ossaudiodev -- Python interface to the OSS (Open Sound System) API.

This module is a replacement for linuxaudiodev, which will eventually
be deprecated.

Initial revision is rev 2.20 of linuxaudiodev.c, with a rewritten
header comment.

1 files changed, 524 insertions, 0 deletions

diff --git a/Modules/ossaudiodev.c b/Modules/ossaudiodev.c
new file mode 100644
index 0000000..96f54af
--- /dev/null
+++ b/Modules/ossaudiodev.c
@@ -0,0 +1,524 @@
+/*
+ * ossaudiodev -- Python interface to the OSS (Open Sound System) API.
+ *                This is the standard audio API for Linux and some
+ *                flavours of BSD [XXX which ones?]; it is also available
+ *                for a wide range of commercial Unices.
+ *
+ * Originally written by Peter Bosch, March 2000, as linuxaudiodev.
+ *
+ * Renamed to ossaudiodev and rearranged/revised/hacked up
+ * by Greg Ward <gward@python.net>, November 2002.
+ *              
+ * (c) 2000 Peter Bosch.  All Rights Reserved.
+ * (c) 2002 Gregory P. Ward.  All Rights Reserved.
+ * (c) 2002 Python Software Foundation.  All Rights Reserved.
+ *
+ * XXX need a license statement
+ *
+ * $Id$
+ */
+
+#include "Python.h"
+#include "structmember.h"
+
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+#else
+#define O_RDONLY 00
+#define O_WRONLY 01
+#endif
+
+
+#include <sys/ioctl.h>
+#if defined(linux)
+#include <linux/soundcard.h>
+
+typedef unsigned long uint32_t;
+
+#elif defined(__FreeBSD__)
+#include <machine/soundcard.h>
+
+#ifndef SNDCTL_DSP_CHANNELS
+#define SNDCTL_DSP_CHANNELS SOUND_PCM_WRITE_CHANNELS
+#endif
+
+#endif
+
+typedef struct {
+    PyObject_HEAD;
+    int		x_fd;		/* The open file */
+    int         x_mode;           /* file mode */
+    int		x_icount;	/* Input count */
+    int		x_ocount;	/* Output count */
+    uint32_t	x_afmts;	/* Audio formats supported by hardware*/
+} lad_t;
+
+/* XXX several format defined in soundcard.h are not supported,
+   including _NE (native endian) options and S32 options
+*/
+
+static struct {
+    int		a_bps;
+    uint32_t	a_fmt;
+    char       *a_name;
+} audio_types[] = {
+    {  8, 	AFMT_MU_LAW, "logarithmic mu-law 8-bit audio" },
+    {  8, 	AFMT_A_LAW,  "logarithmic A-law 8-bit audio" },
+    {  8,	AFMT_U8,     "linear unsigned 8-bit audio" },
+    {  8, 	AFMT_S8,     "linear signed 8-bit audio" },
+    { 16, 	AFMT_U16_BE, "linear unsigned 16-bit big-endian audio" },
+    { 16, 	AFMT_U16_LE, "linear unsigned 16-bit little-endian audio" },
+    { 16, 	AFMT_S16_BE, "linear signed 16-bit big-endian audio" },
+    { 16, 	AFMT_S16_LE, "linear signed 16-bit little-endian audio" },
+    { 16, 	AFMT_S16_NE, "linear signed 16-bit native-endian audio" },
+};
+
+static int n_audio_types = sizeof(audio_types) / sizeof(audio_types[0]);
+
+static PyTypeObject Ladtype;
+
+static PyObject *LinuxAudioError;
+
+static lad_t *
+newladobject(PyObject *arg)
+{
+    lad_t *xp;
+    int fd, afmts, imode;
+    char *basedev = NULL;
+    char *mode = NULL;
+
+    /* Two ways to call linuxaudiodev.open():
+         open(device, mode) (for consistency with builtin open())
+         open(mode)         (for backwards compatibility)
+       because the *first* argument is optional, parsing args is
+       a wee bit tricky. */
+    if (!PyArg_ParseTuple(arg, "s|s:open", &basedev, &mode))
+       return NULL;
+    if (mode == NULL) {                 /* only one arg supplied */
+       mode = basedev;
+       basedev = NULL;
+    }
+
+    if (strcmp(mode, "r") == 0)
+        imode = O_RDONLY;
+    else if (strcmp(mode, "w") == 0)
+        imode = O_WRONLY;
+    else {
+        PyErr_SetString(LinuxAudioError, "mode should be 'r' or 'w'");
+        return NULL;
+    }
+
+    /* Open the correct device.  The base device name comes from the
+     * AUDIODEV environment variable first, then /dev/dsp.  The
+     * control device tacks "ctl" onto the base device name.
