PEP 410

9 files changed, 814 insertions, 174 deletions

diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 06f1452..3f10a32 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -808,13 +808,16 @@ as internal buffering of data.
    Availability: Unix.
 
 
-.. function:: fstat(fd)
+.. function:: fstat(fd, timestamp=None)
 
    Return status for file descriptor *fd*, like :func:`~os.stat`.
 
    Availability: Unix, Windows.
 
-.. function:: fstatat(dirfd, path, flags=0)
+   .. versionchanged:: 3.3
+      Added the *timestamp* argument.
+
+.. function:: fstatat(dirfd, path, flags=0, timestamp="float")
 
    Like :func:`stat` but if *path* is relative, it is taken as relative to *dirfd*.
    *flags* is optional and may be 0 or :data:`AT_SYMLINK_NOFOLLOW`.
@@ -1696,7 +1699,7 @@ Files and Directories
    .. versionadded:: 3.3
 
 
-.. function:: lstat(path)
+.. function:: lstat(path, timestamp=None)
 
    Perform the equivalent of an :c:func:`lstat` system call on the given path.
    Similar to :func:`~os.stat`, but does not follow symbolic links.  On
@@ -1706,6 +1709,9 @@ Files and Directories
    .. versionchanged:: 3.2
       Added support for Windows 6.0 (Vista) symbolic links.
 
+   .. versionchanged:: 3.3
+      The *timestamp* argument was added.
+
 
 .. function:: lutimes(path[, times])
 
@@ -1969,7 +1975,7 @@ Files and Directories
    .. versionadded:: 3.3
 
 
-.. function:: stat(path)
+.. function:: stat(path, timestamp=None)
 
    Perform the equivalent of a :c:func:`stat` system call on the given path.
    (This function follows symlinks; to stat a symlink use :func:`lstat`.)
@@ -1989,6 +1995,11 @@ Files and Directories
    * :attr:`st_ctime` - platform dependent; time of most recent metadata change on
      Unix, or the time of creation on Windows)
 
+   :attr:`st_atime`, :attr:`st_mtime` and :attr:`st_ctime` are :class:`float`
+   by default, or :class:`int` if :func:`os.stat_float_times` is ``False``. Set
+   the *timestamp* argument to get another :ref:`timestamp type
+   <timestamp-types>`.
+
    On some Unix systems (such as Linux), the following attributes may also be
    available:
 
@@ -2044,6 +2055,9 @@ Files and Directories
 
    Availability: Unix, Windows.
 
+   .. versionchanged:: 3.3
+      Added the *timestamp* argument.
+
 
 .. function:: stat_float_times([newvalue])
 
@@ -2069,6 +2083,9 @@ Files and Directories
    are processed, this application should turn the feature off until the library
    has been corrected.
 
+   .. deprecated:: 3.3
+      Use *timestamp* argument of stat functions instead.
+
 
 .. function:: statvfs(path)
 
@@ -2859,27 +2876,39 @@ written in Python, such as a mail server's external command delivery program.
    with :const:`P_NOWAIT` return suitable process handles.
 
 
-.. function:: wait3([options])
+.. function:: wait3(options[, timestamp=float])
 
    Similar to :func:`waitpid`, except no process id argument is given and a
    3-element tuple containing the child's process id, exit status indication, and
    resource usage information is returned.  Refer to :mod:`resource`.\
    :func:`getrusage` for details on resource usage information.  The option
    argument is the same as that provided to :func:`waitpid` and :func:`wait4`.
+   :attr:`ru_utime` and :attr:`ru_stime` attributes of the resource usage are
+   :class:`float` by default, set the *timestamp* argument to get another
+   :ref:`timestamp type <timestamp-types>`.
 
    Availability: Unix.
 
+   .. versionchanged:: 3.3
+      Added the *timestamp* argument.
+
 
-.. function:: wait4(pid, options)
+.. function:: wait4(pid, options[, timestamp=float])
 
    Similar to :func:`waitpid`, except a 3-element tuple, containing the child's
    process id, exit status indication, and resource usage information is returned.
    Refer to :mod:`resource`.\ :func:`getrusage` for details on resource usage
    information.  The arguments to :func:`wait4` are the same as those provided to
    :func:`waitpid`.
+   :attr:`ru_utime` and :attr:`ru_stime` attributes of the resource usage are
+   :class:`float` by default, set the *timestamp* argument to get another
+   :ref:`timestamp type <timestamp-types>`.
 
    Availability: Unix.
 
+   .. versionchanged:: 3.3
+      Added the *timestamp* argument.
+
 
 .. data:: WNOHANG
 
diff --git a/Doc/library/time.rst b/Doc/library/time.rst
index 7865b5a..73a9518 100644
--- a/Doc/library/time.rst
+++ b/Doc/library/time.rst
@@ -95,6 +95,14 @@ An explanation of some terminology and conventions is in order.
   | local time              |                         |                         |
   +-------------------------+-------------------------+-------------------------+
 
+.. _timestamp-types:
+
+* Python supports the following timestamp types:
+
+  * :class:`int`
+  * :class:`float`
+  * :class:`decimal.Decimal`
+
 
 The module defines the following functions and data items:
 
@@ -119,7 +127,7 @@ The module defines the following functions and data items:
       trailing newline.
 
 
-.. function:: clock()
+.. function:: clock(timestamp=float)
 
    .. index::
       single: CPU time
@@ -136,16 +144,27 @@ The module defines the following functions and data items:
    :c:func:`QueryPerformanceCounter`. The resolution is typically better than one
    microsecond.
 
+   Return as a floating point number by default, set the *timestamp* argument
+   to get another :ref:`timestamp type <timestamp-types>`.
+
+   .. versionchanged:: 3.3
+      Added the *timestamp* argument.
+
 
-.. function:: clock_getres(clk_id)
+.. function:: clock_getres(clk_id, timestamp=float)
 
    Return the resolution (precision) of the specified clock *clk_id*.
+   Return a floating point number by default, set the *timestamp* argument to
+   get another :ref:`timestamp type <timestamp-types>`.
+
 
    .. versionadded:: 3.3
 
-.. function:: clock_gettime(clk_id)
+.. function:: clock_gettime(clk_id, timestamp=float)
 
    Return the time of the specified clock *clk_id*.
+   Return a floating point number by default, set the *timestamp* argument to
+   get another :ref:`timestamp type <timestamp-types>`.
 
    .. versionadded:: 3.3
 
@@ -214,19 +233,22 @@ The module defines the following functions and data items:
    flag is set to ``1`` when DST applies to the given time.
 
 
-.. function:: mktime(t)
+.. function:: mktime(t, timestamp=float)
 
    This is the inverse function of :func:`localtime`.  Its argument is the
    :class:`struct_time` or full 9-tuple (since the dst flag is needed; use ``-1``
    as the dst flag if it is unknown) which expresses the time in *local* time, not
-   UTC.  It returns a floating point number, for compatibility with :func:`time`.
+   It returns a floating point number by default, for compatibility with
+   :func:`time`, set the *timestamp* argument to get another :ref:`timestamp
+   type <timestamp-types>`.
+
    If the input value cannot be represented as a valid time, either
    :exc:`OverflowError` or :exc:`ValueError` will be raised (which depends on
    whether the invalid value is caught by Python or the underlying C libraries).
    The earliest date for which it can generate a time is platform-dependent.
 
 
-.. function:: monotonic()
+.. function:: monotonic(timestamp=float)
 
    Monotonic clock.  The reference point of the returned value is undefined so
    only the difference of consecutive calls is valid.
@@ -440,15 +462,20 @@ The module defines the following functions and data items:
    :exc:`TypeError` is raised.
 
 
-.. function:: time()
+.. function:: time(timestamp=float)
 
-   Return the time as a floating point number expressed in seconds since the epoch,
-   in UTC.  Note that even though the time is always returned as a floating point
+   Return the time expressed in seconds since the epoch in UTC. Return a
+   floating point number by default, set the *timestamp* argument to get
+   another :ref:`timestamp type <timestamp-types>`.
+   Note that even though the time is always returned as a floating point
    number, not all systems provide time with a better precision than 1 second.
    While this function normally returns non-decreasing values, it can return a
    lower value than a previous call if the system clock has been set back between
    the two calls.
 
