annotate PyTypeInterface.h @ 53:7e59caea821b

* Make a better job of preloading Python, especially when it's in a
  framework.  Go for the Python file in the frameworks directory in
  preference to any libpythonX.Y.dylib.  Particularly, don't try to
  preload any library without an absolute path until we've exhausted
  all our framework possibilities (so as to avoid picking up an
  ancient system library).

/*

 * Vampy : This plugin is a wrapper around the Vamp plugin API.
 * It allows for writing Vamp plugins in Python.

 * Centre for Digital Music, Queen Mary University of London.
 * Copyright (C) 2008-2009 Gyorgy Fazekas, QMUL. (See Vamp sources 
 * for licence information.)

*/

/*
PyTypeInterface: Type safe conversion utilities between Python types 
and basic C/C++ types and Vamp API types.
*/

#ifndef _PY_TYPE_INTERFACE_H_
#define _PY_TYPE_INTERFACE_H_
#include <Python.h>
#ifdef HAVE_NUMPY
#define PY_ARRAY_UNIQUE_SYMBOL VAMPY_ARRAY_API
#define NO_IMPORT_ARRAY
#include "numpy/arrayobject.h"
#endif
#include "PyExtensionModule.h"
#include <vector>
#include <queue>
#include <string>
#include <sstream>
#include "vamp-sdk/Plugin.h"

using std::cerr;
using std::endl;

#ifdef HAVE_NUMPY
enum eArrayDataType {
	dtype_float32 = (int) NPY_FLOAT,
	dtype_complex64 = (int) NPY_CFLOAT 
	};
#endif 

namespace o {
enum eOutDescriptors {
	not_found,
	identifier,
	name,
	description,
	unit, 
	hasFixedBinCount,
	binCount,
	binNames,
	hasKnownExtents,
	minValue,
	maxValue,
	isQuantized,
	quantizeStep,
	sampleType,	
	sampleRate,
	hasDuration,
	endNode
	}; 
}

namespace p {
enum eParmDescriptors {
	not_found,
	identifier,
	name,
	description,
	unit, 
	minValue,
	maxValue,
	defaultValue,
	isQuantized,
	quantizeStep
	};
}

enum eSampleTypes {
	OneSamplePerStep,
	FixedSampleRate,
	VariableSampleRate
	};

enum eFeatureFields {
	unknown,
	hasTimestamp,
	timestamp,
	hasDuration,
	duration,
	values,
	label
	};

/* C++ mapping of PyNone Type */
struct NoneType {};

class PyTypeInterface
{
public:
	PyTypeInterface();
	~PyTypeInterface();
	
	// Data
 	class ValueError
	{
	public:
		ValueError() {}
		ValueError(std::string m, bool s) : message(m),strict(s) {}
		std::string location;
		std::string message;
		bool strict;
		std::string str() const { 
			return (location.empty()) ? message : message + "\nLocation: " + location;}
		void print() const { cerr << str() << endl; }
		template<typename V> ValueError &operator<< (const V& v)
		{
			std::ostringstream ss;
			ss << v;
			location += ss.str();
			return *this;
		}
	};
	
	// Utilities
	void setStrictTypingFlag(bool b) {m_strict = b;}
	void setNumpyInstalled(bool b) {m_numpyInstalled = b;}
	ValueError getError() const;
	std::string PyValue_Get_TypeName(PyObject*) const;
	bool initMaps() const;

	// Basic type conversion: Python to C++ 
	float 	PyValue_To_Float(PyObject*) const;
	size_t 	PyValue_To_Size_t(PyObject*) const;
	bool 	PyValue_To_Bool(PyObject*) const;
	std::string PyValue_To_String(PyObject*) const;
	long 	PyValue_To_Long(PyObject*) const;
	// int 	PyValue_To_Int(PyObject* pyValue) const;
	
