From 665083fec45c6ed4f6ba226bcbeb8dbcbee6302b Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Thu, 2 Nov 2017 20:54:13 -0700
Subject: [PATCH 01/15] Move normalization funcs up to conversion

---
 pandas/_libs/tslib.pyx             | 145 +----------------------------
 pandas/_libs/tslibs/conversion.pyx | 140 +++++++++++++++++++++++-----
 2 files changed, 121 insertions(+), 164 deletions(-)

diff --git a/pandas/_libs/tslib.pyx b/pandas/_libs/tslib.pyx
index bf22a3a528259..474aad60aee7e 100644
--- a/pandas/_libs/tslib.pyx
+++ b/pandas/_libs/tslib.pyx
@@ -97,13 +97,15 @@ from tslibs.conversion cimport (tz_convert_single, _TSObject,
                                 convert_to_tsobject,
                                 convert_datetime_to_tsobject,
                                 get_datetime64_nanos)
-from tslibs.conversion import (
-    tz_localize_to_utc, tz_convert,
-    tz_convert_single)
+from tslibs.conversion import (tz_localize_to_utc, tz_convert,
+                               tz_convert_single, date_normalize,
+                               pydt_to_i8)
 
 from tslibs.nattype import NaT, nat_strings
 from tslibs.nattype cimport _checknull_with_nat
 
+from tslibs.normalization import dates_normalized
+
 
 cdef inline object create_timestamp_from_ts(
         int64_t value, pandas_datetimestruct dts,
@@ -1849,19 +1851,6 @@ cdef inline _to_i8(object val):
         return val
 
 
-cpdef pydt_to_i8(object pydt):
-    """
-    Convert to int64 representation compatible with numpy datetime64; converts
-    to UTC
-    """
-    cdef:
-        _TSObject ts
-
-    ts = convert_to_tsobject(pydt, None, None, 0, 0)
-
-    return ts.value
-
-
 def i8_to_pydt(int64_t i8, object tzinfo=None):
     """
     Inverse of pydt_to_i8
@@ -1892,130 +1881,6 @@ def get_time_micros(ndarray[int64_t] dtindex):
     return micros
 
 
-cdef int64_t DAY_NS = 86400000000000LL
-
-
-@cython.wraparound(False)
-@cython.boundscheck(False)
-def date_normalize(ndarray[int64_t] stamps, tz=None):
-    cdef:
-        Py_ssize_t i, n = len(stamps)
-        pandas_datetimestruct dts
-        ndarray[int64_t] result = np.empty(n, dtype=np.int64)
-
-    if tz is not None:
-        tz = maybe_get_tz(tz)
-        result = _normalize_local(stamps, tz)
-    else:
-        with nogil:
-            for i in range(n):
-                if stamps[i] == NPY_NAT:
-                    result[i] = NPY_NAT
-                    continue
-                dt64_to_dtstruct(stamps[i], &dts)
-                result[i] = _normalized_stamp(&dts)
-
-    return result
-
-
-@cython.wraparound(False)
-@cython.boundscheck(False)
-cdef _normalize_local(ndarray[int64_t] stamps, object tz):
-    cdef:
-        Py_ssize_t n = len(stamps)
-        ndarray[int64_t] result = np.empty(n, dtype=np.int64)
-        ndarray[int64_t] trans, deltas, pos
-        pandas_datetimestruct dts
-
-    if is_utc(tz):
-        with nogil:
-            for i in range(n):
-                if stamps[i] == NPY_NAT:
-                    result[i] = NPY_NAT
-                    continue
-                dt64_to_dtstruct(stamps[i], &dts)
-                result[i] = _normalized_stamp(&dts)
-    elif is_tzlocal(tz):
-        for i in range(n):
-            if stamps[i] == NPY_NAT:
-                result[i] = NPY_NAT
-                continue
-            dt64_to_dtstruct(stamps[i], &dts)
-            dt = datetime(dts.year, dts.month, dts.day, dts.hour,
-                          dts.min, dts.sec, dts.us, tz)
-            delta = int(get_utcoffset(tz, dt).total_seconds()) * 1000000000
-            dt64_to_dtstruct(stamps[i] + delta, &dts)
-            result[i] = _normalized_stamp(&dts)
-    else:
-        # Adjust datetime64 timestamp, recompute datetimestruct
-        trans, deltas, typ = get_dst_info(tz)
-
-        _pos = trans.searchsorted(stamps, side='right') - 1
-        if _pos.dtype != np.int64:
-            _pos = _pos.astype(np.int64)
-        pos = _pos
-
-        # statictzinfo
-        if typ not in ['pytz', 'dateutil']:
-            for i in range(n):
-                if stamps[i] == NPY_NAT:
-                    result[i] = NPY_NAT
-                    continue
-                dt64_to_dtstruct(stamps[i] + deltas[0], &dts)
-                result[i] = _normalized_stamp(&dts)
-        else:
-            for i in range(n):
-                if stamps[i] == NPY_NAT:
-                    result[i] = NPY_NAT
-                    continue
-                dt64_to_dtstruct(stamps[i] + deltas[pos[i]], &dts)
-                result[i] = _normalized_stamp(&dts)
-
-    return result
-
-cdef inline int64_t _normalized_stamp(pandas_datetimestruct *dts) nogil:
-    dts.hour = 0
-    dts.min = 0
-    dts.sec = 0
-    dts.us = 0
-    dts.ps = 0
-    return dtstruct_to_dt64(dts)
-
-
-def dates_normalized(ndarray[int64_t] stamps, tz=None):
-    cdef:
-        Py_ssize_t i, n = len(stamps)
-        ndarray[int64_t] trans, deltas
-        pandas_datetimestruct dts
-
-    if tz is None or is_utc(tz):
-        for i in range(n):
-            dt64_to_dtstruct(stamps[i], &dts)
-            if (dts.hour + dts.min + dts.sec + dts.us) > 0:
-                return False
-    elif is_tzlocal(tz):
-        for i in range(n):
-            dt64_to_dtstruct(stamps[i], &dts)
-            dt = datetime(dts.year, dts.month, dts.day, dts.hour, dts.min,
-                          dts.sec, dts.us, tz)
-            dt = dt + tz.utcoffset(dt)
-            if (dt.hour + dt.minute + dt.second + dt.microsecond) > 0:
-                return False
-    else:
-        trans, deltas, typ = get_dst_info(tz)
-
-        for i in range(n):
-            # Adjust datetime64 timestamp, recompute datetimestruct
-            pos = trans.searchsorted(stamps[i]) - 1
-            inf = tz._transition_info[pos]
-
-            dt64_to_dtstruct(stamps[i] + deltas[pos], &dts)
-            if (dts.hour + dts.min + dts.sec + dts.us) > 0:
-                return False
-
-    return True
-
-
 # ----------------------------------------------------------------------
 # Some general helper functions
 
diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index 61efc865112a9..83b6688b56592 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -53,7 +53,6 @@ UTC = pytz.UTC
 # ----------------------------------------------------------------------
 # Misc Helpers
 