+   .. versionchanged:: 3.3
+      Added the *timestamp* argument.
+
 
 .. data:: timezone
 
@@ -546,13 +573,16 @@ The module defines the following functions and data items:
       ('EET', 'EEST')
 
 
-.. function:: wallclock()
+.. function:: wallclock(timestamp=float)
 
    .. index::
       single: Wallclock
       single: benchmarking
 
    Return the current time in fractions of a second to the system's best ability.
+   Return a floating point number by default, set the *timestamp* argument to
+   get another :ref:`timestamp type <timestamp-types>`.
+
    Use this when the most accurate representation of wall-clock is required, i.e.
    when "processor time" is inappropriate.  The reference point of the returned
    value is undefined so only the difference of consecutive calls is valid.
diff --git a/Doc/whatsnew/3.3.rst b/Doc/whatsnew/3.3.rst
index 8739584..67408c6 100644
--- a/Doc/whatsnew/3.3.rst
+++ b/Doc/whatsnew/3.3.rst
@@ -270,6 +270,42 @@ new, more precise information::
    '<function C.D.meth at 0x7f46b9fe31e0>'
 
 
+PEP 410: Use decimal.Decimal type for timestamps
+================================================
+
+:pep:`410` - Use decimal.Decimal type for timestamps
+ PEP written and implemented by Victor Stinner.
+
+The following functions have a new optional *timestamp* argument to get a
+timestamp as a :class:`decimal.Decimal` instead of :class:`int` or
+:class:`float`:
+
+ * :mod:`time` module: :func:`~time.clock`, :func:`~time.clock_gettime`,
+   :func:`~time.clock_getres`, :func:`~time.monotonic`, :func:`~time.time` and
+   :func:`~time.wallclock`
+ * :mod:`os` module: :func:`~os.fstat`, :func:`~os.fstatat`, :func:`~os.lstat`
+   and :func:`~os.stat` (``st_atime``, ``st_ctime`` and ``st_mtime`` fields of
+   the stat structure)
+
+:class:`decimal.Decimal` supports a resolution of a nanosecond (10^-9)
+resolution, whereas :class:`float` has only a resolution of a microsecond
+(10^-6) in common cases. See the list of available :ref:`timestamp types
+<timestamp-types>`.
+
+Example::
+
+    >>> import decimal, time
+    >>> time.time()
+    1328006975.681211
+    >>> time.time(timestamp=int)
+    1328006979
+    >>> time.time(timestamp=decimal.Decimal)
+    Decimal('1328006983.761119')
+
+:func:`os.stat_float_times` has been deprecated, use *timestamp* argument of
+`os.stat` instead.
+
+
 Other Language Changes
 ======================
 
diff --git a/Include/pytime.h b/Include/pytime.h
index d707bdb..6d438f3 100644
--- a/Include/pytime.h
+++ b/Include/pytime.h
@@ -2,7 +2,8 @@
 #ifndef Py_PYTIME_H
 #define Py_PYTIME_H
 
-#include "pyconfig.h" /* include for defines */
+#include "pyport.h"
+#include "object.h"
 
 /**************************************************************************
 Symbols and macros to supply platform-independent interfaces to time related
@@ -37,6 +38,31 @@ do { \
     ((tv_end.tv_sec - tv_start.tv_sec) + \
      (tv_end.tv_usec - tv_start.tv_usec) * 0.000001)
 
+#if defined(HAVE_LONG_LONG)
+typedef unsigned PY_LONG_LONG _PyTime_fraction_t;
+#else
+typedef size_t _PyTime_fraction_t;
+#endif
+
+typedef struct
+{
+    /* timestamp = seconds + numerator / denominator */
+    time_t seconds;
+    _PyTime_fraction_t numerator;
+    /* denominator cannot be zero */
+    _PyTime_fraction_t denominator;
+    /* the timestamp resolution is 1/divisor */
+} _PyTime_t;
+
+/* Similar to POSIX gettimeofday.  If system gettimeofday
+   fails or is not available, fall back to lower resolution clocks.  */
+PyAPI_FUNC(void) _PyTime_get(_PyTime_t *tp);
+
+/* Convert a timestamp structure to the specified timestamp type.
+
+   Raise a ValueError if the timestamp type is unknown. */
+PyAPI_FUNC(PyObject*) _PyTime_Convert(_PyTime_t *ts, PyObject *timestamp);
+
 /* Dummy to force linking. */
 PyAPI_FUNC(void) _PyTime_Init(void);
 
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index 4d27c2b..379dc58e 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -2,6 +2,7 @@
 # does add tests for a few functions which have been determined to be more
 # portable than they had been thought to be.
 
+import decimal
 import os
 import errno
 import unittest
@@ -238,6 +239,36 @@ class StatAttributeTests(unittest.TestCase):
             warnings.simplefilter("ignore", DeprecationWarning)
             self.check_stat_attributes(fname)
 
+    def test_stat_timestamp(self):
+        # test deprecation
+        with warnings.catch_warnings():
+            warnings.simplefilter("error", DeprecationWarning)
+            self.assertRaises(DeprecationWarning, os.stat_float_times, False)
+
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            old_value = os.stat_float_times()
+            try:
+                # test invalid timestamp types
+                self.assertRaises(ValueError, os.stat, self.fname,
+                                  timestamp="abc")
+                self.assertRaises(ValueError, os.stat, self.fname,
+                                  timestamp=decimal.Context)
+
+                for float_times in (False, True):
+                    os.stat_float_times(float_times)
+                    t = os.stat(self.fname).st_mtime
+                    if float_times:
+                        self.assertIsInstance(t, float)
+                    else:
+                        self.assertIsInstance(t, int)
+
+                    for type in (int, float, decimal.Decimal):
+                        t = os.stat(self.fname, timestamp=type).st_mtime
+                        self.assertIsInstance(t, type)
+            finally:
+                os.stat_float_times(old_value)
+
     def test_statvfs_attributes(self):
         if not hasattr(os, "statvfs"):
             return
diff --git a/Lib/test/test_time.py b/Lib/test/test_time.py
index a89c511..52904fa 100644
--- a/Lib/test/test_time.py
+++ b/Lib/test/test_time.py
@@ -1,10 +1,10 @@
+import locale
+import platform
+import sys
+import sysconfig
 from test import support
 import time
 import unittest
-import locale
-import sysconfig
-import sys
-import platform
 
 # Max year is only limited by the size of C int.
 SIZEOF_INT = sysconfig.get_config_var('SIZEOF_INT') or 4
@@ -345,6 +345,31 @@ class TimeTestCase(unittest.TestCase):
         self.assertGreater(t2, t1)
         self.assertAlmostEqual(dt, 0.1, delta=0.2)
 
+    def test_timestamp(self):
+        import decimal
+        calls = [
+            (time.time,),
+            (time.mktime, time.localtime()),
+        ]
+        if hasattr(time, 'monotonic'):
+            calls.append((time.monotonic,))
+        if hasattr(time, 'wallclock'):
+            calls.append((time.wallclock,))
+        if hasattr(time, 'CLOCK_REALTIME'):
+            if hasattr(time, 'clock_gettime'):
+                calls.append((time.clock_gettime, time.CLOCK_REALTIME))
+            if hasattr(time, 'clock_getres'):
+                calls.append((time.clock_getres, time.CLOCK_REALTIME))
+        for call in calls:
+            func, *args = call
+
+            # test invalid timestamp
+            for invalid in ("int", decimal.Context):
+                self.assertRaises(ValueError, func, *args, timestamp=invalid)
+
+            for type in (int, float, decimal.Decimal):
+                self.assertIsInstance(func(*args, timestamp=type), type)
+
     def test_wallclock(self):
         t1 = time.wallclock()
         t2 = time.wallclock()
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 8b2b211..0ab63c3 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -1702,6 +1702,12 @@ stat_float_times(PyObject* self, PyObject *args)
     int newval = -1;
     if (!PyArg_ParseTuple(args, "|i:stat_float_times", &newval))
         return NULL;
+    if (PyErr_WarnEx(PyExc_DeprecationWarning,
+                     "os.stat_float_times() has been deprecated, "
+                     "use timestamp argument of os.stat() instead",
+                     1))
+        return NULL;
+
     if (newval == -1)
         /* Return old value */
         return PyBool_FromLong(_stat_float_times);
@@ -1711,9 +1717,12 @@ stat_float_times(PyObject* self, PyObject *args)
 }
 
