/*####COPYRIGHTBEGIN####
 -------------------------------------------
 Copyright (C) 2012 Steve Karg

 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.
 59 Temple Place - Suite 330
 Boston, MA  02111-1307
 USA.

 As a special exception, if other files instantiate templates or
 use macros or inline functions from this file, or you compile
 this file and link it with other works to produce a work based
 on this file, this file does not by itself cause the resulting
 work to be covered by the GNU General Public License. However
 the source code for this file must still be made available in
 accordance with section (3) of the GNU General Public License.

 This exception does not invalidate any other reasons why a work
 based on this file might be covered by the GNU General Public
 License.
 -------------------------------------------
####COPYRIGHTEND####*/
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
/* local includes */
#include "crc.h"
#include "version.h"

#ifndef max
#define max(a,b) (((a) (b)) ? (a) : (b))
#define min(a,b) (((a) < (b)) ? (a) : (b))
#endif

/* buffer needed by CRC functions */
static uint8_t CRC_Buffer[1512];
static unsigned CRC_Buffer_Len = 0;
/* flags needed for options */
static bool ASCII_Decimal = false;
static unsigned CRC_Size = 8;

/******************************************************************
* DESCRIPTION:  Takes one of the arguments passed by the main function
*               and sets flags if it matches one of the predefined args.
* PARAMETERS:   argc (IN) number of arguments.
*               argv (IN) an array of arguments in string form.
* RETURN:       number of arguments parsed
* NOTES:        none
******************************************************************/
static void Parse_Arguments(int argc, char *argv[])
{
    int i = 0;
    long long_value = 0;

    for (i=1;i<argc;i++) {
        if (argv[i][0] == '-') {
            /* numeric arguments */
            if (isdigit(argv[i][1])) {
                long_value = strtol(&argv[i][1], NULL, 10);
                /* dash arguments */
                switch(long_value) {
                    case 8:
                        CRC_Size = 8;
                        break;
                    case 16:
                        CRC_Size = 16;
                        break;
                    case 32:
                        CRC_Size = 32;
                        break;
                    default:
                        break;
                }
            }
            /* dash arguments */
            switch(argv[i][1]) {
                case 'h':
                case 'H':
                    ASCII_Decimal = false;
                    break;
                case 'd':
                case 'D':
                    ASCII_Decimal = true;
                    break;
                default:
                    break;
            }
        } else {
            /* should be number values here */
            if (ASCII_Decimal) {
                long_value = strtol(argv[i], NULL, 10);
            } else {
                long_value = strtol(argv[i], NULL, 16);
            }
            CRC_Buffer[CRC_Buffer_Len] = (uint8_t)long_value;
            CRC_Buffer_Len++;
        }
    }
}

/* simple program to CRC the data and print the CRC */
int main(
    int argc,
    char *argv[])
{
    /* accumulates the crc value */
    uint8_t crc8 = 0xff;
    uint16_t crc16 = 0xffff;
    unsigned i = 0;

    /* initialize our interface */
    if ((argc > 1) && (strcmp(argv[1], "--help") == 0)) {
        printf("mstpcrc [options] <00 00 00 00...>\r\n"
            "perform MS/TP CRC on data bytes.\r\n"
            "options:\r\n"
            "[-x] interprete the arguments as ascii hex (default)\r\n"
            "[-d] interprete the argument as ascii decimal\r\n"
            "[-8] calculate the MS/TP 8-bit Header CRC (default)\r\n"
            "[-16] calculate the MS/TP 16-bit Data CRC\r\n"
            "[-32] calculate the MS/TP 32-bit Extended Frame CRC\r\n");
        return 0;
    }
    if ((argc > 1) && (strcmp(argv[1], "--version") == 0)) {
        printf("mstpcap %s\r\n", BACNET_VERSION_TEXT);
        printf("Copyright (C) 2012 by Steve Karg\r\n"
            "This is free software; see the source for copying conditions.\r\n"
            "There is NO warranty; not even for MERCHANTABILITY or\r\n"
            "FITNESS FOR A PARTICULAR PURPOSE.\r\n");
        return 0;
    }
    Parse_Arguments(argc, argv);
    if (CRC_Buffer_Len) {
        for (i = 0; i < CRC_Buffer_Len; i++) {
            if (CRC_Size == 8) {
                crc8 = CRC_Calc_Header(CRC_Buffer[i], crc8);
            } else if (CRC_Size == 16) {
                crc16 = CRC_Calc_Data(CRC_Buffer[i], crc16);
            }
            if (ASCII_Decimal) {
                printf("%u\r\n", (unsigned)CRC_Buffer[i]);
            } else {
                printf("0x%02X\r\n", CRC_Buffer[i]);
            }
        }
        if (CRC_Size == 8) {
            crc8 = ~crc8;
            if (ASCII_Decimal) {
                printf("%u Header CRC\r\n", (unsigned)crc8);
            } else {
                printf("0x%02X Header CRC\r\n", crc8);
            }
        } else if (CRC_Size == 16) {
            crc16 = ~crc16;
            if (ASCII_Decimal) {
                printf("%u Data CRC\r\n", (unsigned)(crc16 & 0xFF));
                printf("%u Data CRC\r\n", (unsigned)(crc16 >> 8));
            } else {
                printf("0x%02X Data CRC\r\n", (crc16 & 0xFF));
                printf("0x%02X Data CRC\r\n", (crc16 >> 8));
            }
        }
    }

    return 1;
}