-
 # TODO: How to declare np.datetime64 as the input type?
 cdef inline int64_t get_datetime64_nanos(object val) except? -1:
     """
@@ -90,6 +89,19 @@ cdef class _TSObject:
             return self.value
 
 
+cpdef pydt_to_i8(object pydt):
+    """
+    Convert to int64 representation compatible with numpy datetime64; converts
+    to UTC
+    """
+    cdef:
+        _TSObject ts
+
+    ts = convert_to_tsobject(pydt, None, None, 0, 0)
+
+    return ts.value
+
+
 cdef convert_to_tsobject(object ts, object tz, object unit,
                          bint dayfirst, bint yearfirst):
     """
@@ -335,17 +347,15 @@ cdef inline void _localize_tso(_TSObject obj, object tz):
         datetime dt
 
     if is_utc(tz):
-        obj.tzinfo = tz
+        pass
+    elif obj.value == NPY_NAT:
+        pass
     elif is_tzlocal(tz):
         dt64_to_dtstruct(obj.value, &obj.dts)
         dt = datetime(obj.dts.year, obj.dts.month, obj.dts.day, obj.dts.hour,
                       obj.dts.min, obj.dts.sec, obj.dts.us, tz)
         delta = int(get_utcoffset(tz, dt).total_seconds()) * 1000000000
-        if obj.value != NPY_NAT:
-            dt64_to_dtstruct(obj.value + delta, &obj.dts)
-        else:
-            dt64_to_dtstruct(obj.value, &obj.dts)
-        obj.tzinfo = tz
+        dt64_to_dtstruct(obj.value + delta, &obj.dts)
     else:
         # Adjust datetime64 timestamp, recompute datetimestruct
         trans, deltas, typ = get_dst_info(tz)
@@ -355,26 +365,16 @@ cdef inline void _localize_tso(_TSObject obj, object tz):
         # static/pytz/dateutil specific code
         if is_fixed_offset(tz):
             # statictzinfo
-            if len(deltas) > 0 and obj.value != NPY_NAT:
-                dt64_to_dtstruct(obj.value + deltas[0], &obj.dts)
-            else:
-                dt64_to_dtstruct(obj.value, &obj.dts)
-            obj.tzinfo = tz
+            dt64_to_dtstruct(obj.value + deltas[0], &obj.dts)
         elif treat_tz_as_pytz(tz):
-            inf = tz._transition_info[pos]
-            if obj.value != NPY_NAT:
-                dt64_to_dtstruct(obj.value + deltas[pos], &obj.dts)
-            else:
-                dt64_to_dtstruct(obj.value, &obj.dts)
-            obj.tzinfo = tz._tzinfos[inf]
+            tz = tz._tzinfos[tz._transition_info[pos]]
+            dt64_to_dtstruct(obj.value + deltas[pos], &obj.dts)
         elif treat_tz_as_dateutil(tz):
-            if obj.value != NPY_NAT:
-                dt64_to_dtstruct(obj.value + deltas[pos], &obj.dts)
-            else:
-                dt64_to_dtstruct(obj.value, &obj.dts)
-            obj.tzinfo = tz
+            dt64_to_dtstruct(obj.value + deltas[pos], &obj.dts)
         else:
-            obj.tzinfo = tz
+            pass
+
+    obj.tzinfo = tz
 
 
 cdef inline datetime _localize_pydatetime(datetime dt, tzinfo tz):
@@ -782,3 +782,95 @@ cdef inline str _render_tstamp(int64_t val):
     """ Helper function to render exception messages"""
     from pandas._libs.tslib import Timestamp
     return str(Timestamp(val))
+
+
+# ----------------------------------------------------------------------
+# Normalization
+
+@cython.wraparound(False)
+@cython.boundscheck(False)
+def date_normalize(ndarray[int64_t] stamps, tz=None):
+    cdef:
+        Py_ssize_t i, n = len(stamps)
+        pandas_datetimestruct dts
+        ndarray[int64_t] result = np.empty(n, dtype=np.int64)
+
+    if tz is not None:
+        tz = maybe_get_tz(tz)
+        result = _normalize_local(stamps, tz)
+    else:
+        with nogil:
+            for i in range(n):
+                if stamps[i] == NPY_NAT:
+                    result[i] = NPY_NAT
+                    continue
+                dt64_to_dtstruct(stamps[i], &dts)
+                result[i] = _normalized_stamp(&dts)
+
+    return result
+
+
+@cython.wraparound(False)
+@cython.boundscheck(False)
+cdef _normalize_local(ndarray[int64_t] stamps, object tz):
+    cdef:
+        Py_ssize_t n = len(stamps)
+        ndarray[int64_t] result = np.empty(n, dtype=np.int64)
+        ndarray[int64_t] trans, deltas, pos
+        pandas_datetimestruct dts
+        datetime dt
+
+    if is_utc(tz):
+        with nogil:
+            for i in range(n):
+                if stamps[i] == NPY_NAT:
+                    result[i] = NPY_NAT
+                    continue
+                dt64_to_dtstruct(stamps[i], &dts)
+                result[i] = _normalized_stamp(&dts)
+    elif is_tzlocal(tz):
+        for i in range(n):
+            if stamps[i] == NPY_NAT:
+                result[i] = NPY_NAT
+                continue
+            dt64_to_dtstruct(stamps[i], &dts)
+            dt = datetime(dts.year, dts.month, dts.day, dts.hour,
+                          dts.min, dts.sec, dts.us, tz)
+            delta = int(get_utcoffset(tz, dt).total_seconds()) * 1000000000
+            dt64_to_dtstruct(stamps[i] + delta, &dts)
+            result[i] = _normalized_stamp(&dts)
+    else:
+        # Adjust datetime64 timestamp, recompute datetimestruct
+        trans, deltas, typ = get_dst_info(tz)
+
+        _pos = trans.searchsorted(stamps, side='right') - 1
+        if _pos.dtype != np.int64:
+            _pos = _pos.astype(np.int64)
+        pos = _pos
+
+        # statictzinfo
+        if typ not in ['pytz', 'dateutil']:
+            for i in range(n):
+                if stamps[i] == NPY_NAT:
+                    result[i] = NPY_NAT
+                    continue
+                dt64_to_dtstruct(stamps[i] + deltas[0], &dts)
+                result[i] = _normalized_stamp(&dts)
+        else:
+            for i in range(n):
+                if stamps[i] == NPY_NAT:
+                    result[i] = NPY_NAT
+                    continue
+                dt64_to_dtstruct(stamps[i] + deltas[pos[i]], &dts)
+                result[i] = _normalized_stamp(&dts)
+
+    return result
+
+
+cdef inline int64_t _normalized_stamp(pandas_datetimestruct *dts) nogil:
+    dts.hour = 0
+    dts.min = 0
+    dts.sec = 0
+    dts.us = 0
+    dts.ps = 0
+    return dtstruct_to_dt64(dts)

