beremiz

use pregenerated CRC32 lookup tables for retain on Win32 and GNU/Linux

2019-01-06, Andrey Skvortsov
68f4f2d4516b
use pregenerated CRC32 lookup tables for retain on Win32 and GNU/Linux

This code could be possible reused on low-end targets with limited RAM.

code to generate lookup table:
[---------------------------------------------------------------------]

/* CRC lookup table and initial state. */
uint32_t crc32_table[256];

/* Generate CRC32 lookup table. */
void GenerateCRC32Table(void)
{
unsigned int i, j;
/* Use CRC-32-IEEE 802.3 polynomial 0x04C11DB7 (bit reflected). */
uint32_t poly = 0xEDB88320;

for (i = 0; i <= 0xFF; i++)
{
uint32_t c = i;
for (j = 0 ; j < 8 ; j++)
c = (c & 1) ? (c >> 1 ) ^ poly : (c >> 1);
crc32_table[i] = c;
}
}

void main(void)
{
GenerateCRC32Table();
int j=0;
for(int i=0; i<256; i++) {
printf("0x%08X, ", crc32_table[i]);
if (++j >= 8) {
j = 0;
printf("\n");
}
}
}
[---------------------------------------------------------------------]
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# This file is part of Beremiz, a Integrated Development Environment for
# programming IEC 61131-3 automates supporting plcopen standard and CanFestival.
#
# Copyright (C) 2017: Andrey Skvortsov
#
# See COPYING file for copyrights details.
#
# 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 __future__ import absolute_import
import wx
import wx.lib.intctrl
class CustomIntUpdatedEvent(wx.PyCommandEvent):
def __init__(self, id, value=0, object=None):
wx.PyCommandEvent.__init__(self, CustomIntCtrl.wxEVT_COMMAND_CUSTOM_INT_UPDATED, id)
self.__value = value
self.SetEventObject(object)
def GetValue(self):
"""Retrieve the value of the control at the time
this event was generated."""
return self.__value
class CustomIntCtrl(wx.lib.intctrl.IntCtrl):
"""
This class provides a control that takes and returns long as
value, and provides bounds support and optional value limiting.
It handles entering negative numbers more user-friendly than
original wx.lib.intctrl.IntCtrl.
It applies limits as focus is changed to other control and
sends event afterwards to signal that editing is done.
"""
# Used to trap events indicating that the current
# integer value of the control has been changed.
wxEVT_COMMAND_CUSTOM_INT_UPDATED = wx.NewEventType()
EVT_CUSTOM_INT = wx.PyEventBinder(wxEVT_COMMAND_CUSTOM_INT_UPDATED, 1)
def __init__(self, *args, **kwargs):
wx.lib.intctrl.IntCtrl.__init__(self, *args, **kwargs)
self.Bind(wx.EVT_KILL_FOCUS, self.UpdateValue)
self.SetLongAllowed(True)
self.SetLimited(False)
def GetValue(self):
"""
Returns integer (long) value of the control,
but handles entering negative numbers
"""
s = wx.TextCtrl.GetValue(self)
if s == '-':
s = ''
return self._fromGUI(s)
def GetValueStr(self):
"""Returns string value of TextCtrl"""
return wx.TextCtrl.GetValue(self)
def UpdateValue(self, event):
self.SetLimited(True)
self.SetLimited(False)
try:
self.GetEventHandler().ProcessEvent(
CustomIntUpdatedEvent(self.GetId(), self.GetValue(), self))
except ValueError:
return
event.Skip()