make unused_name() faster

gfapy/gfa.py

@@ -31,7 +31,7 @@ def __init__(self, *args, vlevel = 1, version = None):
     if not version in ['gfa1', 'gfa2', None]:
       raise gfapy.VersionError("GFA version unknown ({})".format(version))
     self._vlevel = vlevel
-    self._unused_name_cache = 1
+    self._max_int_name = 0
     self._records = defaultdict(dict)
     self._records["H"] = gfapy.line.Header(["H"], vlevel = vlevel)
     self._records["H"].connect(self)

gfapy/lines/collections.py

@@ -240,13 +240,8 @@ def names(self):
 
   def unused_name(self):
     """Compute a GFA identifier not yet in use in the Gfa object."""
-    names = self.names
-    name = str(self._unused_name_cache)
-    while name in names:
-      self._unused_name_cache += 1
-      name = str(self._unused_name_cache)
-    self._unused_name_cache += 1
-    return name
+    self._max_int_name += 1
+    return str(self._max_int_name)
 
   @property
   def external_names(self):

gfapy/lines/creators.py

@@ -59,6 +59,10 @@ def _register_line(self, gfa_line):
       key = gfa_line.name
       if gfapy.is_placeholder(key):
         key = id(gfa_line)
+      elif key.isdigit():
+        keynum = int(key)
+        if keynum > self._max_int_name:
+          self._max_int_name = keynum
       self._records[gfa_line.record_type][key] = gfa_line
     elif storage_key == "external":
       if gfa_line.external.line not in self._records[gfa_line.record_type]: