Fix microsecond rounding issues

Thanks to nielsenb@jetfuse.net

Fixes #2

3 files changed, 6 insertions, 2 deletions

diff --git a/README.rst b/README.rst
index da5613a..c35624d 100644
--- a/README.rst
+++ b/README.rst
@@ -71,6 +71,7 @@ Changes
 * Make seconds optional in date format ("1997-07-16T19:20+01:00" now valid). https://bitbucket.org/micktwomey/pyiso8601/pull-request/1/make-the-inclusion-of-seconds-optional-in/diff (thanks to Chris Down)
 * Correctly raise ParseError for more invalid inputs (https://bitbucket.org/micktwomey/pyiso8601/issue/1/raise-parseerror-for-invalid-input) (thanks to manish.tomar)
 * Support more variations of ISO 8601 dates, times and time zone specs.
+* Fix microsecond rounding issues (https://bitbucket.org/micktwomey/pyiso8601/issue/2/roundoff-issues-when-parsing-decimal) (thanks to nielsenb@jetfuse.net)
 
 0.1.4
 -----
diff --git a/iso8601/iso8601.py b/iso8601/iso8601.py
index a121e2e..b979f02 100644
--- a/iso8601/iso8601.py
+++ b/iso8601/iso8601.py
@@ -13,6 +13,7 @@ from datetime import (
     timedelta,
     tzinfo
 )
+from decimal import Decimal
 import logging
 import sys
 import re
@@ -28,7 +29,8 @@ else:
 
 
 # Adapted from http://delete.me.uk/2005/03/iso8601.html
-ISO8601_REGEX = re.compile(r"""
+ISO8601_REGEX = re.compile(
+    r"""
     (?P<year>[0-9]{4})
     (-{0,1}(?P<month>[0-9]{1,2})){1}
     (-{0,1}(?P<day>[0-9]{1,2})){1}
@@ -159,7 +161,7 @@ def parse_date(datestring, default_timezone=UTC):
 
     tz = parse_timezone(groups, default_timezone=default_timezone)
 
-    groups["second_fraction"] = int(float("0.%s" % to_int(groups, "second_fraction", default_to_zero=True)) * 1e6)
+    groups["second_fraction"] = int(Decimal("0.%s" % to_int(groups, "second_fraction", default_to_zero=True)) * Decimal("1000000.0"))
 
     try:
         return datetime(
diff --git a/iso8601/test_iso8601.py b/iso8601/test_iso8601.py
index 5b5e760..4a0b05c 100644
--- a/iso8601/test_iso8601.py
+++ b/iso8601/test_iso8601.py
@@ -46,6 +46,7 @@ def test_parse_invalid_date(invalid_date):
     ("2013-10-15T1831Z", datetime.datetime(2013, 10, 15, 18, 31, 0, 0, iso8601.UTC)),  # hhmm
     ("2013-10-15T18Z", datetime.datetime(2013, 10, 15, 18, 0, 0, 0, iso8601.UTC)),  # hh
     ("20131015T18:30Z", datetime.datetime(2013, 10, 15, 18, 30, 0, 0, iso8601.UTC)),  # YYYYMMDD
+    ("2012-12-19T23:21:28.512400+00:00", datetime.datetime(2012, 12, 19, 23, 21, 28, 512400, iso8601.FixedOffset(0, 0, "+00:00"))),  # https://code.google.com/p/pyiso8601/issues/detail?id=21
 ])
 def test_parse_valid_date(valid_date, expected_datetime):
     parsed = iso8601.parse_date(valid_date)