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gstreamer/gst/pygstvalue.c

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/* gst-python
* Copyright (C) 2004 Andy Wingo
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Author: Andy Wingo <wingo@pobox.com>
*/
/* define this for all source files that don't run init_pygobject()
* before including pygobject.h */
#define NO_IMPORT_PYGOBJECT
#include "pygstvalue.h"
static PyObject *gstvalue_class = NULL;
static PyObject *gstfourcc_class = NULL;
static PyObject *gstintrange_class = NULL;
static PyObject *gstdoublerange_class = NULL;
static PyObject *gstfraction_class = NULL;
static PyObject *gstfractionrange_class = NULL;
/* helper function */
/* Finds the greatest common divisor.
* Returns 1 if none other found.
* This is Euclid's algorithm. */
static long
my_gcd (long num, long denom)
{
while (denom != 0) {
long temp = num;
num = denom;
denom = temp % denom;
}
return ABS (num);
}
/**
* pygst_value_as_pyobject:
* @value: the GValue object.
* @copy_boxed: true if boxed values should be copied.
*
* This function creates/returns a Python wrapper object that
* represents the GValue passed as an argument.
*
* Returns: a PyObject representing the value.
*/
PyObject *
pygst_value_as_pyobject (const GValue * value, gboolean copy_boxed)
{
PyObject *ret = pyg_value_as_pyobject (value, copy_boxed);
if (!ret) {
PyErr_Clear ();
if (GST_VALUE_HOLDS_FOURCC (value)) {
gchar str[5];
g_snprintf (str, 5, "%" GST_FOURCC_FORMAT,
GST_FOURCC_ARGS (gst_value_get_fourcc (value)));
ret = PyObject_Call (gstfourcc_class, Py_BuildValue ("(s)", str), NULL);
} else if (GST_VALUE_HOLDS_INT_RANGE (value)) {
ret = PyObject_Call
(gstintrange_class,
Py_BuildValue ("ii",
gst_value_get_int_range_min (value),
gst_value_get_int_range_max (value)), NULL);
} else if (GST_VALUE_HOLDS_DOUBLE_RANGE (value)) {
ret = PyObject_Call
(gstdoublerange_class,
Py_BuildValue ("dd",
gst_value_get_double_range_min (value),
gst_value_get_double_range_max (value)), NULL);
} else if (GST_VALUE_HOLDS_LIST (value)) {
int i, len;
len = gst_value_list_get_size (value);
ret = PyList_New (len);
for (i = 0; i < len; i++) {
PyList_SetItem (ret, i,
pygst_value_as_pyobject
(gst_value_list_get_value (value, i), copy_boxed));
}
} else if (GST_VALUE_HOLDS_ARRAY (value)) {
int i, len;
len = gst_value_array_get_size (value);
ret = PyTuple_New (len);
for (i = 0; i < len; i++) {
PyTuple_SetItem (ret, i,
pygst_value_as_pyobject
(gst_value_array_get_value (value, i), copy_boxed));
}
} else if (GST_VALUE_HOLDS_FRACTION (value)) {
ret = PyObject_Call
(gstfraction_class,
Py_BuildValue ("ii",
gst_value_get_fraction_numerator (value),
gst_value_get_fraction_denominator (value)), NULL);
} else if (GST_VALUE_HOLDS_FRACTION_RANGE (value)) {
const GValue *min, *max;
min = gst_value_get_fraction_range_min (value);
max = gst_value_get_fraction_range_max (value);
ret = PyObject_Call
(gstfractionrange_class,
Py_BuildValue ("OO",
pygst_value_as_pyobject (min, copy_boxed),
pygst_value_as_pyobject (max, copy_boxed)), NULL);
} else if (GST_VALUE_HOLDS_BUFFER (value)) {
return pygstminiobject_new (gst_value_get_mini_object (value));
} else {
gchar buf[256];
g_snprintf (buf, 256, "unknown type: %s",
g_type_name (G_VALUE_TYPE (value)));
PyErr_SetString (PyExc_TypeError, buf);
}
}
if (G_VALUE_TYPE (value) == G_TYPE_STRING) {
PyObject *u = NULL;
/* FIXME: docs are not clear on whether this sets a python
exception when it fails */
u = PyUnicode_FromEncodedObject (ret, "utf-8", NULL);
Py_DECREF (ret);
ret = u;
}
return ret;
}
#define VALUE_TYPE_CHECK(v, t) \
G_STMT_START{\
if (!G_VALUE_HOLDS (v, t)) {\
gchar errbuf[256];\
g_snprintf (errbuf, 256, "Could not convert %s to %s",\
