1# Copyright 2007 Matt Chaput. All rights reserved.
2#
3# Redistribution and use in source and binary forms, with or without
4# modification, are permitted provided that the following conditions are met:
5#
6#    1. Redistributions of source code must retain the above copyright notice,
7#       this list of conditions and the following disclaimer.
8#
9#    2. Redistributions in binary form must reproduce the above copyright
10#       notice, this list of conditions and the following disclaimer in the
11#       documentation and/or other materials provided with the distribution.
12#
13# THIS SOFTWARE IS PROVIDED BY MATT CHAPUT ``AS IS'' AND ANY EXPRESS OR
14# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
15# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
16# EVENT SHALL MATT CHAPUT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
17# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
18# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
19# OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
20# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
21# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
22# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23#
24# The views and conclusions contained in the software and documentation are
25# those of the authors and should not be interpreted as representing official
26# policies, either expressed or implied, of Matt Chaput.
27
28import sys
29from struct import Struct, calcsize
30
31
32IS_LITTLE = sys.byteorder == "little"
33
34_INT_SIZE = calcsize("!i")
35_SHORT_SIZE = calcsize("!H")
36_LONG_SIZE = calcsize("!Q")
37_FLOAT_SIZE = calcsize("!f")
38_DOUBLE_SIZE = calcsize("!d")
39
40_byte_struct = Struct("!B")
41_sbyte_struct = Struct("!b")
42_ushort_struct = Struct("!H")
43_int_struct = Struct("!i")
44_uint_struct = Struct("!I")
45_long_struct = Struct("!q")
46_ulong_struct = Struct("!Q")
47_float_struct = Struct("!f")
48_double_struct = Struct("!d")
49_ushort_le_struct = Struct("<H")
50_uint_le_struct = Struct("<I")
51
52pack_byte = _byte_struct.pack
53pack_sbyte = _sbyte_struct.pack
54pack_ushort = _ushort_struct.pack
55pack_int = _int_struct.pack
56pack_uint = _uint_struct.pack
57pack_long = _long_struct.pack
58pack_ulong = _ulong_struct.pack
59pack_float = _float_struct.pack
60pack_double = _double_struct.pack
61pack_ushort_le = _ushort_le_struct.pack
62pack_uint_le = _uint_le_struct.pack
63
64unpack_byte = _byte_struct.unpack  # ord() might be faster
65unpack_sbyte = _sbyte_struct.unpack
66unpack_ushort = _ushort_struct.unpack
67unpack_int = _int_struct.unpack
68unpack_uint = _uint_struct.unpack
69unpack_long = _long_struct.unpack
70unpack_ulong = _ulong_struct.unpack
71unpack_float = _float_struct.unpack
72unpack_double = _double_struct.unpack
73unpack_ushort_le = _ushort_le_struct.unpack
74unpack_uint_le = _uint_le_struct.unpack
75
76if sys.version_info[0] < 3:
77    emptybytes = ""
78else:
79    emptybytes = "".encode("latin-1")
80