How to use the blosc.decompress_ptr function in blosc

def put(self, compressed):
        bwritten = blosc.decompress_ptr(compressed, self.ptr)
        self.ptr += bwritten
        return bwritten

def put(self, compressed):
        bwritten = blosc.decompress_ptr(compressed, self.ptr)
        self.ptr += bwritten

dtic = time.time()
    out = blosc.unpack_array(c)
    dtoc = time.time()
    assert((in_ == out).all())
    print("  Time for pack_array/unpack_array:     %.3f/%.3f s." % \
          (ctoc-ctic, dtoc-dtic), end='')
    print("\tCompr ratio: %.2f" % (in_.size*in_.dtype.itemsize*1. / len(c)))

    ctic = time.time()
    c = blosc.compress_ptr(in_.__array_interface__['data'][0],
                           in_.size, in_.dtype.itemsize,
                           clevel=clevel, shuffle=True, cname=cname)
    ctoc = time.time()
    out = np.empty(in_.size, dtype=in_.dtype)
    dtic = time.time()
    blosc.decompress_ptr(c, out.__array_interface__['data'][0])
    dtoc = time.time()
    assert((in_ == out).all())
    print("  Time for compress_ptr/decompress_ptr: %.3f/%.3f s." % \
          (ctoc-ctic, dtoc-dtic), end='')
    print("\tCompr ratio: %.2f" % (in_.size*in_.dtype.itemsize*1. / len(c)))

def decompress(size, dtype, data):
    out = np.empty(size, dtype)
    blosc.decompress_ptr(data, out.__array_interface__['data'][0])
    return out

print("\nTimes for compressing/decompressing with clevel=%d and %d threads" % (
    clevel, blosc.ncores))
for (in_, label) in arrays:
    print("\n*** %s ***" % label)
    for cname in blosc.compressor_list():
        for filter in [blosc.NOSHUFFLE, blosc.SHUFFLE, blosc.BITSHUFFLE]:
            t0 = time.time()
            c = blosc.compress_ptr(in_.__array_interface__['data'][0],
                                   in_.size, in_.dtype.itemsize,
                                   clevel=clevel, shuffle=filter, cname=cname)
            tc = time.time() - t0
            # cause page faults here
            out = np.full(in_.size, fill_value=0, dtype=in_.dtype)
            t0 = time.time()
            blosc.decompress_ptr(c, out.__array_interface__['data'][0])
            td = time.time() - t0
            assert((in_ == out).all())
            print("  *** %-8s, %-10s *** %6.3f s (%.2f GB/s) / %5.3f s (%.2f GB/s)" % (
                cname, blosc.filters[filter], tc, ((N*8 / tc) / 2**30), td, ((N*8 / td) / 2**30)), end='')
            print("\tCompr. ratio: %5.1fx" % (N*8. / len(c)))