From 5481d7b114c8a1c41b4944c18e3d70cd025f902b Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Thu, 2 Nov 2017 22:08:25 -0700
Subject: [PATCH 02/15] fixup import typo

---
 pandas/_libs/tslib.pyx             |  7 +++---
 pandas/_libs/tslibs/conversion.pyx | 35 ++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/pandas/_libs/tslib.pyx b/pandas/_libs/tslib.pyx
index 474aad60aee7e..66f4aec5bfc06 100644
--- a/pandas/_libs/tslib.pyx
+++ b/pandas/_libs/tslib.pyx
@@ -97,14 +97,13 @@ from tslibs.conversion cimport (tz_convert_single, _TSObject,
                                 convert_to_tsobject,
                                 convert_datetime_to_tsobject,
                                 get_datetime64_nanos)
-from tslibs.conversion import (tz_localize_to_utc, tz_convert,
-                               tz_convert_single, date_normalize,
-                               pydt_to_i8)
+from tslibs.conversion import (tz_localize_to_utc,
+                               tz_convert_single, date_normalize)
+from tslibs.conversion import dates_normalized, pydt_to_i8, tz_convert  # noqa
 
 from tslibs.nattype import NaT, nat_strings
 from tslibs.nattype cimport _checknull_with_nat
 
-from tslibs.normalization import dates_normalized
 
 
 cdef inline object create_timestamp_from_ts(
diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index 83b6688b56592..8dad573786bc8 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -874,3 +874,38 @@ cdef inline int64_t _normalized_stamp(pandas_datetimestruct *dts) nogil:
     dts.us = 0
     dts.ps = 0
     return dtstruct_to_dt64(dts)
+
+
+def dates_normalized(ndarray[int64_t] stamps, tz=None):
+    cdef:
+        Py_ssize_t i, n = len(stamps)
+        ndarray[int64_t] trans, deltas
+        pandas_datetimestruct dts
+        datetime dt
+
+    if tz is None or is_utc(tz):
+        for i in range(n):
+            dt64_to_dtstruct(stamps[i], &dts)
+            if (dts.hour + dts.min + dts.sec + dts.us) > 0:
+                return False
+    elif is_tzlocal(tz):
+        for i in range(n):
+            dt64_to_dtstruct(stamps[i], &dts)
+            dt = datetime(dts.year, dts.month, dts.day, dts.hour, dts.min,
+                          dts.sec, dts.us, tz)
+            dt = dt + tz.utcoffset(dt)
+            if (dt.hour + dt.minute + dt.second + dt.microsecond) > 0:
+                return False
+    else:
+        trans, deltas, typ = get_dst_info(tz)
+
+        for i in range(n):
+            # Adjust datetime64 timestamp, recompute datetimestruct
+            pos = trans.searchsorted(stamps[i]) - 1
+            inf = tz._transition_info[pos]
+
+            dt64_to_dtstruct(stamps[i] + deltas[pos], &dts)
+            if (dts.hour + dts.min + dts.sec + dts.us) > 0:
+                return False
+
+    return True

From 9db556824ebb8358b51335eb5a4e21b447bff3c1 Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Fri, 3 Nov 2017 07:57:47 -0700
Subject: [PATCH 03/15] whitespace fixup

---
 pandas/_libs/tslib.pyx | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/_libs/tslib.pyx b/pandas/_libs/tslib.pyx
index 66f4aec5bfc06..d9446ab28b444 100644
--- a/pandas/_libs/tslib.pyx
+++ b/pandas/_libs/tslib.pyx
@@ -105,7 +105,6 @@ from tslibs.nattype import NaT, nat_strings
 from tslibs.nattype cimport _checknull_with_nat
 
 
-
 cdef inline object create_timestamp_from_ts(
         int64_t value, pandas_datetimestruct dts,
         object tz, object freq):

From 57e6204786e2ccdfda0067955697239eb32ef9d5 Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Tue, 7 Nov 2017 08:38:25 -0800
Subject: [PATCH 04/15] edits per reviewer request

---
 pandas/_libs/tslib.pyx             | 2 +-
 pandas/_libs/tslibs/conversion.pyx | 3 ++-
 pandas/core/indexes/datetimes.py   | 4 ++--
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/pandas/_libs/tslib.pyx b/pandas/_libs/tslib.pyx
index d9446ab28b444..140fde4fd4de6 100644
--- a/pandas/_libs/tslib.pyx
+++ b/pandas/_libs/tslib.pyx
@@ -99,7 +99,7 @@ from tslibs.conversion cimport (tz_convert_single, _TSObject,
                                 get_datetime64_nanos)
 from tslibs.conversion import (tz_localize_to_utc,
                                tz_convert_single, date_normalize)
-from tslibs.conversion import dates_normalized, pydt_to_i8, tz_convert  # noqa
+from tslibs.conversion import pydt_to_i8, tz_convert  # noqa
 
 from tslibs.nattype import NaT, nat_strings
 from tslibs.nattype cimport _checknull_with_nat
diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index 8dad573786bc8..bb5f85db81ce6 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -365,6 +365,7 @@ cdef inline void _localize_tso(_TSObject obj, object tz):
         # static/pytz/dateutil specific code
         if is_fixed_offset(tz):
             # statictzinfo
+            assert len(deltas) == 1, len(deltas)
             dt64_to_dtstruct(obj.value + deltas[0], &obj.dts)
         elif treat_tz_as_pytz(tz):
             tz = tz._tzinfos[tz._transition_info[pos]]
@@ -876,7 +877,7 @@ cdef inline int64_t _normalized_stamp(pandas_datetimestruct *dts) nogil:
     return dtstruct_to_dt64(dts)
 
