use ccalendar instead of np_datetime (#21549)

Author: jbrockmendel

pandas/_libs/tslibs/ccalendar.pxd

@@ -6,7 +6,7 @@ from cython cimport Py_ssize_t
 from numpy cimport int64_t, int32_t
 
 
-cdef int dayofweek(int y, int m, int m) nogil
+cdef int dayofweek(int y, int m, int d) nogil
 cdef bint is_leapyear(int64_t year) nogil
 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

pandas/_libs/tslibs/np_datetime.pxd

@@ -54,10 +54,6 @@ cdef extern from "../src/datetime/np_datetime.h":
                                            PANDAS_DATETIMEUNIT fr,
                                            pandas_datetimestruct *result) nogil
 
-    int days_per_month_table[2][12]
-    int dayofweek(int y, int m, int d) nogil
-    int is_leapyear(int64_t year) nogil
-
 
 cdef int reverse_ops[6]
 

pandas/_libs/tslibs/offsets.pyx

@@ -18,12 +18,12 @@ cnp.import_array()
 from util cimport is_string_object, is_integer_object
 
 from ccalendar import MONTHS, DAYS
+from ccalendar cimport get_days_in_month, dayofweek
 from conversion cimport tz_convert_single, pydt_to_i8
 from frequencies cimport get_freq_code
 from nattype cimport NPY_NAT
 from np_datetime cimport (pandas_datetimestruct,
-                          dtstruct_to_dt64, dt64_to_dtstruct,
-                          is_leapyear, days_per_month_table, dayofweek)
+                          dtstruct_to_dt64, dt64_to_dtstruct)
 
 # ---------------------------------------------------------------------
 # Constants
@@ -494,12 +494,6 @@ class BaseOffset(_BaseOffset):
 # ----------------------------------------------------------------------
 # RelativeDelta Arithmetic
 
-@cython.wraparound(False)
-@cython.boundscheck(False)
-cdef inline int get_days_in_month(int year, int month) nogil:
-    return days_per_month_table[is_leapyear(year)][month - 1]
-
-
 cdef inline int year_add_months(pandas_datetimestruct dts, int months) nogil:
     """new year number after shifting pandas_datetimestruct number of months"""
     return dts.year + (dts.month + months - 1) / 12

pandas/_libs/tslibs/period.pyx

@@ -45,9 +45,8 @@ from timezones cimport is_utc, is_tzlocal, get_utcoffset, get_dst_info
 from timedeltas cimport delta_to_nanoseconds
 
 cimport ccalendar
-from ccalendar cimport dayofweek, get_day_of_year
+from ccalendar cimport dayofweek, get_day_of_year, is_leapyear
 from ccalendar import MONTH_NUMBERS
-from ccalendar cimport is_leapyear
 from conversion cimport tz_convert_utc_to_tzlocal
 from frequencies cimport (get_freq_code, get_base_alias,
                           get_to_timestamp_base, get_freq_str,

setup.py

@@ -592,6 +592,7 @@ def pxd(name):
     '_libs.tslibs.offsets': {
         'pyxfile': '_libs/tslibs/offsets',
         'pxdfiles': ['_libs/src/util',
+                     '_libs/tslibs/ccalendar',
                      '_libs/tslibs/conversion',
                      '_libs/tslibs/frequencies',
                      '_libs/tslibs/nattype'],