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# prerequisites imports
from ctypes import c_void_p
from django.contrib.gis.gdal.error import OGRException
from django.contrib.gis.gdal.prototypes.ds import \
get_driver, get_driver_by_name, get_driver_count, get_driver_name, register_all
# For more information, see the OGR C API source code:
# http://www.gdal.org/ogr/ogr__api_8h.html
#
# The OGR_Dr_* routines are relevant here.
class Driver(object):
"Wraps an OGR Data Source Driver."
# Case-insensitive aliases for OGR Drivers.
_alias = {'esri' : 'ESRI Shapefile',
'shp' : 'ESRI Shapefile',
'shape' : 'ESRI Shapefile',
'tiger' : 'TIGER',
'tiger/line' : 'TIGER',
}
def __init__(self, dr_input):
"Initializes an OGR driver on either a string or integer input."
if isinstance(dr_input, basestring):
# If a string name of the driver was passed in
self._ptr = None # Initially NULL
self._register()
# Checking the alias dictionary (case-insensitive) to see if an alias
# exists for the given driver.
if dr_input.lower() in self._alias:
name = self._alias[dr_input.lower()]
else:
name = dr_input
# Attempting to get the OGR driver by the string name.
dr = get_driver_by_name(name)
elif isinstance(dr_input, int):
self._register()
dr = get_driver(dr_input)
elif isinstance(dr_input, c_void_p):
dr = dr_input
else:
raise OGRException('Unrecognized input type for OGR Driver: %s' % str(type(dr_input)))
# Making sure we get a valid pointer to the OGR Driver
if not dr:
raise OGRException('Could not initialize OGR Driver on input: %s' % str(dr_input))
self._ptr = dr
def __str__(self):
"Returns the string name of the OGR Driver."
return get_driver_name(self._ptr)
def _register(self):
"Attempts to register all the data source drivers."
# Only register all if the driver count is 0 (or else all drivers
# will be registered over and over again)
if not self.driver_count: register_all()
# Driver properties
@property
def driver_count(self):
"Returns the number of OGR data source drivers registered."
return get_driver_count()
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