#include<stdio.h>

int l2_write(char *b,int n) {
  int x;
  int z;
  int retval;
  char a[4];
  //reject large data segments
  if(n>=1000) {
    return -1;
  }

  //build a header with the number of bytes
  z=n/100;
  sprintf(a,"%d",z);
  z=(n/10)%10;
  sprintf(&a[1],"%d",z);
  z=n%10;
  sprintf(&a[2],"%d",z);
  for(x=0;x<3;x++) {
    retval=l1_write(a[x]);
    if(retval!=1) {
      return -1;
    }
  }
  for(x=0;x<n;x++) {
    retval=l1_write(b[x]);
    if(retval!=1) {
      return -1;
    }
  }
  return n;
}

int l2_read(char *b,int max) {
  char size[4];
  int sizeval;
  int x;

  size[3]=0;
  //read the size
  l1_read(size);
  l1_read(&size[1]);
  l1_read(&size[2]);
  sizeval=atoi(size);
  //reject if the size is >999
  if(sizeval>999) {
    return -1;
  }
  //read into buffer
  for(x=0;x<sizeval;x++) {
    l1_read(&b[x]);
  }
  return(sizeval);
}