98 lines
3.2 KiB
Python
98 lines
3.2 KiB
Python
from ctypes import c_void_p
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from django.contrib.gis.gdal.base import GDALBase
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from django.contrib.gis.gdal.error import GDALException
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from django.contrib.gis.gdal.prototypes import ds as vcapi, raster as rcapi
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from django.utils.encoding import force_bytes, force_text
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class Driver(GDALBase):
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"""
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Wraps a GDAL/OGR Data Source Driver.
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For more information, see the C API source code:
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http://www.gdal.org/gdal_8h.html - http://www.gdal.org/ogr__api_8h.html
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"""
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# Case-insensitive aliases for some GDAL/OGR Drivers.
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# For a complete list of original driver names see
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# http://www.gdal.org/ogr_formats.html (vector)
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# http://www.gdal.org/formats_list.html (raster)
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_alias = {
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# vector
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'esri': 'ESRI Shapefile',
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'shp': 'ESRI Shapefile',
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'shape': 'ESRI Shapefile',
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'tiger': 'TIGER',
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'tiger/line': 'TIGER',
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# raster
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'tiff': 'GTiff',
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'tif': 'GTiff',
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'jpeg': 'JPEG',
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'jpg': 'JPEG',
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}
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def __init__(self, dr_input):
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"""
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Initializes an GDAL/OGR driver on either a string or integer input.
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"""
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if isinstance(dr_input, str):
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# If a string name of the driver was passed in
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self.ensure_registered()
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# Checking the alias dictionary (case-insensitive) to see if an
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# alias exists for the given driver.
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if dr_input.lower() in self._alias:
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name = self._alias[dr_input.lower()]
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else:
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name = dr_input
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# Attempting to get the GDAL/OGR driver by the string name.
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for iface in (vcapi, rcapi):
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driver = c_void_p(iface.get_driver_by_name(force_bytes(name)))
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if driver:
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break
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elif isinstance(dr_input, int):
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self.ensure_registered()
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for iface in (vcapi, rcapi):
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driver = iface.get_driver(dr_input)
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if driver:
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break
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elif isinstance(dr_input, c_void_p):
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driver = dr_input
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else:
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raise GDALException('Unrecognized input type for GDAL/OGR Driver: %s' % type(dr_input))
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# Making sure we get a valid pointer to the OGR Driver
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if not driver:
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raise GDALException('Could not initialize GDAL/OGR Driver on input: %s' % dr_input)
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self.ptr = driver
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def __str__(self):
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return self.name
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@classmethod
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def ensure_registered(cls):
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"""
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Attempts to register all the data source drivers.
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"""
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# Only register all if the driver counts are 0 (or else all drivers
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# will be registered over and over again)
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if not vcapi.get_driver_count():
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vcapi.register_all()
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if not rcapi.get_driver_count():
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rcapi.register_all()
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@classmethod
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def driver_count(cls):
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"""
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Returns the number of GDAL/OGR data source drivers registered.
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"""
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return vcapi.get_driver_count() + rcapi.get_driver_count()
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@property
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def name(self):
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"""
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Returns description/name string for this driver.
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"""
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return force_text(rcapi.get_driver_description(self.ptr))
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