#+
# 
# This file is part of h5py, a low-level Python interface to the HDF5 library.
# 
# Copyright (C) 2008 Andrew Collette
# http://h5py.alfven.org
# License: BSD  (See LICENSE.txt for full license)
# 
# $Date$
# 
#-

"""
    HDF5 "H5T" data-type API

    This module contains the datatype identifier class TypeID, and its
    subclasses which represent things like integer/float/compound identifiers.
    The majority of the H5T API is presented as methods on these identifiers.
"""

include "config.pxi"

# Pyrex compile-time imports
from _objects cimport pdefault

from numpy cimport dtype, ndarray
from h5r cimport Reference, RegionReference

from utils cimport  emalloc, efree, \
                    require_tuple, convert_dims, convert_tuple
import _conv

# Runtime imports
import sys
from h5 import get_config

cfg = get_config()

# === Custom C API ============================================================

cpdef TypeID typewrap(hid_t id_):

    cdef H5T_class_t cls
    cls = H5Tget_class(id_)

    if cls == H5T_INTEGER:
        pcls = TypeIntegerID
    elif cls == H5T_FLOAT:
        pcls = TypeFloatID
    elif cls == H5T_TIME:
        pcls = TypeTimeID
    elif cls == H5T_STRING:
        pcls = TypeStringID
    elif cls == H5T_BITFIELD:
        pcls = TypeBitfieldID
    elif cls == H5T_OPAQUE:
        pcls = TypeOpaqueID
    elif cls == H5T_COMPOUND:
        pcls = TypeCompoundID
    elif cls == H5T_REFERENCE:
        pcls = TypeReferenceID
    elif cls == H5T_ENUM:
        pcls = TypeEnumID
    elif cls == H5T_VLEN:
        pcls = TypeVlenID
    elif cls == H5T_ARRAY:
        pcls = TypeArrayID
    else:
        pcls = TypeID

    return pcls(id_)

cdef object lockid(hid_t id_in):
    cdef TypeID tid
    tid = typewrap(id_in)
    tid.locked = 1
    return tid

# === Public constants and data structures ====================================


# Enumeration H5T_class_t
NO_CLASS  = H5T_NO_CLASS
INTEGER   = H5T_INTEGER
FLOAT     = H5T_FLOAT
TIME      = H5T_TIME
STRING    = H5T_STRING
BITFIELD  = H5T_BITFIELD
OPAQUE    = H5T_OPAQUE
COMPOUND  = H5T_COMPOUND
REFERENCE = H5T_REFERENCE
ENUM      = H5T_ENUM
VLEN      = H5T_VLEN
ARRAY     = H5T_ARRAY

# Enumeration H5T_sign_t
SGN_NONE   = H5T_SGN_NONE
SGN_2      = H5T_SGN_2

# Enumeration H5T_order_t
ORDER_LE    = H5T_ORDER_LE
ORDER_BE    = H5T_ORDER_BE
ORDER_VAX   = H5T_ORDER_VAX
ORDER_NONE  = H5T_ORDER_NONE

DIR_DEFAULT = H5T_DIR_DEFAULT
DIR_ASCEND  = H5T_DIR_ASCEND
DIR_DESCEND = H5T_DIR_DESCEND

# Enumeration H5T_str_t
STR_NULLTERM = H5T_STR_NULLTERM
STR_NULLPAD  = H5T_STR_NULLPAD
STR_SPACEPAD = H5T_STR_SPACEPAD

# Enumeration H5T_norm_t
NORM_IMPLIED = H5T_NORM_IMPLIED
NORM_MSBSET = H5T_NORM_MSBSET
NORM_NONE = H5T_NORM_NONE

# Enumeration H5T_cset_t:
CSET_ASCII = H5T_CSET_ASCII

# Enumeration H5T_pad_t:
PAD_ZERO = H5T_PAD_ZERO
PAD_ONE = H5T_PAD_ONE
PAD_BACKGROUND = H5T_PAD_BACKGROUND

if sys.byteorder == "little":    # Custom python addition
    ORDER_NATIVE = H5T_ORDER_LE
else:
    ORDER_NATIVE = H5T_ORDER_BE

# For conversion
BKG_NO = H5T_BKG_NO
BKG_TEMP = H5T_BKG_TEMP
BKG_YES = H5T_BKG_YES

# --- Built-in HDF5 datatypes -------------------------------------------------

# IEEE floating-point
IEEE_F32LE = lockid(H5T_IEEE_F32LE)
IEEE_F32BE = lockid(H5T_IEEE_F32BE)
IEEE_F64LE = lockid(H5T_IEEE_F64LE)
IEEE_F64BE = lockid(H5T_IEEE_F64BE)

# Signed 2's complement integer types
STD_I8LE  = lockid(H5T_STD_I8LE)
STD_I16LE = lockid(H5T_STD_I16LE)
STD_I32LE = lockid(H5T_STD_I32LE)
STD_I64LE = lockid(H5T_STD_I64LE)

STD_I8BE  = lockid(H5T_STD_I8BE)
STD_I16BE = lockid(H5T_STD_I16BE)
STD_I32BE = lockid(H5T_STD_I32BE)
STD_I64BE = lockid(H5T_STD_I64BE)

# Unsigned integers
STD_U8LE  = lockid(H5T_STD_U8LE)
STD_U16LE = lockid(H5T_STD_U16LE)
STD_U32LE = lockid(H5T_STD_U32LE)
STD_U64LE = lockid(H5T_STD_U64LE)

STD_U8BE  = lockid(H5T_STD_U8BE)
STD_U16BE = lockid(H5T_STD_U16BE)
STD_U32BE = lockid(H5T_STD_U32BE)
STD_U64BE = lockid(H5T_STD_U64BE)

