REF: re-use get_firstbday, get_lastbday in fields.pyx (#35199)

Author: jbrockmendel

pandas/_libs/tslibs/ccalendar.pxd

@@ -10,6 +10,8 @@ cpdef int32_t get_days_in_month(int year, Py_ssize_t month) nogil
 cpdef int32_t get_week_of_year(int year, int month, int day) nogil
 cpdef iso_calendar_t get_iso_calendar(int year, int month, int day) nogil
 cpdef int32_t get_day_of_year(int year, int month, int day) nogil
+cpdef int get_lastbday(int year, int month) nogil
+cpdef int get_firstbday(int year, int month) nogil
 
 cdef int64_t DAY_NANOS
 cdef int64_t HOUR_NANOS

pandas/_libs/tslibs/ccalendar.pyx

@@ -241,3 +241,52 @@ cpdef int32_t get_day_of_year(int year, int month, int day) nogil:
 
     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

pandas/_libs/tslibs/fields.pyx

@@ -19,6 +19,8 @@ from pandas._libs.tslibs.ccalendar cimport (
     get_days_in_month, is_leapyear, dayofweek, get_week_of_year,
     get_day_of_year, get_iso_calendar, iso_calendar_t,
     month_offset,
+    get_firstbday,
+    get_lastbday,
 )
 from pandas._libs.tslibs.np_datetime cimport (
     npy_datetimestruct, pandas_timedeltastruct, dt64_to_dtstruct,
@@ -137,9 +139,7 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
         int end_month = 12
         int start_month = 1
         ndarray[int8_t] out
-        bint isleap
         npy_datetimestruct dts
-        int mo_off, dom, doy, dow, ldom
 
     out = np.zeros(count, dtype='int8')
 
@@ -172,10 +172,8 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                dom = dts.day
-                dow = dayofweek(dts.year, dts.month, dts.day)
 
-                if (dom == 1 and dow < 5) or (dom <= 3 and dow == 0):
+                if dts.day == get_firstbday(dts.year, dts.month):
                     out[i] = 1
 
         else:
@@ -185,9 +183,8 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                dom = dts.day
 
-                if dom == 1:
+                if dts.day == 1:
                     out[i] = 1
 
     elif field == 'is_month_end':
@@ -198,15 +195,8 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                isleap = is_leapyear(dts.year)
-                mo_off = month_offset[isleap * 13 + dts.month - 1]
-                dom = dts.day
-                doy = mo_off + dom
-                ldom = month_offset[isleap * 13 + dts.month]
-                dow = dayofweek(dts.year, dts.month, dts.day)
-
-                if (ldom == doy and dow < 5) or (
-                        dow == 4 and (ldom - doy <= 2)):
+
+                if dts.day == get_lastbday(dts.year, dts.month):
                     out[i] = 1
 
         else:
@@ -216,13 +206,8 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                isleap = is_leapyear(dts.year)
-                mo_off = month_offset[isleap * 13 + dts.month - 1]
-                dom = dts.day
-                doy = mo_off + dom
-                ldom = month_offset[isleap * 13 + dts.month]
 
-                if ldom == doy:
+                if dts.day == get_days_in_month(dts.year, dts.month):
                     out[i] = 1
 
     elif field == 'is_quarter_start':
@@ -233,11 +218,9 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                dom = dts.day
-                dow = dayofweek(dts.year, dts.month, dts.day)
 
                 if ((dts.month - start_month) % 3 == 0) and (
-                        (dom == 1 and dow < 5) or (dom <= 3 and dow == 0)):
+                        dts.day == get_firstbday(dts.year, dts.month)):
                     out[i] = 1
 
         else:
@@ -247,9 +230,8 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                dom = dts.day
 
-                if ((dts.month - start_month) % 3 == 0) and dom == 1:
+                if ((dts.month - start_month) % 3 == 0) and dts.day == 1:
                     out[i] = 1
 
     elif field == 'is_quarter_end':
@@ -260,16 +242,9 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                isleap = is_leapyear(dts.year)
-                mo_off = month_offset[isleap * 13 + dts.month - 1]
-                dom = dts.day
-                doy = mo_off + dom
-                ldom = month_offset[isleap * 13 + dts.month]
-                dow = dayofweek(dts.year, dts.month, dts.day)
 
                 if ((dts.month - end_month) % 3 == 0) and (
-                        (ldom == doy and dow < 5) or (
-                            dow == 4 and (ldom - doy <= 2))):
+                        dts.day == get_lastbday(dts.year, dts.month)):
                     out[i] = 1
 
         else:
@@ -279,13 +254,9 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                isleap = is_leapyear(dts.year)
-                mo_off = month_offset[isleap * 13 + dts.month - 1]
-                dom = dts.day
-                doy = mo_off + dom
-                ldom = month_offset[isleap * 13 + dts.month]
 
