1#
2# Copyright 2015 ClusterHQ
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#    http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15#
16
17"""
18Utility functions for casting to a specific C type.
19"""
20from __future__ import absolute_import, division, print_function
21
22from .bindings.libnvpair import ffi as _ffi
23
24
25def _ffi_cast(type_name):
26    type_info = _ffi.typeof(type_name)
27
28    def _func(value):
29        # this is for overflow / underflow checking only
30        if type_info.kind == 'enum':
31            try:
32                type_info.elements[value]
33            except KeyError as e:
34                raise OverflowError('Invalid enum <%s> value %s: %s' %
35                                    (type_info.cname, value, e))
36        else:
37            _ffi.new(type_name + '*', value)
38        return _ffi.cast(type_name, value)
39    _func.__name__ = type_name
40    return _func
41
42
43uint8_t = _ffi_cast('uint8_t')
44int8_t = _ffi_cast('int8_t')
45uint16_t = _ffi_cast('uint16_t')
46int16_t = _ffi_cast('int16_t')
47uint32_t = _ffi_cast('uint32_t')
48int32_t = _ffi_cast('int32_t')
49uint64_t = _ffi_cast('uint64_t')
50int64_t = _ffi_cast('int64_t')
51boolean_t = _ffi_cast('boolean_t')
52uchar_t = _ffi_cast('uchar_t')
53
54
55# First element of the value tuple is a suffix for a single value function
56# while the second element is for an array function
57_type_to_suffix = {
58    _ffi.typeof('uint8_t'):     ('uint8', 'uint8'),
59    _ffi.typeof('int8_t'):      ('int8', 'int8'),
60    _ffi.typeof('uint16_t'):    ('uint16', 'uint16'),
61    _ffi.typeof('int16_t'):     ('int16', 'int16'),
62    _ffi.typeof('uint32_t'):    ('uint32', 'uint32'),
63    _ffi.typeof('int32_t'):     ('int32', 'int32'),
64    _ffi.typeof('uint64_t'):    ('uint64', 'uint64'),
65    _ffi.typeof('int64_t'):     ('int64', 'int64'),
66    _ffi.typeof('boolean_t'):   ('boolean_value', 'boolean'),
67    _ffi.typeof('uchar_t'):     ('byte', 'byte'),
68}
69
70
71# vim: softtabstop=4 tabstop=4 expandtab shiftwidth=4
72