# Native types by bytesize
NATIVE_INT8 = lockid(H5T_NATIVE_INT8)
NATIVE_UINT8 = lockid(H5T_NATIVE_UINT8)
NATIVE_INT16 = lockid(H5T_NATIVE_INT16)
NATIVE_UINT16 = lockid(H5T_NATIVE_UINT16)
NATIVE_INT32 = lockid(H5T_NATIVE_INT32)
NATIVE_UINT32 = lockid(H5T_NATIVE_UINT32)
NATIVE_INT64 = lockid(H5T_NATIVE_INT64)
NATIVE_UINT64 = lockid(H5T_NATIVE_UINT64)
NATIVE_FLOAT = lockid(H5T_NATIVE_FLOAT)
NATIVE_DOUBLE = lockid(H5T_NATIVE_DOUBLE)

# Unix time types
UNIX_D32LE = lockid(H5T_UNIX_D32LE)
UNIX_D64LE = lockid(H5T_UNIX_D64LE)
UNIX_D32BE = lockid(H5T_UNIX_D32BE)
UNIX_D64BE = lockid(H5T_UNIX_D64BE)

# Reference types
STD_REF_OBJ = lockid(H5T_STD_REF_OBJ)
STD_REF_DSETREG = lockid(H5T_STD_REF_DSETREG)

# Null terminated (C) and Fortran string types
C_S1 = lockid(H5T_C_S1)
FORTRAN_S1 = lockid(H5T_FORTRAN_S1)
VARIABLE = H5T_VARIABLE

# Character sets
CSET_ASCII = H5T_CSET_ASCII
CSET_UTF8 = H5T_CSET_UTF8

# Custom Python object pointer type
PYTHON_OBJECT = lockid(_conv.get_python_obj())

# Translation tables for HDF5 -> NumPy dtype conversion
cdef dict _order_map = { H5T_ORDER_NONE: '|', H5T_ORDER_LE: '<', H5T_ORDER_BE: '>'}
cdef dict _sign_map  = { H5T_SGN_NONE: 'u', H5T_SGN_2: 'i' }


# === General datatype operations =============================================


def create(int classtype, size_t size):
    """(INT classtype, UINT size) => TypeID
        
    Create a new HDF5 type object.  Legal class values are 
    COMPOUND and OPAQUE.  Use enum_create for enums.
    """

    # HDF5 versions 1.6.X segfault with anything else
    if classtype != H5T_COMPOUND and classtype != H5T_OPAQUE:
        raise ValueError("Class must be COMPOUND or OPAQUE.")

    return typewrap(H5Tcreate(<H5T_class_t>classtype, size))


def open(ObjectID group not None, char* name):
    """(ObjectID group, STRING name) => TypeID

    Open a named datatype from a file.
    """
    return typewrap(H5Topen(group.id, name))


def array_create(TypeID base not None, object dims_tpl):
    """(TypeID base, TUPLE dimensions) => TypeArrayID

    Create a new array datatype, using and HDF5 parent type and
    dimensions given via a tuple of positive integers.  "Unlimited" 
    dimensions are not allowed.
    """
    cdef hsize_t rank
    cdef hsize_t *dims = NULL

    require_tuple(dims_tpl, 0, -1, "dims_tpl")
    rank = len(dims_tpl)
    dims = <hsize_t*>emalloc(sizeof(hsize_t)*rank)

    try:
        convert_tuple(dims_tpl, dims, rank)
        return TypeArrayID(H5Tarray_create(base.id, rank, dims, NULL))
    finally:
        efree(dims)


def enum_create(TypeID base not None):
    """(TypeID base) => TypeID

    Create a new enumerated type based on an (integer) parent type.
    """
    return typewrap(H5Tenum_create(base.id))


def vlen_create(TypeID base not None):
    """(TypeID base) => TypeID

    Create a new variable-length datatype, using any HDF5 type as a base.

    Although the Python interface can manipulate these types, there is no
    provision for reading/writing vlen data.
    """
    return typewrap(H5Tvlen_create(base.id))

    
def decode(char* buf):
    """(STRING buf) => TypeID

    Unserialize an HDF5 type.  You can also do this with the native
    Python pickling machinery.
    """
    return typewrap(H5Tdecode(<unsigned char*>buf))

# === Base type class =========================================================

cdef class TypeID(ObjectID):

    """
        Base class for type identifiers (implements common operations)

        * Hashable: If committed; in HDF5 1.8.X, also if locked
        * Equality: Logical H5T comparison
    """

    def __hash__(self):
        if self._hash is None:
            try:
                # Try to use object header first
                return ObjectID.__hash__(self)
            except TypeError:
                # It's a transient type object
                if self.locked:
                    self._hash = hash(self.encode())
                else:
                    raise TypeError("Only locked or committed types can be hashed")

        return self._hash

    def __richcmp__(self, object other, int how):
        cdef bint truthval = 0
        if how != 2 and how != 3:
            return NotImplemented
        if isinstance(other, TypeID):
            truthval = self.equal(other)
        
        if how == 2:
            return truthval
        return not truthval

    def __copy__(self):
        cdef TypeID cpy
        cpy = ObjectID.__copy__(self)
        return cpy

    property dtype:
        """ A Numpy-style dtype object representing this object.
        """
        def __get__(self):
            return self.py_dtype()

    cdef object py_dtype(self):
        raise TypeError("No NumPy equivalent for %s exists" % self.__class__.__name__)


    def commit(self, ObjectID group not None, char* name, ObjectID lcpl=None):
        """(ObjectID group, STRING name, PropID lcpl=None)

