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# -*- coding: utf-8 -*-
#
# AWL simulator - data structs
#
# Copyright 2013 Michael Buesch <m@bues.ch>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
from awlsim.util import *
from awlsim.datatypes import *
class AwlStructField(object):
"Data structure field"
# name => Field name string
# offset => Field offset as AwlOffset
# dataType => AwlDataType
# initialValue => The initilization value
def __init__(self, name, offset, dataType, initialValue=0):
self.name = name
self.offset = offset
self.dataType = dataType
self.initialValue = initialValue
# Store a copy of the data type size, in bits and bytes.
self.bitSize = self.dataType.width
self.byteSize = intDivRoundUp(self.bitSize, 8)
assert(self.bitSize in (1, 8, 16, 32, 64))
class AwlStruct(object):
"Data structure"
def __init__(self):
self.fields = []
self.name2field = {}
# Return size, in bytes.
def getSize(self):
if not self.fields:
return 0
lastField = self.fields[-1]
return lastField.offset.byteOffset + lastField.byteSize
def addField(self, name, dataType):
if dataType.width == 1 and self.fields and\
self.fields[-1].bitSize == 1 and\
self.fields[-1].offset.bitOffset < 7:
# Consecutive bitfields are merged into one byte
offset = AwlOffset(self.fields[-1].offset.byteOffset,
self.fields[-1].offset.bitOffset + 1)
else:
offset = AwlOffset(self.getSize())
field = AwlStructField(name, offset, dataType)
self.fields.append(field)
if name:
self.name2field[name] = field
def addFieldAligned(self, name, dataType, byteAlignment):
padding = byteAlignment - self.getSize() % byteAlignment
if padding == byteAlignment:
padding = 0
while padding:
self.addField(None, AwlDataType.makeByName("BYTE"))
padding -= 1
self.addField(name, dataType)
def addFieldNaturallyAligned(self, name, dataType):
alignment = 1
if dataType.width > 8:
alignment = 2
self.addFieldAligned(name, dataType, alignment)
def getField(self, name):
try:
return self.name2field[name]
except KeyError:
raise AwlSimError("Data structure field '%s' not found" % name)
class AwlStructInstance(object):
"Data structure instance"
def __init__(self, struct):
self.struct = struct
self.__allocate()
def __allocate(self):
# Calculate the size of the data structure, in bytes
size = sum(field.byteSize for field in self.struct.fields)
# Allocate the structure
self.dataBytes = ByteArray(size)
# Initialize the structure
offset = 0
for field in self.struct.fields:
bsize = field.byteSize
value = field.initialValue
for i in range(field.byteSize):
b = (value >> ((bsize - i - 1) * 8)) & 0xFF
self.dataBytes[offset + i] = b
offset += bsize
def getFieldData(self, field):
return self.dataBytes.fetch(field.offset, field.bitSize)
def setFieldData(self, field, value):
self.dataBytes.store(field.offset, field.bitSize, value)
def getFieldDataByName(self, name):
return self.getFieldData(self.struct.getField(name))
def setFieldDataByName(self, name, value):
self.setFieldData(self.struct.getField(name), value)
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