view PyTypeConversions.cpp @ 27:fb6519598734

Some pruning

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/*
    VampyHost

    Use Vamp audio analysis plugins in Python

    Gyorgy Fazekas and Chris Cannam
    Centre for Digital Music, Queen Mary, University of London
    Copyright 2008-2014 Queen Mary, University of London
  
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#include <Python.h>

#include "PyTypeConversions.h"

#include <math.h>
#include <float.h>
#include <limits.h>
#ifndef SIZE_T_MAX
#define SIZE_T_MAX ((size_t) -1)
#endif

using std::string;
using std::vector;
using std::cerr;
using std::endl;

/*  Note: NO FUNCTION IN THIS CLASS SHOULD ALTER REFERENCE COUNTS
	(EXCEPT FOR TEMPORARY PYTHON OBJECTS)! */

PyTypeConversions::PyTypeConversions() : 
	m_strict(false),
	m_error(false),
	error(m_error) // const public reference for easy access
{
}

PyTypeConversions::~PyTypeConversions()
{
}


/// floating point numbers (TODO: check numpy.float128)
float 
PyTypeConversions::PyValue_To_Float(PyObject* pyValue) const
{
	// convert float
	if (pyValue && PyFloat_Check(pyValue)) 
		//TODO: check for limits here (same on most systems)
		return (float) PyFloat_AS_DOUBLE(pyValue);
	
	if (pyValue == NULL)
	{
		setValueError("Error while converting object " + PyValue_Get_TypeName(pyValue) + " to float. ",m_strict);
		return 0.0;		
	}
		
	// in strict mode we will not try harder
	if (m_strict) {
		setValueError("Strict conversion error: object" + PyValue_Get_TypeName(pyValue) +" is not float.",m_strict);
		return 0.0;
	}

	// convert other objects supporting the number protocol
	if (PyNumber_Check(pyValue))
	{
		PyObject* pyFloat = PyNumber_Float(pyValue); // new ref
		if (!pyFloat)
		{
			if (PyErr_Occurred()) {PyErr_Print(); PyErr_Clear();}
			setValueError("Error while converting " + PyValue_Get_TypeName(pyValue) + " object to float.",m_strict);
			return 0.0;
		}
		float rValue = (float) PyFloat_AS_DOUBLE(pyFloat);
		Py_DECREF(pyFloat);
		return rValue;
	}
/*	
	// convert other objects supporting the number protocol
	if (PyNumber_Check(pyValue)) 
	{	
		// PEP353: Py_ssize_t is size_t but signed !
		// This will work up to numpy.float64
		Py_ssize_t rValue = PyNumber_AsSsize_t(pyValue,NULL);
		if (PyErr_Occurred()) 
		{
			PyErr_Print(); PyErr_Clear();
			setValueError("Error while converting integer object.",m_strict);
			return 0.0;
		}
		if (rValue > (Py_ssize_t)FLT_MAX || rValue < (Py_ssize_t)FLT_MIN)
		{
			setValueError("Overflow error. Object can not be converted to float.",m_strict);
			return 0.0;
		}
		return (float) rValue;
	}
*/	
    // convert string
	if (PyString_Check(pyValue))
	{
		PyObject* pyFloat = PyFloat_FromString(pyValue,NULL);
		if (!pyFloat) 
		{
			if (PyErr_Occurred()) { PyErr_Print(); PyErr_Clear(); }
			setValueError("String value can not be converted to float.",m_strict);
			return 0.0;
		}
		float rValue = (float) PyFloat_AS_DOUBLE(pyFloat);
		if (PyErr_Occurred()) 
		{
			PyErr_Print(); PyErr_Clear(); 
			Py_CLEAR(pyFloat);
			setValueError("Error while converting float object.",m_strict);
			return 0.0;
		}
		Py_DECREF(pyFloat);
		return rValue;
	}
	
	// convert the first element of any iterable sequence (for convenience and backwards compatibility)
	if (PySequence_Check(pyValue) && PySequence_Size(pyValue) > 0) 
	{
		PyObject* item = PySequence_GetItem(pyValue,0);
		if (item)
		{
			float rValue = this->PyValue_To_Float(item);
			if (!m_error) {
				Py_DECREF(item);
				return rValue;
			} else {
				Py_CLEAR(item);
				std::string msg = "Could not convert sequence element to float. ";
				setValueError(msg,m_strict);
				return 0.0;
			}
		}
	}

    // give up
	if (PyErr_Occurred()) { PyErr_Print(); PyErr_Clear(); }
	std::string msg = "Conversion from " + PyValue_Get_TypeName(pyValue) + " to float is not possible.";
	setValueError(msg,m_strict);
#ifdef _DEBUG
	cerr << "PyTypeConversions::PyValue_To_Float failed. " << msg << endl;
#endif	
	return 0.0;
}