        Commit this (transient) datatype to a named datatype in a file.
        If present, lcpl may be a link creation property list.
        """
        H5Tcommit2(group.id, name, self.id, pdefault(lcpl),
            H5P_DEFAULT, H5P_DEFAULT)
    
    def committed(self):
        """() => BOOL is_comitted

        Determine if a given type object is named (T) or transient (F).
        """
        return <bint>(H5Tcommitted(self.id))

    
    def copy(self):
        """() => TypeID

        Create a copy of this type object.
        """
        return typewrap(H5Tcopy(self.id))

    
    def equal(self, TypeID typeid):
        """(TypeID typeid) => BOOL

        Logical comparison between datatypes.  Also called by
        Python's "==" operator.
        """
        return <bint>(H5Tequal(self.id, typeid.id))

    
    def lock(self):
        """()

        Lock this datatype, which makes it immutable and indestructible.
        Once locked, it can't be unlocked.
        """
        H5Tlock(self.id)
        self.locked = 1

    
    def get_class(self):
        """() => INT classcode

        Determine the datatype's class code.
        """
        return <int>H5Tget_class(self.id)

    
    def set_size(self, size_t size):
        """(UINT size)

        Set the total size of the datatype, in bytes.
        """
        H5Tset_size(self.id, size)

    
    def get_size(self):
        """ () => INT size

            Determine the total size of a datatype, in bytes.
        """
        return H5Tget_size(self.id)

    
    def get_super(self):
        """() => TypeID

        Determine the parent type of an array, enumeration or vlen datatype.
        """
        return typewrap(H5Tget_super(self.id))

    
    def detect_class(self, int classtype):
        """(INT classtype) => BOOL class_is_present

        Determine if a member of the given class exists in a compound
        datatype.  The search is recursive.
        """
        return <bint>(H5Tdetect_class(self.id, <H5T_class_t>classtype))

    
    def _close(self):
        """()

        Close this datatype.  If it's locked, nothing happens.

        You shouldn't ordinarily need to call this function; datatype
        objects are automatically closed when they're deallocated.
        """
        if not self.locked:
            H5Tclose(self.id)


    def encode(self):
        """() => STRING

        Serialize an HDF5 type.  Bear in mind you can also use the
        native Python pickle/unpickle machinery to do this.  The
        returned string may contain binary values, including NULLs.
        """
        cdef size_t nalloc = 0
        cdef char* buf = NULL

        H5Tencode(self.id, NULL, &nalloc)
        buf = <char*>emalloc(sizeof(char)*nalloc)
        try:
            H5Tencode(self.id, <unsigned char*>buf, &nalloc)
            pystr = PyBytes_FromStringAndSize(buf, nalloc)
        finally:
            efree(buf)

        return pystr


    def __reduce__(self):
        return (type(self), (-1,), self.encode())

    
    def __setstate__(self, char* state):
        self.id = H5Tdecode(<unsigned char*>state)


# === Top-level classes (inherit directly from TypeID) ========================

cdef class TypeArrayID(TypeID):

    """
        Represents an array datatype
    """

    
    def get_array_ndims(self):
        """() => INT rank

        Get the rank of the given array datatype.
        """
        return H5Tget_array_ndims(self.id)

    
    def get_array_dims(self):
        """() => TUPLE dimensions

        Get the dimensions of the given array datatype as
        a tuple of integers.
        """
        cdef hsize_t rank   
        cdef hsize_t* dims = NULL

        rank = H5Tget_array_dims(self.id, NULL, NULL)
        dims = <hsize_t*>emalloc(sizeof(hsize_t)*rank)
        try:
            H5Tget_array_dims(self.id, dims, NULL)
            return convert_dims(dims, rank)
        finally:
            efree(dims)

    cdef object py_dtype(self):
        # Numpy translation function for array types
        cdef TypeID tmp_type
        tmp_type = self.get_super()

        base_dtype = tmp_type.py_dtype()

        shape = self.get_array_dims()
        return dtype( (base_dtype, shape) )


cdef class TypeOpaqueID(TypeID):

    """
        Represents an opaque type
    """

    
    def set_tag(self, char* tag):
        """(STRING tag)

        Set a string describing the contents of an opaque datatype.
        Limited to 256 characters.
        """
        H5Tset_tag(self.id, tag)

    
    def get_tag(self):
        """() => STRING tag

        Get the tag associated with an opaque datatype.
        """
        cdef char* buf = NULL

        try:
            buf = H5Tget_tag(self.id)
            assert buf != NULL
            tag = buf
            return tag
        finally:
            free(buf)

    cdef object py_dtype(self):
        # Numpy translation function for opaque types
        return dtype("|V" + str(self.get_size()))

cdef class TypeStringID(TypeID):

    """
        String datatypes, both fixed and vlen.
    """

    
    def is_variable_str(self):
        """() => BOOL is_variable

        Determine if the given string datatype is a variable-length string.
        """
        return <bint>(H5Tis_variable_str(self.id))

    
    def get_cset(self):
        """() => INT character_set

        Retrieve the character set used for a string.
        """
        return <int>H5Tget_cset(self.id)

    
    def set_cset(self, int cset):
        """(INT character_set)

        Set the character set used for a string.
        """
        H5Tset_cset(self.id, <H5T_cset_t>cset)

    
    def get_strpad(self):
        """() => INT padding_type

        Get the padding type.  Legal values are:

        STR_NULLTERM
            NULL termination only (C style)

        STR_NULLPAD
            Pad buffer with NULLs

        STR_SPACEPAD
            Pad buffer with spaces (FORTRAN style)
        """
        return <int>H5Tget_strpad(self.id)

    
    def set_strpad(self, int pad):
        """(INT pad)

