tapplot.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <stdlib.h>
#include <sys/shm.h> //For generating keys in
#include <semaphore.h>
#include <string.h> //For string compare
#include <stdbool.h>
#include <string.h>
#include <ctype.h>
#define MAX_DATA_LENGTH 20 //Length of the Data name=Value / max length of name / max length of Value
#define MAX_PAIRS_PER_SAMPLE 10 //The maximum number of sample Data
#define MAX_NUM_OF_SAMPLES 500
#define MAX_UNIQUE_NAMES 10
#define MAX_SLOT_LENGTH 1000//Max lenght of each slot of the buffer
int prev = 0;


//Struct that stores parsed data
typedef struct
{
    char name[MAX_DATA_LENGTH];
    char value[MAX_DATA_LENGTH];
}NameValuePair;

//SampleData (contains a list of NameValuePairs) For each sample can hold up to 50 NameValPair
typedef struct
{
    NameValuePair sample[MAX_PAIRS_PER_SAMPLE];
    int numOfNameValuePair;
}sampleData;

typedef enum {bit0=0, bit1=1} bit;


typedef struct
{
  bit latest;
  bit reading;
  bit slot[2];
  sem_t filledSlots;
  sem_t emptySlots;
  int head;
  int tail;
  int bufferSize;
  char buffer[];
}ringBuffer;


//Read from Process 2
char *readFromBuffer(ringBuffer *rb)
{    
    sem_wait(&rb->filledSlots);
    char *source = (char *)(rb->buffer + rb->head*MAX_SLOT_LENGTH);
    //printf("Reading: %s\n", source);
    rb->head = ((rb->head+1) % rb->bufferSize);  
    sem_post(&rb->emptySlots);
    //sleep(1);
    return source;
}

char *bufread(ringBuffer *sb)
{
  bit pair, index;
  pair = sb->latest;
  sb->reading = pair;
  index = sb->slot[pair];
  char *item = "";
  if (prev != 2*pair + index)
  {
    item = (sb->buffer + 2*pair*MAX_SLOT_LENGTH + index*MAX_SLOT_LENGTH);
    //printf("Reading in PROCESS 3: %s\n", item);
    //printf("Index: %d, Value: %s\n", 2*pair*MAX_SLOT_LENGTH + index*MAX_SLOT_LENGTH, item);
    prev = 2*pair + index;
  }
  usleep(50000);
  return (item);
}

NameValuePair parseSampleDataStr(char *sampleData, int argn)
{
    NameValuePair eofCheck;
    if(strcmp(sampleData, "EOF")==0)
    {
        strncpy(eofCheck.name, "EOF", MAX_DATA_LENGTH);
        return eofCheck;
    }

    if (strcmp(sampleData, "")==0)
      {
strncpy(eofCheck.name, "", MAX_DATA_LENGTH);
        return eofCheck;
      }

    int whichNameValuePair = 1;
    char *subString;

    while(subString = strtok_r(sampleData ,",", &sampleData))
    {
        //If its the nameValuePair we care about
        //We create the nameValuePair and return it
        if(whichNameValuePair == argn)
        {
            NameValuePair tempNVP;
            char *name = strtok(subString, "=");
            char *value = strtok(NULL, "=");
            strncpy(tempNVP.name, name, MAX_DATA_LENGTH);
            strncpy(tempNVP.value, value, MAX_DATA_LENGTH);
            return tempNVP;
        }
        else{
            whichNameValuePair++;
        }
    }
}

int main(int argc, char *argv[])
{
  //printf("In process 3\n");
    int p2P3shmid = atoi(argv[1]);  
    int argn = atoi(argv[2]);
    char *sync = argv[3];
    void *test = shmat(p2P3shmid, NULL, 0);  
    if(test == (void *)-1)
       printf("There is an error with shmid");
    ringBuffer * sbP2P3;
    ringBuffer * rbP2P3;

    if (strcmp(sync, "async") == 0)
      {
         sbP2P3 = (ringBuffer *)test;
      }
    else
      {
        rbP2P3 = (ringBuffer *)test;
      }

    //Create/Open the file in append mode
    FILE *file = fopen("dataFile.txt", "w");
    if(file == NULL)
    {
        perror("Error creating/opening the file");
        return 1;
    }

    int x = 1;  //This is sampleNumber
    while(true)
    {
        NameValuePair tempNVP;
        if (strcmp(sync, "async") == 0)
        {
            tempNVP = parseSampleDataStr(bufread(sbP2P3), argn);
        }
        else
        {
            tempNVP = parseSampleDataStr(readFromBuffer(rbP2P3), argn);
        }

        if (strcmp(tempNVP.name, "")!=0)
        {
        //Exit the loop as soon as we reach a EOF signal
        if(strcmp(tempNVP.name, "EOF") == 0)
        break;
            
        fprintf(file, "%d %s\n", x, tempNVP.value);
        fflush(file);

        if (x==1)
        {
            system("gnuplot 'live_plot.gp' &"); //Allows for gnuplot to run in the background
        }
        x++;
        }
    }
 
    fclose(file);
    return 0;
}