Merge from trunk

[plcapi.git] / trunk / psycopg2 / lib / tz.py

diff --git a/trunk/psycopg2/lib/tz.py b/trunk/psycopg2/lib/tz.py
new file mode 100644 (file)
index 0000000..e521b6d
--- /dev/null
+++ b/trunk/psycopg2/lib/tz.py
@@ -0,0 +1,100 @@
+"""tzinfo implementations for psycopg2
+
+This module holds two different tzinfo implementations that can be used as
+the 'tzinfo' argument to datetime constructors, directly passed to psycopg
+functions or used to set the .tzinfo_factory attribute in cursors. 
+"""
+# psycopg/tz.py - tzinfo implementation
+#
+# Copyright (C) 2003-2004 Federico Di Gregorio  <fog@debian.org>
+#
+# 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
+# Free Software Foundation; either version 2, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY
+# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+
+import datetime
+import time
+
+
+ZERO = datetime.timedelta(0)
+
+class FixedOffsetTimezone(datetime.tzinfo):
+    """Fixed offset in minutes east from UTC.
+
+    This is exactly the implementation found in Python 2.3.x documentation,
+    with a small change to the __init__ method to allow for pickling and a
+    default name in the form 'sHH:MM' ('s' is the sign.)
+    """
+    _name = None
+    _offset = ZERO
+    
+    def __init__(self, offset=None, name=None):
+        if offset is not None:
+            self._offset = datetime.timedelta(minutes = offset)
+        if name is not None:
+            self._name = name
+
+    def utcoffset(self, dt):
+        return self._offset
+
+    def tzname(self, dt):
+        if self._name is not None:
+            return self._name
+        else:
+            seconds = self._offset.seconds + self._offset.days * 86400
+            hours, seconds = divmod(seconds, 3600)
+            minutes = seconds/60
+            if minutes:
+                return "%+03d:%d" % (hours, minutes)
+            else:
+                return "%+03d" % hours
+            
+    def dst(self, dt):
+        return ZERO
+
+
+STDOFFSET = datetime.timedelta(seconds = -time.timezone)
+if time.daylight:
+    DSTOFFSET = datetime.timedelta(seconds = -time.altzone)
+else:
+    DSTOFFSET = STDOFFSET
+DSTDIFF = DSTOFFSET - STDOFFSET
+
+class LocalTimezone(datetime.tzinfo):
+    """Platform idea of local timezone.
+
+    This is the exact implementation from the Pyhton 2.3 documentation.
+    """
+    
+    def utcoffset(self, dt):
+        if self._isdst(dt):
+            return DSTOFFSET
+        else:
+            return STDOFFSET
+
+    def dst(self, dt):
+        if self._isdst(dt):
+            return DSTDIFF
+        else:
+            return ZERO
+
+    def tzname(self, dt):
+        return time.tzname[self._isdst(dt)]
+
+    def _isdst(self, dt):
+        tt = (dt.year, dt.month, dt.day,
+              dt.hour, dt.minute, dt.second,
+              dt.weekday(), 0, -1)
+        stamp = time.mktime(tt)
+        tt = time.localtime(stamp)
+        return tt.tm_isdst > 0
+
+LOCAL = LocalTimezone()
+
+# TODO: pre-generate some interesting time zones?