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76 lines
1.7 KiB
Python
76 lines
1.7 KiB
Python
#
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# The Python Imaging Library
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# $Id$
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#
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# GRIB stub adapter
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#
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# Copyright (c) 1996-2003 by Fredrik Lundh
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#
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# See the README file for information on usage and redistribution.
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#
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from __future__ import annotations
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import os
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from typing import IO
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from . import Image, ImageFile
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_handler = None
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def register_handler(handler: ImageFile.StubHandler | None) -> None:
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"""
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Install application-specific GRIB image handler.
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:param handler: Handler object.
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"""
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global _handler
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_handler = handler
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# --------------------------------------------------------------------
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# Image adapter
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def _accept(prefix: bytes) -> bool:
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return prefix.startswith(b"GRIB") and prefix[7] == 1
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class GribStubImageFile(ImageFile.StubImageFile):
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format = "GRIB"
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format_description = "GRIB"
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def _open(self) -> None:
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if not _accept(self.fp.read(8)):
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msg = "Not a GRIB file"
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raise SyntaxError(msg)
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self.fp.seek(-8, os.SEEK_CUR)
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# make something up
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self._mode = "F"
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self._size = 1, 1
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loader = self._load()
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if loader:
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loader.open(self)
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def _load(self) -> ImageFile.StubHandler | None:
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return _handler
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def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
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if _handler is None or not hasattr(_handler, "save"):
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msg = "GRIB save handler not installed"
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raise OSError(msg)
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_handler.save(im, fp, filename)
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# --------------------------------------------------------------------
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# Registry
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Image.register_open(GribStubImageFile.format, GribStubImageFile, _accept)
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Image.register_save(GribStubImageFile.format, _save)
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Image.register_extension(GribStubImageFile.format, ".grib")
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