test weekday consistency

test_date.py

import datetime

WEEK = ['Sun','Mon','Tue','Wed','Thu','Fri','Sat']

def dow(dd,mm,yyyy):
    return (datetime.date(yyyy, mm, dd).weekday()+1) % 7
        
#from python datetimemodule.c
def dow_c(dd, mm, yyyy):
    y = yyyy - 1
    dby = y*365 + y/4 - y/100 + y/400;
    _dbm = [0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334]
    dbm = _dbm[mm]
    if is_leap(yyyy) and mm>2: dbm+=1
    return (dd + dbm + dby) % 7

def dow_gauss(dd,mm,yyyy):
    cc = yyyy / 100
    yy = yyyy % 100
    return (dd + 26 * (1 + mm) / 10 + 5 * yy / 4 + cc / 4 - 2 * cc - 1) % 7
    
def is_leap(yyyy):
    return yyyy % 4 == 0 and (yyyy % 100 != 0 or yyyy % 400 == 0)
    
#from http://en.wikipedia.org/wiki/Determination_of_the_day_of_the_week
def dow_tab(dd,mm,yyyy):
    def cent(t, c): return t[2][(c-t[0]) % t[1]]
    greg_cent = (15, 4, [0,6,4,2])
    years = {
        1: [1,   7, 12, 18, 29, 35, 40, 46, 57, 63, 68, 74, 85, 91, 96],
        2: [2, 13, 19, 24, 30, 41, 47, 52, 58, 69, 75, 80, 86, 97],
        3: [3,   8, 14, 25, 31, 36, 42, 53, 59, 64, 70, 81, 87, 92, 98],
        4: [9, 15, 20, 26, 37, 43, 48, 54, 65, 71, 76, 82, 93, 99],
        5: [4, 10, 21, 27, 32, 38, 49, 55, 60, 66, 77, 83, 88, 94],
        6: [5, 11, 16, 22, 33, 39, 44, 50, 61, 67, 72, 78, 89, 95],
        0: [6, 17, 23, 28, 34, 45, 51, 56, 62, 73, 79, 84, 90,   0]
    }
    leap_years = {4:4, 8:2, 12:1, 16:5, 20:3, 24:1, 28:6, 32:4, 36:2, 40:0, 44:5, 48:3, 52:1, 56:6, 60:4, 64:2, 68:0, 72:5, 76:3, 80:1, 84:6, 88:4, 92:2, 96:0, 0:6}
    months = [0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5]
    cc = yyyy / 100
    yy = yyyy % 100
    
    clut = cent(greg_cent, cc)
    
    for k, v in years.items():
        if yy in v: 
            ylut = k
            break
    if is_leap(yyyy) and mm < 3:
        ylut -= 1
        
    mlut = months[mm-1]
    return (dd + mlut + ylut + clut) % 7
    
def dow_sakamoto(d,m,y):
    t = [0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4]
    y -= m < 3
    return (y + y / 4 - y / 100 + y / 400 + t[m-1] + d) % 7
    
def test_date(fn,y1,y2):
    mm = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 31]
    for y in xrange(y1, y2):
        if (fn(1,1, y+1) - fn(31,12,y)) % 7 != 1: print "wrong", (fn(31,12,y), (31, 12, y), fn(1,1,y+1), (1, 1, y+1))
        for m in xrange(1, 11):
            dd = mm[m-1]
            if is_leap(y) and m == 2: dd += 1
            
            d1 = fn(dd,m,y)
            d2 = fn(1,m+1, y)
            if (d2 - d1) % 7 != 1: 
                print "wrong", (d1, (dd, m, y), d2, (1, m+1, y))

if __name__ == "__main__":
    test_date(dow,1600,2500)
    test_date(dow_tab,1600,2500)
    test_date(dow_sakamoto,1600,2500)
    test_date(dow_c,1600,2500)