g_type_name (t), g_type_name (G_VALUE_TYPE (v)));\
PyErr_SetString (PyExc_TypeError, errbuf);\
return -1;\
}}G_STMT_END
gboolean
pygst_value_init_for_pyobject (GValue * value, PyObject * obj)
{
GType t;
if (obj == Py_None) {
PyErr_SetString (PyExc_TypeError, "value can't be None");
return FALSE;
}
if (!(t = pyg_type_from_object ((PyObject *) obj->ob_type))) {
if (PyObject_IsInstance (obj, gstvalue_class)) {
PyErr_Clear ();
if (PyObject_IsInstance (obj, gstfourcc_class))
t = GST_TYPE_FOURCC;
else if (PyObject_IsInstance (obj, gstintrange_class))
t = GST_TYPE_INT_RANGE;
else if (PyObject_IsInstance (obj, gstdoublerange_class))
t = GST_TYPE_DOUBLE_RANGE;
else if (PyObject_IsInstance (obj, gstfraction_class))
t = GST_TYPE_FRACTION;
else if (PyObject_IsInstance (obj, gstfractionrange_class))
t = GST_TYPE_FRACTION_RANGE;
else {
PyErr_SetString (PyExc_TypeError, "Unexpected gst.Value instance");
return FALSE;
}
} else if (PyObject_IsInstance (obj, (PyObject *) & PyGstMiniObject_Type)) {
PyErr_Clear ();
t = GST_TYPE_MINI_OBJECT;
} else if (PyTuple_Check (obj)) {
PyErr_Clear ();
t = GST_TYPE_ARRAY;
} else if (PyList_Check (obj)) {
PyErr_Clear ();
t = GST_TYPE_LIST;
} else if (PyUnicode_Check (obj)) {
/* unicode strings should be converted to UTF-8 */
PyErr_Clear ();
t = G_TYPE_STRING;
} else {
/* pyg_type_from_object already set the error */
return FALSE;
}
}
g_value_init (value, t);
return TRUE;
}
static int
pygst_value_from_pyobject_internal (GValue * value, PyObject * obj)
{
GType f = g_type_fundamental (G_VALUE_TYPE (value));
/* work around a bug in pygtk whereby pyg_value_from_pyobject claims success
for unknown fundamental types without actually doing anything */
if (f < G_TYPE_MAKE_FUNDAMENTAL (G_TYPE_RESERVED_USER_FIRST)
&& pyg_value_from_pyobject (value, obj) == 0) {
return 0;
} else if (PyObject_IsInstance (obj, gstvalue_class)) {
PyErr_Clear ();
if (PyObject_IsInstance (obj, gstfourcc_class)) {
PyObject *pystr;
gchar *str;
VALUE_TYPE_CHECK (value, GST_TYPE_FOURCC);
if (!(pystr = PyObject_GetAttrString (obj, "fourcc")))
return -1;
if (!(str = PyString_AsString (pystr)))
return -1;
g_assert (strlen (str) == 4);
gst_value_set_fourcc (value, GST_STR_FOURCC (str));
} else if (PyObject_IsInstance (obj, gstintrange_class)) {
PyObject *pyval;
long low, high;
VALUE_TYPE_CHECK (value, GST_TYPE_INT_RANGE);
if (!(pyval = PyObject_GetAttrString (obj, "low")))
return -1;
low = PyInt_AsLong (pyval);
g_assert (G_MININT <= low && low <= G_MAXINT);
if (!(pyval = PyObject_GetAttrString (obj, "high")))
return -1;
high = PyInt_AsLong (pyval);
g_assert (G_MININT <= high && high <= G_MAXINT);
gst_value_set_int_range (value, (int) low, (int) high);
} else if (PyObject_IsInstance (obj, gstdoublerange_class)) {
PyObject *pyval;
double low, high;
VALUE_TYPE_CHECK (value, GST_TYPE_DOUBLE_RANGE);
if (!(pyval = PyObject_GetAttrString (obj, "low")))
return -1;
low = PyFloat_AsDouble (pyval);
if (!(pyval = PyObject_GetAttrString (obj, "high")))
return -1;
high = PyFloat_AsDouble (pyval);
gst_value_set_double_range (value, low, high);
} else if (PyObject_IsInstance (obj, gstfraction_class)) {
PyObject *pyval;
long num, denom;
long gcd = 0;
VALUE_TYPE_CHECK (value, GST_TYPE_FRACTION);
if (!(pyval = PyObject_GetAttrString (obj, "num")))
return -1;
num = PyInt_AsLong (pyval);
if ((num == -1) && PyErr_Occurred ())
return -1;
g_assert (G_MININT <= num && num <= G_MAXINT);
if (!(pyval = PyObject_GetAttrString (obj, "denom")))
return -1;
denom = PyInt_AsLong (pyval);
if ((denom == -1) && PyErr_Occurred ())
return -1;
/* we need to reduce the values to be smaller than MAXINT */
if ((gcd = my_gcd (num, denom))) {
num /= gcd;
denom /= gcd;
}
g_assert (G_MININT <= denom && denom <= G_MAXINT);
