pyffi.object_models.xml.enum

1 """Abstract base class for implementing xml enum types.""" 2 3 # ***** BEGIN LICENSE BLOCK ***** 4 # 5 # Copyright (c) 2007-2011, Python File Format Interface 6 # All rights reserved. 7 # 8 # Redistribution and use in source and binary forms, with or without 9 # modification, are permitted provided that the following conditions 10 # are met: 11 # 12 # * Redistributions of source code must retain the above copyright 13 # notice, this list of conditions and the following disclaimer. 14 # 15 # * Redistributions in binary form must reproduce the above 16 # copyright notice, this list of conditions and the following 17 # disclaimer in the documentation and/or other materials provided 18 # with the distribution. 19 # 20 # * Neither the name of the Python File Format Interface 21 # project nor the names of its contributors may be used to endorse 22 # or promote products derived from this software without specific 23 # prior written permission. 24 # 25 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 27 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 28 # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 29 # COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 30 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 31 # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 32 # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 33 # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 35 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 # POSSIBILITY OF SUCH DAMAGE. 37 # 38 # ***** END LICENSE BLOCK ***** 39 40 import logging 41 import struct 42 from itertools import izip 43 44 from pyffi.object_models.xml.basic import BasicBase 45 from pyffi.object_models.editable import EditableComboBox 46

47 -class _MetaEnumBase(type):

48 """This metaclass checks for the presence of _enumkeys, _enumvalues, 49 and _numbytes attributes. It also adds enum class attributes. 50 51 Used as metaclass of EnumBase."""

52 - def __init__(cls, name, bases, dct):

53 super(_MetaEnumBase, cls).__init__(name, bases, dct) 54 # consistency checks 55 if not '_enumkeys' in dct: 56 raise TypeError('%s: missing _enumkeys attribute'%cls) 57 if not '_enumvalues' in dct: 58 raise TypeError('%s: missing _enumvalues attribute'%cls) 59 if not '_numbytes' in dct: 60 raise TypeError('%s: missing _numbytes attribute'%cls) 61 62 # check storage type 63 if cls._numbytes == 1: 64 cls._struct = 'B' 65 elif cls._numbytes == 2: 66 cls._struct = 'H' 67 elif cls._numbytes == 4: 68 cls._struct = 'I' 69 else: 70 raise RuntimeError("unsupported enum numbytes") 71 72 # template type? 73 cls._is_template = False 74 # does the type contain a Ref or a Ptr? 75 cls._has_links = False 76 # does the type contain a Ref? 77 cls._has_refs = False 78 # does the type contain a string? 79 cls._has_strings = False 80 81 # for other read/write checking 82 cls._min = 0 83 cls._max = (1 << (cls._numbytes * 8)) - 1 84 85 # set enum values as class attributes 86 for item, value in izip(cls._enumkeys, cls._enumvalues): 87 setattr(cls, item, value)

88

89 -class EnumBase(BasicBase, EditableComboBox):

90 __metaclass__ = _MetaEnumBase 91 _enumkeys = [] 92 _enumvalues = [] 93 _numbytes = 1 # default width of an enum 94 95 # 96 # BasicBase methods 97 # 98

99 - def __init__(self, **kwargs):

100 super(EnumBase, self).__init__(**kwargs) 101 self._value = self._enumvalues[0]

102

103 - def get_value(self):

104 """Return stored value.""" 105 return self._value

106

107 - def set_value(self, value):

108 """Set value to C{value}.""" 109 try: 110 val = int(value) 111 except ValueError: 112 try: 113 val = int(value, 16) # for '0x...' strings 114 except ValueError: 115 if value in self._enumkeys: 116 val = getattr(self, value) 117 else: 118 raise ValueError( 119 "cannot convert value '%s' to integer"%value) 120 if not val in self._enumvalues: 121 logger = logging.getLogger("pyffi.object_models.xml.enum") 122 logger.error('invalid enum value (%i)' % val) 123 else: 124 self._value = val

125

126 - def read(self, stream, data):

127 """Read value from stream.""" 128 self._value = struct.unpack(data._byte_order + self._struct, 129 stream.read(self._numbytes))[0]

130

131 - def write(self, stream, data):

132 """Write value to stream.""" 133 stream.write(struct.pack(data._byte_order + self._struct, 134 self._value))

135

136 - def __str__(self):

137 try: 138 return self._enumkeys[self._enumvalues.index(self.get_value())] 139 except ValueError: 140 # not in _enumvalues list 141 return "<INVALID (%i)>" % self.get_value()

142

143 - def get_size(self, data=None):

144 """Return size of this type.""" 145 return self._numbytes

146

147 - def get_hash(self, data=None):

148 """Return a hash value for this value.""" 149 return self.get_value()

150 151 # 152 # EditableComboBox methods 153 # 154

155 - def get_editor_keys(self):

156 """List or tuple of strings, each string describing an item.""" 157 return self._enumkeys

158

159 - def set_editor_value(self, index):

160 """Set value from item index.""" 161 self.set_value(self._enumvalues[index])

162

163 - def get_editor_value(self):

164 """Get the item index from the enum value.""" 165 return self._enumvalues.index(self._value)

166

167 - def get_detail_display(self):

168 """Return object that can be used to display the instance.""" 169 try: 170 return self._enumkeys[self._enumvalues.index(self._value)] 171 except ValueError: 172 # value self._value is not in the self._enumvalues list 173 return "<INVALID (0x%08X)>" % self._value

174

Source Code for Module pyffi.object_models.xml.enum