	
	// C++ to Python
	PyObject *PyValue_From_CValue(const char*) const;
	PyObject *PyValue_From_CValue(const std::string& x) const { return PyValue_From_CValue(x.c_str()); }
	PyObject *PyValue_From_CValue(size_t) const;
	PyObject *PyValue_From_CValue(double) const;
	PyObject *PyValue_From_CValue(float x) const { return PyValue_From_CValue((double)x); }
	PyObject *PyValue_From_CValue(bool) const;
	
	// Sequence types
	std::vector<std::string> PyValue_To_StringVector (PyObject*) const;
	std::vector<float> PyValue_To_FloatVector (PyObject*) const;
	std::vector<float> PyList_To_FloatVector (PyObject*) const;

	// Input buffers to Python
	PyObject* InputBuffers_As_PythonLists(const float *const *inputBuffers,const size_t& channels, const size_t& blockSize, const Vamp::Plugin::InputDomain& dtype);
	PyObject* InputBuffers_As_SharedMemoryList(const float *const *inputBuffers,const size_t& channels, const size_t& blockSize, const Vamp::Plugin::InputDomain& dtype);

	// Numpy types
#ifdef HAVE_NUMPY
	std::vector<float> PyArray_To_FloatVector (PyObject *pyValue) const;
	PyObject* InputBuffers_As_NumpyArray(const float *const *inputBuffers, const size_t&, const size_t&, const Vamp::Plugin::InputDomain& dtype);
#endif

	


/* 						Template functions 							*/


	/// Common wrappers to set values in Vamp API structs. (to be used in template functions)
	void SetValue(Vamp::Plugin::OutputDescriptor& od, std::string& key, PyObject* pyValue) const;
	void SetValue(Vamp::Plugin::ParameterDescriptor& od, std::string& key, PyObject* pyValue) const;
	bool SetValue(Vamp::Plugin::Feature& od, std::string& key, PyObject* pyValue) const;
    PyObject* GetDescriptor_As_Dict(PyObject* pyValue) const 
	{
		if PyFeature_CheckExact(pyValue) return PyFeature_AS_DICT(pyValue);
		if PyOutputDescriptor_CheckExact(pyValue) return PyOutputDescriptor_AS_DICT(pyValue);
		if PyParameterDescriptor_CheckExact(pyValue) return PyParameterDescriptor_AS_DICT(pyValue);
		return NULL;
	}
	
	//returns e.g. Vamp::Plugin::OutputDescriptor or Vamp::Plugin::Feature
	template<typename RET> 
	RET PyValue_To_VampDescriptor(PyObject* pyValue) const
	{
		PyObject* pyDict;

		// Descriptors encoded as dicts
		pyDict = GetDescriptor_As_Dict(pyValue);
		if (!pyDict) pyDict = pyValue;
	
		// TODO: support full mapping protocol as fallback.
		if (!PyDict_Check(pyDict)) {
			setValueError("Error while converting descriptor or feature object.\nThe value is neither a dictionary nor a Vamp Feature or Descriptor type.",m_strict);
#ifdef _DEBUG
			cerr << "PyTypeInterface::PyValue_To_VampDescriptor failed. Error: Unexpected return type." << endl;
#endif			
			return RET();
		}

		Py_ssize_t pyPos = 0;
		PyObject *pyKey, *pyDictValue;
		initMaps();
		int errors = 0;
		m_error = false;
		RET rd;

		//Python Dictionary Iterator:
		while (PyDict_Next(pyDict, &pyPos, &pyKey, &pyDictValue))
		{
			std::string key = PyValue_To_String(pyKey);
#ifdef _DEBUG_VALUES			
			cerr << "key: '" << key << "' value: '" << PyValue_To_String(pyDictValue) << "' " << endl;
#endif			
			SetValue(rd,key,pyDictValue);
			if (m_error) {
				errors++;
				lastError() << "attribute '" << key << "'";// << " of " << getDescriptorId(rd);
			}
		}
		if (errors) {
			lastError() << " of " << getDescriptorId(rd);
			m_error = true;
#ifdef _DEBUG
			cerr << "PyTypeInterface::PyValue_To_VampDescriptor: Warning: Value error in descriptor." << endl;
#endif				
		}
		return rd;
	}