 static void
-fill_time(PyObject *v, int index, time_t sec, unsigned long nsec)
+fill_time(PyObject *v, int index, time_t sec, unsigned long nsec,
+          int has_nsec, PyObject *timestamp)
 {
     PyObject *fval,*ival;
+    _PyTime_t ts;
+
 #if SIZEOF_TIME_T > SIZEOF_LONG
     ival = PyLong_FromLongLong((PY_LONG_LONG)sec);
 #else
@@ -1721,9 +1730,21 @@ fill_time(PyObject *v, int index, time_t sec, unsigned long nsec)
 #endif
     if (!ival)
         return;
-    if (_stat_float_times) {
-        fval = PyFloat_FromDouble(sec + 1e-9*nsec);
-    } else {
+    if (timestamp == NULL && _stat_float_times)
+        timestamp = (PyObject*)&PyFloat_Type;
+    if (timestamp != NULL) {
+        ts.seconds = sec;
+        if (has_nsec) {
+            ts.numerator = nsec;
+            ts.denominator = 1000000000;
+        }
+        else {
+            ts.numerator = 0;
+            ts.denominator = 1;
+        }
+        fval = _PyTime_Convert(&ts, timestamp);
+    }
+    else {
         fval = ival;
         Py_INCREF(fval);
     }
@@ -1734,9 +1755,14 @@ fill_time(PyObject *v, int index, time_t sec, unsigned long nsec)
 /* pack a system stat C structure into the Python stat tuple
    (used by posix_stat() and posix_fstat()) */
 static PyObject*
-_pystat_fromstructstat(STRUCT_STAT *st)
+_pystat_fromstructstat(STRUCT_STAT *st, PyObject *timestamp)
 {
     unsigned long ansec, mnsec, cnsec;
+    int has_nsec;
+#ifdef HAVE_STRUCT_STAT_ST_BIRTHTIME
+    _PyTime_t ts;
+#endif
+
     PyObject *v = PyStructSequence_New(&StatResultType);
     if (v == NULL)
         return NULL;
@@ -1768,20 +1794,24 @@ _pystat_fromstructstat(STRUCT_STAT *st)
     ansec = st->st_atim.tv_nsec;
     mnsec = st->st_mtim.tv_nsec;
     cnsec = st->st_ctim.tv_nsec;
+    has_nsec = 1;
 #elif defined(HAVE_STAT_TV_NSEC2)
     ansec = st->st_atimespec.tv_nsec;
     mnsec = st->st_mtimespec.tv_nsec;
     cnsec = st->st_ctimespec.tv_nsec;
+    has_nsec = 1;
 #elif defined(HAVE_STAT_NSEC)
     ansec = st->st_atime_nsec;
     mnsec = st->st_mtime_nsec;
     cnsec = st->st_ctime_nsec;
+    has_nsec = 1;
 #else
     ansec = mnsec = cnsec = 0;
+    has_nsec = 0;
 #endif
-    fill_time(v, 7, st->st_atime, ansec);
-    fill_time(v, 8, st->st_mtime, mnsec);
-    fill_time(v, 9, st->st_ctime, cnsec);
+    fill_time(v, 7, st->st_atime, ansec, has_nsec, timestamp);
+    fill_time(v, 8, st->st_mtime, mnsec, has_nsec, timestamp);
+    fill_time(v, 9, st->st_ctime, cnsec, has_nsec, timestamp);
 
 #ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
     PyStructSequence_SET_ITEM(v, ST_BLKSIZE_IDX,
@@ -1801,21 +1831,26 @@ _pystat_fromstructstat(STRUCT_STAT *st)
 #endif
 #ifdef HAVE_STRUCT_STAT_ST_BIRTHTIME
     {
-      PyObject *val;
-      unsigned long bsec,bnsec;
-      bsec = (long)st->st_birthtime;
+        PyObject *val;
+        ts.seconds = (long)st->st_birthtime;
 #ifdef HAVE_STAT_TV_NSEC2
-      bnsec = st->st_birthtimespec.tv_nsec;
+        ts.numerator = st->st_birthtimespec.tv_nsec;
+        ts.denominator = 1000000000;
 #else
-      bnsec = 0;
+        ts.numerator = 0;
+        ts.denominator = 1;
 #endif
-      if (_stat_float_times) {
-        val = PyFloat_FromDouble(bsec + 1e-9*bnsec);
-      } else {
-        val = PyLong_FromLong((long)bsec);
-      }
-      PyStructSequence_SET_ITEM(v, ST_BIRTHTIME_IDX,
-                                val);
+        if (timestamp == NULL) {
+            if (_stat_float_times)
+                val = _PyTime_Convert(&ts, (PyObject*)&PyFloat_Type);
+            else
+                val = _PyTime_Convert(&ts, (PyObject*)&PyLong_Type);
+        }
+        else {
+            val = _PyTime_Convert(&ts, timestamp);
+        }
+        PyStructSequence_SET_ITEM(v, ST_BIRTHTIME_IDX,
+                val);
     }
 #endif
 #ifdef HAVE_STRUCT_STAT_ST_FLAGS
@@ -1832,7 +1867,7 @@ _pystat_fromstructstat(STRUCT_STAT *st)
 }
 
 static PyObject *
-posix_do_stat(PyObject *self, PyObject *args,
+posix_do_stat(PyObject *self, PyObject *args, PyObject *kw,
               char *format,
 #ifdef __VMS
               int (*statfunc)(const char *, STRUCT_STAT *, ...),
@@ -1842,15 +1877,18 @@ posix_do_stat(PyObject *self, PyObject *args,
               char *wformat,
               int (*wstatfunc)(const wchar_t *, STRUCT_STAT *))
 {
+    static char *kwlist[] = {"path", "timestamp", NULL};
     STRUCT_STAT st;
     PyObject *opath;
     char *path;
     int res;
     PyObject *result;
+    PyObject *timestamp = NULL;
 
 #ifdef MS_WINDOWS
     PyObject *po;
-    if (PyArg_ParseTuple(args, wformat, &po)) {
+    if (PyArg_ParseTupleAndKeywords(args, kw, wformat, kwlist,
+                                    &po, &timestamp)) {
         wchar_t *wpath = PyUnicode_AsUnicode(po);
         if (wpath == NULL)
             return NULL;
@@ -1861,15 +1899,17 @@ posix_do_stat(PyObject *self, PyObject *args,
 
         if (res != 0)
             return win32_error_object("stat", po);
-        return _pystat_fromstructstat(&st);
+        return _pystat_fromstructstat(&st, timestamp);
     }
     /* Drop the argument parsing error as narrow strings
        are also valid. */
     PyErr_Clear();
+    timestamp = NULL;
 #endif
 
-    if (!PyArg_ParseTuple(args, format,
-                          PyUnicode_FSConverter, &opath))
+    if (!PyArg_ParseTupleAndKeywords(args, kw, format, kwlist,
+                                     PyUnicode_FSConverter, &opath,
+                                     &timestamp))
         return NULL;
 #ifdef MS_WINDOWS
     if (win32_warn_bytes_api()) {
@@ -1890,7 +1930,7 @@ posix_do_stat(PyObject *self, PyObject *args,
 #endif
     }
     else
-        result = _pystat_fromstructstat(&st);
+        result = _pystat_fromstructstat(&st, timestamp);
 
     Py_DECREF(opath);
     return result;
@@ -3381,16 +3421,16 @@ posix_rmdir(PyObject *self, PyObject *args)
 
 
 PyDoc_STRVAR(posix_stat__doc__,
-"stat(path) -> stat result\n\n\
+"stat(path, timestamp=None) -> stat result\n\n\
 Perform a stat system call on the given path.");
 
 static PyObject *
-posix_stat(PyObject *self, PyObject *args)
+posix_stat(PyObject *self, PyObject *args, PyObject *kw)
 {
 #ifdef MS_WINDOWS
-    return posix_do_stat(self, args, "O&:stat", STAT, "U:stat", win32_stat_w);
+    return posix_do_stat(self, args, kw, "O&|O:stat", STAT, "U|O:stat", win32_stat_w);
 #else
-    return posix_do_stat(self, args, "O&:stat", STAT, NULL, NULL);
+    return posix_do_stat(self, args, kw, "O&|O:stat", STAT, NULL, NULL);
 #endif
 }
 
@@ -6118,11 +6158,12 @@ posix_setgroups(PyObject *self, PyObject *groups)
 