 
-def dates_normalized(ndarray[int64_t] stamps, tz=None):
+def are_dates_normalized(ndarray[int64_t] stamps, tz=None):
     cdef:
         Py_ssize_t i, n = len(stamps)
         ndarray[int64_t] trans, deltas
diff --git a/pandas/core/indexes/datetimes.py b/pandas/core/indexes/datetimes.py
index 78869de318dce..501797c1310a6 100644
--- a/pandas/core/indexes/datetimes.py
+++ b/pandas/core/indexes/datetimes.py
@@ -56,7 +56,7 @@
                           algos as libalgos, join as libjoin,
                           Timestamp, period as libperiod)
 from pandas._libs.tslibs import timezones
-
+from pandas._libs.tslibs.conversion import are_dates_normalized
 
 # -------- some conversion wrapper functions
 
@@ -1683,7 +1683,7 @@ def is_normalized(self):
         """
         Returns True if all of the dates are at midnight ("no time")
         """
-        return libts.dates_normalized(self.asi8, self.tz)
+        return are_dates_normalized(self.asi8, self.tz)
 
     @cache_readonly
     def _resolution(self):

From 1c7a1b19b76f9821a94411059280ca95ae68cacf Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Tue, 7 Nov 2017 09:08:23 -0800
Subject: [PATCH 05/15] assert obj.tzinfo is None inbound

---
 pandas/_libs/tslibs/conversion.pyx | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index bb5f85db81ce6..eb4a468e68e49 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -346,6 +346,8 @@ cdef inline void _localize_tso(_TSObject obj, object tz):
         Py_ssize_t delta, posn
         datetime dt
 
+    assert obj.tzinfo is None
+
     if is_utc(tz):
         pass
     elif obj.value == NPY_NAT:

From 8192f870634e096db1a876fdb7713ab1e5694b38 Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Tue, 7 Nov 2017 10:05:01 -0800
Subject: [PATCH 06/15] update imports

---
 pandas/_libs/tslib.pyx                 |  1 -
 pandas/_libs/tslibs/conversion.pxd     |  2 ++
 pandas/_libs/tslibs/offsets.pyx        |  4 +---
 pandas/core/indexes/datetimes.py       | 33 +++++++++++++-------------
 pandas/tests/scalar/test_timestamp.py  | 21 ++++++++--------
 pandas/tests/tseries/test_timezones.py | 22 ++++++++---------
 pandas/tseries/frequencies.py          |  4 +++-
 7 files changed, 44 insertions(+), 43 deletions(-)

diff --git a/pandas/_libs/tslib.pyx b/pandas/_libs/tslib.pyx
index 140fde4fd4de6..c51c1bad01aa8 100644
--- a/pandas/_libs/tslib.pyx
+++ b/pandas/_libs/tslib.pyx
@@ -99,7 +99,6 @@ from tslibs.conversion cimport (tz_convert_single, _TSObject,
                                 get_datetime64_nanos)
 from tslibs.conversion import (tz_localize_to_utc,
                                tz_convert_single, date_normalize)
-from tslibs.conversion import pydt_to_i8, tz_convert  # noqa
 
 from tslibs.nattype import NaT, nat_strings
 from tslibs.nattype cimport _checknull_with_nat
diff --git a/pandas/_libs/tslibs/conversion.pxd b/pandas/_libs/tslibs/conversion.pxd
index 843a688a2630c..77888e0946dcb 100644
--- a/pandas/_libs/tslibs/conversion.pxd
+++ b/pandas/_libs/tslibs/conversion.pxd
@@ -15,6 +15,8 @@ cdef class _TSObject:
         object tzinfo
 
 
+cpdef pydt_to_i8(object pydt)
+
 cdef convert_to_tsobject(object ts, object tz, object unit,
                          bint dayfirst, bint yearfirst)
 
diff --git a/pandas/_libs/tslibs/offsets.pyx b/pandas/_libs/tslibs/offsets.pyx
index 87be9fa910101..dafa8244c6e19 100644
--- a/pandas/_libs/tslibs/offsets.pyx
+++ b/pandas/_libs/tslibs/offsets.pyx
@@ -15,10 +15,8 @@ np.import_array()
 
 from util cimport is_string_object
 
-from pandas._libs.tslib import pydt_to_i8
-
+from conversion cimport tz_convert_single, pydt_to_i8
 from frequencies cimport get_freq_code
-from conversion cimport tz_convert_single
 
 # ---------------------------------------------------------------------
 # Constants
diff --git a/pandas/core/indexes/datetimes.py b/pandas/core/indexes/datetimes.py
index 501797c1310a6..3329cccfcdfec 100644
--- a/pandas/core/indexes/datetimes.py
+++ b/pandas/core/indexes/datetimes.py
@@ -55,8 +55,7 @@
 from pandas._libs import (lib, index as libindex, tslib as libts,
                           algos as libalgos, join as libjoin,
                           Timestamp, period as libperiod)
-from pandas._libs.tslibs import timezones
-from pandas._libs.tslibs.conversion import are_dates_normalized
+from pandas._libs.tslibs import timezones, conversion
 
 # -------- some conversion wrapper functions
 
@@ -384,8 +383,8 @@ def __new__(cls, data=None,
                         getattr(data, 'tz', None) is None):
                     # Convert tz-naive to UTC
                     ints = subarr.view('i8')
-                    subarr = libts.tz_localize_to_utc(ints, tz,
-                                                      ambiguous=ambiguous)
+                    subarr = conversion.tz_localize_to_utc(ints, tz,
+                                                           ambiguous=ambiguous)
                 subarr = subarr.view(_NS_DTYPE)
 
         subarr = cls._simple_new(subarr, name=name, freq=freq, tz=tz)
@@ -531,8 +530,8 @@ def _generate(cls, start, end, periods, name, offset,
                 index = _generate_regular_range(start, end, periods, offset)
 
             if tz is not None and getattr(index, 'tz', None) is None:
-                index = libts.tz_localize_to_utc(_ensure_int64(index), tz,
-                                                 ambiguous=ambiguous)
+                index = conversion.tz_localize_to_utc(_ensure_int64(index), tz,
+                                                      ambiguous=ambiguous)
                 index = index.view(_NS_DTYPE)
 
