Subversion Repositories Projects

#include <Parser.h>

/**

 * create a frame that can be send to the MK using the

 * connection class.

 * see http://www.mikrokopter.com/ucwiki/en/SerialProtocol

 * how the protocol is encoded and

 * see http://www.mikrokopter.com/ucwiki/en/SerialCommands

 * to look at the possible commands that are already coded

 * in data

 */

void Parser::create_frame(char cmd, int address, char * data, unsigned int length) {

    //if # is cmd we do not touch anything, because

    // the command is already encoded in data

    if (cmd != '#') {

        /*

        //calculate buffer length

        //(4 Bytes for 1-byte '#', 1-byte address, and 2-byte crc)

        //(the rest for the data length - see encode how this is calculated)

        int buff_len = 4+(length/3 + (length%3==0?0:1) )*4;

        //allociate memory for the data we want to send

        char * send_data = (char *)malloc(buf_len);

        */

        Parser::encode64(data, length);

        char send_data[150];

        send_data[0]='#';

        send_data[1]=(char)address+'a';

        send_data[2]=cmd;

        for (int i = 0; i < length; i++)

            send_data[i+3] = data[i];

        add_CRC(send_data, length+3);

        data = send_data;

    }

}

/**

 * Base64 Decoder

 * see Parser.h for details about sRxData

 * data = data that will be decoded

 * len = length of data

 * ptrOut = pointer to decoded data

 * offset = offset in data

 */

int Parser::decode64(char * data, int len, unsigned char *ptrOut, int offset)

{

    unsigned char a,b,c,d;

    unsigned char ptr = 0;

    unsigned char x,y,z;

    int decLen = 0;

/*

    //FIXME: dies wieder einklammern!

    if (data[ptrIn] == 0) {

        return -1;

        //TODO: catch error to show that something went wrong during the decode process

        //throw "Nothing received";

    }

*/

    //decode data

    while(len) {

        a = data[offset++] - '=';

        b = data[offset++] - '=';

        c = data[offset++] - '=';

        d = data[offset++] - '=';

        //if(offset > max - 2) break;

        x = (a << 2) | (b >> 4);

        y = ((b & 0x0f) << 4) | (c >> 2);

        z = ((c & 0x03) << 6) | d;

        if(len--) ptrOut[ptr++] = x; else break;

        if(len--) ptrOut[ptr++] = y; else break;

        if(len--) ptrOut[ptr++] = z; else break;

    }

    //decoded data

    unsigned char * decData;

    for (int a=0; a<ptr; a++) {

        if (len) {

            decData[decLen] = ptrOut[a];

            decLen++;

        } else {

            int b1, b2, b3;

            b1 = ptrOut[a++];

            b2 = ptrOut[a];

            b3 = (b2 << 8) | b1;

            if (b3 > 32767)

                b3 = b3 - 65536;

            decData[decLen] = b3;

            decLen++;

        }

    }

    ptrOut = decData;

    return decLen;

}

/**

 * base64 encoder

 */

void Parser::encode64(char data[150],unsigned int length)

{

    unsigned int pt = 0;

    unsigned char a,b,c;

    unsigned char ptr = 0;

    char tx_buff[150];

    while(length > 0)

    {

        if(length) { a = data[ptr++]; length--;} else a = 0;

        if(length) { b = data[ptr++]; length--;} else b = 0;

        if(length) { c = data[ptr++]; length--;} else c = 0;

        tx_buff[pt++] = '=' + (a >> 2);

        tx_buff[pt++] = '=' + (((a & 0x03) << 4) | ((b & 0xf0) >> 4));

        tx_buff[pt++] = '=' + (((b & 0x0f) << 2) | ((c & 0xc0) >> 6));

        tx_buff[pt++] = '=' + ( c & 0x3f);

    }

    tx_buff[pt] = 0;

    //move pointer of tx_buff to data

    data = tx_buff;

}

// Datensatz nach 8bit Integer

int Parser::dataToChar(char *data , int start, bool is_signed) {

    int out = (data[start]);

    if ((out > 128) && (is_signed))

      out = out - 256;

    return out;

}

/**

 * received char to 8 bit integer

 */

int Parser::charToData(int data) {

    if (data < 0)

        return data + 256;

    return data;

}

/**

 * convert data to 16bit Integer

 */

int Parser::dataToInt(char *Data , int Start, bool is_signed)

{

    int Out = (Data[Start+1]<<8) | (Data[Start+0]);

    if ((Out > 32767) && (is_signed))

      Out = Out - 65536;

    return Out;

}

/**

 * convert data to 32bit Long

 */

long Parser::dataToLong(char *Data , int Start, bool is_signed)

{

    long Out = (Data[Start+3]<<24) | (Data[Start+2]<<16) | (Data[Start+1]<<8) | (Data[Start+0]);

    if ((Out > 32767) && (is_signed))

      Out = Out;

    return Out;

}

std::string Parser::dataToString(char * data, int start, int end)

{

    char tmp[MAX_DATA_SIZE];

    for (int i = start; i < end; i++)

        tmp[i-start] = data[i];

    return std::string(tmp);

}

float Parser::getFloat(long value, int count)

{

    long num = pow(10, count);

    float temp = value;

    return temp / num;

}

/**

 * check CRC

 */

bool Parser::check_CRC(char * rx, int length)

{

    int CRC = 0;

    if (rx[1] == 127)

    {

        rx[1] = 0;

    }

    for(int i=0; i < length-2; i++)

    {

            CRC+=rx[i];

    }

    CRC = CRC % 4096;

    if(rx[length - 2] != ('=' + (CRC / 64)))

    {

        return false;

    }

    if(rx[length - 1] != ('=' + CRC % 64))

    {

        return false;

    }

    return true;

}

/**

 * create CRC and add it to tx

 */

void Parser::add_CRC(char * tx, int length)

{

    unsigned int tmpCRC = 0;

    for(int i = 0; i < length; i++)

    {

        tmpCRC += tx[i];

    }

    tmpCRC %= 4096;

    tx[length] = '=' + tmpCRC / 64;

    tx[length+1] = '=' + tmpCRC % 64;

    tx[length+2] = '\0';

}