 #if defined(HAVE_WAIT3) || defined(HAVE_WAIT4)
 static PyObject *
-wait_helper(pid_t pid, int status, struct rusage *ru)
+wait_helper(pid_t pid, int status, struct rusage *ru, PyObject *timestamp)
 {
     PyObject *result;
     static PyObject *struct_rusage;
     _Py_IDENTIFIER(struct_rusage);
+    _PyTime_t ts;
 
     if (pid == -1)
         return posix_error();
@@ -6146,10 +6187,17 @@ wait_helper(pid_t pid, int status, struct rusage *ru)
 #define doubletime(TV) ((double)(TV).tv_sec + (TV).tv_usec * 0.000001)
 #endif
 
+    ts.seconds = ru->ru_utime.tv_sec;
+    ts.numerator = ru->ru_utime.tv_usec;
+    ts.denominator = 1000000;
     PyStructSequence_SET_ITEM(result, 0,
-                              PyFloat_FromDouble(doubletime(ru->ru_utime)));
+                              _PyTime_Convert(&ts, timestamp));
+
+    ts.seconds = ru->ru_stime.tv_sec;
+    ts.numerator = ru->ru_stime.tv_usec;
+    ts.denominator = 1000000;
     PyStructSequence_SET_ITEM(result, 1,
-                              PyFloat_FromDouble(doubletime(ru->ru_stime)));
+                              _PyTime_Convert(&ts, timestamp));
 #define SET_INT(result, index, value)\
         PyStructSequence_SET_ITEM(result, index, PyLong_FromLong(value))
     SET_INT(result, 2, ru->ru_maxrss);
@@ -6179,51 +6227,55 @@ wait_helper(pid_t pid, int status, struct rusage *ru)
 
 #ifdef HAVE_WAIT3
 PyDoc_STRVAR(posix_wait3__doc__,
-"wait3(options) -> (pid, status, rusage)\n\n\
+"wait3(options[, timestamp=float]) -> (pid, status, rusage)\n\n\
 Wait for completion of a child process.");
 
 static PyObject *
-posix_wait3(PyObject *self, PyObject *args)
+posix_wait3(PyObject *self, PyObject *args, PyObject *kwargs)
 {
+    static char *kwlist[] = {"options", "timestamp", NULL};
     pid_t pid;
     int options;
     struct rusage ru;
     WAIT_TYPE status;
     WAIT_STATUS_INT(status) = 0;
+    PyObject *timestamp = NULL;
 
-    if (!PyArg_ParseTuple(args, "i:wait3", &options))
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "i|O:wait3", kwlist, &options, &timestamp))
         return NULL;
 
     Py_BEGIN_ALLOW_THREADS
     pid = wait3(&status, options, &ru);
     Py_END_ALLOW_THREADS
 
-    return wait_helper(pid, WAIT_STATUS_INT(status), &ru);
+    return wait_helper(pid, WAIT_STATUS_INT(status), &ru, timestamp);
 }
 #endif /* HAVE_WAIT3 */
 
 #ifdef HAVE_WAIT4
 PyDoc_STRVAR(posix_wait4__doc__,
-"wait4(pid, options) -> (pid, status, rusage)\n\n\
+"wait4(pid, options[, timestamp=float]) -> (pid, status, rusage)\n\n\
 Wait for completion of a given child process.");
 
 static PyObject *
-posix_wait4(PyObject *self, PyObject *args)
+posix_wait4(PyObject *self, PyObject *args, PyObject *kwargs)
 {
+    static char *kwlist[] = {"pid", "options", "timestamp", NULL};
     pid_t pid;
     int options;
     struct rusage ru;
     WAIT_TYPE status;
     WAIT_STATUS_INT(status) = 0;
+    PyObject *timestamp = NULL;
 
-    if (!PyArg_ParseTuple(args, _Py_PARSE_PID "i:wait4", &pid, &options))
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, _Py_PARSE_PID "i|O:wait4", kwlist, &pid, &options, &timestamp))
         return NULL;
 
     Py_BEGIN_ALLOW_THREADS
     pid = wait4(pid, &status, options, &ru);
     Py_END_ALLOW_THREADS
 
-    return wait_helper(pid, WAIT_STATUS_INT(status), &ru);
+    return wait_helper(pid, WAIT_STATUS_INT(status), &ru, timestamp);
 }
 #endif /* HAVE_WAIT4 */
 
@@ -6350,20 +6402,20 @@ posix_wait(PyObject *self, PyObject *noargs)
 
 
 PyDoc_STRVAR(posix_lstat__doc__,
-"lstat(path) -> stat result\n\n\
+"lstat(path, timestamp=None) -> stat result\n\n\
 Like stat(path), but do not follow symbolic links.");
 
 static PyObject *
-posix_lstat(PyObject *self, PyObject *args)
+posix_lstat(PyObject *self, PyObject *args, PyObject *kw)
 {
 #ifdef HAVE_LSTAT
-    return posix_do_stat(self, args, "O&:lstat", lstat, NULL, NULL);
+    return posix_do_stat(self, args, kw, "O&|O:lstat", lstat, NULL, NULL);
 #else /* !HAVE_LSTAT */
 #ifdef MS_WINDOWS
-    return posix_do_stat(self, args, "O&:lstat", win32_lstat, "U:lstat",
+    return posix_do_stat(self, args, kw, "O&|O:lstat", win32_lstat, "U|O:lstat",
                          win32_lstat_w);
 #else
-    return posix_do_stat(self, args, "O&:lstat", STAT, NULL, NULL);
+    return posix_do_stat(self, args, "kw, O&|O:lstat", STAT, NULL, NULL);
 #endif
 #endif /* !HAVE_LSTAT */
 }
@@ -7322,16 +7374,19 @@ done:
 #endif
 
 PyDoc_STRVAR(posix_fstat__doc__,
-"fstat(fd) -> stat result\n\n\
+"fstat(fd, timestamp=None) -> stat result\n\n\
 Like stat(), but for an open file descriptor.");
 
 static PyObject *
-posix_fstat(PyObject *self, PyObject *args)
+posix_fstat(PyObject *self, PyObject *args, PyObject *kwargs)
 {
+    static char *kwlist[] = {"fd", "timestamp", NULL};
     int fd;
     STRUCT_STAT st;
     int res;
-    if (!PyArg_ParseTuple(args, "i:fstat", &fd))
+    PyObject *timestamp = NULL;
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "i|O:fstat", kwlist,
+                                     &fd, &timestamp))
         return NULL;
 #ifdef __VMS
     /* on OpenVMS we must ensure that all bytes are written to the file */
@@ -7350,7 +7405,7 @@ posix_fstat(PyObject *self, PyObject *args)
 #endif
     }
 
-    return _pystat_fromstructstat(&st);
+    return _pystat_fromstructstat(&st, timestamp);
 }
 
 PyDoc_STRVAR(posix_isatty__doc__,
@@ -9634,22 +9689,25 @@ posix_fchownat(PyObject *self, PyObject *args)
 
 #ifdef HAVE_FSTATAT
 PyDoc_STRVAR(posix_fstatat__doc__,
-"fstatat(dirfd, path, flags=0) -> stat result\n\n\
+"fstatat(dirfd, path, flags=0, timestamp=None) -> stat result\n\n\
 Like stat() but if path is relative, it is taken as relative to dirfd.\n\
 flags is optional and may be 0 or AT_SYMLINK_NOFOLLOW.\n\
 If path is relative and dirfd is the special value AT_FDCWD, then path\n\
 is interpreted relative to the current working directory.");
 
 static PyObject *
-posix_fstatat(PyObject *self, PyObject *args)
+posix_fstatat(PyObject *self, PyObject *args, PyObject *kwargs)
 {
+    static char *kwlist[] = {"dirfd", "path", "flags", "timestamp", NULL};
     PyObject *opath;
     char *path;
     STRUCT_STAT st;
     int dirfd, res, flags = 0;
+    PyObject *timestamp = NULL;
 
-    if (!PyArg_ParseTuple(args, "iO&|i:fstatat",
-            &dirfd, PyUnicode_FSConverter, &opath, &flags))
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "iO&|iO:fstatat", kwlist,
+                                     &dirfd, PyUnicode_FSConverter, &opath,
+                                     &flags, &timestamp))
         return NULL;
     path = PyBytes_AsString(opath);
 
@@ -9660,7 +9718,7 @@ posix_fstatat(PyObject *self, PyObject *args)
     if (res != 0)
         return posix_error();
 
-    return _pystat_fromstructstat(&st);
+    return _pystat_fromstructstat(&st, timestamp);
 }
 #endif
 
