Repo created

tools/python/mwm/ft2osm.py

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+from mwm.mwm_python import read_uint
+from mwm.mwm_python import read_varuint
+
+
+class OsmIdCode:
+    # We use here obsolete types. If we change this types to new types,
+    # we must support it here. See base/geo_object_id.hpp.
+    NODE = 0x4000000000000000
+    WAY = 0x8000000000000000
+    RELATION = 0xC000000000000000
+    FULL_MASK = NODE | WAY | RELATION
+    RESET = ~FULL_MASK
+
+    @staticmethod
+    def is_node(code):
+        return code & OsmIdCode.FULL_MASK == OsmIdCode.NODE
+
+    @staticmethod
+    def is_way(code):
+        return code & OsmIdCode.FULL_MASK == OsmIdCode.WAY
+
+    @staticmethod
+    def is_relation(code):
+        return code & OsmIdCode.FULL_MASK == OsmIdCode.RELATION
+
+    @staticmethod
+    def get_type(code):
+        if OsmIdCode.is_relation(code):
+            return "r"
+        elif OsmIdCode.is_node(code):
+            return "n"
+        elif OsmIdCode.is_way(code):
+            return "w"
+        return None
+
+    @staticmethod
+    def get_id(code):
+        return code & OsmIdCode.RESET
+
+
+def unpack_osmid(num):
+    typ = OsmIdCode.get_type(num)
+    if typ is None:
+        return None
+    return typ, OsmIdCode.get_id(num)
+
+
+def _read_osm2ft_v0(f, ft2osm, tuples):
+    count = read_varuint(f)
+    result = {}
+    for i in range(count):
+        osmid = read_uint(f, 8)
+        if tuples:
+            osmid = unpack_osmid(osmid)
+        fid = read_uint(f, 4)
+        read_uint(f, 4)  # filler
+        if osmid is not None:
+            if ft2osm:
+                result[fid] = osmid
+            else:
+                result[osmid] = fid
+    return result
+
+
+def _read_osm2ft_v1(f, ft2osm, tuples):
+    count = read_varuint(f)
+    result = {}
+    for i in range(count):
+        osmid = read_uint(f, 8)
+        # V1 use complex ids. Here we want to skip second part of complex id
+        # to save old interface osm2ft.
+        read_uint(f, 8)
+        if tuples:
+            osmid = unpack_osmid(osmid)
+        fid = read_uint(f, 4)
+        read_uint(f, 4)  # filler
+        if osmid is not None:
+            if ft2osm:
+                result[fid] = osmid
+            else:
+                result[osmid] = fid
+    return result
+
+
+def read_osm2ft(f, ft2osm=False, tuples=True):
+    """Reads mwm.osm2ft file, returning a dict of feature id <-> osm id."""
+    header = read_uint(f, 4)
+    is_new_format = header == 0xFFFFFFFF
+    if is_new_format:
+        version = read_uint(f, 1)
+        if version == 1:
+            return _read_osm2ft_v1(f, ft2osm, tuples)
+        else:
+            raise Exception("Format {0} is not supported".format(version))
+    else:
+        f.seek(0)
+        return _read_osm2ft_v0(f, ft2osm, tuples)
+
+
+def ft2osm(path, ftid):
+    with open(path, "rb") as f:
+        ft2osm = read_osm2ft(f, ft2osm=True)
+
+    type_abbr = {"n": "node", "w": "way", "r": "relation"}
+    ftid = int(ftid)
+    if ftid in ft2osm:
+        return f"https://www.openstreetmap.org/{type_abbr[ft2osm[ftid][0]]}/{ft2osm[ftid][1]}"
+    return None