blendfile.py 文件源码

def get_data_hash(self):
        """
        Generates a 'hash' that can be used instead of addr_old as block id, and that should be 'stable' across .blend
        file load & save (i.e. it does not changes due to pointer addresses variations).
        """
        # TODO This implementation is most likely far from optimal... and CRC32 is not renown as the best hashing
        #      algo either. But for now does the job!
        import zlib
        def _is_pointer(self, k):
            return self.file.structs[self.sdna_index].field_from_path(
                    self.file.header, self.file.handle, k).dna_name.is_pointer

        hsh = 1
        for k, v in self.items_recursive_iter():
            if not _is_pointer(self, k):
                hsh = zlib.adler32(str(v).encode(), hsh)
        return hsh