        Set the padding type.  Legal values are:

        STR_NULLTERM
            NULL termination only (C style)

        STR_NULLPAD
            Pad buffer with NULLs

        STR_SPACEPAD
            Pad buffer with spaces (FORTRAN style)
        """
        H5Tset_strpad(self.id, <H5T_str_t>pad)

    cdef object py_dtype(self):
        # Numpy translation function for string types
        if self.is_variable_str():
            return special_dtype(vlen=bytes)

        return dtype("|S" + str(self.get_size()))

cdef class TypeVlenID(TypeID):

    """
        Non-string vlen datatypes.
    """
    pass

cdef class TypeTimeID(TypeID):

    """
        Unix-style time_t (deprecated)
    """
    pass

cdef class TypeBitfieldID(TypeID):

    """
        HDF5 bitfield type
    """
    pass

cdef class TypeReferenceID(TypeID):

    """
        HDF5 object or region reference
    """
    
    cdef object py_dtype(self):
        if H5Tequal(self.id, H5T_STD_REF_OBJ):
            return special_dtype(ref=Reference)
        elif H5Tequal(self.id, H5T_STD_REF_DSETREG):
            return special_dtype(ref=RegionReference)
        else:
            raise TypeError("Unknown reference type")


# === Numeric classes (integers and floats) ===================================

cdef class TypeAtomicID(TypeID):

    """
        Base class for atomic datatypes (float or integer)
    """

    
    def get_order(self):
        """() => INT order

        Obtain the byte order of the datatype; one of:

        - ORDER_LE
        - ORDER_BE
        """
        return <int>H5Tget_order(self.id)

    
    def set_order(self, int order):
        """(INT order)

        Set the byte order of the datatype; one of:

        - ORDER_LE
        - ORDER_BE
        """
        H5Tset_order(self.id, <H5T_order_t>order)

    
    def get_precision(self):
        """() => UINT precision

        Get the number of significant bits (excludes padding).
        """
        return H5Tget_precision(self.id)

    
    def set_precision(self, size_t precision):
        """(UINT precision)
            
        Set the number of significant bits (excludes padding).
        """
        H5Tset_precision(self.id, precision)

    
    def get_offset(self):
        """() => INT offset

        Get the offset of the first significant bit.
        """
        return H5Tget_offset(self.id)

    
    def set_offset(self, size_t offset):
        """(UINT offset)

        Set the offset of the first significant bit.
        """
        H5Tset_offset(self.id, offset)

    
    def get_pad(self):
        """() => (INT lsb_pad_code, INT msb_pad_code)

        Determine the padding type.  Possible values are:

        - PAD_ZERO
        - PAD_ONE
        - PAD_BACKGROUND
        """
        cdef H5T_pad_t lsb
        cdef H5T_pad_t msb
        H5Tget_pad(self.id, &lsb, &msb)
        return (<int>lsb, <int>msb)

    
    def set_pad(self, int lsb, int msb):
        """(INT lsb_pad_code, INT msb_pad_code)

        Set the padding type.  Possible values are:

        - PAD_ZERO
        - PAD_ONE
        - PAD_BACKGROUND
        """
        H5Tset_pad(self.id, <H5T_pad_t>lsb, <H5T_pad_t>msb)


cdef class TypeIntegerID(TypeAtomicID):

    """
        Integer atomic datatypes
    """

    
    def get_sign(self):
        """() => INT sign

        Get the "signedness" of the datatype; one of:

        SGN_NONE
            Unsigned

        SGN_2
            Signed 2's complement
        """
        return <int>H5Tget_sign(self.id)

    
    def set_sign(self, int sign):
        """(INT sign)

        Set the "signedness" of the datatype; one of:

        SGN_NONE
            Unsigned

        SGN_2
            Signed 2's complement
        """
        H5Tset_sign(self.id, <H5T_sign_t>sign)

    cdef object py_dtype(self):
        # Translation function for integer types
        return dtype( _order_map[self.get_order()] + 
                      _sign_map[self.get_sign()] + str(self.get_size()) )


cdef class TypeFloatID(TypeAtomicID):

    """
        Floating-point atomic datatypes
    """

    
    def get_fields(self):
        """() => TUPLE field_info

        Get information about floating-point bit fields.  See the HDF5
        docs for a full description.  Tuple has the following members:

        0. UINT spos
        1. UINT epos
        2. UINT esize
        3. UINT mpos
        4. UINT msize
        """
        cdef size_t spos, epos, esize, mpos, msize
        H5Tget_fields(self.id, &spos, &epos, &esize, &mpos, &msize)
        return (spos, epos, esize, mpos, msize)

    
    def set_fields(self, size_t spos, size_t epos, size_t esize, 
                          size_t mpos, size_t msize):
        """(UINT spos, UINT epos, UINT esize, UINT mpos, UINT msize)

        Set floating-point bit fields.  Refer to the HDF5 docs for
        argument definitions.
        """
        H5Tset_fields(self.id, spos, epos, esize, mpos, msize)

    
    def get_ebias(self):
        """() => UINT ebias

        Get the exponent bias.
        """
        return H5Tget_ebias(self.id)

    
    def set_ebias(self, size_t ebias):
        """(UINT ebias)

        Set the exponent bias.
        """
        H5Tset_ebias(self.id, ebias)

    
    def get_norm(self):
        """() => INT normalization_code

        Get the normalization strategy.  Legal values are:

        - NORM_IMPLIED
        - NORM_MSBSET
        - NORM_NONE
        """
        return <int>H5Tget_norm(self.id)

    
    def set_norm(self, int norm):
        """(INT normalization_code)

        Set the normalization strategy.  Legal values are:

        - NORM_IMPLIED
        - NORM_MSBSET
        - NORM_NONE
        """
        H5Tset_norm(self.id, <H5T_norm_t>norm)

    
    def get_inpad(self):
        """() => INT pad_code

        Determine the internal padding strategy.  Legal values are:

        - PAD_ZERO
        - PAD_ONE
        - PAD_BACKGROUND
        """
        return <int>H5Tget_inpad(self.id)

    
    def set_inpad(self, int pad_code):
        """(INT pad_code)

        Set the internal padding strategy.  Legal values are:

        - PAD_ZERO
        - PAD_ONE
        - PAD_BACKGROUND
        """
        H5Tset_inpad(self.id, <H5T_pad_t>pad_code)

    cdef object py_dtype(self):
        # Translation function for floating-point types
        return dtype( _order_map[self.get_order()] + "f" + \
                      str(self.get_size()) )


# === Composite types (enums and compound) ====================================

cdef class TypeCompositeID(TypeID):

    """
        Base class for enumerated and compound types.
    """

    
    def get_nmembers(self):
        """() => INT number_of_members

        Determine the number of members in a compound or enumerated type.
        """
        return H5Tget_nmembers(self.id)

    
    def get_member_name(self, int member):
        """(INT member) => STRING name
        
        Determine the name of a member of a compound or enumerated type,
        identified by its index (0 <= member < nmembers).
        """
        cdef char* name
        name = NULL

        if member < 0:
            raise ValueError("Member index must be non-negative.")

        try:
            name = H5Tget_member_name(self.id, member)
            assert name != NULL
            pyname = <bytes>name
        finally:
            free(name)

        return pyname

    
    def get_member_index(self, char* name):
        """(STRING name) => INT index

        Determine the index of a member of a compound or enumerated datatype
        identified by a string name.
        """
        return H5Tget_member_index(self.id, name)


cdef class TypeCompoundID(TypeCompositeID):

    """
        Represents a compound datatype
    """


    
    def get_member_class(self, int member):
        """(INT member) => INT class

        Determine the datatype class of the member of a compound type,
        identified by its index (0 <= member < nmembers).
        """
        if member < 0:
            raise ValueError("Member index must be non-negative.")
        return H5Tget_member_class(self.id, member)


    
    def get_member_offset(self, int member):
        """(INT member) => INT offset

        Determine the offset, in bytes, of the beginning of the specified
        member of a compound datatype.
        """
        if member < 0:
            raise ValueError("Member index must be non-negative.")
        return H5Tget_member_offset(self.id, member)

    
    def get_member_type(self, int member):
        """(INT member) => TypeID

        Create a copy of a member of a compound datatype, identified by its
        index.
        """
        if member < 0:
            raise ValueError("Member index must be non-negative.")
        return typewrap(H5Tget_member_type(self.id, member))

    
    def insert(self, char* name, size_t offset, TypeID field not None):
        """(STRING name, UINT offset, TypeID field)

        Add a named member datatype to a compound datatype.  The parameter
        offset indicates the offset from the start of the compound datatype,
        in bytes.
        """
        H5Tinsert(self.id, name, offset, field.id)

    
    def pack(self):
        """()

        Recursively removes padding (introduced on account of e.g. compiler
        alignment rules) from a compound datatype.
        """
        H5Tpack(self.id)

    cdef object py_dtype(self):

        cdef TypeID tmp_type
        cdef list field_names
        cdef list field_types
        cdef int nfields
        field_names = []
        field_types = []
        nfields = self.get_nmembers()

        import sys

        # First step: read field names and their Numpy dtypes into 
        # two separate arrays.
        for i from 0 <= i < nfields:
            tmp_type = self.get_member_type(i)
            name = self.get_member_name(i)
            field_names.append(name)
            field_types.append(tmp_type.py_dtype())


        # 1. Check if it should be converted to a complex number
        if len(field_names) == 2                                and \
            tuple(field_names) == (cfg._r_name, cfg._i_name)    and \
            field_types[0] == field_types[1]                    and \
            field_types[0].kind == 'f':

            bstring = field_types[0].str
            blen = int(bstring[2:])
            nstring = bstring[0] + "c" + str(2*blen)
            typeobj = dtype(nstring)

        # 2. Otherwise, read all fields of the compound type, in HDF5 order.
        else:
            if sys.version[0] == '3':
                field_names = [x.decode('utf8') for x in field_names]
            typeobj = dtype(list(zip(field_names, field_types)))

        return typeobj

cdef class TypeEnumID(TypeCompositeID):

    """
        Represents an enumerated type
    """

    cdef int enum_convert(self, long long *buf, int reverse) except -1:
        # Convert the long long value in "buf" to the native representation
        # of this (enumerated) type.  Conversion performed in-place.
        # Reverse: false => llong->type; true => type->llong

        cdef hid_t basetype
        cdef H5T_class_t class_code

        class_code = H5Tget_class(self.id)
        if class_code != H5T_ENUM:
            raise ValueError("This type (class %d) is not of class ENUM" % class_code)

        basetype = H5Tget_super(self.id)
        assert basetype > 0

        try:
            if not reverse:
                H5Tconvert(H5T_NATIVE_LLONG, basetype, 1, buf, NULL, H5P_DEFAULT)
            else:
                H5Tconvert(basetype, H5T_NATIVE_LLONG, 1, buf, NULL, H5P_DEFAULT)
        finally:
            H5Tclose(basetype)

    
    def enum_insert(self, char* name, long long value):
        """(STRING name, INT/LONG value)