                 # index is localized datetime64 array -> have to convert
@@ -561,11 +560,11 @@ def _convert_for_op(self, value):
 
     def _local_timestamps(self):
         if self.is_monotonic:
-            return libts.tz_convert(self.asi8, utc, self.tz)
+            return conversion.tz_convert(self.asi8, utc, self.tz)
         else:
             values = self.asi8
             indexer = values.argsort()
-            result = libts.tz_convert(values.take(indexer), utc, self.tz)
+            result = conversion.tz_convert(values.take(indexer), utc, self.tz)
 
             n = len(indexer)
             reverse = np.empty(n, dtype=np.int_)
@@ -1644,7 +1643,7 @@ def normalize(self):
         -------
         normalized : DatetimeIndex
         """
-        new_values = libts.date_normalize(self.asi8, self.tz)
+        new_values = conversion.date_normalize(self.asi8, self.tz)
         return DatetimeIndex(new_values, freq='infer', name=self.name,
                              tz=self.tz)
 
@@ -1683,7 +1682,7 @@ def is_normalized(self):
         """
         Returns True if all of the dates are at midnight ("no time")
         """
-        return are_dates_normalized(self.asi8, self.tz)
+        return conversion.are_dates_normalized(self.asi8, self.tz)
 
     @cache_readonly
     def _resolution(self):
@@ -1724,7 +1723,7 @@ def insert(self, loc, item):
             new_dates = np.concatenate((self[:loc].asi8, [item.view(np.int64)],
                                         self[loc:].asi8))
             if self.tz is not None:
-                new_dates = libts.tz_convert(new_dates, 'UTC', self.tz)
+                new_dates = conversion.tz_convert(new_dates, 'UTC', self.tz)
             return DatetimeIndex(new_dates, name=self.name, freq=freq,
                                  tz=self.tz)
 
@@ -1764,7 +1763,7 @@ def delete(self, loc):
                     freq = self.freq
 
         if self.tz is not None:
-            new_dates = libts.tz_convert(new_dates, 'UTC', self.tz)
+            new_dates = conversion.tz_convert(new_dates, 'UTC', self.tz)
         return DatetimeIndex(new_dates, name=self.name, freq=freq, tz=self.tz)
 
     def tz_convert(self, tz):
@@ -1844,16 +1843,16 @@ def tz_localize(self, tz, ambiguous='raise', errors='raise'):
         """
         if self.tz is not None:
             if tz is None:
-                new_dates = libts.tz_convert(self.asi8, 'UTC', self.tz)
+                new_dates = conversion.tz_convert(self.asi8, 'UTC', self.tz)
             else:
                 raise TypeError("Already tz-aware, use tz_convert to convert.")
         else:
             tz = timezones.maybe_get_tz(tz)
             # Convert to UTC
 
-            new_dates = libts.tz_localize_to_utc(self.asi8, tz,
-                                                 ambiguous=ambiguous,
-                                                 errors=errors)
+            new_dates = conversion.tz_localize_to_utc(self.asi8, tz,
+                                                      ambiguous=ambiguous,
+                                                      errors=errors)
         new_dates = new_dates.view(_NS_DTYPE)
         return self._shallow_copy(new_dates, tz=tz)
 
@@ -2194,7 +2193,7 @@ def _to_m8(key, tz=None):
         # this also converts strings
         key = Timestamp(key, tz=tz)
 
-    return np.int64(libts.pydt_to_i8(key)).view(_NS_DTYPE)
+    return np.int64(conversion.pydt_to_i8(key)).view(_NS_DTYPE)
 
 
 _CACHE_START = Timestamp(datetime(1950, 1, 1))
diff --git a/pandas/tests/scalar/test_timestamp.py b/pandas/tests/scalar/test_timestamp.py
index 4cd9a2fadeb32..517fc062fad80 100644
--- a/pandas/tests/scalar/test_timestamp.py
+++ b/pandas/tests/scalar/test_timestamp.py
@@ -18,6 +18,7 @@
 from pandas.tseries import offsets, frequencies
 from pandas._libs import tslib, period
 from pandas._libs.tslibs.timezones import get_timezone
+from pandas._libs.tslibs import conversion
 
 from pandas.compat import lrange, long, PY3
 from pandas.util.testing import assert_series_equal
@@ -77,12 +78,12 @@ def test_constructor(self):
             for result in [Timestamp(date_str), Timestamp(date)]:
                 # only with timestring
                 assert result.value == expected
-                assert tslib.pydt_to_i8(result) == expected
+                assert conversion.pydt_to_i8(result) == expected
 
                 # re-creation shouldn't affect to internal value
                 result = Timestamp(result)
                 assert result.value == expected
-                assert tslib.pydt_to_i8(result) == expected
+                assert conversion.pydt_to_i8(result) == expected
 
             # with timezone
             for tz, offset in timezones:
@@ -90,18 +91,18 @@ def test_constructor(self):
                                                                      tz=tz)]:
                     expected_tz = expected - offset * 3600 * 1000000000
                     assert result.value == expected_tz
-                    assert tslib.pydt_to_i8(result) == expected_tz
+                    assert conversion.pydt_to_i8(result) == expected_tz
 
                     # should preserve tz
                     result = Timestamp(result)
                     assert result.value == expected_tz
-                    assert tslib.pydt_to_i8(result) == expected_tz
+                    assert conversion.pydt_to_i8(result) == expected_tz
 
                     # should convert to UTC
                     result = Timestamp(result, tz='UTC')
                     expected_utc = expected - offset * 3600 * 1000000000
                     assert result.value == expected_utc
-                    assert tslib.pydt_to_i8(result) == expected_utc
+                    assert conversion.pydt_to_i8(result) == expected_utc
 
     def test_constructor_with_stringoffset(self):
         # GH 7833
@@ -129,30 +130,30 @@ def test_constructor_with_stringoffset(self):
             for result in [Timestamp(date_str)]:
                 # only with timestring
                 assert result.value == expected
-                assert tslib.pydt_to_i8(result) == expected
+                assert conversion.pydt_to_i8(result) == expected
 
                 # re-creation shouldn't affect to internal value
                 result = Timestamp(result)
                 assert result.value == expected
-                assert tslib.pydt_to_i8(result) == expected
+                assert conversion.pydt_to_i8(result) == expected
 
             # with timezone
             for tz, offset in timezones:
                 result = Timestamp(date_str, tz=tz)
                 expected_tz = expected
                 assert result.value == expected_tz
-                assert tslib.pydt_to_i8(result) == expected_tz
+                assert conversion.pydt_to_i8(result) == expected_tz
 
                 # should preserve tz
                 result = Timestamp(result)
                 assert result.value == expected_tz
-                assert tslib.pydt_to_i8(result) == expected_tz
+                assert conversion.pydt_to_i8(result) == expected_tz
 
                 # should convert to UTC
                 result = Timestamp(result, tz='UTC')
                 expected_utc = expected
                 assert result.value == expected_utc
-                assert tslib.pydt_to_i8(result) == expected_utc
+                assert conversion.pydt_to_i8(result) == expected_utc
 
