cyclicRead.c

#include <stdio.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdbool.h>
#include <unistd.h>
#include "cyclicBuf.h"
#include "gen.h"
int main()
{
	int shmFd = shm_open( "shared_buffer", O_RDONLY, 0 );
	
	if( shmFd == -1 )
	{
		perror("Can't open file");
		return 1;
	}
	struct cyclic_buf* mem = mmap( NULL, sizeof(struct cyclic_buf), PROT_READ, MAP_SHARED, shmFd, 0 );
	if( mem == NULL )
	{
		perror("Can't mmap");
		return -1;
	}	

	uint64_t cur_pos = mem -> pos;
	if(cur_pos == 0){
		cur_pos = 1;
	}
	uint64_t prev_seed = verify((void *)mem->BUFFER[cur_pos % 1000 - 1].arr); //get the seed of the previous element before we start reading 
	printf("starting at %ld\n", cur_pos);
	while( true )
	{
		if(mem -> pos - cur_pos >= 1000){
			printf("Lap error!");
			break;
		}
		while(mem -> pos == cur_pos){};
		int64_t cur_seed = verify((void *)mem->BUFFER[cur_pos % 1000].arr);
		if(cur_seed == -1){
			printf("Error!");
			break;
		}
		if(cur_seed != prev_seed +1){ // checking if the seed of the current element is 1 less than previous one 
			printf("Wrong seed!");
			break;
		}
		prev_seed +=1;
		printf("Verified at %ld with seed %ld\n", cur_pos % 1000, cur_seed);
		cur_pos ++;
		//sleep(1); seems like the lap error check is working if this is not commented ;d
	}
	return 0;
}