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");
}
}
}
[---------------------------------------------------------------------]
/**************************************************************************
*
* Copyright (C) 2006 Steve Karg <skarg@users.sourceforge.net>
* Copyright (C) 2017 Mario de Sousa <msousa@fe.up.pt>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*********************************************************************/
#ifndef SERVER_H_
#define SERVER_H_
#include <stddef.h>
#include <stdint.h>
typedef struct{
const char *location;
const char *network_interface;
const char *port_number;
const char *device_name;
const char *comm_control_passwd;
uint32_t device_id; // device ID is 22 bits long! uint16_t is not enough!
int init_state; // store how far along the server's initialization has progressed
pthread_t thread_id; // thread handling this server
} server_node_t;
/*initialization following all parameters given by user in application*/
static server_node_t server_node = {
"%(locstr)s",
"%(network_interface)s", // interface (NULL => use default (eth0))
"%(port_number)s", // Port number (NULL => use default)
"%(BACnet_Device_Name)s", // BACnet server's device (object) name
"%(BACnet_Comm_Control_Password)s",// BACnet server's device (object) name
%(BACnet_Device_ID)s // BACnet server's device (object) ID
};
#endif /* SERVER_H_ */