-                if ((dts.month - end_month) % 3 == 0) and (ldom == doy):
+                if ((dts.month - end_month) % 3 == 0) and (
+                        dts.day == get_days_in_month(dts.year, dts.month)):
                     out[i] = 1
 
     elif field == 'is_year_start':
@@ -296,11 +267,9 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                dom = dts.day
-                dow = dayofweek(dts.year, dts.month, dts.day)
 
                 if (dts.month == start_month) and (
-                        (dom == 1 and dow < 5) or (dom <= 3 and dow == 0)):
+                        dts.day == get_firstbday(dts.year, dts.month)):
                     out[i] = 1
 
         else:
@@ -310,9 +279,8 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                dom = dts.day
 
-                if (dts.month == start_month) and dom == 1:
+                if (dts.month == start_month) and dts.day == 1:
                     out[i] = 1
 
     elif field == 'is_year_end':
@@ -323,16 +291,9 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                isleap = is_leapyear(dts.year)
-                dom = dts.day
-                mo_off = month_offset[isleap * 13 + dts.month - 1]
-                doy = mo_off + dom
-                dow = dayofweek(dts.year, dts.month, dts.day)
-                ldom = month_offset[isleap * 13 + dts.month]
 
                 if (dts.month == end_month) and (
-                        (ldom == doy and dow < 5) or (
-                            dow == 4 and (ldom - doy <= 2))):
+                        dts.day == get_lastbday(dts.year, dts.month)):
                     out[i] = 1
 
         else:
@@ -342,13 +303,9 @@ def get_start_end_field(const int64_t[:] dtindex, str field,
                     continue
 
                 dt64_to_dtstruct(dtindex[i], &dts)
-                isleap = is_leapyear(dts.year)
-                mo_off = month_offset[isleap * 13 + dts.month - 1]
-                dom = dts.day
-                doy = mo_off + dom
-                ldom = month_offset[isleap * 13 + dts.month]
 
-                if (dts.month == end_month) and (ldom == doy):
+                if (dts.month == end_month) and (
+                        dts.day == get_days_in_month(dts.year, dts.month)):
                     out[i] = 1
 
     else:

pandas/_libs/tslibs/offsets.pyx

@@ -34,7 +34,13 @@ from pandas._libs.tslibs.util cimport (
 from pandas._libs.tslibs.ccalendar import (
     MONTH_ALIASES, MONTH_TO_CAL_NUM, weekday_to_int, int_to_weekday,
 )
-from pandas._libs.tslibs.ccalendar cimport DAY_NANOS, get_days_in_month, dayofweek
+from pandas._libs.tslibs.ccalendar cimport (
+    DAY_NANOS,
+    dayofweek,
+    get_days_in_month,
+    get_firstbday,
+    get_lastbday,
+)
 from pandas._libs.tslibs.conversion cimport (
     convert_datetime_to_tsobject,
     localize_pydatetime,
@@ -177,51 +183,6 @@ cdef _wrap_timedelta_result(result):
 # ---------------------------------------------------------------------
 # 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
-
 
 cdef _get_calendar(weekmask, holidays, calendar):
     """Generate busdaycalendar"""

pandas/tests/tslibs/test_liboffsets.py

@@ -5,6 +5,7 @@
 
 import pytest
 
+from pandas._libs.tslibs.ccalendar import get_firstbday, get_lastbday
 import pandas._libs.tslibs.offsets as liboffsets
 from pandas._libs.tslibs.offsets import roll_qtrday
 
@@ -25,7 +26,7 @@ def day_opt(request):
 )
 def test_get_last_bday(dt, exp_week_day, exp_last_day):
     assert dt.weekday() == exp_week_day
-    assert liboffsets.get_lastbday(dt.year, dt.month) == exp_last_day
+    assert get_lastbday(dt.year, dt.month) == exp_last_day
 
 
 @pytest.mark.parametrize(
@@ -37,7 +38,7 @@ def test_get_last_bday(dt, exp_week_day, exp_last_day):
 )
 def test_get_first_bday(dt, exp_week_day, exp_first_day):
     assert dt.weekday() == exp_week_day
-    assert liboffsets.get_firstbday(dt.year, dt.month) == exp_first_day
+    assert get_firstbday(dt.year, dt.month) == exp_first_day
 
 
 @pytest.mark.parametrize(