         # This should be 2013-11-01 05:00 in UTC
         # converted to Chicago tz
diff --git a/pandas/tests/tseries/test_timezones.py b/pandas/tests/tseries/test_timezones.py
index ddcf1bb7d8b7b..fe340a7e3196f 100644
--- a/pandas/tests/tseries/test_timezones.py
+++ b/pandas/tests/tseries/test_timezones.py
@@ -17,7 +17,7 @@
 from pandas.core.indexes.datetimes import bdate_range, date_range
 from pandas.core.dtypes.dtypes import DatetimeTZDtype
 from pandas._libs import tslib
-from pandas._libs.tslibs import timezones
+from pandas._libs.tslibs import timezones, conversion
 from pandas import (Index, Series, DataFrame, isna, Timestamp, NaT,
                     DatetimeIndex, to_datetime)
 from pandas.util.testing import (assert_frame_equal, assert_series_equal,
@@ -1732,14 +1732,14 @@ class TestTslib(object):
 
     def test_tslib_tz_convert(self):
         def compare_utc_to_local(tz_didx, utc_didx):
-            f = lambda x: tslib.tz_convert_single(x, 'UTC', tz_didx.tz)
-            result = tslib.tz_convert(tz_didx.asi8, 'UTC', tz_didx.tz)
+            f = lambda x: conversion_single(x, 'UTC', tz_didx.tz)
+            result = conversion(tz_didx.asi8, 'UTC', tz_didx.tz)
             result_single = np.vectorize(f)(tz_didx.asi8)
             tm.assert_numpy_array_equal(result, result_single)
 
         def compare_local_to_utc(tz_didx, utc_didx):
-            f = lambda x: tslib.tz_convert_single(x, tz_didx.tz, 'UTC')
-            result = tslib.tz_convert(utc_didx.asi8, tz_didx.tz, 'UTC')
+            f = lambda x: conversion_single(x, tz_didx.tz, 'UTC')
+            result = conversion(utc_didx.asi8, tz_didx.tz, 'UTC')
             result_single = np.vectorize(f)(utc_didx.asi8)
             tm.assert_numpy_array_equal(result, result_single)
 
@@ -1764,14 +1764,14 @@ def compare_local_to_utc(tz_didx, utc_didx):
             compare_local_to_utc(tz_didx, utc_didx)
 
         # Check empty array
-        result = tslib.tz_convert(np.array([], dtype=np.int64),
-                                  timezones.maybe_get_tz('US/Eastern'),
-                                  timezones.maybe_get_tz('Asia/Tokyo'))
+        result = conversion.tz_convert(np.array([], dtype=np.int64),
+                                       timezones.maybe_get_tz('US/Eastern'),
+                                       timezones.maybe_get_tz('Asia/Tokyo'))
         tm.assert_numpy_array_equal(result, np.array([], dtype=np.int64))
 
         # Check all-NaT array
-        result = tslib.tz_convert(np.array([tslib.iNaT], dtype=np.int64),
-                                  timezones.maybe_get_tz('US/Eastern'),
-                                  timezones.maybe_get_tz('Asia/Tokyo'))
+        result = conversion.tz_convert(np.array([tslib.iNaT], dtype=np.int64),
+                                       timezones.maybe_get_tz('US/Eastern'),
+                                       timezones.maybe_get_tz('Asia/Tokyo'))
         tm.assert_numpy_array_equal(result, np.array(
             [tslib.iNaT], dtype=np.int64))
diff --git a/pandas/tseries/frequencies.py b/pandas/tseries/frequencies.py
index be25a439f9075..128dd51a2abea 100644
--- a/pandas/tseries/frequencies.py
+++ b/pandas/tseries/frequencies.py
@@ -21,6 +21,7 @@
 
 from pandas._libs import lib, tslib
 from pandas._libs.tslib import Timedelta
+from pandas._libs.tslibs import conversion
 from pandas._libs.tslibs.frequencies import (  # noqa
     get_freq_code, _base_and_stride, _period_str_to_code,
     _INVALID_FREQ_ERROR, opattern, _lite_rule_alias, _dont_uppercase,
@@ -583,7 +584,8 @@ def __init__(self, index, warn=True):
         # the timezone so they are in local time
         if hasattr(index, 'tz'):
             if index.tz is not None:
-                self.values = tslib.tz_convert(self.values, 'UTC', index.tz)
+                self.values = conversion.tz_convert(self.values,
+                                                    'UTC', index.tz)
 
         self.warn = warn
 

From 7b7e719d630db53097013ce13709deb7c629d175 Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Tue, 7 Nov 2017 18:37:34 -0800
Subject: [PATCH 07/15] declare pydt_to_i8 in pxd

---
 pandas/_libs/tslibs/conversion.pxd | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pandas/_libs/tslibs/conversion.pxd b/pandas/_libs/tslibs/conversion.pxd
index 77888e0946dcb..087020323b24c 100644
--- a/pandas/_libs/tslibs/conversion.pxd
+++ b/pandas/_libs/tslibs/conversion.pxd
@@ -28,3 +28,5 @@ cdef void _localize_tso(_TSObject obj, object tz)
 cpdef int64_t tz_convert_single(int64_t val, object tz1, object tz2)
 
 cdef int64_t get_datetime64_nanos(object val) except? -1
+
+cpdef pydt_to_i8(object pydt)

From 3c7e5aa254c3f50492c4396c1e3b264483aa5373 Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Tue, 7 Nov 2017 21:38:24 -0800
Subject: [PATCH 08/15] typo fixup

---
 pandas/tests/scalar/test_timestamp.py  | 2 +-
 pandas/tests/tseries/test_timezones.py | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/pandas/tests/scalar/test_timestamp.py b/pandas/tests/scalar/test_timestamp.py
index 517fc062fad80..a695de6952ae1 100644
--- a/pandas/tests/scalar/test_timestamp.py
+++ b/pandas/tests/scalar/test_timestamp.py
@@ -16,7 +16,7 @@
 
 import pandas.util.testing as tm
 from pandas.tseries import offsets, frequencies
-from pandas._libs import tslib, period
+from pandas._libs import period
 from pandas._libs.tslibs.timezones import get_timezone
 from pandas._libs.tslibs import conversion
 
diff --git a/pandas/tests/tseries/test_timezones.py b/pandas/tests/tseries/test_timezones.py
index fe340a7e3196f..1604a1cd61f6b 100644
--- a/pandas/tests/tseries/test_timezones.py
+++ b/pandas/tests/tseries/test_timezones.py
@@ -1732,14 +1732,14 @@ class TestTslib(object):
 
