python api: allow timeval and timespec init with float/datetime

qa/737.out

@@ -6,3 +6,7 @@ pmCtime from int:        Mon Feb  3 04:46:19 2014
 pmCtime from float:      Mon Feb  3 04:46:19 2014
 pmWhichZone:  UTC
 pmWhichZone:  UTC
+timeval from int:    1391402779.000
+timeval from float:  1391402779.500
+timespec from int:    1391402779.000
+timespec from float:  1391402779.500

qa/src/test_pcp_time.python

@@ -1,6 +1,6 @@
 #!/usr/bin/env pmpython
 #
-# Copyright (C) 2014,2016 Red Hat.
+# Copyright (C) 2014,2016,2024 Red Hat.
 #
 # This program is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by the
@@ -13,7 +13,7 @@
 # for more details.
 #
 
-""" Exercise the pmCtime and pmLocaltime interfaces """
+""" Exercise pmCtime, pmLocaltime, timeval and timespec interfaces """
 
 from pcp import pmapi
 import time
@@ -44,3 +44,14 @@ print("pmCtime from float:      %s" % str(context.pmCtime(sample_time_f)).rstrip
 print("pmWhichZone:  %s" % str(context.pmWhichZone()))
 # https://bugzilla.redhat.com/show_bug.cgi?id=1352465
 print("pmWhichZone:  %s" % str(context.pmWhichZone()))
+
+timevali = pmapi.timeval(sample_time_i)
+timevalf = pmapi.timeval(sample_time_f)
+print("timeval from int:    %s" % timevali)
+print("timeval from float:  %s" % timevalf)
+
+sample_time_f += 0.5	# sub-second component
+timespeci = pmapi.timespec(sample_time_i)
+timespecf = pmapi.timespec(sample_time_f)
+print("timespec from int:    %s" % timespeci)
+print("timespec from float:  %s" % timespecf)

src/python/pcp/pmapi.py.in

@@ -1,6 +1,6 @@
 """ Wrapper module for LIBPCP - the core Performace Co-Pilot API
 #
-# Copyright (C) 2012-2022 Red Hat
+# Copyright (C) 2012-2024 Red Hat
 # Copyright (C) 2009-2012 Michael T. Werner
 #
 # This file is part of the "pcp" module, the python interfaces for the
@@ -94,9 +94,11 @@ import os
 import sys
 import time
 import errno
-import datetime
 import json
 
+from datetime import datetime
+from math import modf
+
 # constants adapted from C header file <pcp/pmapi.h>
 import cpmapi as c_api
 
@@ -227,8 +229,18 @@ class timeval(Structure):
     _fields_ = [("tv_sec", c_time_t),
                 ("tv_usec", c_suseconds_t)]
 
-    def __init__(self, sec=0, usec=0):
+    def __init__(self, sec=0, usec=None):
         Structure.__init__(self)
+        if usec is None:
+            if isinstance(sec, datetime):
+                epoch = datetime.utcfromtimestamp(0)
+                sec = float((sec - epoch).total_seconds())
+            if isinstance(sec, float):
+                ts = modf(sec)
+                sec = int(ts[1])
+                usec = int(ts[0] * 1000000)
+            else:
+                usec = 0
         self.tv_sec = sec
         self.tv_usec = usec
 
@@ -270,8 +282,18 @@ class timespec(Structure):
     _fields_ = [("tv_sec", c_time_t),
                 ("tv_nsec", c_long)]
 
-    def __init__(self, sec=0, nsec=0):
+    def __init__(self, sec=0, nsec=None):
         Structure.__init__(self)
+        if nsec is None:
+            if isinstance(sec, datetime):
+                epoch = datetime.utcfromtimestamp(0)
+                sec = float((sec - epoch).total_seconds())
+            if isinstance(sec, float):
+                ts = modf(sec)
+                sec = int(ts[1])
+                nsec = int(ts[0] * 1000000000)
+            else:
+                nsec = 0
         self.tv_sec = sec
         self.tv_nsec = nsec
 
@@ -2900,7 +2922,7 @@ class pmContext(object):
     @staticmethod
     def datetime_to_secs(value, precision=c_api.PM_TIME_SEC):
         """ Convert datetime value to seconds of given precision """
-        tdt = value - datetime.datetime.fromtimestamp(0)
+        tdt = value - datetime.fromtimestamp(0)
         if precision == c_api.PM_TIME_SEC:
             tst = (tdt.microseconds + (tdt.seconds + tdt.days * 24.0 * 3600.0) * 10.0**6) / 10.0**6
         elif precision == c_api.PM_TIME_MSEC:
@@ -3030,8 +3052,8 @@ class fetchgroup(object):
             """
             ts = self.ctx.pmLocaltime(self.value.tv_sec)
             us = int(self.value.tv_nsec) // 1000
-            dt = datetime.datetime(ts.tm_year+1900, ts.tm_mon+1, ts.tm_mday,
-                                   ts.tm_hour, ts.tm_min, ts.tm_sec, us, None)
+            dt = datetime(ts.tm_year+1900, ts.tm_mon+1, ts.tm_mday,
+                          ts.tm_hour, ts.tm_min, ts.tm_sec, us, None)
             return dt
 
     class fetchgroup_timeval(object):
@@ -3054,8 +3076,8 @@ class fetchgroup(object):
             """
             ts = self.ctx.pmLocaltime(self.value.tv_sec)
             us = int(self.value.tv_usec)
-            dt = datetime.datetime(ts.tm_year+1900, ts.tm_mon+1, ts.tm_mday,
-                                   ts.tm_hour, ts.tm_min, ts.tm_sec, us, None)
+            dt = datetime(ts.tm_year+1900, ts.tm_mon+1, ts.tm_mday,
+                          ts.tm_hour, ts.tm_min, ts.tm_sec, us, None)
             return dt
 
     # create the backward compatibility alias
@@ -3140,8 +3162,8 @@ class fetchgroup(object):
 
                 ts = self.ctx.pmLocaltime(self.times[i].tv_sec)
                 us = int(self.times[i].tv_nsec) // 1000
-                dt = datetime.datetime(ts.tm_year+1900, ts.tm_mon+1, ts.tm_mday,
-                                       ts.tm_hour, ts.tm_min, ts.tm_sec, us, None)
+                dt = datetime(ts.tm_year+1900, ts.tm_mon+1, ts.tm_mday,
+                              ts.tm_hour, ts.tm_min, ts.tm_sec, us, None)
                 # nested lambda for proper i capture
                 # pylint: disable=cell-var-from-loop,unnecessary-direct-lambda-call
                 vv.append((dt,