#include <stdio.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <poll.h>

#define BUF_SIZE 32

int main(int argc, char **argv) {
  int file = 0;
  ssize_t bytesRead = 0;
  void *buf[BUF_SIZE];
  int *stringStart;
  int *stringLength;
  int i = 0;
  int stringNumber = 1; // Nomer stroki
  int absolutePosition = -1; // Pozitsiya v fajle
  char *s;
  struct pollfd fds[1];
  char c;

  fds[0].fd = 0; // stdin
  fds[0].events = POLLIN;
  fds[0].revents = 0;

  stringStart = (int *)malloc(sizeof(int)*2);
  stringLength = (int *)malloc(sizeof(int)*2);
  stringStart[0] = 0; // Fiktivnaya 0-aya stroka
  stringStart[1] = 0; // Stroki nachinayutsya s 1
  stringLength[0] = 0;
  stringLength[1] = 0;

  // Open file
  if (argv[1] == NULL) {
    printf("Ne ukazan fajl\n");
    return -1;
  }
  file = open(argv[1], O_RDONLY);
  if (file == -1) {
    printf("Ne udalos' otkryt' fajl\n");
    return -1;
  }

  // Read, make table
  while((bytesRead = read(file, buf, (size_t) BUF_SIZE)) > 0) {
    for(i = 0; i < bytesRead; i++) {
      absolutePosition++;
//      printf("%c", ((char *)buf)[i]);
      if(((char *)buf)[i] == '\n') {
        stringLength[stringNumber] = absolutePosition - stringStart[stringNumber];
        stringNumber++;
        stringStart = (int *) realloc(stringStart, sizeof(int)*(stringNumber + 1));
        stringLength = (int *) realloc(stringLength, sizeof(int)*(stringNumber + 1));
        stringStart[stringNumber] = absolutePosition + 1;
      }
    }
  }
//  stringNumber--;
  if (absolutePosition == -1) {
    printf("Razmer fajla 0\n");
    close(file);
    return 0;
  }

  /*
  // Print table
  for(i = 1; i < stringNumber; i++)
    printf("%d : %d : %d\n", i, stringStart[i], stringLength[i]);
  */

/******************************************************
******************************************************/
  while(poll(fds, 1, 5000))
    if((i = atoi(gets(s))) > 0) {
      if(i < stringNumber) {
        char buf[stringLength[i] + 1];
        buf[stringLength[i]] = 0;
        lseek(file, (off_t)stringStart[i], SEEK_SET);
        read(file, buf, (size_t)stringLength[i]);
        printf("%s\n", buf);
      } else printf("Takoj stroki net\n");
      fds[0].revents = 0;
    }
    else {
      close(file);
      free(stringLength);
      free(stringStart);
      return 0;
    }

  // Vyvod vsego fajla
  for(i = 1; i < stringNumber; i++) {
    char buf[stringLength[i] + 1];
    buf[stringLength[i]] = 0;
    lseek(file, (off_t)stringStart[i], SEEK_SET);
    read(file, buf, (size_t)stringLength[i]);
    printf("%s\n", buf);
  }

/******************************************************
******************************************************/

  // Finish
  close(file);
  free(stringLength);
  free(stringStart);
  return 0;
}