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#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';
}