     def test_tslib_tz_convert(self):
         def compare_utc_to_local(tz_didx, utc_didx):
-            f = lambda x: conversion_single(x, 'UTC', tz_didx.tz)
-            result = conversion(tz_didx.asi8, 'UTC', tz_didx.tz)
+            f = lambda x: conversion.tz_convert_single(x, 'UTC', tz_didx.tz)
+            result = conversion.tz_convert(tz_didx.asi8, 'UTC', tz_didx.tz)
             result_single = np.vectorize(f)(tz_didx.asi8)
             tm.assert_numpy_array_equal(result, result_single)
 
         def compare_local_to_utc(tz_didx, utc_didx):
-            f = lambda x: conversion_single(x, tz_didx.tz, 'UTC')
-            result = conversion(utc_didx.asi8, tz_didx.tz, 'UTC')
+            f = lambda x: conversion.tz_convert_single(x, tz_didx.tz, 'UTC')
+            result = conversion.tz_convert(utc_didx.asi8, tz_didx.tz, 'UTC')
             result_single = np.vectorize(f)(utc_didx.asi8)
             tm.assert_numpy_array_equal(result, result_single)
 

From ec6757f04353d0c1d8083dbeac0ef9bf6a93dd71 Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Tue, 7 Nov 2017 22:06:11 -0800
Subject: [PATCH 09/15] edits per reviewer request

---
 pandas/_libs/tslib.pyx             |  7 -----
 pandas/_libs/tslibs/conversion.pxd |  2 +-
 pandas/_libs/tslibs/conversion.pyx | 41 +++++++++++++++++++++++++++---
 pandas/core/indexes/datetimes.py   |  2 +-
 4 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/pandas/_libs/tslib.pyx b/pandas/_libs/tslib.pyx
index c51c1bad01aa8..b5285d158b1ed 100644
--- a/pandas/_libs/tslib.pyx
+++ b/pandas/_libs/tslib.pyx
@@ -1848,13 +1848,6 @@ cdef inline _to_i8(object val):
         return val
 
 
-def i8_to_pydt(int64_t i8, object tzinfo=None):
-    """
-    Inverse of pydt_to_i8
-    """
-    return Timestamp(i8)
-
-
 # ----------------------------------------------------------------------
 # Accessors
 
diff --git a/pandas/_libs/tslibs/conversion.pxd b/pandas/_libs/tslibs/conversion.pxd
index 087020323b24c..98582c0c6d9c7 100644
--- a/pandas/_libs/tslibs/conversion.pxd
+++ b/pandas/_libs/tslibs/conversion.pxd
@@ -29,4 +29,4 @@ cpdef int64_t tz_convert_single(int64_t val, object tz1, object tz2)
 
 cdef int64_t get_datetime64_nanos(object val) except? -1
 
-cpdef pydt_to_i8(object pydt)
+cpdef int64_t pydt_to_i8(object pydt) except? -1
\ No newline at end of file
diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index eb4a468e68e49..178147e2ec375 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -89,7 +89,7 @@ cdef class _TSObject:
             return self.value
 
 
-cpdef pydt_to_i8(object pydt):
+cpdef int64_t pydt_to_i8(object pydt) except? -1:
     """
     Convert to int64 representation compatible with numpy datetime64; converts
     to UTC
@@ -102,6 +102,14 @@ cpdef pydt_to_i8(object pydt):
     return ts.value
 
 
+def i8_to_pydt(int64_t i8, object tzinfo=None):
+    """
+    Inverse of pydt_to_i8
+    """
+    from pandas import Timestamp
+    return Timestamp(i8)
+
+
 cdef convert_to_tsobject(object ts, object tz, object unit,
                          bint dayfirst, bint yearfirst):
     """
@@ -793,6 +801,15 @@ cdef inline str _render_tstamp(int64_t val):
 @cython.wraparound(False)
 @cython.boundscheck(False)
 def date_normalize(ndarray[int64_t] stamps, tz=None):
+    """
+    Normalize each of the (nanosecond) timestamps in the given array by
+    rounding down to the beginning of the day (i.e. midnight).  If `tz`
+    is not None, then this is midnight for this timezone.
+
+    Returns
+    -------
+    result : int64 ndarray of converted of normalized nanosecond timestamps
+    """
     cdef:
         Py_ssize_t i, n = len(stamps)
         pandas_datetimestruct dts
@@ -815,7 +832,16 @@ def date_normalize(ndarray[int64_t] stamps, tz=None):
 
 @cython.wraparound(False)
 @cython.boundscheck(False)
-cdef _normalize_local(ndarray[int64_t] stamps, object tz):
+cdef ndarray[int64_t] _normalize_local(ndarray[int64_t] stamps, object tz):
+    """
+    Normalize each of the (nanosecond) timestamps in the given array by
+    rounding down to the beginning of the day (i.e. midnight) for the
+    given timezone `tz`.
+
+    Returns
+    -------
+    result : int64 ndarray of converted of normalized nanosecond timestamps
+    """
     cdef:
         Py_ssize_t n = len(stamps)
         ndarray[int64_t] result = np.empty(n, dtype=np.int64)
@@ -879,7 +905,16 @@ cdef inline int64_t _normalized_stamp(pandas_datetimestruct *dts) nogil:
     return dtstruct_to_dt64(dts)
 
 
-def are_dates_normalized(ndarray[int64_t] stamps, tz=None):
+def bint is_date_array_normalized(ndarray[int64_t] stamps, tz=None):
+    """
+    Check if all of the given (nanosecond) timestamps are normalized to
+    midnight, i.e. hour == minute == second == 0.  If the optional timezone
+    `tz` is not None, then this is midnight for this timezone.
+
+    Returns
+    -------
+    is_normalizaed : bool True if all stamps are normalized
+    """
     cdef:
         Py_ssize_t i, n = len(stamps)
         ndarray[int64_t] trans, deltas
diff --git a/pandas/core/indexes/datetimes.py b/pandas/core/indexes/datetimes.py
index 3329cccfcdfec..8a1a36db5ac64 100644
--- a/pandas/core/indexes/datetimes.py
+++ b/pandas/core/indexes/datetimes.py
@@ -1682,7 +1682,7 @@ def is_normalized(self):
         """
         Returns True if all of the dates are at midnight ("no time")
         """
-        return conversion.are_dates_normalized(self.asi8, self.tz)
+        return conversion.is_date_array_normalized(self.asi8, self.tz)
 
     @cache_readonly
     def _resolution(self):