gst_value_set_fraction (value, (int) num, (int) denom);
} else if (PyObject_IsInstance (obj, gstfractionrange_class)) {
GValue low = { 0, };
GValue high = { 0, };
PyObject *pylow, *pyhigh;
VALUE_TYPE_CHECK (value, GST_TYPE_FRACTION_RANGE);
if (!(pylow = PyObject_GetAttrString (obj, "low")))
return -1;
if (!pygst_value_init_for_pyobject (&low, pylow))
return -1;
if (pygst_value_from_pyobject (&low, pylow) != 0)
return -1;
if (!(pyhigh = PyObject_GetAttrString (obj, "high")))
return -1;
if (!pygst_value_init_for_pyobject (&high, pyhigh))
return -1;
if (pygst_value_from_pyobject (&high, pyhigh) != 0)
return -1;
gst_value_set_fraction_range (value, &low, &high);
} else {
gchar buf[256];
gchar *str = PyString_AsString (PyObject_Repr (obj));
g_snprintf (buf, 256, "Unknown gst.Value type: %s", str);
PyErr_SetString (PyExc_TypeError, buf);
return -1;
}
return 0;
} else if (PyObject_IsInstance (obj, (PyObject *) & PyGstMiniObject_Type)) {
VALUE_TYPE_CHECK (value, GST_TYPE_MINI_OBJECT);
gst_value_set_mini_object (value, pygstminiobject_get (obj));
return 0;
} else if (PyTuple_Check (obj)) {
gint i, len;
PyErr_Clear ();
VALUE_TYPE_CHECK (value, GST_TYPE_ARRAY);
len = PyTuple_Size (obj);
for (i = 0; i < len; i++) {
PyObject *o;
GValue new = { 0, };
o = PyTuple_GetItem (obj, i);
if (!pygst_value_init_for_pyobject (&new, o))
return -1;
if (pygst_value_from_pyobject (&new, o) != 0) {
g_value_unset (&new);
return -1;
}
gst_value_array_append_value (value, &new);
g_value_unset (&new);
}
return 0;
} else if (PyList_Check (obj)) {
gint i, len;
PyErr_Clear ();
VALUE_TYPE_CHECK (value, GST_TYPE_LIST);
len = PyList_Size (obj);
for (i = 0; i < len; i++) {
PyObject *o;
GValue new = { 0, };
o = PyList_GetItem (obj, i);
if (!pygst_value_init_for_pyobject (&new, o))
return -1;
if (pygst_value_from_pyobject (&new, o) != 0) {
g_value_unset (&new);
return -1;
}
gst_value_list_append_value (value, &new);
g_value_unset (&new);
}
return 0;
} else {
return -1;
}
}
/**
* pygst_value_from_pyobject:
* @value: the GValue object to store the converted value in.
* @obj: the Python object to convert.
*
* This function converts a Python object and stores the result in a
* GValue. The GValue must be initialised in advance with
* g_value_init(). If the Python object can't be converted to the
* type of the GValue, then an error is returned.
*
* Returns: 0 on success, -1 on error.
*/
int
pygst_value_from_pyobject (GValue * value, PyObject * obj)
{
PyObject *v = NULL;
int res;
/* Unicode objects should be converted to utf-8 strings */
if (PyObject_TypeCheck (obj, &PyUnicode_Type)) {
v = PyUnicode_AsUTF8String (obj);
obj = v;
}
res = pygst_value_from_pyobject_internal (value, obj);
if (v) {
Py_DECREF (obj);
}
return res;
}
#define NULL_CHECK(o) if (!o) goto err
gboolean
pygst_value_init (void)
{
PyObject *module, *dict;
if ((module = PyImport_ImportModule ("gst")) == NULL)
return FALSE;
dict = PyModule_GetDict (module);
gstvalue_class = (PyObject *) PyDict_GetItemString (dict, "Value");
NULL_CHECK (gstvalue_class);
gstfourcc_class = (PyObject *) PyDict_GetItemString (dict, "Fourcc");
NULL_CHECK (gstfourcc_class);
gstintrange_class = (PyObject *) PyDict_GetItemString (dict, "IntRange");
NULL_CHECK (gstintrange_class);
gstdoublerange_class =
(PyObject *) PyDict_GetItemString (dict, "DoubleRange");
NULL_CHECK (gstdoublerange_class);
gstfraction_class = (PyObject *) PyDict_GetItemString (dict, "Fraction");
NULL_CHECK (gstfraction_class);
gstfractionrange_class =
(PyObject *) PyDict_GetItemString (dict, "FractionRange");
NULL_CHECK (gstfractionrange_class);
return TRUE;
err:
PyErr_SetString (PyExc_ImportError,
"Failed to get GstValue classes from gst module");
return FALSE;
}
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