text: /*
   * diff-delta code taken from git.git. See diff-delta.c for details.
   *
   */
  #ifndef INCLUDE_git_delta_h__
  #define INCLUDE_git_delta_h__
  
  #include BOSS_LIBGIT2_U_common_h //original-code:"common.h"
  
  /* opaque object for delta index */
  struct git_delta_index;
  
  /*
   * create_delta_index: compute index data from given buffer
   *
   * This returns a pointer to a struct delta_index that should be passed to
   * subsequent create_delta() calls, or to free_delta_index().  A NULL pointer
   * is returned on failure.  The given buffer must not be freed nor altered
   * before free_delta_index() is called.  The returned pointer must be freed
   * using free_delta_index().
   */
  extern struct git_delta_index *
  git_delta_create_index(const void *buf, unsigned long bufsize);
  
  /*
   * free_delta_index: free the index created by create_delta_index()
   *
   * Given pointer must be what create_delta_index() returned, or NULL.
   */
  extern void git_delta_free_index(struct git_delta_index *index);
  
  /*
   * sizeof_delta_index: returns memory usage of delta index
   *
   * Given pointer must be what create_delta_index() returned, or NULL.
   */
  extern unsigned long git_delta_sizeof_index(struct git_delta_index *index);
  
  /*
   * create_delta: create a delta from given index for the given buffer
   *
   * This function may be called multiple times with different buffers using
   * the same delta_index pointer.  If max_delta_size is non-zero and the
   * resulting delta is to be larger than max_delta_size then NULL is returned.
   * On success, a non-NULL pointer to the buffer with the delta data is
   * returned and *delta_size is updated with its size.  The returned buffer
   * must be freed by the caller.
   */
  extern void *git_delta_create(
  	const struct git_delta_index *index,
  	const void *buf,
  	unsigned long bufsize,
  	unsigned long *delta_size,
  	unsigned long max_delta_size);
  
  /*
   * diff_delta: create a delta from source buffer to target buffer
   *
   * If max_delta_size is non-zero and the resulting delta is to be larger
   * than max_delta_size then NULL is returned.  On success, a non-NULL
   * pointer to the buffer with the delta data is returned and *delta_size is
   * updated with its size.  The returned buffer must be freed by the caller.
   */
  GIT_INLINE(void *) git_delta(
  	const void *src_buf, unsigned long src_bufsize,
  	const void *trg_buf, unsigned long trg_bufsize,
  	unsigned long *delta_size,
  	unsigned long max_delta_size)
  {
  	struct git_delta_index *index = git_delta_create_index(src_buf, src_bufsize);
  	if (index) {
  		void *delta = git_delta_create(
  			index, trg_buf, trg_bufsize, delta_size, max_delta_size);
  		git_delta_free_index(index);
  		return delta;
  	}
  	return NULL;
  }
  
  /*
   * patch_delta: recreate target buffer given source buffer and delta data
   *
   * On success, a non-NULL pointer to the target buffer is returned and
   * *trg_bufsize is updated with its size.  On failure a NULL pointer is
   * returned.  The returned buffer must be freed by the caller.
   */
  extern void *git_delta_patch(
  	const void *src_buf, unsigned long src_size,
  	const void *delta_buf, unsigned long delta_size,
  	unsigned long *dst_size);
  
  /* the smallest possible delta size is 4 bytes */
  #define GIT_DELTA_SIZE_MIN	4
  
  /*
   * This must be called twice on the delta data buffer, first to get the
   * expected source buffer size, and again to get the target buffer size.
   */
  GIT_INLINE(unsigned long) git_delta_get_hdr_size(
  	const unsigned char **datap, const unsigned char *top)
  {
  	const unsigned char *data = *datap;
  	unsigned long cmd, size = 0;
  	int i = 0;
  	do {
  		cmd = *data++;
  		size |= (cmd & 0x7f) << i;
  		i += 7;
  	} while (cmd & 0x80 && data < top);
  	*datap = data;
  	return size;
  }
  
  #endif
  