def corridorGraphReduction(g, rg, cost=None, outcost="cost", edataname="edata", pathname = "path", reversepathname="reversepath"):
vset = set()
eset = set()
equeue = deque()
#first find all vertices with order =1 or >2
for v in g.getVertexList():
ae = g.getAdjacentEdges(v)
o = len(ae)
if o == 1 or o > 2:
#add it to the set and the new graph
vset.add(v)
rg.addVertex(v)
for key in g.getVertexDataKeys(v):
rg.setVertexData(v, key, g.getVertexData(v, key))
#put properties here
for e in ae:
equeue.append(e)
while (len(equeue) > 0):
e = equeue.popleft()
if e in eset: continue
ce = e
ei = g.getEdgeInfo(ce)
fromv = ei[0] if ei[0] in vset else ei[1]
startv = fromv
add = 0
datae = {}
path = []
#follow the current path
while True:
if outcost is not None:
effc = 1 if cost is None else g.getEdgeData(ce, cost)
add += effc
if pathname is not None: path.append((fromv, ce))
if edataname is not None:
datae[ce] = {}
for key in g.getEdgeDataKeys(ce):
datae[ce][key] = g.getEdgeData(ce, key)
tov = g.getEdgeEnd(fromv, ce)
if tov in vset:
eset.add(ce) #get the other edge on tov and
addede = rg.addEdge(startv, tov)
if outcost is not None: rg.setEdgeData(addede, outcost, add)
if edataname is not None: rg.setEdgeData(addede, edataname, datae)
if pathname is not None:
path.append((tov, None))
rg.setEdgeData(addede, pathname, path)
if reversepathname is not None: rg.setEdgeData(addede, reversepathname, Paths.getReversePath(path))
break
#get the other edge on tov and set ce and fromv
ae = g.getAdjacentEdges(tov)
ne = None
for e in ae:
if ce != e: ne = e; break
ce = ne
fromv = tov
return
