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from ctypes import c_void_p
from django.contrib.gis.gdal.base import GDALBase
from django.contrib.gis.gdal.error import GDALException
from django.contrib.gis.gdal.prototypes import ds as vcapi, raster as rcapi
from django.utils import six
from django.utils.encoding import force_bytes, force_text
class Driver(GDALBase):
"""
Wraps a GDAL/OGR Data Source Driver.
For more information, see the C API source code:
http://www.gdal.org/gdal_8h.html - http://www.gdal.org/ogr__api_8h.html
"""
# Case-insensitive aliases for some GDAL/OGR Drivers.
# For a complete list of original driver names see
# http://www.gdal.org/ogr_formats.html (vector)
# http://www.gdal.org/formats_list.html (raster)
_alias = {
# vector
'esri': 'ESRI Shapefile',
'shp': 'ESRI Shapefile',
'shape': 'ESRI Shapefile',
'tiger': 'TIGER',
'tiger/line': 'TIGER',
# raster
'tiff': 'GTiff',
'tif': 'GTiff',
'jpeg': 'JPEG',
'jpg': 'JPEG',
}
def __init__(self, dr_input):
"""
Initializes an GDAL/OGR driver on either a string or integer input.
"""
if isinstance(dr_input, six.string_types):
# If a string name of the driver was passed in
self.ensure_registered()
# 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 GDAL/OGR driver by the string name.
for iface in (vcapi, rcapi):
driver = iface.get_driver_by_name(force_bytes(name))
if driver:
break
elif isinstance(dr_input, int):
self.ensure_registered()
for iface in (vcapi, rcapi):
driver = iface.get_driver(dr_input)
if driver:
break
elif isinstance(dr_input, c_void_p):
driver = dr_input
else:
raise GDALException('Unrecognized input type for GDAL/OGR Driver: %s' % str(type(dr_input)))
# Making sure we get a valid pointer to the OGR Driver
if not driver:
raise GDALException('Could not initialize GDAL/OGR Driver on input: %s' % str(dr_input))
self.ptr = driver
def __str__(self):
return self.name
@classmethod
def ensure_registered(cls):
"""
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 cls.driver_count():
vcapi.register_all()
rcapi.register_all()
@classmethod
def driver_count(cls):
"""
Returns the number of GDAL/OGR data source drivers registered.
"""
return vcapi.get_driver_count() + rcapi.get_driver_count()
@property
def name(self):
"""
Returns description/name string for this driver.
"""
return force_text(rcapi.get_driver_description(self.ptr))
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