REF: move more of Tick into liboffsets._Tick (#34148)

Author: jbrockmendel

doc/source/reference/offset_frequency.rst

@@ -1044,6 +1044,7 @@ Properties
     Tick.nanos
     Tick.normalize
     Tick.rule_code
+    Tick.n
 
 Methods
 ~~~~~~~
@@ -1077,6 +1078,7 @@ Properties
     Day.nanos
     Day.normalize
     Day.rule_code
+    Day.n
 
 Methods
 ~~~~~~~
@@ -1110,6 +1112,7 @@ Properties
     Hour.nanos
     Hour.normalize
     Hour.rule_code
+    Hour.n
 
 Methods
 ~~~~~~~
@@ -1143,6 +1146,7 @@ Properties
     Minute.nanos
     Minute.normalize
     Minute.rule_code
+    Minute.n
 
 Methods
 ~~~~~~~
@@ -1176,6 +1180,7 @@ Properties
     Second.nanos
     Second.normalize
     Second.rule_code
+    Second.n
 
 Methods
 ~~~~~~~
@@ -1209,6 +1214,7 @@ Properties
     Milli.nanos
     Milli.normalize
     Milli.rule_code
+    Milli.n
 
 Methods
 ~~~~~~~
@@ -1242,6 +1248,7 @@ Properties
     Micro.nanos
     Micro.normalize
     Micro.rule_code
+    Micro.n
 
 Methods
 ~~~~~~~
@@ -1275,6 +1282,7 @@ Properties
     Nano.nanos
     Nano.normalize
     Nano.rule_code
+    Nano.n
 
 Methods
 ~~~~~~~

pandas/_libs/tslibs/offsets.pyx

@@ -35,6 +35,7 @@ from pandas._libs.tslibs.np_datetime cimport (
 from pandas._libs.tslibs.timezones cimport utc_pytz as UTC
 from pandas._libs.tslibs.tzconversion cimport tz_convert_single
 
+from pandas._libs.tslibs.timedeltas import Timedelta
 from pandas._libs.tslibs.timestamps import Timestamp
 
 # ---------------------------------------------------------------------
@@ -649,7 +650,10 @@ class _BaseOffset:
 
     # ------------------------------------------------------------------
 
-    def _validate_n(self, n):
+    # Staticmethod so we can call from _Tick.__init__, will be unnecessary
+    #  once BaseOffset is a cdef class and is inherited by _Tick
+    @staticmethod
+    def _validate_n(n):
         """
         Require that `n` be an integer.
 
@@ -766,13 +770,69 @@ cdef class _Tick(ABCTick):
     # ensure that reversed-ops with numpy scalars return NotImplemented
     __array_priority__ = 1000
     _adjust_dst = False
+    _inc = Timedelta(microseconds=1000)
+    _prefix = "undefined"
+    _attributes = frozenset(["n", "normalize"])
+
+    cdef readonly:
+        int64_t n
+        bint normalize
+        dict _cache
+
+    def __init__(self, n=1, normalize=False):
+        n = _BaseOffset._validate_n(n)
+        self.n = n
+        self.normalize = False
+        self._cache = {}
+        if normalize:
+            # GH#21427
+            raise ValueError(
+                "Tick offset with `normalize=True` are not allowed."
+            )
+
+    @property
+    def delta(self) -> Timedelta:
+        return self.n * self._inc
+
+    @property
+    def nanos(self) -> int64_t:
+        return self.delta.value
 
     def is_on_offset(self, dt) -> bool:
         return True
 
     def is_anchored(self) -> bool:
         return False
 
+    # --------------------------------------------------------------------
+    # Comparison and Arithmetic Methods
+
+    def __eq__(self, other):
+        if isinstance(other, str):
+            try:
+                # GH#23524 if to_offset fails, we are dealing with an
+                #  incomparable type so == is False and != is True
+                other = to_offset(other)
+            except ValueError:
+                # e.g. "infer"
+                return False
+        return self.delta == other
+
+    def __ne__(self, other):
+        return not (self == other)
+
+    def __le__(self, other):
+        return self.delta.__le__(other)
+
+    def __lt__(self, other):
+        return self.delta.__lt__(other)
+
+    def __ge__(self, other):
+        return self.delta.__ge__(other)
+
+    def __gt__(self, other):
+        return self.delta.__gt__(other)
+
     def __truediv__(self, other):
         if not isinstance(self, _Tick):
             # cython semantics mean the args are sometimes swapped
@@ -781,11 +841,15 @@ cdef class _Tick(ABCTick):
             result = self.delta.__truediv__(other)
         return _wrap_timedelta_result(result)
 
