mirror of
https://github.com/drasko/codezero.git
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328 lines
9.3 KiB
Python
328 lines
9.3 KiB
Python
import mmap
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import struct
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import os
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class GFile(object):
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def __init__(self, filename, size):
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handle = open(filename, 'rb+')
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self.mapping = mmap.mmap(handle.fileno(), size)
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def set_byte_ordering(self, ordering):
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self.byte_ordering = ordering
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def get_byte_ordering(self):
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return self.byte_ordering
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def create_new(filename, size):
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assert size < 10240 # This is only for testing, really
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handle = open(filename, 'wb')
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handle.write('\0' * size)
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handle.close()
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return GFile(filename, size)
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create_new = staticmethod(create_new)
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def existing(filename):
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assert os.path.exists(filename)
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size = os.path.getsize(filename)
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return GFile(filename, size)
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existing = staticmethod(existing)
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class BitPoker(object):
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""" """
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SIZE_MAP = {1: 'B',
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2: 'H',
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4: 'I',
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8: 'Q'}
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def set_mmapfile(self, mmapfile, offset_bytes = 0):
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self.mmapfile = mmapfile
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self.master_offset_bytes = offset_bytes
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def set_byte_ordering(self, byte_ordering):
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self.byte_ordering = byte_ordering
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self.struct_byte_ordering = {'lsb': '<', 'msb': '>'}[byte_ordering]
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def get_byte_ordering(self):
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return self.byte_ordering
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def read_value(self, numbytes, offset_bytes):
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# Seek to the right spot using absolute (whence=0) positioning
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self.mmapfile.seek(offset_bytes + self.master_offset_bytes, 0)
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data = self.mmapfile.read(numbytes)
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return struct.unpack('%s%s' % (self.struct_byte_ordering,
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self.SIZE_MAP[numbytes]), data)
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def write_value_sized(self, value, numbytes, offset_bytes):
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data = struct.pack('%s%s' % (self.struct_byte_ordering,
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self.SIZE_MAP[numbytes]), value)
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self.mmapfile.seek(offset_bytes + self.master_offset_bytes, 0)
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self.mmapfile.write(data)
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def read_value_sized(self, numbytes, offset_bytes):
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self.mmapfile.seek(offset_bytes + self.master_offset_bytes, 0)
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raw_data = self.mmapfile.read(numbytes)
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data = struct.unpack('%s%s' % (self.struct_byte_ordering,
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self.SIZE_MAP[numbytes]), raw_data)
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return data[0]
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def read_c_string(self, offset_bytes):
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self.mmapfile.seek(offset_bytes + self.master_offset_bytes.get(), 0)
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result = ''
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c = self.mmapfile.read_byte()
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while c != '\0':
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result += c
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c = self.mmapfile.read_byte()
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return result
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def new_with_gfile(gfile, offset):
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poker = BitPoker()
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poker.set_mmapfile(gfile.mapping, offset)
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poker.set_byte_ordering(gfile.get_byte_ordering())
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return poker
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new_with_gfile = staticmethod(new_with_gfile)
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def new_with_poker(origpoker, offset):
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poker = BitPoker()
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poker.set_mmapfile(origpoker.mmapfile, origpoker.master_offset_bytes + offset)
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poker.set_byte_ordering(origpoker.get_byte_ordering())
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return poker
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new_with_poker = staticmethod(new_with_poker)
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class AIStruct(object):
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SIZE32 = 32
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SIZE64 = 64
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class AIElement(object):
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_natural_size = None
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def __init__(self, word_size_in_bits, offset, names, format):
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self.offset = offset #offset into memory-mapped file.
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self.set_target_word_size(word_size_in_bits)
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self.value = 0
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self.names = names
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self.format = format
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def set_target_word_size(self, target_word_size):
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self.target_word_size = target_word_size
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def get_size_bits(self):
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return self._natural_size
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def set_args(self):
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pass
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def set(self, value):
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if type(value) is str and len(value) == 1:
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value = ord(value)
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self.value = value
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def get(self):
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return self.value
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def write(self, bitpoker):
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bitpoker.write_value_sized(self.value, self.get_size_bits() / 8,
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self.offset)
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def read(self, bitpoker):
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self.value = bitpoker.read_value_sized(self.get_size_bits() / 8, self.offset)
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def __cmp__(self, value):
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return cmp(self.value, value)
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def __add__(self, other):
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if isinstance(other, AIStruct.AIElement):
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return self.value + other.value
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else:
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return self.value + other
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def __mul__(self, other):
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if isinstance(other, AIStruct.AIElement):
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return self.value * other.value
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else:
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return self.value * other
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def __str__(self):
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if self.format:
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if type(self.format) == type(""):
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return self.format % self.value
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else:
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return self.format(self.value)
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if self.names:
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return self.names.get(self.value, str(self.value))
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else:
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return str(self.value)
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class WORD(AIElement):
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def get_size_bits(self):
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return self.target_word_size
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class INT8(AIElement):
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_natural_size = 8
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UINT8 = INT8
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class INT16(AIElement):
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_natural_size = 16
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UINT16 = INT16
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class INT32(AIElement):
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_natural_size = 32
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UINT32 = INT32
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class INT64(AIElement):
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_natural_size = 64
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UINT64 = INT64
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class BITFIELD(AIElement):
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class AttributeBasedProperty(object):
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def __init__(self, bitfield_inst):
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self.bitfield_inst = bitfield_inst
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def get_length_and_offset_for_key(self, key):
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offset = 0
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length = 0
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for name, sizes_dict in self.bitfield_inst.components:
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if name == key:
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length = sizes_dict[self.bitfield_inst.target_word_size]
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break
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offset += sizes_dict[self.bitfield_inst.target_word_size]
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if length == 0:
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raise AttributeError(key)
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return length, offset
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def __getitem__(self, key):
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length, offset = self.get_length_and_offset_for_key(key)
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# We have the position of the desired key in value.