From 07c95944151135a1b1a25d6c7b1095101dc8982b Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Wed, 8 Nov 2017 07:19:17 -0800
Subject: [PATCH 10/15] remove unallowed type declaration

---
 pandas/_libs/tslibs/conversion.pyx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index 178147e2ec375..9d1db0eb8b137 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -905,7 +905,7 @@ cdef inline int64_t _normalized_stamp(pandas_datetimestruct *dts) nogil:
     return dtstruct_to_dt64(dts)
 
 
-def bint is_date_array_normalized(ndarray[int64_t] stamps, tz=None):
+def is_date_array_normalized(ndarray[int64_t] stamps, tz=None):
     """
     Check if all of the given (nanosecond) timestamps are normalized to
     midnight, i.e. hour == minute == second == 0.  If the optional timezone

From 505f740ed0d2323207c5a30a1a0eb25a48877deb Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Thu, 9 Nov 2017 07:56:27 -0800
Subject: [PATCH 11/15] edits per reviewer request

---
 pandas/_libs/tslibs/conversion.pyx | 36 +++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index 9d1db0eb8b137..abe0b3d3cda7e 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -93,6 +93,14 @@ cpdef int64_t pydt_to_i8(object pydt) except? -1:
     """
     Convert to int64 representation compatible with numpy datetime64; converts
     to UTC
+
+    Parameters
+    ----------
+    pydt : object
+
+    Returns
+    -------
+    i8value : np.int64
     """
     cdef:
         _TSObject ts
@@ -806,6 +814,11 @@ def date_normalize(ndarray[int64_t] stamps, tz=None):
     rounding down to the beginning of the day (i.e. midnight).  If `tz`
     is not None, then this is midnight for this timezone.
 
+    Parameters
+    ----------
+    stamps : int64 ndarray
+    tz : tzinfo or None
+
     Returns
     -------
     result : int64 ndarray of converted of normalized nanosecond timestamps
@@ -838,6 +851,11 @@ cdef ndarray[int64_t] _normalize_local(ndarray[int64_t] stamps, object tz):
     rounding down to the beginning of the day (i.e. midnight) for the
     given timezone `tz`.
 
+    Parameters
+    ----------
+    stamps : int64 ndarray
+    tz : tzinfo or None
+
     Returns
     -------
     result : int64 ndarray of converted of normalized nanosecond timestamps
@@ -897,6 +915,17 @@ cdef ndarray[int64_t] _normalize_local(ndarray[int64_t] stamps, object tz):
 
 
 cdef inline int64_t _normalized_stamp(pandas_datetimestruct *dts) nogil:
+    """
+    Normalize the given datetimestruct to midnight, then convert to int64_t.
+
+    Parameters
+    ----------
+    *dts : pointer to pandas_datetimestruct
+
+    Returns
+    -------
+    stamp : int64
+    """
     dts.hour = 0
     dts.min = 0
     dts.sec = 0
@@ -911,9 +940,14 @@ def is_date_array_normalized(ndarray[int64_t] stamps, tz=None):
     midnight, i.e. hour == minute == second == 0.  If the optional timezone
     `tz` is not None, then this is midnight for this timezone.
 
+    Parameters
+    ----------
+    stamps : int64 ndarray
+    tz : tzinfo or None
+
     Returns
     -------
-    is_normalizaed : bool True if all stamps are normalized
+    is_normalized : bool True if all stamps are normalized
     """
     cdef:
         Py_ssize_t i, n = len(stamps)

From e7456ce124ab376dba26729bd18d326ab4d8c49b Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Thu, 9 Nov 2017 09:26:44 -0800
Subject: [PATCH 12/15] dummy commit to force CI

---
 pandas/_libs/groupby.pyx | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pandas/_libs/groupby.pyx b/pandas/_libs/groupby.pyx
index 2fbbc81c4b5a1..e1312a40971f0 100644
--- a/pandas/_libs/groupby.pyx
+++ b/pandas/_libs/groupby.pyx
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 # cython: profile=False
 
 cimport numpy as cnp

From 69d086556c9ea3bcfcb5656fba176da444b112b8 Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Sun, 12 Nov 2017 10:48:13 -0800
Subject: [PATCH 13/15] remove duplicate declaration

---
 pandas/_libs/tslibs/conversion.pxd | 2 --
 1 file changed, 2 deletions(-)

diff --git a/pandas/_libs/tslibs/conversion.pxd b/pandas/_libs/tslibs/conversion.pxd
index 98582c0c6d9c7..2423a273bdbd1 100644
--- a/pandas/_libs/tslibs/conversion.pxd
+++ b/pandas/_libs/tslibs/conversion.pxd
@@ -15,8 +15,6 @@ cdef class _TSObject:
         object tzinfo
 
 
-cpdef pydt_to_i8(object pydt)
-
 cdef convert_to_tsobject(object ts, object tz, object unit,
                          bint dayfirst, bint yearfirst)
 

From 84594cb2af61503070a1f4ee76cb698c71b4806b Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Sun, 12 Nov 2017 10:48:35 -0800
Subject: [PATCH 14/15] whitespace fixup

---
 pandas/_libs/tslibs/conversion.pxd | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/_libs/tslibs/conversion.pxd b/pandas/_libs/tslibs/conversion.pxd
index 2423a273bdbd1..ad817ce8852f2 100644
--- a/pandas/_libs/tslibs/conversion.pxd
+++ b/pandas/_libs/tslibs/conversion.pxd
@@ -27,4 +27,4 @@ cpdef int64_t tz_convert_single(int64_t val, object tz1, object tz2)
 
 cdef int64_t get_datetime64_nanos(object val) except? -1
 
-cpdef int64_t pydt_to_i8(object pydt) except? -1
\ No newline at end of file
+cpdef int64_t pydt_to_i8(object pydt) except? -1

From 3fa05bd68c8cb2a794b1d39f392ca4f4c8ef26c1 Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Sun, 12 Nov 2017 11:04:04 -0800
Subject: [PATCH 15/15] remove i8_to_pydt per request

---
 pandas/_libs/tslibs/conversion.pyx | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index abe0b3d3cda7e..88372699911c4 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -110,14 +110,6 @@ cpdef int64_t pydt_to_i8(object pydt) except? -1:
     return ts.value
 
 
-def i8_to_pydt(int64_t i8, object tzinfo=None):
-    """
-    Inverse of pydt_to_i8
-    """
-    from pandas import Timestamp
-    return Timestamp(i8)
-
-
 cdef convert_to_tsobject(object ts, object tz, object unit,
                          bint dayfirst, bint yearfirst):
     """