@@ -10524,7 +10582,7 @@ static PyMethodDef posix_methods[] = {
 #ifdef HAVE_FDOPENDIR
     {"flistdir",       posix_flistdir, METH_VARARGS, posix_flistdir__doc__},
 #endif
-    {"lstat",           posix_lstat, METH_VARARGS, posix_lstat__doc__},
+    {"lstat",           (PyCFunction)posix_lstat, METH_VARARGS | METH_KEYWORDS, posix_lstat__doc__},
     {"mkdir",           posix_mkdir, METH_VARARGS, posix_mkdir__doc__},
 #ifdef HAVE_NICE
     {"nice",            posix_nice, METH_VARARGS, posix_nice__doc__},
@@ -10544,7 +10602,8 @@ static PyMethodDef posix_methods[] = {
     {"rename",          posix_rename, METH_VARARGS, posix_rename__doc__},
     {"replace",         posix_replace, METH_VARARGS, posix_replace__doc__},
     {"rmdir",           posix_rmdir, METH_VARARGS, posix_rmdir__doc__},
-    {"stat",            posix_stat, METH_VARARGS, posix_stat__doc__},
+    {"stat",            (PyCFunction)posix_stat,
+                        METH_VARARGS | METH_KEYWORDS, posix_stat__doc__},
     {"stat_float_times", stat_float_times, METH_VARARGS, stat_float_times__doc__},
 #if defined(HAVE_SYMLINK) && !defined(MS_WINDOWS)
     {"symlink",         posix_symlink, METH_VARARGS, posix_symlink__doc__},
@@ -10705,10 +10764,12 @@ static PyMethodDef posix_methods[] = {
     {"wait",            posix_wait, METH_NOARGS, posix_wait__doc__},
 #endif /* HAVE_WAIT */
 #ifdef HAVE_WAIT3
-    {"wait3",           posix_wait3, METH_VARARGS, posix_wait3__doc__},
+    {"wait3",           (PyCFunction)posix_wait3,
+                        METH_VARARGS | METH_KEYWORDS, posix_wait3__doc__},
 #endif /* HAVE_WAIT3 */
 #ifdef HAVE_WAIT4
-    {"wait4",           posix_wait4, METH_VARARGS, posix_wait4__doc__},
+    {"wait4",           (PyCFunction)posix_wait4,
+                        METH_VARARGS | METH_KEYWORDS, posix_wait4__doc__},
 #endif /* HAVE_WAIT4 */
 #if defined(HAVE_WAITID) && !defined(__APPLE__)
     {"waitid",          posix_waitid, METH_VARARGS, posix_waitid__doc__},
@@ -10759,7 +10820,8 @@ static PyMethodDef posix_methods[] = {
     {"sendfile",        (PyCFunction)posix_sendfile, METH_VARARGS | METH_KEYWORDS,
                             posix_sendfile__doc__},
 #endif
-    {"fstat",           posix_fstat, METH_VARARGS, posix_fstat__doc__},
+    {"fstat",           (PyCFunction)posix_fstat, METH_VARARGS | METH_KEYWORDS,
+                            posix_fstat__doc__},
     {"isatty",          posix_isatty, METH_VARARGS, posix_isatty__doc__},
 #ifdef HAVE_PIPE
     {"pipe",            posix_pipe, METH_NOARGS, posix_pipe__doc__},
@@ -10894,7 +10956,8 @@ static PyMethodDef posix_methods[] = {
     {"fchownat",        posix_fchownat, METH_VARARGS, posix_fchownat__doc__},
 #endif /* HAVE_FCHOWNAT */
 #ifdef HAVE_FSTATAT
-    {"fstatat",         posix_fstatat, METH_VARARGS, posix_fstatat__doc__},
+    {"fstatat",         (PyCFunction)posix_fstatat, METH_VARARGS | METH_KEYWORDS,
+                            posix_fstatat__doc__},
 #endif
 #ifdef HAVE_FUTIMESAT
     {"futimesat",       posix_futimesat, METH_VARARGS, posix_futimesat__doc__},
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index 34c7019..16940fe 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -40,24 +40,30 @@
 #include <sys/time.h>
 #endif
 
+#if (defined(MS_WINDOWS) && !defined(__BORLANDC__)) || defined(HAVE_CLOCK)
+#  define HAVE_PYCLOCK
+#endif
+
 /* Forward declarations */
 static int floatsleep(double);
-static double floattime(void);
 
 static PyObject *
-time_time(PyObject *self, PyObject *unused)
+time_time(PyObject *self, PyObject *args, PyObject *kwargs)
 {
-    double secs;
-    secs = floattime();
-    if (secs == 0.0) {
-        PyErr_SetFromErrno(PyExc_IOError);
+    static char *kwlist[] = {"timestamp", NULL};
+    PyObject *timestamp = NULL;
+    _PyTime_t ts;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|O:time", kwlist,
+                                     &timestamp))
         return NULL;
-    }
-    return PyFloat_FromDouble(secs);
+
+    _PyTime_get(&ts);
+    return _PyTime_Convert(&ts, timestamp);
 }
 
 PyDoc_STRVAR(time_doc,
-"time() -> floating point number\n\
+"time(timestamp=float) -> floating point number\n\
 \n\
 Return the current time in seconds since the Epoch.\n\
 Fractions of a second may be present if the system clock provides them.");
@@ -72,65 +78,91 @@ Fractions of a second may be present if the system clock provides them.");
 #endif
 #endif
 
-static PyObject *
-pyclock(void)
+static int
+pyclock(_PyTime_t *ts)
 {
-    clock_t value;
-    value = clock();
-    if (value == (clock_t)-1) {
+    clock_t processor_time;
+    processor_time = clock();
+    if (processor_time == (clock_t)-1) {
         PyErr_SetString(PyExc_RuntimeError,
                 "the processor time used is not available "
                 "or its value cannot be represented");
-        return NULL;
+        return -1;
     }
-    return PyFloat_FromDouble((double)value / CLOCKS_PER_SEC);
+    ts->seconds = 0;
+    assert(sizeof(clock_t) <= sizeof(_PyTime_fraction_t));
+    ts->numerator = Py_SAFE_DOWNCAST(processor_time,
+                                     clock_t, _PyTime_fraction_t);
+    ts->denominator = CLOCKS_PER_SEC;
+    return 0;
 }
 #endif /* HAVE_CLOCK */
 
 #if defined(MS_WINDOWS) && !defined(__BORLANDC__)
 /* Win32 has better clock replacement; we have our own version, due to Mark
    Hammond and Tim Peters */
-static PyObject *
-win32_clock(int fallback)
+static int
+win32_clock(_PyTime_t *ts, int fallback)
 {
     static LONGLONG cpu_frequency = 0;
-    static LONGLONG ctrStart;
+    static LONGLONG start;
     LARGE_INTEGER now;
-    double diff;
+    LONGLONG dt;
 
     if (cpu_frequency == 0) {
         LARGE_INTEGER freq;
         QueryPerformanceCounter(&now);
-        ctrStart = now.QuadPart;
+        start = now.QuadPart;
         if (!QueryPerformanceFrequency(&freq) || freq.QuadPart == 0) {
             /* Unlikely to happen - this works on all intel
                machines at least!  Revert to clock() */
-            if (fallback)
-                return pyclock();
-            else
-                return PyErr_SetFromWindowsErr(0);
+            if (fallback) {
+                return pyclock(ts);
+            }
+            else {
+                PyErr_SetFromWindowsErr(0);
+                return  -1;
+            }
         }
         cpu_frequency = freq.QuadPart;
     }
     QueryPerformanceCounter(&now);
-    diff = (double)(now.QuadPart - ctrStart);
-    return PyFloat_FromDouble(diff / (double)cpu_frequency);
+    dt = now.QuadPart - start;
+
+    ts->seconds = 0;
+    assert(sizeof(LONGLONG) <= sizeof(_PyTime_fraction_t));
+    ts->numerator = Py_SAFE_DOWNCAST(dt,
+                                     LONGLONG, _PyTime_fraction_t);
+    ts->denominator = Py_SAFE_DOWNCAST(cpu_frequency,
+                                       LONGLONG, _PyTime_fraction_t);
+    return 0;
 }
 #endif
 