        Define a new member of an enumerated type.  The value will be
        automatically converted to the base type defined for this enum.  If
        the conversion results in overflow, the value will be silently 
        clipped.
        """
        cdef long long buf

        buf = value
        self.enum_convert(&buf, 0)
        H5Tenum_insert(self.id, name, &buf)

    
    def enum_nameof(self, long long value):
        """(LONG value) => STRING name

        Determine the name associated with the given value.  Due to a
        limitation of the HDF5 library, this can only retrieve names up to
        1023 characters in length.
        """
        cdef herr_t retval
        cdef char name[1024]
        cdef long long buf

        buf = value
        self.enum_convert(&buf, 0)
        retval = H5Tenum_nameof(self.id, &buf, name, 1024)
        assert retval >= 0
        retstring = name
        return retstring

    
    def enum_valueof(self, char* name):
        """(STRING name) => LONG value

        Get the value associated with an enum name.
        """
        cdef long long buf

        H5Tenum_valueof(self.id, name, &buf)
        self.enum_convert(&buf, 1)
        return buf

    
    def get_member_value(self, int idx):
        """(UINT index) => LONG value

        Determine the value for the member at the given zero-based index.
        """
        cdef herr_t retval
        cdef hid_t ptype
        cdef long long val
        ptype = 0

        if idx < 0:
            raise ValueError("Index must be non-negative.")

        H5Tget_member_value(self.id, idx, &val)
        self.enum_convert(&val, 1)
        return val

    cdef object py_dtype(self):
        # Translation function for enum types

        cdef TypeID basetype = self.get_super()

        nmembers = self.get_nmembers()
        members = {}

        for idx in xrange(nmembers):
            name = self.get_member_name(idx)
            val = self.get_member_value(idx) 
            members[name] = val

        ref = {cfg._f_name: 0, cfg._t_name: 1}

        # Boolean types have priority over standard enums
        if members == ref:
            return dtype('bool')
    
        return special_dtype(enum=(basetype.py_dtype(), members))


# === Translation from NumPy dtypes to HDF5 type objects ======================

# The following series of native-C functions each translate a specific class
# of NumPy dtype into an HDF5 type object.  The result is guaranteed to be
# transient and unlocked.

cdef dict _float_le = {4: H5T_IEEE_F32LE, 8: H5T_IEEE_F64LE}
cdef dict _float_be = {4: H5T_IEEE_F32BE, 8: H5T_IEEE_F64BE}
cdef dict _float_nt = {4: H5T_NATIVE_FLOAT, 8: H5T_NATIVE_DOUBLE}

cdef dict _int_le = {1: H5T_STD_I8LE, 2: H5T_STD_I16LE, 4: H5T_STD_I32LE, 8: H5T_STD_I64LE}
cdef dict _int_be = {1: H5T_STD_I8BE, 2: H5T_STD_I16BE, 4: H5T_STD_I32BE, 8: H5T_STD_I64BE}
cdef dict _int_nt = {1: H5T_NATIVE_INT8, 2: H5T_NATIVE_INT16, 4: H5T_NATIVE_INT32, 8: H5T_NATIVE_INT64}

cdef dict _uint_le = {1: H5T_STD_U8LE, 2: H5T_STD_U16LE, 4: H5T_STD_U32LE, 8: H5T_STD_U64LE}
cdef dict _uint_be = {1: H5T_STD_U8BE, 2: H5T_STD_U16BE, 4: H5T_STD_U32BE, 8: H5T_STD_U64BE}
cdef dict _uint_nt = {1: H5T_NATIVE_UINT8, 2: H5T_NATIVE_UINT16, 4: H5T_NATIVE_UINT32, 8: H5T_NATIVE_UINT64} 

cdef TypeFloatID _c_float(dtype dt):
    # Floats (single and double)
    cdef hid_t tid

    try:
        if dt.byteorder == c'<':
            tid =  _float_le[dt.elsize]
        elif dt.byteorder == c'>':
            tid =  _float_be[dt.elsize]
        else:
            tid =  _float_nt[dt.elsize]
    except KeyError:
        raise TypeError("Unsupported float size (%s)" % dt.elsize)

    return TypeFloatID(H5Tcopy(tid))

cdef TypeIntegerID _c_int(dtype dt):
    # Integers (ints and uints)
    cdef hid_t tid

    try:
        if dt.kind == c'i':
            if dt.byteorder == c'<':
                tid = _int_le[dt.elsize]
            elif dt.byteorder == c'>':
                tid = _int_be[dt.elsize]
            else:
                tid = _int_nt[dt.elsize]
        elif dt.kind == c'u':
            if dt.byteorder == c'<':
                tid = _uint_le[dt.elsize]
            elif dt.byteorder == c'>':
                tid = _uint_be[dt.elsize]
            else:
                tid = _uint_nt[dt.elsize]
        else:
            raise TypeError('Illegal int kind "%s"' % dt.kind)
    except KeyError:
        raise TypeError("Unsupported integer size (%s)" % dt.elsize)

    return TypeIntegerID(H5Tcopy(tid))

cdef TypeEnumID _c_enum(dtype dt, dict vals):
    # Enums
    cdef TypeIntegerID base
    cdef TypeEnumID out

    base = _c_int(dt)

    out = TypeEnumID(H5Tenum_create(base.id))
    for name in sorted(vals):
        out.enum_insert(name, vals[name])
    return out

cdef TypeEnumID _c_bool(dtype dt):
    # Booleans
    global cfg

    cdef TypeEnumID out
    out = TypeEnumID(H5Tenum_create(H5T_NATIVE_INT8))

    out.enum_insert(cfg._f_name, 0)
    out.enum_insert(cfg._t_name, 1)

    return out

cdef TypeArrayID _c_array(dtype dt, int logical):
    # Arrays
    cdef dtype base
    cdef TypeID type_base
    cdef object shape

