c code for random bit generator

random_bit_generator.c

#include <stdio.h>
#include <stdint.h>
#include <string.h>
//#include <stdlib.h>


int main(int argc, char* argv[])
{
    uint32_t lfsr = 0xACE1ACE1u;
    unsigned period = 0;
    int state;
    //printf("Number of LFSR state : ");
    //scanf("%d", &state);

    char s[32 + 1];

    int i, nb_input_bits, nb_buffer;
    printf("Enter number of the input bits: ");
    scanf("%d", &nb_input_bits);

    nb_buffer = nb_input_bits / 32;
    int buffer_count = 0;
    int ignore = 0;
    char *line = malloc(nb_buffer * 32   + 13); // 10+2+1

    // file operation
    int first_line = 1;
    FILE *fp = fopen("binary.txt", "a");

    do {
          unsigned lsb = lfsr & 1;  /* Get lsb (i.e., the output bit). */
          lfsr >>= 1;               /* Shift register */
          if (lsb == 1)             /* Only apply toggle mask if output bit is 1. */
            lfsr ^= 0xB400B400u;        /* Apply toggle mask, value has 1 at bits corresponding
                                    /* to taps, 0 elsewhere. */
          ++buffer_count;

          //seed = ACE1 = 1010110011100001, feedback polynomial = 1011010000000000
          for (i = 0; i < 32; i++){
             s[31 - i] = (lfsr & (1 << i)) ? '1' : '0';
          }

          // for nb_buffer = 1 value
          if(nb_buffer == 1){
              if (first_line == 1){
                sprintf(line, "%d: %s", period, s);
              }

              else if(first_line > 1){
                ++period;
                s[32] = '\0';
                fprintf(fp, "%d: ", period);
                fprintf(fp,"%s\n", s);
              }
              
              first_line++;

          // for nb_buffer large value
          }else if (nb_buffer > 1){

            if(first_line != 1){
                if(buffer_count == 1){
                    ++period;
                    fprintf(fp, "%d: ", period);
                    fprintf(fp,"%s", s);
                
                }else if (buffer_count == nb_buffer){
                    buffer_count = 0;
                    
                    s[32] = '\0';
                    if (ignore != 0){
                        fprintf(fp,"%s\n", s);
                    }
                    ignore = 61;
                    
                    
                }else{
                    if (ignore != 0)
                    fprintf(fp,"%s", s);
                }
            } //end of if loop
            first_line++;
        }//end of do loop
          
    } while(lfsr != 0xACE1ACE1u);
    fclose(fp);
    return 0;
}