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391 Brean 1
#include <Parser.h>
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/**
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 * create a frame that can be send to the MK using the
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 * connection class.
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 * see http://www.mikrokopter.com/ucwiki/en/SerialProtocol
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 * how the protocol is encoded and
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 * see http://www.mikrokopter.com/ucwiki/en/SerialCommands
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 * to look at the possible commands that are already coded
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 * in data
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 */
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void Parser::create_frame(char cmd, int address, char * data, unsigned int length) {
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        //if # is cmd we do not touch anything, because
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        // the command is already encoded in data
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        if (cmd != '#') {
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            /*
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            //calculate buffer length
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            //(4 Bytes for 1-byte '#', 1-byte address, and 2-byte crc)
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            //(the rest for the data length - see encode how this is calculated)
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            int buff_len = 4+(length/3 + (length%3==0?0:1) )*4;
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            //allociate memory for the data we want to send
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            char * send_data = (char *)malloc(buf_len);
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            */
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            char send_data[150];
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            send_data[0]='#';
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            send_data[1]=(char)address;
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            send_data[2]=cmd;
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            for (int i = 0; i < length; i++)
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                send_data[i+3] = data[i];
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            //TODO: abgleich mit MKCommunication::send_command
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            Parser::encode64(send_data, length);
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            address = 'a' + address;
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        }
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}
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/**
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 * Base64 Decoder
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 * see Parser.h for details about sRxData
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 * data = data that will be decoded
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 * len = length of data
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 * ptrOut = pointer to decoded data
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 * offset = offset in data
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 */
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int Parser::decode64(char * data, int len, unsigned char *ptrOut, int offset)
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{
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    unsigned char a,b,c,d;
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    unsigned char ptr = 0;
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    unsigned char x,y,z;
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    int decLen = 0;
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/*
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    //FIXME: dies wieder einklammern!
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    if (data[ptrIn] == 0) {
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        return -1;
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        //TODO: catch error to show that something went wrong during the decode process
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        //throw "Nothing received";
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    }
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*/
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    //decode data
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    while(len) {
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        a = data[offset++] - '=';
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        b = data[offset++] - '=';
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        c = data[offset++] - '=';
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        d = data[offset++] - '=';
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        //if(offset > max - 2) break;
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        x = (a << 2) | (b >> 4);
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        y = ((b & 0x0f) << 4) | (c >> 2);
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        z = ((c & 0x03) << 6) | d;
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        if(len--) ptrOut[ptr++] = x; else break;
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        if(len--) ptrOut[ptr++] = y; else break;
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        if(len--) ptrOut[ptr++] = z; else break;
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    }
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    //decoded data
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    unsigned char * decData;
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    for (int a=0; a<ptr; a++) {
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        if (len) {
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            decData[decLen] = ptrOut[a];
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            decLen++;
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        } else {
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            int b1, b2, b3;
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            b1 = ptrOut[a++];
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            b2 = ptrOut[a];
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            b3 = (b2 << 8) | b1;
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            if (b3 > 32767)
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                b3 = b3 - 65536;
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            decData[decLen] = b3;
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            decLen++;
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        }
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    }
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    ptrOut = decData;
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    return decLen;
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}
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/**
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 * base64 encoder
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 */
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void Parser::encode64(char data[150],unsigned int length)
391 Brean 108
{
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    unsigned int pt = 0;
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    unsigned char a,b,c;
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    unsigned char ptr = 0;
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    char tx_buff[150];
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    while(length > 0)
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    {
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        if(length) { a = data[ptr++]; length--;} else a = 0;
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        if(length) { b = data[ptr++]; length--;} else b = 0;
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        if(length) { c = data[ptr++]; length--;} else c = 0;
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        tx_buff[pt++] = '=' + (a >> 2);
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        tx_buff[pt++] = '=' + (((a & 0x03) << 4) | ((b & 0xf0) >> 4));
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        tx_buff[pt++] = '=' + (((b & 0x0f) << 2) | ((c & 0xc0) >> 6));
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        tx_buff[pt++] = '=' + ( c & 0x3f);
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    }
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    tx_buff[pt] = 0;
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    //move pointer of tx_buff to data
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    data = tx_buff;
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}
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// Datensatz nach 8bit Integer
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int Parser::dataToChar(int *data , int start, bool is_signed) {
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    int out = (data[start]);
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    if ((out > 128) && (is_signed))
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      out = out - 256;
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    return out;
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}
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/**
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 * received char to 8 bit integer
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 */
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int Parser::charToData(int data) {
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    if (data < 0)
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        return data + 256;
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    return data;
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}
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/**
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 * convert data to 16bit Integer
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 */
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int Parser::dataToInt(int *Data , int Start, bool is_signed)
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{
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    int Out = (Data[Start+1]<<8) | (Data[Start+0]);
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    if ((Out > 32767) && (is_signed))
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      Out = Out - 65536;
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    return Out;
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}
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/**
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 * convert data to 32bit Long
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 */
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long Parser::dataToLong(int *Data , int Start, bool is_signed)
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{
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    long Out = (Data[Start+3]<<24) | (Data[Start+2]<<16) | (Data[Start+1]<<8) | (Data[Start+0]);
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    if ((Out > 32767) && (is_signed))
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      Out = Out;
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    return Out;
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}
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float Parser::getFloat(long value, int count)
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{
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    long num = pow(10, count);
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    float temp = value;
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    return temp / num;
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}
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/**
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 * check CRC
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 */
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bool Parser::check_CRC(char * rx, int length)
391 Brean 191
{
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    int CRC = 0;
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449 Brean 194
    if (rx[1] == 127)
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    {
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        rx[1] = 0;
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    }
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    for(int i=0; i < length-2; i++)
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    {
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            CRC+=rx[i];
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    }
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    CRC = CRC % 4096;
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    if(rx[length - 2] != ('=' + (CRC / 64)))
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    {
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        return false;
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    }
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    if(rx[length - 1] != ('=' + CRC % 64))
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    {
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        return false;
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    }
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    return true;
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}
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/**
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 * create CRC and add it to tx
221
 */
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void Parser::add_CRC(char * tx, int length)
391 Brean 223
{
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    unsigned int tmpCRC = 0;
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226
    for(int i = 0; i < length; i++)
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    {
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        tmpCRC += tx[i];
391 Brean 229
    }
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    tmpCRC %= 4096;
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    tx[length-2] = '=' + tmpCRC / 64;
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    tx[length-1] = '=' + tmpCRC % 64;
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    tx[length] = '\0';
391 Brean 236
}
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