	/// Convert a sequence (tipically list) of PySomething to 
	/// OutputList,ParameterList or FeatureList
	/// <OutputList> <OutputDescriptor>
	template<typename RET,typename ELEM> 
	RET PyValue_To_VampList(PyObject* pyValue) const
	{
		RET list; // e.g. Vamp::Plugin::OutputList
		ELEM element; // e.g. Vamp::Plugin::OutputDescriptor

		/// convert lists (ParameterList, OutputList, FeatureList)
		if (PyList_Check(pyValue)) {
			PyObject *pyDict; //This reference will be borrowed
			m_error = false; int errors = 0;
			for (Py_ssize_t i = 0; i < PyList_GET_SIZE(pyValue); ++i) {
				//Get i-th Vamp output descriptor (Borrowed Reference)
				pyDict = PyList_GET_ITEM(pyValue,i);
				element = PyValue_To_VampDescriptor<ELEM>(pyDict);
				if (m_error) errors++;
				// Check for empty Feature/Descriptor as before?
				list.push_back(element);
			}
			if (errors) m_error=true;
			return list;
		}
		
		/// convert other types implementing the sequence protocol
		if (PySequence_Check(pyValue)) {
			PyObject *pySequence = PySequence_Fast(pyValue,"Returned value can not be converted to list or tuple.");
			PyObject **pyElements =  PySequence_Fast_ITEMS(pySequence);
			m_error = false; int errors = 0;
			for (Py_ssize_t i = 0; i < PySequence_Fast_GET_SIZE(pySequence); ++i) 
			{
				element = PyValue_To_VampDescriptor<ELEM>(pyElements[i]);
				if (m_error) errors++;
				list.push_back(element);
			}
			if (errors) m_error=true;
			Py_XDECREF(pySequence);
			return list;
		}

		// accept None as an empty list
		if (pyValue == Py_None) return list;
		
		// in strict mode, returning a single value is not allowed 
		if (m_strict) {
			setValueError("Strict conversion error: object is not list or iterable sequence.",m_strict);
			return list;
		}
		
		/// try to insert single, non-iterable values. i.e. feature <- [feature]
		element = PyValue_To_VampDescriptor<ELEM>(pyValue);
		if (m_error) {
			setValueError("Could not insert returned value to Vamp List.",m_strict);
			return list; 
		}
		list.push_back(element);
		return list;
		
#ifdef _DEBUG
			cerr << "PyTypeInterface::PyValue_To_VampList failed. Expected iterable return type." << endl;
#endif			

	}

	/// Convert DTYPE type 1D NumpyArray to std::vector<RET>
	template<typename RET, typename DTYPE>
	std::vector<RET> PyArray_Convert(char* raw_data_ptr, long length, size_t strides) const
	{
		std::vector<RET> rValue;
		
		/// check if the array is continuous, if not use strides info
		if (sizeof(DTYPE)!=strides) {
#ifdef _DEBUG_VALUES
			cerr << "Warning: discontinuous numpy array. Strides: " << strides << " bytes. sizeof(dtype): " << sizeof(DTYPE) << endl;
#endif
			char* data = (char*) raw_data_ptr;
			for (long i = 0; i<length; ++i){
				rValue.push_back((RET)(*((DTYPE*)data)));
#ifdef _DEBUG_VALUES
				cerr << "value: " << (RET)(*((DTYPE*)data)) << endl;
#endif				
				data+=strides;
			}
			return rValue;
		}

		DTYPE* data = (DTYPE*) raw_data_ptr;
		for (long i = 0; i<length; ++i){
#ifdef _DEBUG_VALUES
			cerr << "value: " << (RET)data[i] << endl;
#endif
			rValue.push_back((RET)data[i]);
		}
		return rValue;
	}