/*			 			Sequence Types to C++ Types	    		  	*/

//convert PyFeature.value (typically a list or numpy array) to C++ vector of floats
std::vector<float> 
PyTypeConversions::PyValue_To_FloatVector (PyObject *pyValue) const 
{
	// there are four types of values we may receive from a numpy process:
	// * a python scalar, 
	// * an array scalar, (e.g. numpy.float32)
	// * an array with nd = 0  (0D array)
	// * an array with nd > 0

	/// check for scalars
	if (PyArray_CheckScalar(pyValue) || PyFloat_Check(pyValue)) {

		std::vector<float> Output;

		// we rely on the behaviour the scalars are either floats
		// or support the number protocol
		// TODO: a potential optimisation is to handle them directly
		Output.push_back(PyValue_To_Float(pyValue));
		return Output;
	}

	/// numpy array
	if (PyArray_CheckExact(pyValue)) 
		return PyArray_To_FloatVector(pyValue);

	/// python list of floats (backward compatible)
	if (PyList_Check(pyValue)) {
		return PyList_To_FloatVector(pyValue);
	}

	std::vector<float> Output;
	
	/// finally assume a single value supporting the number protocol 
	/// this allows to write e.g. Feature.values = 5 instead of [5.00]
	Output.push_back(PyValue_To_Float(pyValue));
	if (m_error) {
		std::string msg = "Value is not list or array of floats nor can be casted as float. ";
		setValueError(msg,m_strict);
#ifdef _DEBUG
	cerr << "PyTypeConversions::PyValue_To_FloatVector failed. " << msg << endl;
#endif
	}
	return Output;
}

//convert a list of python floats
std::vector<float> 
PyTypeConversions::PyList_To_FloatVector (PyObject *inputList) const 
{
	std::vector<float> Output;
	
#ifdef _DEBUG
	// This is a low level function normally called from 
	// PyValue_To_FloatVector(). Checking for list is not required.
	if (!PyList_Check(inputList)) {
		std::string msg = "Value is not list.";
		setValueError(msg,true);
		cerr << "PyTypeConversions::PyList_To_FloatVector failed. " << msg << endl;
		return Output; 
	} 
#endif

	float ListElement;
	PyObject *pyFloat = NULL;
	PyObject **pyObjectArray = PySequence_Fast_ITEMS(inputList);

	for (Py_ssize_t i = 0; i < PyList_GET_SIZE(inputList); ++i) {

		// pyFloat = PyList_GET_ITEM(inputList,i);
		pyFloat = pyObjectArray[i];

#ifdef _DEBUG
		if (!pyFloat) {
			if (PyErr_Occurred()) {PyErr_Print(); PyErr_Clear();}
			cerr << "PyTypeConversions::PyList_To_FloatVector: Could not obtain list element: " 
			<< i << " PyList_GetItem returned NULL! Skipping value." << endl;
			continue;
		}
#endif		

		// ListElement = (float) PyFloat_AS_DOUBLE(pyFloat);
		ListElement = PyValue_To_Float(pyFloat);
		

#ifdef _DEBUG_VALUES
		cerr << "value: " << ListElement << endl;
#endif
		Output.push_back(ListElement);
	}
	return Output;
}

// if numpy is not installed this will not be called, 
// therefor we do not check again
std::vector<float> 
PyTypeConversions::PyArray_To_FloatVector (PyObject *pyValue) const 
{
	std::vector<float> Output;
	
#ifdef _DEBUG
	// This is a low level function, normally called from 
	// PyValue_To_FloatVector(). Checking the array here is not required.
	if (!PyArray_Check(pyValue)) {
		std::string msg = "Object has no array conversions.";
		setValueError(msg,true);
		cerr << "PyTypeConversions::PyArray_To_FloatVector failed. " << msg << endl;
		return Output; 
	} 
#endif

	PyArrayObject* pyArray = (PyArrayObject*) pyValue;
	PyArray_Descr* descr = PyArray_DESCR(pyArray);
	
	/// check raw data and descriptor pointers
	if (PyArray_DATA(pyArray) == 0 || descr == 0) {
		std::string msg = "NumPy array with NULL data or descriptor pointer encountered.";
		setValueError(msg,m_strict);
#ifdef _DEBUG
		cerr << "PyTypeConversions::PyArray_To_FloatVector failed. Error: " << msg << endl;
#endif		
		return Output;
	}