+    # --------------------------------------------------------------------
+    # Pickle Methods
+
     def __reduce__(self):
         return (type(self), (self.n,))
 
     def __setstate__(self, state):
-        object.__setattr__(self, "n", state["n"])
+        self.n = state["n"]
+        self.normalize = False
 
 
 class BusinessMixin:

pandas/tests/scalar/timestamp/test_arithmetic.py

@@ -52,7 +52,7 @@ def test_overflow_offset_raises(self):
         # used to crash, so check for proper overflow exception
 
         stamp = Timestamp("2000/1/1")
-        offset_overflow = to_offset("D") * 100 ** 25
+        offset_overflow = to_offset("D") * 100 ** 5
 
         with pytest.raises(OverflowError, match=msg):
             stamp + offset_overflow

pandas/tseries/offsets.py

@@ -1,6 +1,6 @@
 from datetime import date, datetime, timedelta
 import operator
-from typing import Any, Optional
+from typing import Optional
 
 from dateutil.easter import easter
 import numpy as np
@@ -2134,35 +2134,7 @@ def is_on_offset(self, dt: datetime) -> bool:
 # Ticks
 
 
-def _tick_comp(op):
-    """
-    Tick comparisons should behave identically to Timedelta comparisons.
-    """
-
-    def f(self, other):
-        return op(self.delta, other)
-
-    f.__name__ = f"__{op.__name__}__"
-    return f
-
-
 class Tick(liboffsets._Tick, SingleConstructorOffset):
-    _inc = Timedelta(microseconds=1000)
-    _prefix = "undefined"
-    _attributes = frozenset(["n", "normalize"])
-
-    def __init__(self, n=1, normalize=False):
-        BaseOffset.__init__(self, n, normalize)
-        if normalize:
-            raise ValueError(
-                "Tick offset with `normalize=True` are not allowed."
-            )  # GH#21427
-
-    __gt__ = _tick_comp(operator.gt)
-    __ge__ = _tick_comp(operator.ge)
-    __lt__ = _tick_comp(operator.lt)
-    __le__ = _tick_comp(operator.le)
-
     def __add__(self, other):
         if isinstance(other, Tick):
             if type(self) == type(other):
@@ -2180,47 +2152,11 @@ def __add__(self, other):
                 f"the add operation between {self} and {other} will overflow"
             ) from err
 
-    def __eq__(self, other: Any) -> bool:
-        if isinstance(other, str):
-            from pandas.tseries.frequencies import to_offset
-
-            try:
-                # GH#23524 if to_offset fails, we are dealing with an
-                #  incomparable type so == is False and != is True
-                other = to_offset(other)
-            except ValueError:
-                # e.g. "infer"
-                return False
-
-        return _tick_comp(operator.eq)(self, other)
-
     # This is identical to DateOffset.__hash__, but has to be redefined here
     # for Python 3, because we've redefined __eq__.
     def __hash__(self) -> int:
         return hash(self._params)
 
-    def __ne__(self, other):
-        if isinstance(other, str):
-            from pandas.tseries.frequencies import to_offset
-
-            try:
-                # GH#23524 if to_offset fails, we are dealing with an
-                #  incomparable type so == is False and != is True
-                other = to_offset(other)
-            except ValueError:
-                # e.g. "infer"
-                return True
-
-        return _tick_comp(operator.ne)(self, other)
-
-    @property
-    def delta(self) -> Timedelta:
-        return self.n * self._inc
-
-    @property
-    def nanos(self):
-        return delta_to_nanoseconds(self.delta)
-
     def apply(self, other):
         # Timestamp can handle tz and nano sec, thus no need to use apply_wraps
         if isinstance(other, Timestamp):
@@ -2240,6 +2176,9 @@ def apply(self, other):
         if isinstance(other, timedelta):
             return other + self.delta
         elif isinstance(other, type(self)):
+            # TODO: this is reached in tests that specifically call apply,
+            #  but should not be reached "naturally" because __add__ should
+            #  catch this case first.
             return type(self)(self.n + other.n)
 
         raise ApplyTypeError(f"Unhandled type: {type(other).__name__}")