docs: init doc for .osrm.mldgr

Author: wangyoucao577

osrm/doc/osrm-toolchain-files/README.md

@@ -38,7 +38,7 @@ tar -tvf nevada-latest.osrm.nbg_nodes
 
 ## Files produced by `osrm-customize`
 - [.osrm.cell_metrics](./map.osrm.cell_metrics.md)
-
+- [.osrm.mldgr](./map.osrm.mldgr.md)
 
 ## References
 - [Toolchain-file-overview wiki](https://github.com/Project-OSRM/osrm-backend/wiki/Toolchain-file-overview)

osrm/doc/osrm-toolchain-files/map.osrm.mldgr.md

@@ -0,0 +1,37 @@
+# .osrm.mldgr
+MLD search graph.    
+
+## List
+
+```bash
+tar -tvf nevada-latest.osrm.mldgr
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 osrm_fingerprint.meta
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 /mld/connectivity_checksum.meta
+-rw-rw-r-- 0/0               4 1970-01-01 00:00 /mld/connectivity_checksum
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 /mld/multilevelgraph/node_array.meta
+-rw-rw-r-- 0/0         3056848 1970-01-01 00:00 /mld/multilevelgraph/node_array
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 /mld/multilevelgraph/node_weights.meta
+-rw-rw-r-- 0/0         3056844 1970-01-01 00:00 /mld/multilevelgraph/node_weights
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 /mld/multilevelgraph/node_durations.meta
+-rw-rw-r-- 0/0         3056844 1970-01-01 00:00 /mld/multilevelgraph/node_durations
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 /mld/multilevelgraph/node_distances.meta
+-rw-rw-r-- 0/0         3056844 1970-01-01 00:00 /mld/multilevelgraph/node_distances
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 /mld/multilevelgraph/edge_array.meta
+-rw-rw-r-- 0/0        23744064 1970-01-01 00:00 /mld/multilevelgraph/edge_array
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 /mld/multilevelgraph/is_forward_edge.meta
+-rw-rw-r-- 0/0          371008 1970-01-01 00:00 /mld/multilevelgraph/is_forward_edge
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 /mld/multilevelgraph/is_backward_edge.meta
+-rw-rw-r-- 0/0          371008 1970-01-01 00:00 /mld/multilevelgraph/is_backward_edge
+-rw-rw-r-- 0/0               8 1970-01-01 00:00 /mld/multilevelgraph/node_to_edge_offset.meta
+-rw-rw-r-- 0/0          337541 1970-01-01 00:00 /mld/multilevelgraph/node_to_edge_offset
+```
+
+## osrm_fingerprint.meta
+- [osrm_fingerprint.meta](./fingerprint.md)
+
+## /mld/*
+TODO:    
+
+### Layout
+
+### Implementation