    base, shape = dt.subdtype
    try:
        shape = tuple(shape)
    except TypeError:
        try:
            shape = (int(shape),)
        except TypeError:
            raise TypeError("Array shape for dtype must be a sequence or integer")
    type_base = py_create(base, logical=logical)
    return array_create(type_base, shape)

cdef TypeOpaqueID _c_opaque(dtype dt):
    # Opaque
    return TypeOpaqueID(H5Tcreate(H5T_OPAQUE, dt.itemsize))

cdef TypeStringID _c_string(dtype dt):
    # Strings (fixed-length)
    cdef hid_t tid

    tid = H5Tcopy(H5T_C_S1)
    H5Tset_size(tid, dt.itemsize)
    H5Tset_strpad(tid, H5T_STR_NULLPAD)
    return TypeStringID(tid)

cdef TypeCompoundID _c_complex(dtype dt):
    # Complex numbers (names depend on cfg)
    global cfg

    cdef hid_t tid, tid_sub
    cdef size_t size, off_r, off_i

    cdef size_t length = dt.itemsize
    cdef char byteorder = dt.byteorder

    if length == 8:
        size = h5py_size_n64
        off_r = h5py_offset_n64_real
        off_i = h5py_offset_n64_imag
        if byteorder == c'<':
            tid_sub = H5T_IEEE_F32LE
        elif byteorder == c'>':
            tid_sub = H5T_IEEE_F32BE
        else:
            tid_sub = H5T_NATIVE_FLOAT
    elif length == 16:
        size = h5py_size_n128
        off_r = h5py_offset_n128_real
        off_i = h5py_offset_n128_imag
        if byteorder == c'<':
            tid_sub = H5T_IEEE_F64LE
        elif byteorder == c'>':
            tid_sub = H5T_IEEE_F64BE
        else:
            tid_sub = H5T_NATIVE_DOUBLE
    else:
        raise TypeError("Illegal length %d for complex dtype" % length)

    tid = H5Tcreate(H5T_COMPOUND, size)
    H5Tinsert(tid, cfg._r_name, off_r, tid_sub)
    H5Tinsert(tid, cfg._i_name, off_i, tid_sub)

    return TypeCompoundID(tid)

cdef TypeCompoundID _c_compound(dtype dt, int logical):
    # Compound datatypes

    cdef hid_t tid
    cdef TypeID type_tmp
    cdef dtype dt_tmp
    cdef size_t offset

    cdef dict fields = dt.fields
    cdef tuple names = dt.names

    # Initial size MUST be 1 to avoid segfaults (issue 166)
    tid = H5Tcreate(H5T_COMPOUND, 1)  

    offset = 0
    for name in names:
        ename = name.encode('utf8') if isinstance(name, unicode) else name
        dt_tmp = dt.fields[name][0]
        type_tmp = py_create(dt_tmp, logical=logical)
        H5Tset_size(tid, offset+type_tmp.get_size())
        H5Tinsert(tid, ename, offset, type_tmp.id)
        offset += type_tmp.get_size()

    return TypeCompoundID(tid)

cdef TypeStringID _c_vlen_str(object basetype):
    # Variable-length strings
    cdef hid_t tid
    tid = H5Tcopy(H5T_C_S1)
    H5Tset_size(tid, H5T_VARIABLE)
    return TypeStringID(tid)

cdef TypeReferenceID _c_ref(object refclass):
    if refclass is Reference:
        return STD_REF_OBJ
    elif refclass is RegionReference:
        return STD_REF_DSETREG
    raise TypeError("Unrecognized reference code")

cpdef TypeID py_create(object dtype_in, bint logical=0):
    """(OBJECT dtype_in, BOOL logical=False) => TypeID

    Given a Numpy dtype object, generate a byte-for-byte memory-compatible
    HDF5 datatype object.  The result is guaranteed to be transient and
    unlocked.

    Argument dtype_in may be a dtype object, or anything which can be
    converted to a dtype, including strings like '<i4'.

    logical
        If this flag is set, instead of returning a byte-for-byte identical
        representation of the type, the function returns the closest logically
        appropriate HDF5 type.  For example, in the case of a "hinted" dtype
        of kind "O" representing a string, it would return an HDF5 variable-
        length string type.
    """
    cdef dtype dt = dtype(dtype_in)
    cdef char kind = dt.kind

    # Float
    if kind == c'f':
        return _c_float(dt)
    
    # Integer
    elif kind == c'u' or kind == c'i':

        if logical:
            # Check for an enumeration hint
            enum_vals = check_dtype(enum=dt)
            if enum_vals is not None:
                return _c_enum(dt, enum_vals)

        return _c_int(dt)

    # Complex
    elif kind == c'c':
        return _c_complex(dt)

    # Compound
    elif kind == c'V' and dt.names is not None:
        return _c_compound(dt, logical)

    # Array or opaque
    elif kind == c'V':
        if dt.subdtype is not None:
            return _c_array(dt, logical)
        else:
            return _c_opaque(dt)

    # String
    elif kind == c'S':
        return _c_string(dt)

    # Boolean
    elif kind == c'b':
        return _c_bool(dt)

    # Object types (including those with vlen hints)
    elif kind == c'O':

        if logical:
            vlen = check_dtype(vlen=dt)
            if vlen is not None:
                return _c_vlen_str(vlen)

            refclass = check_dtype(ref=dt)
            if refclass is not None:
                    return _c_ref(refclass)

            raise TypeError("Object dtype %r has no native HDF5 equivalent" % (dt,))

        return PYTHON_OBJECT

    # Unrecognized
    else:
        raise TypeError("No conversion path for dtype: %s" % repr(dt))

def special_dtype(**kwds):
    """ Create a new h5py "special" type.  Only one keyword may be given.