	/// this is a special case. numpy.float64 has an array interface but no array descriptor
	inline std::vector<float> PyArray0D_Convert(PyArrayInterface *ai) const
	{
		std::vector<float> rValue;
		if ((ai->typekind) == *"f") 
			rValue.push_back((float)*(double*)(ai->data));
		else { 
			setValueError("Unsupported NumPy data type.",m_strict); 
			return rValue;
		}
#ifdef _DEBUG_VALUES
		cerr << "value: " << rValue[0] << endl;
#endif
		return rValue;
	}

	//Vamp specific types
	Vamp::Plugin::FeatureSet PyValue_To_FeatureSet(PyObject*) const;
	inline void PyValue_To_rValue(PyObject *pyValue, Vamp::Plugin::FeatureSet &r) const
		{ r = this->PyValue_To_FeatureSet(pyValue); }

	Vamp::RealTime PyValue_To_RealTime(PyObject*) const;
	inline void PyValue_To_rValue(PyObject *pyValue, Vamp::RealTime &r) const
		{ r = this->PyValue_To_RealTime(pyValue); }
	
	Vamp::Plugin::OutputDescriptor::SampleType PyValue_To_SampleType(PyObject*) const;

	Vamp::Plugin::InputDomain PyValue_To_InputDomain(PyObject*) const;
	inline void PyValue_To_rValue(PyObject *pyValue, Vamp::Plugin::InputDomain &r) const
		{ r = this->PyValue_To_InputDomain(pyValue); }
	
	
	/* Overloaded PyValue_To_rValue() to support generic functions */
	inline void PyValue_To_rValue(PyObject *pyValue, float &defValue) const 
		{ float tmp = this->PyValue_To_Float(pyValue);                                              
			if(!m_error) defValue = tmp; }
	inline void PyValue_To_rValue(PyObject *pyValue, size_t &defValue) const
		{ size_t tmp = this->PyValue_To_Size_t(pyValue); 
			if(!m_error) defValue = tmp; }
	inline void PyValue_To_rValue(PyObject *pyValue, bool &defValue) const
		{ bool tmp = this->PyValue_To_Bool(pyValue); 
			if(!m_error) defValue = tmp; }
	inline void PyValue_To_rValue(PyObject *pyValue, std::string &defValue) const
		{ std::string tmp = this->PyValue_To_String(pyValue); 
			if(!m_error) defValue = tmp; }
	/*used by templates where we expect no return value, if there is one it will be ignored*/			
	inline void PyValue_To_rValue(PyObject *pyValue, NoneType &defValue) const
		{ if (m_strict && pyValue != Py_None) 
				setValueError("Strict conversion error: Expected 'None' type.",m_strict); 
		}

	/* convert sequence types to Vamp List types */			
	inline void PyValue_To_rValue(PyObject *pyValue, Vamp::Plugin::OutputList &r) const
		{ r = this->PyValue_To_VampList<Vamp::Plugin::OutputList,Vamp::Plugin::OutputDescriptor>(pyValue); }
	inline void PyValue_To_rValue(PyObject *pyValue, Vamp::Plugin::ParameterList &r) const
		{ r = this->PyValue_To_VampList<Vamp::Plugin::ParameterList,Vamp::Plugin::ParameterDescriptor>(pyValue); }
	inline void PyValue_To_rValue(PyObject *pyValue, Vamp::Plugin::FeatureList &r) const
		{ r = this->PyValue_To_VampList<Vamp::Plugin::FeatureList,Vamp::Plugin::Feature>(pyValue); }
	
	/// this is only needed for RealTime->Frame conversion
	void setInputSampleRate(float inputSampleRate)
		{ m_inputSampleRate = (unsigned int) inputSampleRate; }
	
private:
	bool m_strict;
	mutable bool m_error;
	mutable std::queue<ValueError> m_errorQueue;
	unsigned int m_inputSampleRate; 
	bool m_numpyInstalled;
	
	void setValueError(std::string,bool) const;
	ValueError& lastError() const;

