text: #ifndef BDC_READERSYSTEM_H
  #define BDC_READERSYSTEM_H
  
  #include <stdio.h>
  
  typedef struct {
      char *pointer;
      unsigned short block;
  } sentinelPointer;
  
  typedef struct {
      char *pointer;
  } blockOfData;
  
  typedef struct {
      unsigned int blockSize;
      FILE *file;
      sentinelPointer beg;
      sentinelPointer end;
      blockOfData block0;
      blockOfData block1;
      unsigned int currentLine;
      unsigned int currentPosition;
      unsigned int lengthOfCurrentLex;
  } readerSystem;
  
  
  void initReaderSystem(readerSystem **rs, char *filename);
  
  void deleteReaderSystem(readerSystem **rs);
  
  char getNextChar(readerSystem *rs);
  
  void returnChar(readerSystem *rs);
  
  char *getCurrentLex(readerSystem *rs);
  
  void advanceBeginning(readerSystem *rs);
  
  #endif //BDC_READERSYSTEM_H
  