    Legal keywords are:

    vlen = basetype
        Base type for HDF5 variable-length datatype.  Currently only the
        builtin string class (str) is allowed.
        Example: special_dtype( vlen=str )

    enum = (basetype, values_dict)
        Create a NumPy representation of an HDF5 enumerated type.  Provide
        a 2-tuple containing an (integer) base dtype and a dict mapping
        string names to integer values.

    ref = Reference | RegionReference
        Create a NumPy representation of an HDF5 object or region reference
        type.
    """
    
    if len(kwds) != 1:
        raise TypeError("Exactly one keyword may be provided")

    name, val = kwds.popitem()

    if name == 'vlen':
        if val is not bytes:
            raise NotImplementedError("Only byte-string vlens are currently supported")

        return dtype(('O', [( ({'type': val},'vlen'), 'O' )] ))

    if name == 'enum':

        try:
            dt, enum_vals = val
        except TypeError:
            raise TypeError("Enums must be created from a 2-tuple (basetype, values_dict)")

        dt = dtype(dt)
        if dt.kind not in "iu":
            raise TypeError("Only integer types can be used as enums")

        return dtype((dt, [( ({'vals': enum_vals},'enum'), dt )] ))

    if name == 'ref':

        if val not in (Reference, RegionReference):
            raise ValueError("Ref class must be Reference or RegionReference")

        return dtype(('O', [( ({'type': val},'ref'), 'O' )] ))

    raise TypeError('Unknown special type "%s"' % name)
   
def check_dtype(**kwds):
    """ Check a dtype for h5py special type "hint" information.  Only one
    keyword may be given.

    vlen = dtype
        If the dtype represents an HDF5 vlen, returns the Python base class.
        Currently only builting string vlens (str) are supported.  Returns
        None if the dtype does not represent an HDF5 vlen.

    enum = dtype
        If the dtype represents an HDF5 enumerated type, returns the dictionary
        mapping string names to integer values.  Returns None if the dtype does
        not represent an HDF5 enumerated type.

    ref = dtype
        If the dtype represents an HDF5 reference type, returns the reference
        class (either Reference or RegionReference).  Returns None if the dtype
        does not represent an HDF5 reference type.
    """

    if len(kwds) != 1:
        raise TypeError("Exactly one keyword may be provided")

    name, dt = kwds.popitem()

    if name not in ('vlen', 'enum', 'ref'):
        raise TypeError('Unknown special type "%s"' % name)

    hintkey = 'type' if name is not 'enum' else 'vals'

    if dt.fields is not None and name in dt.fields:
        tpl = dt.fields[name]
        if len(tpl) == 3:
            hint_dict = tpl[2]
            if hintkey in hint_dict:
                return hint_dict[hintkey]

    return None

def convert(TypeID src not None, TypeID dst not None, size_t n,
            ndarray buf not None, ndarray bkg=None, ObjectID dxpl=None):
    """ (TypeID src, TypeID dst, UINT n, NDARRAY buf, NDARRAY bkg=None,
    PropID dxpl=None)

    Convert n contiguous elements of a buffer in-place.  The array dtype
    is ignored.  The backing buffer is optional; for conversion of compound
    types, a temporary copy of conversion buffer will used for backing if
    one is not supplied.
    """
    cdef void* bkg_ = NULL
    cdef void* buf_ = buf.data

    if bkg is None and (src.detect_class(H5T_COMPOUND) or
                        dst.detect_class(H5T_COMPOUND)):
        bkg = buf.copy()
    if bkg is not None:
        bkg_ = bkg.data

    H5Tconvert(src.id, dst.id, n, buf_, bkg_, pdefault(dxpl))

def find(TypeID src not None, TypeID dst not None):
    """ (TypeID src, TypeID dst) => TUPLE or None

    Determine if a conversion path exists from src to dst.  Result is None
    or a tuple describing the conversion path.  Currently tuple entries are:

    1. INT need_bkg:    Whether this routine requires a backing buffer.
                        Values are BKG_NO, BKG_TEMP and BKG_YES.
    """
    cdef H5T_cdata_t *data
    cdef H5T_conv_t result = NULL
    
    try:
        result = H5Tfind(src.id, dst.id, &data)
        if result == NULL:
            return None
        return (data[0].need_bkg,)
    except:
        return None

# ============================================================================
# Deprecated functions

import warnings

cpdef dtype py_new_enum(object dt_in, dict enum_vals):
    """ (DTYPE dt_in, DICT enum_vals) => DTYPE

    Deprecated; use special_dtype() instead.
    """
    #warnings.warn("Deprecated; use special_dtype(enum=(dtype, values)) instead", DeprecationWarning)
    return special_dtype(enum = (dt_in, enum_vals))

cpdef dict py_get_enum(object dt):
    """ (DTYPE dt_in) => DICT

    Deprecated; use check_dtype() instead.
    """
    #warnings.warn("Deprecated; use check_dtype(enum=dtype) instead", DeprecationWarning)
    return check_dtype(enum=dt)

cpdef dtype py_new_vlen(object kind):
    """ (OBJECT kind) => DTYPE

    Deprecated; use special_dtype() instead.
    """
    #warnings.warn("Deprecated; use special_dtype(vlen=basetype) instead", DeprecationWarning)
    return special_dtype(vlen=kind)

cpdef object py_get_vlen(object dt_in):
    """ (OBJECT dt_in) => TYPE

    Deprecated; use check_dtype() instead.
    """
    #warnings.warn("Deprecated; use check_dtype(vlen=dtype) instead", DeprecationWarning)
    return check_dtype(vlen=dt_in)


