# cython: boundscheck=False """ Cython implementations of functions resembling the stdlib calendar module """ cimport cython from numpy cimport ( int32_t, int64_t, ) # ---------------------------------------------------------------------- # Constants # Slightly more performant cython lookups than a 2D table # The first 12 entries correspond to month lengths for non-leap years. # The remaining 12 entries give month lengths for leap years cdef int32_t* days_per_month_array = [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31] cdef int* em = [0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334] # The first 13 entries give the month days elapsed as of the first of month N # (or the total number of days in the year for N=13) in non-leap years. # The remaining 13 entries give the days elapsed in leap years. cdef int32_t* month_offset = [ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366] # Canonical location for other modules to find name constants MONTHS = ["JAN", "FEB", "MAR", "APR", "MAY", "JUN", "JUL", "AUG", "SEP", "OCT", "NOV", "DEC"] # The first blank line is consistent with calendar.month_name in the calendar # standard library MONTHS_FULL = ["", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"] MONTH_NUMBERS = {name: num for num, name in enumerate(MONTHS)} cdef dict c_MONTH_NUMBERS = MONTH_NUMBERS MONTH_ALIASES = {(num + 1): name for num, name in enumerate(MONTHS)} MONTH_TO_CAL_NUM = {name: num + 1 for num, name in enumerate(MONTHS)} DAYS = ["MON", "TUE", "WED", "THU", "FRI", "SAT", "SUN"] DAYS_FULL = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"] int_to_weekday = {num: name for num, name in enumerate(DAYS)} weekday_to_int = {int_to_weekday[key]: key for key in int_to_weekday} # ---------------------------------------------------------------------- @cython.wraparound(False) @cython.boundscheck(False) cpdef int32_t get_days_in_month(int year, Py_ssize_t month) noexcept nogil: """ Return the number of days in the given month of the given year. Parameters ---------- year : int month : int Returns ------- days_in_month : int Notes ----- Assumes that the arguments are valid. Passing a month not between 1 and 12 risks a segfault. """ return days_per_month_array[12 * is_leapyear(year) + month - 1] @cython.wraparound(False) @cython.boundscheck(False) @cython.cdivision(True) cdef long quot(long a , long b) noexcept nogil: cdef long x x = a/b if (a < 0): x -= (a % b != 0) return x @cython.wraparound(False) @cython.boundscheck(False) @cython.cdivision(True) cdef int dayofweek(int y, int m, int d) noexcept nogil: """ Find the day of week for the date described by the Y/M/D triple y, m, d using Gauss' method, from wikipedia. 0 represents Monday. See [1]_. Parameters ---------- y : int m : int d : int Returns ------- weekday : int Notes ----- Assumes that y, m, d, represents a valid date. See Also -------- [1] https://docs.python.org/3/library/calendar.html#calendar.weekday [2] https://en.wikipedia.org/wiki/\ Determination_of_the_day_of_the_week#Gauss's_algorithm """ # Note: this particular implementation comes from # http://berndt-schwerdtfeger.de/wp-content/uploads/pdf/cal.pdf cdef: long c int g int f int e if (m < 3): y -= 1 c = quot(y, 100) g = y - c * 100 f = 5 * (c - quot(c, 4) * 4) e = em[m] if (m > 2): e -= 1 return (-1 + d + e + f + g + g/4) % 7 cdef bint is_leapyear(int64_t year) noexcept nogil: """ Returns 1 if the given year is a leap year, 0 otherwise. Parameters ---------- year : int Returns ------- is_leap : bool """ return ((year & 0x3) == 0 and # year % 4 == 0 ((year % 100) != 0 or (year % 400) == 0)) @cython.wraparound(False) @cython.boundscheck(False) cpdef int32_t get_week_of_year(int year, int month, int day) noexcept nogil: """ Return the ordinal week-of-year for the given day. Parameters ---------- year : int month : int day : int Returns ------- week_of_year : int32_t Notes ----- Assumes the inputs describe a valid date. """ return get_iso_calendar(year, month, day)[1] @cython.wraparound(False) @cython.boundscheck(False) cpdef iso_calendar_t get_iso_calendar(int year, int month, int day) noexcept nogil: """ Return the year, week, and day of year corresponding to ISO 8601 Parameters ---------- year : int month : int day : int Returns ------- year : int32_t week : int32_t day : int32_t Notes ----- Assumes the inputs describe a valid date. """ cdef: int32_t doy, dow int32_t iso_year, iso_week doy = get_day_of_year(year, month, day) dow = dayofweek(year, month, day) # estimate iso_week = (doy - 1) - dow + 3 if iso_week >= 0: iso_week = iso_week // 7 + 1 # verify if iso_week < 0: if (iso_week > -2) or (iso_week == -2 and is_leapyear(year - 1)): iso_week = 53 else: iso_week = 52 elif iso_week == 53: if 31 - day + dow < 3: iso_week = 1 iso_year = year if iso_week == 1 and month == 12: iso_year += 1 elif iso_week >= 52 and month == 1: iso_year -= 1 return iso_year, iso_week, dow + 1 @cython.wraparound(False) @cython.boundscheck(False) cpdef int32_t get_day_of_year(int year, int month, int day) noexcept nogil: """ Return the ordinal day-of-year for the given day. Parameters ---------- year : int month : int day : int Returns ------- day_of_year : int32_t Notes ----- Assumes the inputs describe a valid date. """ cdef: bint isleap int32_t mo_off int day_of_year isleap = is_leapyear(year) mo_off = month_offset[isleap * 13 + month - 1] day_of_year = mo_off + day return day_of_year # --------------------------------------------------------------------- # Business Helpers cpdef int get_lastbday(int year, int month) noexcept nogil: """ Find the last day of the month that is a business day. Parameters ---------- year : int month : int Returns ------- last_bday : int """ cdef: int wkday, days_in_month wkday = dayofweek(year, month, 1) days_in_month = get_days_in_month(year, month) return days_in_month - max(((wkday + days_in_month - 1) % 7) - 4, 0) cpdef int get_firstbday(int year, int month) noexcept nogil: """ Find the first day of the month that is a business day. Parameters ---------- year : int month : int Returns ------- first_bday : int """ cdef: int first, wkday wkday = dayofweek(year, month, 1) first = 1 if wkday == 5: # on Saturday first = 3 elif wkday == 6: # on Sunday first = 2 return first