+     * 
+     * Note that the only difference between /dev/audio and /dev/dsp
+     * is that the former uses logarithmic mu-law encoding and the
+     * latter uses 8-bit unsigned encoding.
+     */
+
+    if (basedev == NULL) {              /* called with one arg */
+       basedev = getenv("AUDIODEV");
+       if (basedev == NULL)             /* $AUDIODEV not set */
+          basedev = "/dev/dsp";
+    }
+
+    if ((fd = open(basedev, imode)) == -1) {
+        PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
+        return NULL;
+    }
+    if (imode == O_WRONLY && ioctl(fd, SNDCTL_DSP_NONBLOCK, NULL) == -1) {
+        PyErr_SetFromErrnoWithFilename(LinuxAudioError, basedev);
+        return NULL;
+    }
+    if (ioctl(fd, SNDCTL_DSP_GETFMTS, &afmts) == -1) {
+        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_mode = imode;
+    xp->x_icount = xp->x_ocount = 0;
+    xp->x_afmts  = afmts;
+    return xp;
+}
+
+static void
+lad_dealloc(lad_t *xp)
+{
+    /* if already closed, don't reclose it */
+    if (xp->x_fd != -1)
+	close(xp->x_fd);
+    PyObject_Del(xp);
+}
+
+static PyObject *
+lad_read(lad_t *self, PyObject *args)
+{
+    int size, count;
+    char *cp;
+    PyObject *rv;
+	
+    if (!PyArg_ParseTuple(args, "i:read", &size))
+        return NULL;
+    rv = PyString_FromStringAndSize(NULL, size);
+    if (rv == NULL)
+        return NULL;
+    cp = PyString_AS_STRING(rv);
+    if ((count = read(self->x_fd, cp, size)) < 0) {
+        PyErr_SetFromErrno(LinuxAudioError);
+        Py_DECREF(rv);
+        return NULL;
+    }
+    self->x_icount += count;
+    _PyString_Resize(&rv, count);
+    return rv;
+}
+
+static PyObject *
+lad_write(lad_t *self, PyObject *args)
+{
+    char *cp;
+    int rv, size;
+    fd_set write_set_fds;
+    struct timeval tv;
+    int select_retval;
+    
+    if (!PyArg_ParseTuple(args, "s#:write", &cp, &size)) 
+	return NULL;
+
+    /* use select to wait for audio device to be available */
+    FD_ZERO(&write_set_fds);
+    FD_SET(self->x_fd, &write_set_fds);
+    tv.tv_sec = 4; /* timeout values */
+    tv.tv_usec = 0; 
+
+    while (size > 0) {
+      select_retval = select(self->x_fd+1, NULL, &write_set_fds, NULL, &tv);
+      tv.tv_sec = 1; tv.tv_usec = 0; /* willing to wait this long next time*/
+      if (select_retval) {
+        if ((rv = write(self->x_fd, cp, size)) == -1) {
+	  if (errno != EAGAIN) {
+	    PyErr_SetFromErrno(LinuxAudioError);
+	    return NULL;
+	  } else {
+	    errno = 0; /* EAGAIN: buffer is full, try again */
+	  }
+        } else {
+	  self->x_ocount += rv;
+	  size -= rv;
+	  cp += rv;
+	}
+      } else {
+	/* printf("Not able to write to linux audio device within %ld seconds\n", tv.tv_sec); */
+	PyErr_SetFromErrno(LinuxAudioError);
+	return NULL;
+      }
+    }
+    Py_INCREF(Py_None);
+    return Py_None;
+}
+
+static PyObject *
+lad_close(lad_t *self, PyObject *args)
+{
+    if (!PyArg_ParseTuple(args, ":close"))
+	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, ":fileno")) 
+	return NULL;
+    return PyInt_FromLong(self->x_fd);
+}
+
+static PyObject *
+lad_setparameters(lad_t *self, PyObject *args)
+{
+    int rate, ssize, nchannels, n, fmt, emulate=0;
+
+    if (!PyArg_ParseTuple(args, "iiii|i:setparameters",
+                          &rate, &ssize, &nchannels, &fmt, &emulate))
+        return NULL;
+  
+    if (rate < 0) {
+	PyErr_Format(PyExc_ValueError, "expected rate >= 0, not %d",
+		     rate); 
+	return NULL;
+    }
+    if (ssize < 0) {
+	PyErr_Format(PyExc_ValueError, "expected sample size >= 0, not %d",
+		     ssize);
+	return NULL;
+    }
+    if (nchannels != 1 && nchannels != 2) {
+	PyErr_Format(PyExc_ValueError, "nchannels must be 1 or 2, not %d",
+		     nchannels);
+	return NULL;
+    }
+
+    for (n = 0; n < n_audio_types; n++)
