tspparse.py

from collections import deque
from city        import GeoCoord, GeoCity, Euc_2D

def minimal_tsp():
    return { "COMMENT"          : ""
           , "DIMENSION"        : None
           , "TYPE"             : None
           , "EDGE_WEIGHT_TYPE" : None
           , "CITIES"           : []}

def scan_keywords(tsp,tspfile):
    for line in tspfile:
        words   = deque(line.split())
        keyword = words.popleft().strip(": ")

        if keyword == "COMMENT":
            tsp["COMMENT"] += " ".join(words).strip(": ")
        elif keyword == "NAME":
            tsp["NAME"] = " ".join(words).strip(": ")
        elif keyword == "TYPE":
            tsp["TYPE"] = " ".join(words).strip(": ")
        elif keyword == "DIMENSION":
            tsp["DIMENSION"] = int(" ".join(words).strip(": "))
        elif keyword == "EDGE_WEIGHT_TYPE":
            tsp["EDGE_WEIGHT_TYPE"] = " ".join(words).strip(": ")
        elif keyword == "NODE_COORD_SECTION":
            break

def read_int(words):
    return int(words.popleft())

def read_euc_2d_city(words):
    x = float(words.popleft())
    y = float(words.popleft())
    return Euc_2D(x, y)

def read_geo_coord(words):
    [degrees, minutes] = map(int, words.popleft().split("."))
    return GeoCoord(degrees, minutes)

def read_geo_city(words):
    lat = read_geo_coord(words)
    lon = read_geo_coord(words)
    return GeoCity(lat, lon)

def read_numbered_geo_city_line(desired_number, words):
    city_number = read_int(words)
    if city_number == desired_number:
        return read_geo_city(words)
    else:
        print("Missing or mislabeld city: expected {0}".format(desired_number))

def read_numbered_euc_2d_city_line(desired_number, words):
    city_number = read_int(words)
    if city_number == desired_number:
        return read_euc_2d_city(words)
    else:
        print("Missing or mislabeld city: expected {0}".format(desired_number))

def read_cities(tsp,tspfile):
    for n in range(1, tsp["DIMENSION"] + 1):
        line  = tspfile.readline()
        words = deque(line.split())
        if tsp["EDGE_WEIGHT_TYPE"] == "EUC_2D":
            tsp["CITIES"].append(read_numbered_euc_2d_city_line(n, words))
        elif tsp["EDGE_WEIGHT_TYPE"] == "GEO":
            tsp["CITIES"].append(read_numbered_geo_city_line(n, words))
        else:
            print("Unsupported coordinate type: " + tsp["EDGE_WEIGHT_TYPE"])
            
def read_tsp_file(path):
    tspfile = open(path,'r')
    tsp     = minimal_tsp()
    scan_keywords(tsp,tspfile)
    read_cities(tsp,tspfile)
    tspfile.close()
    return tsp