#include <stdio.h>

#include <windows.h>

#include <stdlib.h>                   

char FaultField[4] = {'P', 'C', 'B', 'U'};

char HexField[16] = {0x00, 0x01, 0x02, 0x03, 

                     0x04, 0x05, 0x06, 0x07, 

                     0x08, 0x09, 0x0A, 0x0B, 

                     0x0C, 0x0D, 0x0E, 0x0F};

char DTCType[4] = {'0', '1', '2', '3'};

//#define clear_buffer(buffer,SIZE) for (int i = 0; i < SIZE; i++) { buffer[i] = 0; }

void Hex2SAE(FILE* ipf, FILE* opf);

void SAE2Hex(FILE* ipf, FILE* opf);

int main(void) {

    FILE *ipf = fopen("SAE.txt" , "r");

    FILE *opf = fopen("hex.txt" , "w+");

    if (NULL == ipf) {

        printf("error! failed to open input file.\n");

        exit(EXIT_FAILURE);

    } else if (NULL == opf) {

        printf("error! failed to open output file.\n");

        exit(EXIT_FAILURE);

    }

    // Hex2SAE(ipf, opf);

    SAE2Hex(ipf, opf);

    fclose(ipf);

    fclose(opf);

    system("pause");         

    return 0;

}

void SAE2Hex(FILE* ipf, FILE* opf) {

    char buffer[9];

    char tmp[7] = {0};

    while (fgets(buffer, sizeof(buffer), ipf) != NULL) {

        for (int i = 2; i < 7; i++) {

                tmp[i-1] = buffer[i];

        }

        // Get DTCHighByte bit6_7 from SAE's FaultField

        char bit6_7 = 0x8;

        if (buffer[0] >= 97 && buffer[0] <= 102) {

            buffer[0] -= 32;

        }

        switch (buffer[0]) {

        case 'P': 

            bit6_7 = 0x0;

            break;

        case 'C':

            bit6_7 = 0x1;

            break;

        case 'B':

            bit6_7 = 0x2;

            break;

        case 'U':

            bit6_7 = 0x3;

            break;

        default:

            break;

        }

        // Get DTCHighByte bit4_5 from SAE's DTCType

        char bit4_5 = buffer[1] - 48;

        // Get DTCHighByte bit6_7 by merging bit6_7 and bit4_5

        char bit4_7 = 0;

        bit4_7 |= (bit6_7 & 0x03) << 2;

        bit4_7 |= (bit4_5 & 0x03);

        // Convert to ASCII

        if (bit4_7 >=0 && bit4_7 <= 9) {

            tmp[0] = bit4_7 + 48;

        } else if (bit4_7 >= 10 && bit4_7 <= 15) {

            tmp[0] = bit4_7 + 55;

        }

        tmp[6] = '\n';

        // clear buffer

        for (int i = 0; i < sizeof(buffer); i++) {

                buffer[i] = 0;  

        }

        fputs(tmp, opf);        

    }

    // return 0;

}

void Hex2SAE(FILE* ipf, FILE* opf) {

    char buffer[8];

    char tmp[8] = {0};

    while (fgets(buffer, sizeof(buffer), ipf) != NULL) {

        for (int i = 0; i < 6; i++) {

                tmp[i+1] = buffer[i];

        }

        // Get bit 4~7 from DTCHighByte

        char bit4_7 = tmp[1];

        // '0' ~ '9'

        if (bit4_7 >= 48 && bit4_7 <= 57) {

                bit4_7 -= 48;

        // 'A' ~ 'F'

        } else if (bit4_7 >= 65 && bit4_7 <= 70) {

                bit4_7 -= 55;

        // 'a' ~ 'f'

        } else if (bit4_7 >= 97 && bit4_7 <= 102) {

                bit4_7 -= 87;

        }

        bit4_7 = HexField[bit4_7];

        // Caluate Fault Field from DTCHighByte bit 6~7 and

        // DTC Type from DTCHighByte bit 4~5

        char bit6_7 = (bit4_7 & 0x0C) >> 2;

        tmp[0] = FaultField[bit6_7];

        char bit4_5 = bit4_7 & 0x03;

        tmp[1] = DTCType[bit4_5];

        tmp[7] = '\n';

        // clear buffer

        for (int i = 0; i < sizeof(buffer); i++) {

                buffer[i] = 0;  

        }

        fputs(tmp, opf);        

    }

    // return 0;

}