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#include <SimplePacket.h>
#include <avr/io.h>
SimplePacket::SimplePacket(txFuncPtr myPtr)
{
txFunc = myPtr;
init();
}
void SimplePacket::init()
{
//zero out our data arrays.
for (rx_length = 0; rx_length < MAX_PACKET_LENGTH; rx_length++)
rx_data[rx_length] = 0;
for (tx_length = 0; tx_length < MAX_PACKET_LENGTH; tx_length++)
tx_data[tx_length] = 0;
//init our other variables.
state = PS_START;
response_code = RC_OK;
target_length = 0;
rx_length = 0;
rx_crc = 0;
tx_length = 0;
tx_crc = 0;
}
//process a byte from our packet
void SimplePacket::process_byte(uint8_t b)
{
if (state == PS_START) // process start byte
{
//cool! its the start of a packet.
if (b == START_BYTE)
{
init();
state = PS_LEN;
}
else
{
// throw an error message?
// nah, ignore it as garbage.
// FIXME: Consider reporting such error in a special debug mode
}
}
else if (state == PS_LEN) // process length byte
{
target_length = b;
rx_length = 0;
state = PS_PAYLOAD;
if (target_length > MAX_PACKET_LENGTH)
response_code = RC_PACKET_TOO_BIG;
}
else if (state == PS_PAYLOAD) // process payload byte
{
//just keep reading bytes while we got them.
if (rx_length < target_length)
{
//keep track of CRC.
rx_crc = _crc_ibutton_update(rx_crc, b);
//will it fit?
if (rx_length < MAX_PACKET_LENGTH)
rx_data[rx_length] = b;
//keep track.
rx_length++;
}
//are we done?
if (rx_length >= target_length)
state = PS_CRC;
}
else if (state == PS_CRC) // check crc
{
// did the packet check out?
if (rx_crc != b)
response_code = RC_CRC_MISMATCH;
//okay, the packet is done.
state = PS_LAST;
}
}
bool SimplePacket::isFinished()
{
return (state == PS_LAST);
}
uint8_t SimplePacket::getLength()
{
return rx_length;
}
PacketState SimplePacket::getState()
{
return state;
}
ResponseCode SimplePacket::getResponseCode()
{
return response_code;
}
void SimplePacket::unsupported()
{
response_code = RC_CMD_UNSUPPORTED;
}
void SimplePacket::overflow()
{
response_code = RC_BUFFER_OVERFLOW;
}
void SimplePacket::sendReply()
{
//initialize our response CRC
tx_crc = 0;
tx_crc = _crc_ibutton_update(tx_crc, response_code);
//actually send our response.
transmit(START_BYTE);
transmit(tx_length+1);
transmit(response_code);
//loop through our reply packet payload and send it.
for (uint8_t i=0; i<tx_length; i++)
{
transmit(tx_data[i]);
tx_crc = _crc_ibutton_update(tx_crc, tx_data[i]);
}
//okay, send our CRC.
transmit(tx_crc);
//okay, now reset.
init();
}
void SimplePacket::sendPacket()
{
tx_crc = 0;
transmit(START_BYTE);
transmit(tx_length);
//loop through our reply packet payload and send it.
for (uint8_t i=0; i<tx_length; i++)
{
transmit(tx_data[i]);
tx_crc = _crc_ibutton_update(tx_crc, tx_data[i]);
}
//okay, send our CRC.
transmit(tx_crc);
}
void SimplePacket::transmit(uint8_t d)
{
txFunc(d);
}
//add a four byte chunk of data to our reply
void SimplePacket::add_32(uint32_t d)
{
add_16(d);
add_16(d >> 16);
}
//add a two byte chunk of data to our reply
void SimplePacket::add_16(uint16_t d)
{
add_8(d & 0xff);
add_8(d >> 8);
}
//add a byte to our reply.
void SimplePacket::add_8(uint8_t d)
{
//only add it if it will fit.
if (tx_length < MAX_PACKET_LENGTH)
tx_data[tx_length++] = d;
}
uint8_t SimplePacket::get_8(uint8_t idx)
{
return rx_data[idx];
}
uint16_t SimplePacket::get_16(uint8_t idx)
{
return (((int16_t)get_8(idx+1)) << 8) | get_8(idx);
}
uint32_t SimplePacket::get_32(uint8_t idx)
{
return (((uint32_t)get_16(idx+2)) << 16) | get_16(idx);
}
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