"""Generate std_ref_hdf5_2_0.h5: a dataset of H5T_STD_REF (the reference
datatype introduced in HDF5 1.12, datatype message version 4) holding two
object references — to /target (a dataset) and /grp (a group).

h5py has no API for this type, so the file is written by calling the libhdf5
bundled in the h5py wheel directly through ctypes. Written with h5py 3.16.0 /
HDF5 2.0.0. Re-run only if the fixture ever needs regenerating:

    python gen_std_ref.py std_ref_hdf5_2_0.h5
"""
import ctypes
import glob
import os
import sys

import h5py
import numpy as np

libdir = os.path.join(os.path.dirname(os.path.dirname(h5py.__file__)), "h5py.libs")
libs = [p for p in glob.glob(os.path.join(libdir, "libhdf5*.so*")) if "_hl" not in os.path.basename(p)]
lib = ctypes.CDLL(libs[0])
lib.H5open()
hid = ctypes.c_int64
std_ref = hid.in_dll(lib, "H5T_STD_REF_g").value

lib.H5Screate_simple.restype = hid
lib.H5Screate_simple.argtypes = [ctypes.c_int, ctypes.POINTER(ctypes.c_uint64), ctypes.POINTER(ctypes.c_uint64)]
lib.H5Dcreate2.restype = hid
lib.H5Dcreate2.argtypes = [hid, ctypes.c_char_p, hid, hid, hid, hid, hid]
lib.H5Rcreate_object.argtypes = [hid, ctypes.c_char_p, hid, ctypes.c_void_p]
lib.H5Dwrite.argtypes = [hid, hid, hid, hid, hid, ctypes.c_void_p]
lib.H5Dclose.argtypes = [hid]

with h5py.File(sys.argv[1], "w", libver="latest") as f:
    f.create_dataset("target", data=np.arange(5, dtype="<i4"))
    f.create_group("grp")
    fid = f.id.id
    sid = lib.H5Screate_simple(1, (ctypes.c_uint64 * 1)(2), None)
    did = lib.H5Dcreate2(fid, b"refs", std_ref, sid, 0, 0, 0)
    refs = ((ctypes.c_ubyte * 64) * 2)()  # H5R_ref_t is a 64-byte buffer
    assert lib.H5Rcreate_object(fid, b"/target", 0, ctypes.byref(refs[0])) == 0
    assert lib.H5Rcreate_object(fid, b"/grp", 0, ctypes.byref(refs[1])) == 0
    assert lib.H5Dwrite(did, std_ref, 0, 0, 0, ctypes.byref(refs)) == 0
    lib.H5Dclose(did)