_INCREF(Py_None);
+  return Py_None;
+}
+
+static PyMethodDef lad_methods[] = {
+  { "read",		(PyCFunction)lad_read, 1 },
+  { "write",		(PyCFunction)lad_write, 1 },
+  { "setparameters",	(PyCFunction)lad_setparameters, 1 },
+  { "bufsize",		(PyCFunction)lad_bufsize, 1 },
+  { "obufcount",	(PyCFunction)lad_obufcount, 1 },
+  { "obuffree",		(PyCFunction)lad_obuffree, 1 },
+  { "flush",		(PyCFunction)lad_flush, 1 },
+  { "close",		(PyCFunction)lad_close, 1 },
+  { "fileno",     	(PyCFunction)lad_fileno, 1 },
+  { NULL,		NULL}		/* sentinel */
+};
+
+static PyObject *
+lad_getattr(lad_t *xp, char *name)
+{
+  return Py_FindMethod(lad_methods, (PyObject *)xp, name);
+}
+
+static PyTypeObject Ladtype = {
+  PyObject_HEAD_INIT(&PyType_Type)
+  0,				/*ob_size*/
+  "linux_audio_device",		/*tp_name*/
+  sizeof(lad_t),		/*tp_size*/
+  0,				/*tp_itemsize*/
+  /* methods */
+  (destructor)lad_dealloc,	/*tp_dealloc*/
+  0,				/*tp_print*/
+  (getattrfunc)lad_getattr,	/*tp_getattr*/
+  0,				/*tp_setattr*/
+  0,				/*tp_compare*/
+  0,				/*tp_repr*/
+};
+
+static PyObject *
+ladopen(PyObject *self, PyObject *args)
+{
+  return (PyObject *)newladobject(args);
+}
+
+static PyMethodDef linuxaudiodev_methods[] = {
+  { "open", ladopen, 1 },
+  { 0, 0 },
+};
+
+static int
+ins(PyObject *d, char *symbol, long value)
+{
+  PyObject* v = PyInt_FromLong(value);
+  if (!v || PyDict_SetItemString(d, symbol, v) < 0)
+    return -1;                   /* triggers fatal error */
+
+  Py_DECREF(v);
+  return 0;
+}
+void
+initlinuxaudiodev()
+{
+  PyObject *m, *d, *x;
+  
+  m = Py_InitModule("linuxaudiodev", linuxaudiodev_methods);
+  d = PyModule_GetDict(m);
+
+  LinuxAudioError = PyErr_NewException("linuxaudiodev.error", NULL, NULL);
+  if (LinuxAudioError)
+    PyDict_SetItemString(d, "error", LinuxAudioError);
+
+  x = PyInt_FromLong((long) AFMT_MU_LAW);
+  if (x == NULL || PyDict_SetItemString(d, "AFMT_MU_LAW", x) < 0)
+    goto error;
+  Py_DECREF(x);
+
+  x = PyInt_FromLong((long) AFMT_U8);
+  if (x == NULL || PyDict_SetItemString(d, "AFMT_U8", x) < 0)
+    goto error;
+  Py_DECREF(x);
+
+  x = PyInt_FromLong((long) AFMT_S8);
+  if (x == NULL || PyDict_SetItemString(d, "AFMT_S8", x) < 0)
+    goto error;
+  Py_DECREF(x);
+
+  x = PyInt_FromLong((long) AFMT_U16_BE);
+  if (x == NULL || PyDict_SetItemString(d, "AFMT_U16_BE", x) < 0)
+    goto error;
+  Py_DECREF(x);
+
+  x = PyInt_FromLong((long) AFMT_U16_LE);
+  if (x == NULL || PyDict_SetItemString(d, "AFMT_U16_LE", x) < 0)
+    goto error;
+  Py_DECREF(x);
+
+  x = PyInt_FromLong((long) AFMT_S16_BE);
+  if (x == NULL || PyDict_SetItemString(d, "AFMT_S16_BE", x) < 0)
+    goto error;
+  Py_DECREF(x);
+
+  x = PyInt_FromLong((long) AFMT_S16_LE);
+  if (x == NULL || PyDict_SetItemString(d, "AFMT_S16_LE", x) < 0)
+    goto error;
+  Py_DECREF(x);
+
+  /* Check for errors */
+  if (PyErr_Occurred()) {
+  error:
+    Py_FatalError("can't initialize module linuxaudiodev");
+  }
+}