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# Retrieve it by right-shifting by "offset" and
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# then masking away anything > length.
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result = self.bitfield_inst.value >> offset
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result &= ( (1<<length) - 1)
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if self.bitfield_inst.post_get is not None:
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return self.bitfield_inst.post_get(key, result)
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else:
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return result
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def __setitem__(self, key, new_value):
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if self.bitfield_inst.pre_set is not None:
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new_value = self.bitfield_inst.pre_set(key, new_value)
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length, offset = self.get_length_and_offset_for_key(key)
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assert new_value < (1 << length)
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# Generate the result in three stages
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# ... insert the new value:
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result = new_value << offset
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# ... | the stuff above the value:
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result |= ( self.bitfield_inst.value >> (offset + length) << (offset + length) )
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# ... | the stuff below the value.
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result |= ( self.bitfield_inst.value & ( (1 << offset) - 1 ) )
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self.bitfield_inst.value = result
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def __init__(self, *args, **kwargs):
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super(AIStruct.BITFIELD, self).__init__(*args, **kwargs)
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self.components = []
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self.attribute_based_property = AIStruct.BITFIELD.AttributeBasedProperty(self)
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def set_args(self, components=None, post_get=None, pre_set=None):
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if components is not None:
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self.components = components
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self.post_get = post_get
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self.pre_set = pre_set
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def get_size_bits(self):
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size_bits = 0
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for comp_name, comp_sizes in self.components:
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size_bits += comp_sizes[self.target_word_size]
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return size_bits
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def get(self):
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return self.attribute_based_property
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def set(self, value):
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raise AttributeError("set() shouldn't be called here!")
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def __init__(self, word_size_in_bits):
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self.word_size_in_bits = word_size_in_bits
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self.thestruct = []
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def _setup_attributes(self, allprops):
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# So Python sucks and you can only set properties on class objects,
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# not class instance objects. Hence this crud...
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class AI(object):
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pass
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for key in allprops:
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setattr(AI, key, allprops[key])
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self.ai = AI()
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def _setup_one(self, etypename, ename, args, offset, names, format):
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elementclass = getattr(self, etypename)
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elementinst = elementclass(self.word_size_in_bits, offset, names, format)
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elementinst.set_args(**args)
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self.thestruct.append(elementinst)
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def get_item(obj):
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return elementinst
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def set_item(obj, value):
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return elementinst.set(value)
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newprop = {'%s' % (ename): property(get_item, set_item)}
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return (elementinst.get_size_bits() / 8, newprop)
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def _setup_multiprop(self, ename, times):
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def mp_get(obj):
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return [getattr(self.ai, '%s_%s' % (ename, counter)) for counter in range(1, times+1)]
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def mp_set(obj, value):
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for num, item in enumerate(value):
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setattr(self.ai, '%s_%s' % (ename, num + 1), item)
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return {'%s' % (ename): property(mp_get, mp_set)}
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def setup(self, *elements):
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offset = 0
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allprops = {}
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for element in elements:
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etypename, ename = element[:2]
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args = {}
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if len(element) == 3:
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args = element[2]
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times = args.get('times', None)
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names = args.get('names', None)
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format = args.get('format', None)
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if names is not None:
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del args['names']
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if format is not None:
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del args['format']
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if times is not None:
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del args['times']
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for time in range(times):
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size, propdict = self._setup_one(etypename, '%s_%s' % (ename, time + 1), args, offset, names, format)
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offset += size
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allprops.update(propdict)
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allprops.update(self._setup_multiprop(ename, times))
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else:
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size, propdict = self._setup_one(etypename, ename, args, offset, names, format)
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offset += size
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allprops.update(propdict)
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self._setup_attributes(allprops)
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def struct_size(self):
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size = 0
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for element in self.thestruct:
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size += element.get_size_bits()
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return size / 8
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def set_poker(self, poker):
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self.poker = poker
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def write(self):
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for element in self.thestruct:
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element.write(self.poker)
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def read_from_poker(self, poker):
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self.set_poker(poker)
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for element in self.thestruct:
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element.read(self.poker)
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def write_new(self, filename):
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"""convenience function to create a new file and store the KCP in it. """
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newfile = GFile.create_new(filename, self.struct_size())
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poker = BitPoker('lsb') #FIXME
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poker.set_mmapfile(newfile.mapping, offset_bytes = 0)
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self.set_poker(poker)
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self.write()
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