text: #ifndef SHA1_ARRAY_H
  #define SHA1_ARRAY_H
  
  struct sha1_array {
  	unsigned char (*sha1)[20];
  	int nr;
  	int alloc;
  	int sorted;
  };
  
  #define SHA1_ARRAY_INIT { NULL, 0, 0, 0 }
  
  void sha1_array_append(struct sha1_array *array, const unsigned char *sha1);
  void sha1_array_sort(struct sha1_array *array);
  int sha1_array_lookup(struct sha1_array *array, const unsigned char *sha1);
  void sha1_array_clear(struct sha1_array *array);
  
  typedef void (*for_each_sha1_fn)(const unsigned char sha1[20],
  				 void *data);
  void sha1_array_for_each_unique(struct sha1_array *array,
  				for_each_sha1_fn fn,
  				void *data);
  
  #endif /* SHA1_ARRAY_H */
  