 #if (defined(MS_WINDOWS) && !defined(__BORLANDC__)) || defined(HAVE_CLOCK)
 static PyObject *
-time_clock(PyObject *self, PyObject *unused)
+time_clock(PyObject *self, PyObject *args, PyObject *kwargs)
 {
+    static char *kwlist[] = {"timestamp", NULL};
+    _PyTime_t ts;
+    PyObject *timestamp = NULL;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|O:clock", kwlist,
+                                     &timestamp))
+        return NULL;
+
 #if defined(MS_WINDOWS) && !defined(__BORLANDC__)
-    return win32_clock(1);
+    if (win32_clock(&ts, 1) == -1)
+        return NULL;
 #else
-    return pyclock();
+    if (pyclock(&ts) == -1)
+        return NULL;
 #endif
+    return _PyTime_Convert(&ts, timestamp);
 }
 
 PyDoc_STRVAR(clock_doc,
-"clock() -> floating point number\n\
+"clock(timestamp=float) -> floating point number\n\
 \n\
 Return the CPU time or real time since the start of the process or since\n\
 the first call to clock().  This has as much precision as the system\n\
@@ -139,13 +171,17 @@ records.");
 
 #ifdef HAVE_CLOCK_GETTIME
 static PyObject *
-time_clock_gettime(PyObject *self, PyObject *args)
+time_clock_gettime(PyObject *self, PyObject *args, PyObject *kwargs)
 {
+    static char *kwlist[] = {"clk_id", "timestamp", NULL};
+    PyObject *timestamp = NULL;
     int ret;
     clockid_t clk_id;
     struct timespec tp;
+    _PyTime_t ts;
 
-    if (!PyArg_ParseTuple(args, "i:clock_gettime", &clk_id))
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "i|O:clock_gettime", kwlist,
+                                     &clk_id, &timestamp))
         return NULL;
 
     ret = clock_gettime((clockid_t)clk_id, &tp);
@@ -153,25 +189,31 @@ time_clock_gettime(PyObject *self, PyObject *args)
         PyErr_SetFromErrno(PyExc_IOError);
         return NULL;
     }
-
-    return PyFloat_FromDouble(tp.tv_sec + tp.tv_nsec * 1e-9);
+    ts.seconds = tp.tv_sec;
+    ts.numerator = tp.tv_nsec;
+    ts.denominator = 1000000000;
+    return _PyTime_Convert(&ts, timestamp);
 }
 
 PyDoc_STRVAR(clock_gettime_doc,
-"clock_gettime(clk_id) -> floating point number\n\
+"clock_gettime(clk_id, timestamp=float) -> floating point number\n\
 \n\
 Return the time of the specified clock clk_id.");
 #endif
 
 #ifdef HAVE_CLOCK_GETRES
 static PyObject *
-time_clock_getres(PyObject *self, PyObject *args)
+time_clock_getres(PyObject *self, PyObject *args, PyObject *kwargs)
 {
+    static char *kwlist[] = {"clk_id", "timestamp", NULL};
+    PyObject *timestamp = NULL;
     int ret;
     clockid_t clk_id;
     struct timespec tp;
+    _PyTime_t ts;
 
-    if (!PyArg_ParseTuple(args, "i:clock_getres", &clk_id))
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "i|O:clock_getres", kwlist,
+                                     &clk_id, &timestamp))
         return NULL;
 
     ret = clock_getres((clockid_t)clk_id, &tp);
@@ -179,12 +221,14 @@ time_clock_getres(PyObject *self, PyObject *args)
         PyErr_SetFromErrno(PyExc_IOError);
         return NULL;
     }
-
-    return PyFloat_FromDouble(tp.tv_sec + tp.tv_nsec * 1e-9);
+    ts.seconds = tp.tv_sec;
+    ts.numerator = tp.tv_nsec;
+    ts.denominator = 1000000000;
+    return _PyTime_Convert(&ts, timestamp);
 }
 
 PyDoc_STRVAR(clock_getres_doc,
-"clock_getres(clk_id) -> floating point number\n\
+"clock_getres(clk_id, timestamp=float) -> floating point number\n\
 \n\
 Return the resolution (precision) of the specified clock clk_id.");
 #endif
@@ -707,10 +751,19 @@ not present, current time as returned by localtime() is used.");
 
 #ifdef HAVE_MKTIME
 static PyObject *
-time_mktime(PyObject *self, PyObject *tup)
+time_mktime(PyObject *self, PyObject *args, PyObject *kwargs)
 {
+    static char *kwlist[] = {"t", "timestamp", NULL};
+    PyObject *timestamp = NULL;
+    PyObject *tup;
     struct tm buf;
     time_t tt;
+    _PyTime_t ts;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O|O:mktime", kwlist,
+                                     &tup, &timestamp))
+        return NULL;
+
     if (!gettmarg(tup, &buf))
         return NULL;
     buf.tm_wday = -1;  /* sentinel; original value ignored */
@@ -722,7 +775,10 @@ time_mktime(PyObject *self, PyObject *tup)
                         "mktime argument out of range");
         return NULL;
     }
-    return PyFloat_FromDouble((double)tt);
+    ts.seconds = tt;
+    ts.numerator = 0;
+    ts.denominator = 1;
+    return _PyTime_Convert(&ts, timestamp);
 }
 
 PyDoc_STRVAR(mktime_doc,
@@ -768,12 +824,14 @@ the local timezone used by methods such as localtime, but this behaviour\n\
 should not be relied on.");
 #endif /* HAVE_WORKING_TZSET */
 
-static PyObject *
-time_wallclock(PyObject *self, PyObject *unused)
+static int
+pywallclock(_PyTime_t *ts)
 {
 #if defined(MS_WINDOWS) && !defined(__BORLANDC__)
-    return win32_clock(1);
-#elif defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
+    return win32_clock(ts, 1);
+#else
+
+#if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
     static int clk_index = 0;
     clockid_t clk_ids[] = {
 #ifdef CLOCK_MONOTONIC_RAW
@@ -793,20 +851,41 @@ time_wallclock(PyObject *self, PyObject *unused)
         clockid_t clk_id = clk_ids[clk_index];
         ret = clock_gettime(clk_id, &tp);
         if (ret == 0)
-            return PyFloat_FromDouble(tp.tv_sec + tp.tv_nsec * 1e-9);
+        {
+            ts->seconds = tp.tv_sec;
+            ts->numerator = tp.tv_nsec;
+            ts->denominator = 1000000000;
+            return 0;
+        }
 
         clk_index++;
         if (Py_ARRAY_LENGTH(clk_ids) <= clk_index)
             clk_index = -1;
     }
-    return time_time(self, NULL);
-#else
-    return time_time(self, NULL);
+#endif /* defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC) */
+
+    _PyTime_get(ts);
+    return 0;
 #endif
 }
 
+static PyObject *
+time_wallclock(PyObject *self, PyObject *args, PyObject *kwargs)
+{
+    static char *kwlist[] = {"timestamp", NULL};
+    PyObject *timestamp = NULL;
+    _PyTime_t ts;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|O:wallclock", kwlist,
+                                     &timestamp))
+        return NULL;
+    if (pywallclock(&ts))
+        return NULL;
+    return _PyTime_Convert(&ts, timestamp);
+}
+
 PyDoc_STRVAR(wallclock_doc,
-"wallclock() -> float\n\
+"wallclock(timestamp=float)\n\
 \n\
 Return the current time in fractions of a second to the system's best\n\
 ability. Use this when the most accurate representation of wall-clock is\n\
@@ -821,11 +900,11 @@ calls is valid.");
 
 #ifdef HAVE_PYTIME_MONOTONIC
 static PyObject *
-time_monotonic(PyObject *self, PyObject *unused)
+time_monotonic(PyObject *self, PyObject *args, PyObject *kwargs)
 {
-#if defined(MS_WINDOWS) && !defined(__BORLANDC__)
-    return win32_clock(0);
-#else
+    static char *kwlist[] = {"timestamp", NULL};
+    PyObject *timestamp = NULL;
+#if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
     static int clk_index = 0;
     clockid_t clk_ids[] = {
 #ifdef CLOCK_MONOTONIC_RAW
@@ -835,12 +914,28 @@ time_monotonic(PyObject *self, PyObject *unused)
     };
     int ret;
     struct timespec tp;
+#endif
+    _PyTime_t ts;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|O:monotonic", kwlist,
+                                     &timestamp))
+        return NULL;
 
