text: from __future__ import absolute_import
  
  import cffi
  import os
  
  ffi = cffi.FFI()
  mpatch_c = os.path.join(
      os.path.join(os.path.dirname(__file__), '..', 'mpatch.c')
  )
  with open(mpatch_c) as f:
      ffi.set_source(
          "mercurial.cffi._mpatch", f.read(), include_dirs=["mercurial"]
      )
  ffi.cdef(
      """
  
  struct mpatch_frag {
         int start, end, len;
         const char *data;
  };
  
  struct mpatch_flist {
         struct mpatch_frag *base, *head, *tail;
  };
  
  extern "Python" struct mpatch_flist* cffi_get_next_item(void*, ssize_t);
  
  int mpatch_decode(const char *bin, ssize_t len, struct mpatch_flist** res);
  ssize_t mpatch_calcsize(size_t len, struct mpatch_flist *l);
  void mpatch_lfree(struct mpatch_flist *a);
  static int mpatch_apply(char *buf, const char *orig, size_t len,
                          struct mpatch_flist *l);
  struct mpatch_flist *mpatch_fold(void *bins,
                         struct mpatch_flist* (*get_next_item)(void*, ssize_t),
                         ssize_t start, ssize_t end);
  """
  )
  
  if __name__ == '__main__':
      ffi.compile()
  