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# Source code for PIL.ImageMode

    #
    # The Python Imaging Library.
    # $Id$
    #
    # standard mode descriptors
    #
    # History:
    # 2006-03-20 fl   Added
    #
    # Copyright (c) 2006 by Secret Labs AB.
    # Copyright (c) 2006 by Fredrik Lundh.
    #
    # See the README file for information on usage and redistribution.
    #
    from __future__ import annotations

    import sys
    from functools import lru_cache
    from typing import NamedTuple

    from ._deprecate import deprecate

    class ModeDescriptor(NamedTuple):
        """Wrapper for mode strings."""

        mode: str
        bands: tuple[str, ...]
        basemode: str
        basetype: str
        typestr: str

        def __str__(self) -> str:
            return self.mode

    @lru_cache
    def getmode(mode: str) -> ModeDescriptor:
        """Gets a mode descriptor for the given mode."""
        endian = "<" if sys.byteorder == "little" else ">"

        modes = {
            # core modes
            # Bits need to be extended to bytes
            "1": ("L", "L", ("1",), "|b1"),
            "L": ("L", "L", ("L",), "|u1"),
            "I": ("L", "I", ("I",), f"{endian}i4"),
            "F": ("L", "F", ("F",), f"{endian}f4"),
            "P": ("P", "L", ("P",), "|u1"),
            "RGB": ("RGB", "L", ("R", "G", "B"), "|u1"),
            "RGBX": ("RGB", "L", ("R", "G", "B", "X"), "|u1"),
            "RGBA": ("RGB", "L", ("R", "G", "B", "A"), "|u1"),
            "CMYK": ("RGB", "L", ("C", "M", "Y", "K"), "|u1"),
            "YCbCr": ("RGB", "L", ("Y", "Cb", "Cr"), "|u1"),
            # UNDONE - unsigned |u1i1i1
            "LAB": ("RGB", "L", ("L", "A", "B"), "|u1"),
            "HSV": ("RGB", "L", ("H", "S", "V"), "|u1"),
            # extra experimental modes
            "RGBa": ("RGB", "L", ("R", "G", "B", "a"), "|u1"),
            "BGR;15": ("RGB", "L", ("B", "G", "R"), "|u1"),
            "BGR;16": ("RGB", "L", ("B", "G", "R"), "|u1"),
            "BGR;24": ("RGB", "L", ("B", "G", "R"), "|u1"),
            "LA": ("L", "L", ("L", "A"), "|u1"),
            "La": ("L", "L", ("L", "a"), "|u1"),
            "PA": ("RGB", "L", ("P", "A"), "|u1"),
        }
        if mode in modes:
            if mode in ("BGR;15", "BGR;16", "BGR;24"):
                deprecate(mode, 12)
            base_mode, base_type, bands, type_str = modes[mode]
            return ModeDescriptor(mode, bands, base_mode, base_type, type_str)

        mapping_modes = {
            # I;16 == I;16L, and I;32 == I;32L
            "I;16": "<u2",
            "I;16S": "<i2",
            "I;16L": "<u2",
            "I;16LS": "<i2",
            "I;16B": ">u2",
            "I;16BS": ">i2",
            "I;16N": f"{endian}u2",
            "I;16NS": f"{endian}i2",
            "I;32": "<u4",
            "I;32B": ">u4",
            "I;32L": "<u4",
            "I;32S": "<i4",
            "I;32BS": ">i4",
            "I;32LS": "<i4",
        }

        type_str = mapping_modes[mode]
        return ModeDescriptor(mode, ("I",), "L", "L", type_str)