+#if defined(MS_WINDOWS) && !defined(__BORLANDC__)
+    if (win32_clock(&ts, 0) == -1)
+        return NULL;
+    return _PyTime_Convert(&ts, timestamp);
+#else
     while (0 <= clk_index) {
         clockid_t clk_id = clk_ids[clk_index];
         ret = clock_gettime(clk_id, &tp);
         if (ret == 0)
-            return PyFloat_FromDouble(tp.tv_sec + tp.tv_nsec * 1e-9);
+        {
+            ts.seconds = tp.tv_sec;
+            ts.numerator = tp.tv_nsec;
+            ts.denominator = 1000000000;
+            return _PyTime_Convert(&ts, timestamp);
+        }
 
         clk_index++;
         if (Py_ARRAY_LENGTH(clk_ids) <= clk_index)
@@ -968,15 +1063,19 @@ PyInit_timezone(PyObject *m) {
 
 
 static PyMethodDef time_methods[] = {
-    {"time",            time_time, METH_NOARGS, time_doc},
-#if (defined(MS_WINDOWS) && !defined(__BORLANDC__)) || defined(HAVE_CLOCK)
-    {"clock",           time_clock, METH_NOARGS, clock_doc},
+    {"time",            (PyCFunction)time_time,
+                        METH_VARARGS | METH_KEYWORDS, time_doc},
+#ifdef HAVE_PYCLOCK
+    {"clock",           (PyCFunction)time_clock,
+                        METH_VARARGS | METH_KEYWORDS, clock_doc},
 #endif
 #ifdef HAVE_CLOCK_GETTIME
-    {"clock_gettime",   time_clock_gettime, METH_VARARGS, clock_gettime_doc},
+    {"clock_gettime",   (PyCFunction)time_clock_gettime,
+                        METH_VARARGS | METH_KEYWORDS, clock_gettime_doc},
 #endif
 #ifdef HAVE_CLOCK_GETRES
-    {"clock_getres",    time_clock_getres, METH_VARARGS, clock_getres_doc},
+    {"clock_getres",    (PyCFunction)time_clock_getres,
+                        METH_VARARGS | METH_KEYWORDS, clock_getres_doc},
 #endif
     {"sleep",           time_sleep, METH_VARARGS, sleep_doc},
     {"gmtime",          time_gmtime, METH_VARARGS, gmtime_doc},
@@ -984,10 +1083,12 @@ static PyMethodDef time_methods[] = {
     {"asctime",         time_asctime, METH_VARARGS, asctime_doc},
     {"ctime",           time_ctime, METH_VARARGS, ctime_doc},
 #ifdef HAVE_MKTIME
-    {"mktime",          time_mktime, METH_O, mktime_doc},
+    {"mktime",          (PyCFunction)time_mktime,
+                        METH_VARARGS | METH_KEYWORDS, mktime_doc},
 #endif
 #ifdef HAVE_PYTIME_MONOTONIC
-    {"monotonic",       time_monotonic, METH_NOARGS, monotonic_doc},
+    {"monotonic",       (PyCFunction)time_monotonic,
+                        METH_VARARGS | METH_KEYWORDS, monotonic_doc},
 #endif
 #ifdef HAVE_STRFTIME
     {"strftime",        time_strftime, METH_VARARGS, strftime_doc},
@@ -996,7 +1097,8 @@ static PyMethodDef time_methods[] = {
 #ifdef HAVE_WORKING_TZSET
     {"tzset",           time_tzset, METH_NOARGS, tzset_doc},
 #endif
-    {"wallclock",       time_wallclock, METH_NOARGS, wallclock_doc},
+    {"wallclock",       (PyCFunction)time_wallclock,
+                        METH_VARARGS | METH_KEYWORDS, wallclock_doc},
     {NULL,              NULL}           /* sentinel */
 };
 
@@ -1081,15 +1183,6 @@ PyInit_time(void)
     return m;
 }
 
-static double
-floattime(void)
-{
-    _PyTime_timeval t;
-    _PyTime_gettimeofday(&t);
-    return (double)t.tv_sec + t.tv_usec*0.000001;
-}
-
-
 /* Implement floatsleep() for various platforms.
    When interrupted (or when another error occurs), return -1 and
    set an exception; else return 0. */
diff --git a/Python/pytime.c b/Python/pytime.c
index bec1c71..8679bcc 100644
--- a/Python/pytime.c
+++ b/Python/pytime.c
@@ -18,24 +18,36 @@
 extern int ftime(struct timeb *);
 #endif
 
+#define MICROSECONDS    1000000
+
 void
-_PyTime_gettimeofday(_PyTime_timeval *tp)
+_PyTime_get(_PyTime_t *ts)
 {
 #ifdef MS_WINDOWS
     FILETIME system_time;
     ULARGE_INTEGER large;
-    ULONGLONG microseconds;
+    ULONGLONG value;
 
     GetSystemTimeAsFileTime(&system_time);
     large.u.LowPart = system_time.dwLowDateTime;
     large.u.HighPart = system_time.dwHighDateTime;
-    /* 11,644,473,600,000,000: number of microseconds between
+    /* 116,444,736,000,000,000: number of 100 ns between
        the 1st january 1601 and the 1st january 1970 (369 years + 89 leap
        days). */
-    microseconds = large.QuadPart / 10 - 11644473600000000;
-    tp->tv_sec = microseconds / 1000000;
-    tp->tv_usec = microseconds % 1000000;
+    value = large.QuadPart - 116444736000000000;
+    ts->seconds = 0;
+    ts->numerator = value;
+    ts->denominator = (_PyTime_fraction_t)10000000;
 #else
+
+#ifdef HAVE_GETTIMEOFDAY
+    struct timeval tv;
+    int err;
+#endif
+#if defined(HAVE_FTIME)
+    struct timeb t;
+#endif
+
     /* There are three ways to get the time:
       (1) gettimeofday() -- resolution in microseconds
       (2) ftime() -- resolution in milliseconds
@@ -47,30 +59,325 @@ _PyTime_gettimeofday(_PyTime_timeval *tp)
 
 #ifdef HAVE_GETTIMEOFDAY
 #ifdef GETTIMEOFDAY_NO_TZ
-    if (gettimeofday(tp) == 0)
-        return;
+    err = gettimeofday(&tv);
 #else /* !GETTIMEOFDAY_NO_TZ */
-    if (gettimeofday(tp, (struct timezone *)NULL) == 0)
-        return;
+    err = gettimeofday(&tv, (struct timezone *)NULL);
 #endif /* !GETTIMEOFDAY_NO_TZ */
+    if (err == 0)
+    {
+        ts->seconds = tv.tv_sec;
+        ts->numerator = tv.tv_usec;
+        ts->denominator = MICROSECONDS;
+        return;
+    }
 #endif /* !HAVE_GETTIMEOFDAY */
 
 #if defined(HAVE_FTIME)
-    {
-        struct timeb t;
-        ftime(&t);
-        tp->tv_sec = t.time;
-        tp->tv_usec = t.millitm * 1000;
-    }
+    ftime(&t);
+    ts->seconds = t.time;
+    ts->numerator = t.millitm;
+    ts->denominator = 1000;
 #else /* !HAVE_FTIME */
-    tp->tv_sec = time(NULL);
-    tp->tv_usec = 0;
+    ts->seconds = time(NULL);
+    ts->numerator = 0;
+    ts->denominator = 1;
 #endif /* !HAVE_FTIME */
 