	/* Overloaded _convert(), bypasses error checking to avoid doing it twice in internals. */
	inline void _convert(PyObject *pyValue,float &r) const 
		{ r = PyValue_To_Float(pyValue); }
	inline void _convert(PyObject *pyValue,size_t &r) const 
		{ r = PyValue_To_Size_t(pyValue); }
    inline void _convert(PyObject *pyValue,bool &r) const 
		{ r = PyValue_To_Bool(pyValue); }
	inline void _convert(PyObject *pyValue,std::string &r) const
		{ r = PyValue_To_String(pyValue); }
	inline void _convert(PyObject *pyValue,std::vector<std::string> &r) const
		{ r = PyValue_To_StringVector(pyValue); }
	inline void _convert(PyObject *pyValue,std::vector<float> &r) const
		{ r = PyValue_To_FloatVector(pyValue); }
    inline void _convert(PyObject *pyValue,Vamp::RealTime &r) const 
		{ r = PyValue_To_RealTime(pyValue); }
	inline void _convert(PyObject *pyValue,Vamp::Plugin::OutputDescriptor::SampleType &r) const 
		{ r = PyValue_To_SampleType(pyValue); }
	// inline void _convert(PyObject *pyValue,Vamp::Plugin::InputDomain &r) const 
	// 	{ r = PyValue_To_InputDomain(pyValue); }
	    

	/* Identify descriptors for error reporting */
	inline std::string getDescriptorId(Vamp::Plugin::OutputDescriptor d) const
		{return std::string("Output Descriptor '") + d.identifier +"' ";}
	inline std::string getDescriptorId(Vamp::Plugin::ParameterDescriptor d) const
		{return std::string("Parameter Descriptor '") + d.identifier +"' ";}
	inline std::string getDescriptorId(Vamp::Plugin::Feature f) const
		{return std::string("Feature (") + f.label + ")"; }
	
public:
	const bool& error;

};

/* 		   		  Convert Sample Buffers to Python 	         		*/

/// passing the sample buffers as builtin python lists
/// Optimization: using fast sequence protocol
inline PyObject*
PyTypeInterface::InputBuffers_As_PythonLists(const float *const *inputBuffers,const size_t& channels, const size_t& blockSize, const Vamp::Plugin::InputDomain& dtype)
{
	//create a list of lists (new references)
	PyObject *pyChannelList = PyList_New((Py_ssize_t) channels);
	
	// Pack samples into a Python List Object
	// pyFloat/pyComplex types will always be new references, 
	// they will be freed when the lists are deallocated.
	
	PyObject **pyChannelListArray =  PySequence_Fast_ITEMS(pyChannelList);
	for (size_t i=0; i < channels; ++i) {
		
        size_t arraySize;
		if (dtype==Vamp::Plugin::FrequencyDomain) 
			arraySize = (blockSize / 2) + 1; //blockSize + 2; if cplx list isn't used
		else 
			arraySize = blockSize;

		PyObject *pySampleList = PyList_New((Py_ssize_t) arraySize);
		PyObject **pySampleListArray =  PySequence_Fast_ITEMS(pySampleList);
		
		// Note: passing a complex list crashes the C-style plugin
		// when it tries to convert it to a numpy array directly.
		// This plugin will be obsolete, but we have to find a way
		// to prevent such crash: possibly a numpy bug, 
		// works fine above 1.0.4
		
		switch (dtype) //(Vamp::Plugin::TimeDomain)
		{
			case Vamp::Plugin::TimeDomain :

			for (size_t j = 0; j < arraySize; ++j) {
				PyObject *pyFloat=PyFloat_FromDouble(
					(double) inputBuffers[i][j]);
				pySampleListArray[j] = pyFloat;
			}
			break;

			case Vamp::Plugin::FrequencyDomain :

			size_t k = 0;
			for (size_t j = 0; j < arraySize; ++j) {
				PyObject *pyComplex=PyComplex_FromDoubles(
					(double) inputBuffers[i][k], 
					(double) inputBuffers[i][k+1]);
				pySampleListArray[j] = pyComplex;
				k += 2;
			}
			break;
			
