+ ret = parse_commit_graph(graph_map, fd, graph_size);
+
+ if (!ret) {
+ munmap(graph_map, graph_size);
+ close(fd);
+ exit(1);
+ }
+
+ return ret;
+}
+
+struct commit_graph *parse_commit_graph(void *graph_map, int fd,
+ size_t graph_size)
+{
+ const unsigned char *data, *chunk_lookup;
+ uint32_t i;
+ struct commit_graph *graph;
+ uint64_t last_chunk_offset;
+ uint32_t last_chunk_id;
+ uint32_t graph_signature;
+ unsigned char graph_version, hash_version;
+
+ if (!graph_map)
+ return NULL;
+
+ if (graph_size < GRAPH_MIN_SIZE)
+ return NULL;
+