 #endif /* MS_WINDOWS */
 }
 
 void
+_PyTime_gettimeofday(_PyTime_timeval *tv)
+{
+    _PyTime_t ts;
+    _PyTime_fraction_t k;
+    time_t sec;
+
+    _PyTime_get(&ts);
+    tv->tv_sec = ts.seconds;
+    if (ts.numerator) {
+        if (ts.numerator > ts.denominator) {
+            sec = Py_SAFE_DOWNCAST(ts.numerator / ts.denominator,
+                                   _PyTime_fraction_t, time_t);
+            /* ignore integer overflow because _PyTime_gettimeofday() has
+               no return value */
+            tv->tv_sec += sec;
+            ts.numerator = ts.numerator % ts.denominator;
+        }
+        if (MICROSECONDS >= ts.denominator) {
+            k = (_PyTime_fraction_t)MICROSECONDS / ts.denominator;
+            tv->tv_usec = (long)(ts.numerator * k);
+        }
+        else {
+            k = ts.denominator / (_PyTime_fraction_t)MICROSECONDS;
+            tv->tv_usec = (long)(ts.numerator / k);
+        }
+    }
+    else {
+        tv->tv_usec = 0;
+    }
+}
+
+static PyObject*
+_PyLong_FromTime_t(time_t value)
+{
+#if SIZEOF_TIME_T <= SIZEOF_LONG
+    return PyLong_FromLong(value);
+#else
+    assert(sizeof(time_t) <= sizeof(PY_LONG_LONG));
+    return PyLong_FromLongLong(value);
+#endif
+}
+
+#if defined(HAVE_LONG_LONG)
+#  define _PyLong_FromTimeFraction_t PyLong_FromLongLong
+#else
+#  define _PyLong_FromTimeFraction_t PyLong_FromSize_t
+#endif
+
+/* Convert a timestamp to a PyFloat object */
+static PyObject*
+_PyTime_AsFloat(_PyTime_t *ts)
+{
+    double d;
+    d = (double)ts->seconds;
+    d += (double)ts->numerator / (double)ts->denominator;
+    return PyFloat_FromDouble(d);
+}
+
+/* Convert a timestamp to a PyLong object */
+static PyObject*
+_PyTime_AsLong(_PyTime_t *ts)
+{
+    PyObject *a, *b, *c;
+
+    a = _PyLong_FromTime_t(ts->seconds);
+    if (a == NULL)
+        return NULL;
+    b = _PyLong_FromTimeFraction_t(ts->numerator / ts->denominator);
+    if (b == NULL)
+    {
+        Py_DECREF(a);
+        return NULL;
+    }
+    c = PyNumber_Add(a, b);
+    Py_DECREF(a);
+    Py_DECREF(b);
+    return c;
+}
+
+/* Convert a timestamp to a decimal.Decimal object */
+static PyObject*
+_PyTime_AsDecimal(_PyTime_t *ts)
+{
+    static PyObject* module = NULL;
+    static PyObject* decimal = NULL;
+    static PyObject* exponent_context = NULL;
+    static PyObject* context = NULL;
+    /* exponent cache, dictionary of:
+       int (denominator) => Decimal (1/denominator) */
+    static PyObject* exponent_cache = NULL;
+    PyObject *t = NULL;
+    PyObject *key, *exponent, *quantized;
+    _Py_IDENTIFIER(quantize);
+    _Py_IDENTIFIER(__truediv__);
+
+    if (!module) {
+        module = PyImport_ImportModuleNoBlock("decimal");
+        if (module == NULL)
+            return NULL;
+    }
+
+    if (!decimal) {
+        decimal = PyObject_GetAttrString(module, "Decimal");
+        if (decimal == NULL)
+            return NULL;
+    }
+
+    if (context == NULL)
+    {
+        /* Use 12 decimal digits to store 10,000 years in seconds + 9
+           decimal digits for the floating part in nanoseconds + 1 decimal
+           digit to round correctly.
+
+           context = decimal.Context(22, rounding=decimal.ROUND_HALF_EVEN)
+           exponent_context = decimal.Context(1, rounding=decimal.ROUND_HALF_EVEN)
+        */
+        PyObject *context_class, *rounding;
+        context_class = PyObject_GetAttrString(module, "Context");
+        if (context_class == NULL)
+            return NULL;
+        rounding = PyObject_GetAttrString(module, "ROUND_HALF_EVEN");
+        if (rounding == NULL)
+        {
+            Py_DECREF(context_class);
+            return NULL;
+        }
+        context = PyObject_CallFunction(context_class, "iO", 22, rounding);
+        if (context == NULL)
+        {
+            Py_DECREF(context_class);
+            Py_DECREF(rounding);
+            return NULL;
+        }
+
+        exponent_context = PyObject_CallFunction(context_class, "iO", 1, rounding);
+        Py_DECREF(context_class);
+        Py_DECREF(rounding);
+        if (exponent_context == NULL)
+        {
+            Py_CLEAR(context);
+            return NULL;
+        }
+    }
+
+    /* t = decimal.Decimal(value) */
+    if (ts->seconds) {
+        PyObject *f = _PyLong_FromTime_t(ts->seconds);
+        t = PyObject_CallFunction(decimal, "O", f);
+        Py_CLEAR(f);
+    }
+    else {
+        t = PyObject_CallFunction(decimal, "iO", 0, context);
+    }
+    if (t == NULL)
+        return NULL;
+
+    if (ts->numerator)
+    {
+        /* t += decimal.Decimal(numerator, ctx) / decimal.Decimal(denominator, ctx) */
+        PyObject *a, *b, *c, *d, *x;
+
+        x = _PyLong_FromTimeFraction_t(ts->numerator);
+        if (x == NULL)
+            goto error;
+        a = PyObject_CallFunction(decimal, "OO", x, context);
+        Py_CLEAR(x);
+        if (a == NULL)
+            goto error;
+
+        x = _PyLong_FromTimeFraction_t(ts->denominator);
+        if (x == NULL)
+        {
+            Py_DECREF(a);
+            goto error;
+        }
+        b = PyObject_CallFunction(decimal, "OO", x, context);
+        Py_CLEAR(x);
+        if (b == NULL)
+        {
+            Py_DECREF(a);
+            goto error;
+        }
+
+        c = _PyObject_CallMethodId(a, &PyId___truediv__, "OO",
+                                   b, context);
+        Py_DECREF(a);
+        Py_DECREF(b);
+        if (c == NULL)
+            goto error;
+
+        d = PyNumber_Add(t, c);
+        Py_DECREF(c);
+        if (d == NULL)
+            goto error;
+        Py_DECREF(t);
+        t = d;
+    }
+
+    if (exponent_cache == NULL) {
+        exponent_cache = PyDict_New();
+        if (exponent_cache == NULL)
+            goto error;
+    }
+
+    key = _PyLong_FromTimeFraction_t(ts->denominator);
+    if (key == NULL)
+        goto error;
+    exponent = PyDict_GetItem(exponent_cache, key);
+    if (exponent == NULL) {
+        /* exponent = decimal.Decimal(1) / decimal.Decimal(resolution) */
+        PyObject *one, *denominator;
+
+        one = PyObject_CallFunction(decimal, "i", 1);
+        if (one == NULL) {
+            Py_DECREF(key);
+            goto error;
+        }
+
+        denominator = PyObject_CallFunction(decimal, "O", key);
+        if (denominator == NULL) {
+            Py_DECREF(key);
+            Py_DECREF(one);
+            goto error;
+        }
+
+        exponent = _PyObject_CallMethodId(one, &PyId___truediv__, "OO",
+                                          denominator, exponent_context);
+        Py_DECREF(one);
+        Py_DECREF(denominator);
+        if (exponent == NULL) {
+            Py_DECREF(key);
+            goto error;
+        }
+
+        if (PyDict_SetItem(exponent_cache, key, exponent) < 0) {
+            Py_DECREF(key);
+            Py_DECREF(exponent);
+            goto error;
+        }
+        Py_DECREF(key);
+    }
+
+    /* t = t.quantize(exponent, None, context) */
+    quantized = _PyObject_CallMethodId(t, &PyId_quantize, "OOO",
+                                       exponent, Py_None, context);
+    if (quantized == NULL)
+        goto error;
+    Py_DECREF(t);
+    t = quantized;
+
+    return t;
+
+error:
+    Py_XDECREF(t);
+    return NULL;
+}
+
+PyObject*
+_PyTime_Convert(_PyTime_t *ts, PyObject *format)
+{
+    assert(ts->denominator != 0);
+
+    if (format == NULL || (PyTypeObject *)format == &PyFloat_Type)
+        return _PyTime_AsFloat(ts);
+    if ((PyTypeObject *)format == &PyLong_Type)
+        return _PyTime_AsLong(ts);
+
+    if (PyType_Check(format))
+    {
+        PyObject *module, *name;
+        _Py_IDENTIFIER(__name__);
+        _Py_IDENTIFIER(__module__);
+
+        module = _PyObject_GetAttrId(format, &PyId___module__);
+        name = _PyObject_GetAttrId(format, &PyId___name__);
+        if (module != NULL && PyUnicode_Check(module)
+            && name != NULL && PyUnicode_Check(name))
+        {
+            if (PyUnicode_CompareWithASCIIString(module, "decimal") == 0
+                && PyUnicode_CompareWithASCIIString(name, "Decimal") == 0)
+                return _PyTime_AsDecimal(ts);
+        }
+        else
+            PyErr_Clear();
+    }
+
+    PyErr_Format(PyExc_ValueError, "Unknown timestamp format: %R", format);
+    return NULL;
+}
+
+void
 _PyTime_Init()
 {
     /* Do nothing.  Needed to force linking. */