Add the option to define a channel time offset in the sources.xml

This allows epgimport to correct start- and endtimes of events, as several xmltv sources use local time with +0000 instead of the correct timezone offset. To use this, define the offset like so:
````
<source type="gen_xmltv" nocheck="1" offset="-0200" channels="/etc/epgimport/some.xmltvfile.channels.xml">
 <description>Some XMLTV file</description>
 <url>http://epg.example.org/some,xlmtvfile.gz></url>
</source>
````
in this case because the times in the file are in GMT+2, but the offset is +0000, indicating GMT was used. The offset "-0200" corrects GMT+2 to GMT.

src/EPGImport/EPGConfig.py

@@ -23,7 +23,7 @@ def isLocalFile(filename):
 	return '://' not in filename
 
 
-def getChannels(path, name):
+def getChannels(path, name, offset):
 	global channelCache
 	if name in channelCache:
 		return channelCache[name]
@@ -39,20 +39,21 @@ def getChannels(path, name):
 		return channelCache[channelfile]
 	except KeyError:
 		pass
-	c = EPGChannel(channelfile)
+	c = EPGChannel(channelfile, offset=offset)
 	channelCache[channelfile] = c
 	return c
 
 
 class EPGChannel:
-	def __init__(self, filename, urls=None):
+	def __init__(self, filename, urls=None, offset=0):
 		self.mtime = None
 		self.name = filename
 		if urls is None:
 			self.urls = [filename]
 		else:
 			self.urls = urls
 		self.items = None
+		self.offset = offset
 
 	def openStream(self, filename):
 		fd = open(filename, 'rb')
@@ -122,7 +123,7 @@ def __repr__(self):
 
 
 class EPGSource:
-	def __init__(self, path, elem, category=None):
+	def __init__(self, path, elem, category=None, offset=0):
 		self.parser = elem.get('type')
 		nocheck = elem.get('nocheck')
 		if nocheck == None:
@@ -135,10 +136,11 @@ def __init__(self, path, elem, category=None):
 		self.url = random.choice(self.urls)
 		self.description = elem.findtext('description')
 		self.category = category
+		self.offset = offset
 		if not self.description:
 			self.description = self.url
 		self.format = elem.get('format', 'xml')
-		self.channels = getChannels(path, elem.get('channels'))
+		self.channels = getChannels(path, elem.get('channels'), offset)
 
 
 def enumSourcesFile(sourcefile, filter=None, categories=False):
@@ -147,7 +149,9 @@ def enumSourcesFile(sourcefile, filter=None, categories=False):
 	for event, elem in iterparse(open(sourcefile, 'rb'), events=("start", "end")):
 		if event == 'end':
 			if elem.tag == 'source':
-				s = EPGSource(sourcefile, elem, category)
+				# calculate custom time offset in minutes
+				offset = int(elem.get('offset', '+0000')) * 3600 // 100
+				s = EPGSource(sourcefile, elem, category, offset)
 				elem.clear()
 				if (filter is None) or (s.description in filter):
 					yield s

src/EPGImport/EPGImport.py

@@ -317,7 +317,7 @@ def channelDownloadFail(self, failure):
     def createIterator(self, filename):
 #       print("[EPGImport][createIterator], filename", filename)
         self.source.channels.update(self.channelFilter, filename)
-        return getParser(self.source.parser).iterator(self.fd, self.source.channels.items)
+        return getParser(self.source.parser).iterator(self.fd, self.source.channels.items, self.source.offset)
 
     def readEpgDatFile(self, filename, deleteFile=False):
         if not hasattr(self.epgcache, 'load'):

src/EPGImport/gen_xmltv.py

@@ -30,9 +30,9 @@ def new():
 
 
 class Gen_Xmltv():
-	def iterator(self, fd, channelsDict):
+	def iterator(self, fd, channelsDict, offset=0):
 		try:
-			xmltv_parser = xmltvconverter.XMLTVConverter(channelsDict, gen_categories, date_format)
+			xmltv_parser = xmltvconverter.XMLTVConverter(channelsDict, gen_categories, date_format, offset)
 			for r in xmltv_parser.enumFile(fd):
 				yield r
 		except Exception as e:

src/EPGImport/xmltvconverter.py

@@ -61,13 +61,15 @@ def enumerateProgrammes(fp):
 
 
 class XMLTVConverter:
-	def __init__(self, channels_dict, category_dict, dateformat='%Y%m%d%H%M%S %Z'):
+	def __init__(self, channels_dict, category_dict, dateformat='%Y%m%d%H%M%S %Z', offset=0):
 	    self.channels = channels_dict
 	    self.categories = category_dict
 	    if dateformat.startswith('%Y%m%d%H%M%S'):
 		    self.dateParser = quickptime
 	    else:
 		    self.dateParser = lambda x: time.strptime(x, dateformat)
+		self.offset = offset
+		print("[XMLTVConverter] Using a custom time offset of %d" % offset)
 
 	def enumFile(self, fileobj):
 		print("[XMLTVConverter] Enumerating event information", file=log)
@@ -87,8 +89,8 @@ def enumFile(self, fileobj):
 				continue
 			try:
 				services = self.channels[channel]
-				start = get_time_utc(elem.get('start'), self.dateParser)
-				stop = get_time_utc(elem.get('stop'), self.dateParser)
+				start = get_time_utc(elem.get('start'), self.dateParser) + self.offset
+				stop = get_time_utc(elem.get('stop'), self.dateParser) + self.offset
 				title = get_xml_string(elem, 'title')
 				# try/except for EPG XML files with program entries containing <sub-title ... />
 				try: