Fixed another precision problem on conversion of decimal seconds to

microseconds, as reported by Erik Brown.  Now they're gone for real,
since it's not using floating point arithmetic anymore.

3 files changed, 38 insertions, 8 deletions

diff --git a/NEWS b/NEWS
index eb97d98..6a80ca4 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,12 @@
+Version 1.4
+-----------
+
+- Fixed another precision problem on conversion of decimal seconds to
+  microseconds, as reported by Erik Brown.  Now they're gone for real,
+  since it's not using floating point arithmetic anymore.
+
+
+
 Version 1.3
 -----------
 
diff --git a/dateutil/parser.py b/dateutil/parser.py
index 951c09e..b1b7cc2 100644
--- a/dateutil/parser.py
+++ b/dateutil/parser.py
@@ -361,9 +361,11 @@ class parser(object):
 
                 # Check if it's a number
                 try:
-                    value = float(l[i])
+                    value_repr = l[i]
+                    value = float(value_repr)
                 except ValueError:
                     value = None
+
                 if value is not None:
                     # Token is a number
                     len_li = len(l[i])
@@ -387,8 +389,7 @@ class parser(object):
                             # 19990101T235959[.59]
                             res.hour = int(s[:2])
                             res.minute = int(s[2:4])
-                            value = float(s[4:])
-                            res.second, res.microsecond = _parsems(value)
+                            res.second, res.microsecond = _parsems(s[4:])
                     elif len_li == 8:
                         # YYYYMMDD
                         s = l[i-1]
@@ -422,13 +423,15 @@ class parser(object):
                                 if value%1:
                                     res.second = int(60*(value%1))
                             elif idx == 2:
-                                res.second, res.microsecond = _parsems(value)
+                                res.second, res.microsecond = \
+                                    _parsems(value_repr)
                             i += 1
                             if i >= len_l or idx == 2:
                                 break
                             # 12h00
                             try:
-                                value = float(l[i])
+                                value_repr = l[i]
+                                value = float(value_repr)
                             except ValueError:
                                 break
                             else:
@@ -448,8 +451,7 @@ class parser(object):
                             res.second = int(60*(value%1))
                         i += 1
                         if i < len_l and l[i] == ':':
-                            value = float(l[i+1])
-                            res.second, res.microsecond = _parsems(value)
+                            res.second, res.microsecond = _parsems(l[i+1])
                             i += 2
                     elif i < len_l and l[i] in ('-', '/', '.'):
                         sep = l[i]
@@ -871,7 +873,12 @@ def _parsetz(tzstr):
 
 
 def _parsems(value):
-    return int(value), int(value * 1000000) - int(value) * 1000000
+    """Parse a I[.F] seconds value into (seconds, microseconds)."""
+    if "." not in value:
+        return int(value), 0
+    else:
+        i, f = value.split(".")
+        return int(i), int(f.ljust(6, "0")[:6])
 
 
 # vim:ts=4:sw=4:et
diff --git a/test.py b/test.py
index 9a3c53c..c99efff 100644
--- a/test.py
+++ b/test.py
@@ -3557,6 +3557,20 @@ class ParserTest(unittest.TestCase):
         self.assertEquals(dt1.microsecond, 10000)
         self.assertEquals(dt2.microsecond, 10000)
 
+    def testMicrosecondPrecisionErrorReturns(self):
+        # One more precision issue, discovered by Eric Brown.  This should
+        # be the last one, as we're no longer using floating points.
+        for ms in [100001, 100000, 99999, 99998,
+                    10001,  10000,  9999,  9998,
+                     1001,   1000,   999,   998,
+                      101,    100,    99,    98]:
+            dt = datetime(2008, 2, 27, 21, 26, 1, ms)
+            self.assertEquals(parse(dt.isoformat()), dt)
+
+    def testHighPrecisionSeconds(self):
+        self.assertEquals(parse("20080227T21:26:01.123456789"),
+                          datetime(2008, 2, 27, 21, 26, 1, 123456))
+
     def testCustomParserInfo(self):
         # Custom parser info wasn't working, as Michael Elsdörfer discovered.
         from dateutil.parser import parserinfo, parser