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cpython/Modules/linuxaudiodev.c

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/* Hey Emacs, this is -*-C-*-
******************************************************************************
* linuxaudiodev.c -- Linux audio device for python.
*
* Author : Peter Bosch
* Created On : Thu Mar 2 21:10:33 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_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;
}
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