		}
		pyChannelListArray[i] = pySampleList;
	}
	return pyChannelList;
}

/// numpy buffer interface: passing the sample buffers as shared memory buffers
/// Optimization: using sequence protocol for creating the buffer list
inline PyObject*
PyTypeInterface::InputBuffers_As_SharedMemoryList(const float *const *inputBuffers,const size_t& channels, const size_t& blockSize, const Vamp::Plugin::InputDomain& dtype)
{	
	//create a list of buffers (returns new references)
	PyObject *pyChannelList = PyList_New((Py_ssize_t) channels);
	PyObject **pyChannelListArray =  PySequence_Fast_ITEMS(pyChannelList);

	// Expose memory using the Buffer Interface.		
	// This will pass a pointer which can be recasted in Python code 
	// as complex or float array using Numpy's frombuffer() method
	// (this will not copy values just keep the starting adresses 
	// for each channel in a list)
	Py_ssize_t bufferSize;
	
	if (dtype==Vamp::Plugin::FrequencyDomain) 
		bufferSize = (Py_ssize_t) sizeof(float) * (blockSize+2);
	else 
		bufferSize = (Py_ssize_t) sizeof(float) * blockSize;
	
	for (size_t i=0; i < channels; ++i) {
		PyObject *pyBuffer = PyBuffer_FromMemory
		((void *) (float *) inputBuffers[i],bufferSize);
		pyChannelListArray[i] = pyBuffer;
	}
	return pyChannelList;
}


/// numpy array interface: passing the sample buffers as 2D numpy array
/// Optimization: using array API (needs numpy headers)
#ifdef HAVE_NUMPY
inline PyObject*
PyTypeInterface::InputBuffers_As_NumpyArray(const float *const *inputBuffers,const size_t& channels, const size_t& blockSize, const Vamp::Plugin::InputDomain& dtype)
{	
/*
NOTE: We create a list of 1D Numpy arrays for each channel instead
of a matrix, because the address space of inputBuffers doesn't seem
to be continuous. Although the array strides could be calculated for
2 channels (i.e. inputBuffers[1] - inputBuffers[0]) i'm not sure
if this can be trusted, especially for more than 2 channels.

	cerr << "First channel: " << inputBuffers[0][0] << " address: " <<  inputBuffers[0] << endl;
	if (channels == 2)
		cerr << "Second channel: " << inputBuffers[1][0] << " address: " <<  inputBuffers[1] << endl;

*/	
	
	// create a list of arrays (returns new references)
	PyObject *pyChannelList = PyList_New((Py_ssize_t) channels);
	PyObject **pyChannelListArray =  PySequence_Fast_ITEMS(pyChannelList);
	
	// Expose memory using the Numpy Array Interface.		
	// This will wrap an array objects around the data.
	// (will not copy values just steal the starting adresses)

	int arraySize, typenum;
	
	switch (dtype)
	{
		case Vamp::Plugin::TimeDomain :
		typenum = dtype_float32; //NPY_FLOAT; 
		arraySize = (int) blockSize;
		break;

		case Vamp::Plugin::FrequencyDomain :
		typenum = dtype_complex64; //NPY_CFLOAT;
		arraySize = (int) (blockSize / 2) + 1;
		break;
		
		default :
		cerr << "PyTypeInterface::InputBuffers_As_NumpyArray: Error: Unsupported numpy array data type." << endl;
		return pyChannelList;
	}

	// size for each dimension
	npy_intp ndims[1]={arraySize}; 
	
	for (size_t i=0; i < channels; ++i) {
		PyObject *pyChannelArray = 
			//args: (dimensions, size in each dim, type kind, pointer to continuous array)
			PyArray_SimpleNewFromData(1, ndims, typenum, (void*) inputBuffers[i]);
		// make it read-only: set all flags to false except NPY_C_CONTIGUOUS 
		((PyArrayObject*)pyChannelArray)->flags = NPY_C_CONTIGUOUS;
		pyChannelListArray[i] = pyChannelArray;
	}
	return pyChannelList;
}
#endif