	/// check dimensions
	if (PyArray_NDIM(pyArray) != 1) {
		std::string msg = "NumPy array must be a one dimensional vector.";
		setValueError(msg,m_strict);
#ifdef _DEBUG
		cerr << "PyTypeConversions::PyArray_To_FloatVector failed. Error: " << msg << " Dims: " << (int) PyArray_NDIM(pyArray) << endl;
#endif	
		return Output;
	}

#ifdef _DEBUG_VALUES
	cerr << "PyTypeConversions::PyArray_To_FloatVector: Numpy array verified." << endl;
#endif
	
	/// check strides (useful if array is not continuous)
	size_t strides =  *((size_t*) PyArray_STRIDES(pyArray));
    
	/// convert the array
	switch (descr->type_num)
	{
		case NPY_FLOAT : // dtype='float32'
			return PyArray_Convert<float,float>(PyArray_DATA(pyArray),PyArray_DIMS(pyArray)[0],strides);
		case NPY_DOUBLE : // dtype='float64'
			return PyArray_Convert<float,double>(PyArray_DATA(pyArray),PyArray_DIMS(pyArray)[0],strides);
		case NPY_INT : // dtype='int'
			return PyArray_Convert<float,int>(PyArray_DATA(pyArray),PyArray_DIMS(pyArray)[0],strides);
		case NPY_LONG : // dtype='long'
			return PyArray_Convert<float,long>(PyArray_DATA(pyArray),PyArray_DIMS(pyArray)[0],strides);
		default :
			std::string msg = "Unsupported value type in NumPy array object.";
			setValueError(msg,m_strict);
#ifdef _DEBUG
			cerr << "PyTypeConversions::PyArray_To_FloatVector failed. Error: " << msg << endl;
#endif			
			return Output;
	}
}

PyObject *
PyTypeConversions::FloatVector_To_PyArray(const vector<float> &v) const
{
	npy_intp ndims[1];
	ndims[0] = (int)v.size();
	PyObject *arr = PyArray_SimpleNew(1, ndims, dtype_float32);
	float *data = (float *)PyArray_DATA((PyArrayObject *)arr);
	for (int i = 0; i < ndims[0]; ++i) {
		data[i] = v[i];
	}
	return arr;
}

PyObject *
PyTypeConversions::PyValue_From_StringVector(const std::vector<std::string> &v) const
{
	PyObject *pyList = PyList_New(v.size());
	for (size_t i = 0; i < v.size(); ++i) {
		PyObject *pyStr = PyString_FromString(v[i].c_str());
		PyList_SET_ITEM(pyList, i, pyStr);
	}
	return pyList;
}


/*			   			  	Error handling		   			  		*/

void
PyTypeConversions::setValueError (std::string message, bool strict) const
{
	m_error = true;
	m_errorQueue.push(ValueError(message,strict));
}

/// return a reference to the last error or creates a new one.
ValueError&
PyTypeConversions::lastError() const 
{
	m_error = false;
	if (!m_errorQueue.empty()) return m_errorQueue.back();
	else {
		m_errorQueue.push(ValueError("Type conversion error.",m_strict));
		return m_errorQueue.back();
	}
}

/// helper function to iterate over the error message queue:
/// pops the oldest item
ValueError 
PyTypeConversions::getError() const
{
	if (!m_errorQueue.empty()) {
		ValueError e = m_errorQueue.front();
		m_errorQueue.pop();
		if (m_errorQueue.empty()) m_error = false;
		return e;
	}
	else {
		m_error = false;
		return ValueError();
	}
}

/*			   			  	Utilities						  		*/

/// get the type name of an object
std::string
PyTypeConversions::PyValue_Get_TypeName(PyObject* pyValue) const
{
	PyObject *pyType = PyObject_Type(pyValue);
	if (!pyType) 
	{
		cerr << "Warning: Object type name could not be found." << endl;
		if (PyErr_Occurred()) {PyErr_Print(); PyErr_Clear();}
		return std::string ("< unknown type >");
	}
	PyObject *pyString = PyObject_Str(pyType);
	if (!pyString)
	{
		cerr << "Warning: Object type name could not be found." << endl;
		if (PyErr_Occurred()) {PyErr_Print(); PyErr_Clear();}
		Py_CLEAR(pyType);
		return std::string ("< unknown type >");
	}
	char *cstr = PyString_AS_STRING(pyString);
	if (!cstr)
	{
		cerr << "Warning: Object type name could not be found." << endl;
		if (PyErr_Occurred()) {PyErr_Print(); PyErr_Clear();}
		Py_DECREF(pyType);
		Py_CLEAR(pyString);
		return std::string("< unknown type >");
	}
	Py_DECREF(pyType);
	Py_DECREF(pyString);
	return std::string(cstr);
	
}