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.venv/Lib/site-packages/pandas/_libs/tslibs/ccalendar.pyx

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+# cython: boundscheck=False
+"""
+Cython implementations of functions resembling the stdlib calendar module
+"""
+
+import 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* sakamoto_arr = [0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4]
+
+# 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}
+
+DAY_SECONDS = 86400
+HOUR_SECONDS = 3600
+
+cdef int64_t DAY_NANOS = DAY_SECONDS * 1_000_000_000
+cdef int64_t HOUR_NANOS = HOUR_SECONDS * 1_000_000_000
+
+# ----------------------------------------------------------------------
+
+
+@cython.wraparound(False)
+@cython.boundscheck(False)
+cpdef int32_t get_days_in_month(int year, Py_ssize_t month) 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
+cdef int dayofweek(int y, int m, int d) nogil:
+    """
+    Find the day of week for the date described by the Y/M/D triple y, m, d
+    using Sakamoto's 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#Sakamoto.27s_methods
+    """
+    cdef:
+        int day
+
+    y -= m < 3
+    day = (y + y / 4 - y / 100 + y / 400 + sakamoto_arr[m - 1] + d) % 7
+    # convert to python day
+    return (day + 6) % 7
+
+
+cdef bint is_leapyear(int64_t year) 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) 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) 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) 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) 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) 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