#ifdef NUMPY_REFERENCE
/// This should be all we need to compile without direct dependency,
/// but we don't do that. (it may not work on some platforms)
typedef struct {
    int two;              /* contains the integer 2 -- simple sanity check */
    int nd;               /* number of dimensions */
    char typekind;        /* kind in array --- character code of typestr */
    int itemsize;         /* size of each element */
    int flags;            /* flags indicating how the data should be interpreted */
                          /*   must set ARR_HAS_DESCR bit to validate descr */
    Py_intptr_t *shape;   /* A length-nd array of shape information */
    Py_intptr_t *strides; /* A length-nd array of stride information */
    void *data;           /* A pointer to the first element of the array */
    PyObject *descr;      /* NULL or data-description (same as descr key */
                          /*        of __array_interface__) -- must set ARR_HAS_DESCR */
                          /*        flag or this will be ignored. */
} PyArrayInterface;

typedef struct PyArrayObject {
        PyObject_HEAD
        char *data;             /* pointer to raw data buffer */
        int nd;                 /* number of dimensions, also called ndim */
        npy_intp *dimensions;       /* size in each dimension */
        npy_intp *strides;          /* bytes to jump to get to the
                                   next element in each dimension */
        PyObject *base;         /* This object should be decref'd
                                   upon deletion of array */
                                /* For views it points to the original array */
                                /* For creation from buffer object it points
                                   to an object that shold be decref'd on
                                   deletion */
                                /* For UPDATEIFCOPY flag this is an array
                                   to-be-updated upon deletion of this one */
        PyArray_Descr *descr;   /* Pointer to type structure */
        int flags;              /* Flags describing array -- see below*/
        PyObject *weakreflist;  /* For weakreferences */
} PyArrayObject;

typedef struct _PyArray_Descr {
        PyObject_HEAD
        PyTypeObject *typeobj;  /* the type object representing an
                                   instance of this type -- should not
                                   be two type_numbers with the same type
                                   object. */
        char kind;              /* kind for this type */
        char type;              /* unique-character representing this type */
        char byteorder;         /* '>' (big), '<' (little), '|'
                                   (not-applicable), or '=' (native). */
        char hasobject;         /* non-zero if it has object arrays
                                   in fields */
        int type_num;          /* number representing this type */
        int elsize;             /* element size for this type */
        int alignment;          /* alignment needed for this type */
        struct _arr_descr                                       \
        *subarray;              /* Non-NULL if this type is
                                   is an array (C-contiguous)
                                   of some other type
                                */
        PyObject *fields;       /* The fields dictionary for this type */
                                /* For statically defined descr this
                                   is always Py_None */

        PyObject *names;        /* An ordered tuple of field names or NULL
                                   if no fields are defined */

        PyArray_ArrFuncs *f;     /* a table of functions specific for each
                                    basic data descriptor */
} PyArray_Descr;

enum NPY_TYPES {    NPY_BOOL=0,
                    NPY_BYTE, NPY_UBYTE,
                    NPY_SHORT, NPY_USHORT,
                    NPY_INT, NPY_UINT,
                    NPY_LONG, NPY_ULONG,
                    NPY_LONGLONG, NPY_ULONGLONG,
                    NPY_FLOAT, NPY_DOUBLE, NPY_LONGDOUBLE,
                    NPY_CFLOAT, NPY_CDOUBLE, NPY_CLONGDOUBLE,
                    NPY_OBJECT=17,
                    NPY_STRING, NPY_UNICODE,
                    NPY_VOID,
                    NPY_NTYPES,
                    NPY_NOTYPE,
                    NPY_CHAR,      /* special flag */
                    NPY_USERDEF=256  /* leave room for characters */
};
#endif /*NUMPY_REFERENCE*/
#endif