Packet.cpp

#include "Packet.h"
#include <string.h>
#include <stdio.h>

Packet::Packet()
{
}

Packet::Packet(unsigned char *Frame,int Len)
{
    SetPacketFromFrame(Frame,Len);
}

Packet::~Packet()
{
}

int Packet::SetPacketFromFrame(unsigned char *Frame,int Len)
{
    Reset();
    crc8=Frame[Len-1];
    if(computecrc_8(0x00,Frame, Len-1)==crc8) IsValid=true;

    ID1=(Frame[0]<<24)|(Frame[1]<<16)|(Frame[2]<<8)|(Frame[3]);
    Sequence=Frame[4]&0x1F;
    Type=(Frame[4]>>5);
    PacketLen=Len-1-5;
    memcpy(Body,Frame+5,PacketLen);
    clock_gettime(CLOCK_REALTIME, &arrival_time);
    return 0;
}

/**
 * \file
 * Functions and types for CRC checks.
 *
 * Generated on Thu Oct 12 16:51:00 2017
 * by pycrc v0.9.1, https://pycrc.org
 * using the configuration:
 *  - Width         = 8
 *  - Poly          = 0x07
 *  - XorIn         = 0x00
 *  - ReflectIn     = False
 *  - XorOut        = 0x00
 *  - ReflectOut    = False
 *  - Algorithm     = table-driven
 */

static const unsigned char crc_table[256] = {
    0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15, 0x38, 0x3f, 0x36, 0x31, 0x24, 0x23, 0x2a, 0x2d,
    0x70, 0x77, 0x7e, 0x79, 0x6c, 0x6b, 0x62, 0x65, 0x48, 0x4f, 0x46, 0x41, 0x54, 0x53, 0x5a, 0x5d,
    0xe0, 0xe7, 0xee, 0xe9, 0xfc, 0xfb, 0xf2, 0xf5, 0xd8, 0xdf, 0xd6, 0xd1, 0xc4, 0xc3, 0xca, 0xcd,
    0x90, 0x97, 0x9e, 0x99, 0x8c, 0x8b, 0x82, 0x85, 0xa8, 0xaf, 0xa6, 0xa1, 0xb4, 0xb3, 0xba, 0xbd,
    0xc7, 0xc0, 0xc9, 0xce, 0xdb, 0xdc, 0xd5, 0xd2, 0xff, 0xf8, 0xf1, 0xf6, 0xe3, 0xe4, 0xed, 0xea,
    0xb7, 0xb0, 0xb9, 0xbe, 0xab, 0xac, 0xa5, 0xa2, 0x8f, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9d, 0x9a,
    0x27, 0x20, 0x29, 0x2e, 0x3b, 0x3c, 0x35, 0x32, 0x1f, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0d, 0x0a,
    0x57, 0x50, 0x59, 0x5e, 0x4b, 0x4c, 0x45, 0x42, 0x6f, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7d, 0x7a,
    0x89, 0x8e, 0x87, 0x80, 0x95, 0x92, 0x9b, 0x9c, 0xb1, 0xb6, 0xbf, 0xb8, 0xad, 0xaa, 0xa3, 0xa4,
    0xf9, 0xfe, 0xf7, 0xf0, 0xe5, 0xe2, 0xeb, 0xec, 0xc1, 0xc6, 0xcf, 0xc8, 0xdd, 0xda, 0xd3, 0xd4,
    0x69, 0x6e, 0x67, 0x60, 0x75, 0x72, 0x7b, 0x7c, 0x51, 0x56, 0x5f, 0x58, 0x4d, 0x4a, 0x43, 0x44,
    0x19, 0x1e, 0x17, 0x10, 0x05, 0x02, 0x0b, 0x0c, 0x21, 0x26, 0x2f, 0x28, 0x3d, 0x3a, 0x33, 0x34,
    0x4e, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5c, 0x5b, 0x76, 0x71, 0x78, 0x7f, 0x6a, 0x6d, 0x64, 0x63,
    0x3e, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2c, 0x2b, 0x06, 0x01, 0x08, 0x0f, 0x1a, 0x1d, 0x14, 0x13,
    0xae, 0xa9, 0xa0, 0xa7, 0xb2, 0xb5, 0xbc, 0xbb, 0x96, 0x91, 0x98, 0x9f, 0x8a, 0x8d, 0x84, 0x83,
    0xde, 0xd9, 0xd0, 0xd7, 0xc2, 0xc5, 0xcc, 0xcb, 0xe6, 0xe1, 0xe8, 0xef, 0xfa, 0xfd, 0xf4, 0xf3
};


unsigned char Packet::computecrc_8(unsigned char crc, const void *data, int data_len)
{
    const unsigned char *d = (const unsigned char *)data;
    unsigned int tbl_idx;

    while (data_len--) {
        tbl_idx = crc ^ *d;
        crc = crc_table[tbl_idx] & 0xff;
        d++;
    }
    return crc & 0xff;
};

void Packet::PrintState()
{
    fprintf(stderr,"Packet Layer(%ld.%ld):",arrival_time.tv_sec,arrival_time.tv_nsec/(int)1e6);    
    switch(Type)
    {
       case PDM:fprintf(stderr,"PDM ");break;
       case POD:fprintf(stderr,"POD ");break;
       case ACK:fprintf(stderr,"ACK ");break;
       case CON:fprintf(stderr,"CON ");break;
       default:fprintf(stderr,"UNKOWN ");break;         
    } 
 
    fprintf(stderr,"ID1:%08x ",ID1);
    fprintf(stderr,"Seq:%d PktLen:%d crc8:%x",Sequence,PacketLen,crc8);
    if(IsValid) fprintf(stderr,"(OK)"); else fprintf(stderr,"(KO)");
    for(int i=0;i<PacketLen;i++) fprintf(stderr,"%02x",Body[i]);
    fprintf(stderr,"\n");
}

int Packet::GetFrame(unsigned char *Frame)
{
    int FrameLen=0;
    // Physical address
    Frame[0]=ID1>>24;
    Frame[1]=ID1>>16;
    Frame[2]=ID1>>8;
    Frame[3]=ID1&0xFF; 
    Frame[4]=(Type<<5)|(Sequence&0x1F);
    memcpy(Frame+5,Body,PacketLen);
    FrameLen=PacketLen+5;
    Frame[FrameLen]=computecrc_8(0,Frame,FrameLen);
    FrameLen++;
    return FrameLen;
    
}

void Packet::Reset()
{
   ID1=0;
   Type=0;
   Sequence=0;
   PacketLen=0;
   crc8=0;
  IsValid=false;
}