+        if (fmt == audio_types[n].a_fmt)
+            break;
+    if (n == n_audio_types) {
+	PyErr_Format(PyExc_ValueError, "unknown audio encoding: %d", fmt);
+	return NULL;
+    }
+    if (audio_types[n].a_bps != ssize) {
+	PyErr_Format(PyExc_ValueError, 
+		     "for %s, expected sample size %d, not %d",
+		     audio_types[n].a_name, audio_types[n].a_bps, ssize);
+	return NULL;
+    }
+
+    if (emulate == 0) {
+	if ((self->x_afmts & audio_types[n].a_fmt) == 0) {
+	    PyErr_Format(PyExc_ValueError, 
+			 "%s format not supported by device",
+			 audio_types[n].a_name);
+	    return NULL;
+	}
+    }
+    if (ioctl(self->x_fd, SNDCTL_DSP_SETFMT, 
+	      &audio_types[n].a_fmt) == -1) {
+        PyErr_SetFromErrno(LinuxAudioError);
+        return NULL;
+    }
+    if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, &nchannels) == -1) {
+        PyErr_SetFromErrno(LinuxAudioError);
+        return NULL;
+    }
+    if (ioctl(self->x_fd, SNDCTL_DSP_SPEED, &rate) == -1) {
+        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, ":bufsize")) 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, ":obufcount"))
+        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, ":obuffree"))
+        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, ":flush")) return NULL;
+
+    if (ioctl(self->x_fd, SNDCTL_DSP_SYNC, NULL) == -1) {
+        PyErr_SetFromErrno(LinuxAudioError);
+        return NULL;
+    }
+    Py_INCREF(Py_None);
+    return Py_None;
+}
+
+static PyObject *
+lad_getptr(lad_t *self, PyObject *args)
+{
+    count_info info;
+    int req;
+
+    if (!PyArg_ParseTuple(args, ":getptr"))
+	return NULL;
+    
+    if (self->x_mode == O_RDONLY)
+	req = SNDCTL_DSP_GETIPTR;
+    else
+	req = SNDCTL_DSP_GETOPTR;
+    if (ioctl(self->x_fd, req, &info) == -1) {
+        PyErr_SetFromErrno(LinuxAudioError);
+        return NULL;
+    }
+    return Py_BuildValue("iii", info.bytes, info.blocks, info.ptr);
+}
+
+static PyMethodDef lad_methods[] = {
+    { "read",		(PyCFunction)lad_read, METH_VARARGS },
+    { "write",		(PyCFunction)lad_write, METH_VARARGS },
+    { "setparameters",	(PyCFunction)lad_setparameters, METH_VARARGS },
+    { "bufsize",	(PyCFunction)lad_bufsize, METH_VARARGS },
+    { "obufcount",	(PyCFunction)lad_obufcount, METH_VARARGS },
+    { "obuffree",	(PyCFunction)lad_obuffree, METH_VARARGS },
+    { "flush",		(PyCFunction)lad_flush, METH_VARARGS },
+    { "close",		(PyCFunction)lad_close, METH_VARARGS },
+    { "fileno",     	(PyCFunction)lad_fileno, METH_VARARGS },
+    { "getptr",         (PyCFunction)lad_getptr, METH_VARARGS },
+    { 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*/
+    "linuxaudiodev.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, METH_VARARGS },
+    { 0, 0 },
+};
+
+void
+initlinuxaudiodev(void)
+{
+    PyObject *m;
+  
+    m = Py_InitModule("linuxaudiodev", linuxaudiodev_methods);
+
+    LinuxAudioError = PyErr_NewException("linuxaudiodev.error", NULL, NULL);
+    if (LinuxAudioError)
+	PyModule_AddObject(m, "error", LinuxAudioError);
+
+    if (PyModule_AddIntConstant(m, "AFMT_MU_LAW", (long)AFMT_MU_LAW) == -1)
+	return;
+    if (PyModule_AddIntConstant(m, "AFMT_A_LAW", (long)AFMT_A_LAW) == -1)
+	return;
+    if (PyModule_AddIntConstant(m, "AFMT_U8", (long)AFMT_U8) == -1)
+	return;
+    if (PyModule_AddIntConstant(m, "AFMT_S8", (long)AFMT_S8) == -1)
+	return;
+    if (PyModule_AddIntConstant(m, "AFMT_U16_BE", (long)AFMT_U16_BE) == -1)
+	return;
+    if (PyModule_AddIntConstant(m, "AFMT_U16_LE", (long)AFMT_U16_LE) == -1)
+	return;
+    if (PyModule_AddIntConstant(m, "AFMT_S16_BE", (long)AFMT_S16_BE) == -1)
+	return;
+    if (PyModule_AddIntConstant(m, "AFMT_S16_LE", (long)AFMT_S16_LE) == -1)
+	return;
+    if (PyModule_AddIntConstant(m, "AFMT_S16_NE", (long)AFMT_S16_NE) == -1)
+	return;
+
+    return;
+}