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Optimise ImageMode.getmode

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This commit is contained in:
Hugo van Kemenade 2023-12-22 16:30:45 +02:00
parent ef0b0d232a
commit 26f58e7afc
1 changed files with 55 additions and 56 deletions
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111
src/PIL/ImageMode.py
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@ -15,9 +15,7 @@
from __future__ import annotations from __future__ import annotations
import sys import sys
from functools import lru_cache
# mode descriptor cache
_modes = None
class ModeDescriptor: class ModeDescriptor:
@ -41,58 +39,59 @@ class ModeDescriptor:
return self.mode return self.mode
@lru_cache
def getmode(mode: str) -> ModeDescriptor: def getmode(mode: str) -> ModeDescriptor:
"""Gets a mode descriptor for the given mode.""" """Gets a mode descriptor for the given mode."""
global _modes # if not _modes:
if not _modes: # initialize mode cache
# initialize mode cache endian = "<" if sys.byteorder == "little" else ">"
modes = {}
endian = "<" if sys.byteorder == "little" else ">" modes = {
for m, (basemode, basetype, bands, typestr) in { # core modes
# core modes # Bits need to be extended to bytes
# Bits need to be extended to bytes "1": ("L", "L", ("1",), "|b1"),
"1": ("L", "L", ("1",), "|b1"), "L": ("L", "L", ("L",), "|u1"),
"L": ("L", "L", ("L",), "|u1"), "I": ("L", "I", ("I",), endian + "i4"),
"I": ("L", "I", ("I",), endian + "i4"), "F": ("L", "F", ("F",), endian + "f4"),
"F": ("L", "F", ("F",), endian + "f4"), "P": ("P", "L", ("P",), "|u1"),
"P": ("P", "L", ("P",), "|u1"), "RGB": ("RGB", "L", ("R", "G", "B"), "|u1"),
"RGB": ("RGB", "L", ("R", "G", "B"), "|u1"), "RGBX": ("RGB", "L", ("R", "G", "B", "X"), "|u1"),
"RGBX": ("RGB", "L", ("R", "G", "B", "X"), "|u1"), "RGBA": ("RGB", "L", ("R", "G", "B", "A"), "|u1"),
"RGBA": ("RGB", "L", ("R", "G", "B", "A"), "|u1"), "CMYK": ("RGB", "L", ("C", "M", "Y", "K"), "|u1"),
"CMYK": ("RGB", "L", ("C", "M", "Y", "K"), "|u1"), "YCbCr": ("RGB", "L", ("Y", "Cb", "Cr"), "|u1"),
"YCbCr": ("RGB", "L", ("Y", "Cb", "Cr"), "|u1"), # UNDONE - unsigned |u1i1i1
# UNDONE - unsigned |u1i1i1 "LAB": ("RGB", "L", ("L", "A", "B"), "|u1"),
"LAB": ("RGB", "L", ("L", "A", "B"), "|u1"), "HSV": ("RGB", "L", ("H", "S", "V"), "|u1"),
"HSV": ("RGB", "L", ("H", "S", "V"), "|u1"), # extra experimental modes
# extra experimental modes "RGBa": ("RGB", "L", ("R", "G", "B", "a"), "|u1"),
"RGBa": ("RGB", "L", ("R", "G", "B", "a"), "|u1"), "BGR;15": ("RGB", "L", ("B", "G", "R"), "|u1"),
"BGR;15": ("RGB", "L", ("B", "G", "R"), "|u1"), "BGR;16": ("RGB", "L", ("B", "G", "R"), "|u1"),
"BGR;16": ("RGB", "L", ("B", "G", "R"), "|u1"), "BGR;24": ("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"), "La": ("L", "L", ("L", "a"), "|u1"),
"La": ("L", "L", ("L", "a"), "|u1"), "PA": ("RGB", "L", ("P", "A"), "|u1"),
"PA": ("RGB", "L", ("P", "A"), "|u1"), }
}.items(): if mode in modes:
modes[m] = ModeDescriptor(m, bands, basemode, basetype, typestr) base_mode, base_type, bands, type_str = modes[mode]
# mapping modes return ModeDescriptor(mode, bands, base_mode, base_type, type_str)
for i16mode, typestr in {
# I;16 == I;16L, and I;32 == I;32L mapping_modes = {
"I;16": "<u2", # I;16 == I;16L, and I;32 == I;32L
"I;16S": "<i2", "I;16": "<u2",
"I;16L": "<u2", "I;16S": "<i2",
"I;16LS": "<i2", "I;16L": "<u2",
"I;16B": ">u2", "I;16LS": "<i2",
"I;16BS": ">i2", "I;16B": ">u2",
"I;16N": endian + "u2", "I;16BS": ">i2",
"I;16NS": endian + "i2", "I;16N": endian + "u2",
"I;32": "<u4", "I;16NS": endian + "i2",
"I;32B": ">u4", "I;32": "<u4",
"I;32L": "<u4", "I;32B": ">u4",
"I;32S": "<i4", "I;32L": "<u4",
"I;32BS": ">i4", "I;32S": "<i4",
"I;32LS": "<i4", "I;32BS": ">i4",
}.items(): "I;32LS": "<i4",
modes[i16mode] = ModeDescriptor(i16mode, ("I",), "L", "L", typestr) }
# set global mode cache atomically
_modes = modes type_str = mapping_modes[mode]
return _modes[mode] return ModeDescriptor(mode, ("I",), "L", "L", type_str)