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Optimise ImageMode.getmode using functools.lru_cache #7641

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Merged
radarhere merged 2 commits into from
Dec 26, 2023
Merged

Optimise ImageMode.getmode using functools.lru_cache #7641

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26f58e7
Optimise ImageMode.getmode
hugovk Dec 22, 2023
396b96f
Optimise ImageMode.getmode
hugovk Dec 26, 2023
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110 changes: 54 additions & 56 deletions src/PIL/ImageMode.py
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Original file line number Diff line number Diff line change
Expand Up @@ -15,9 +15,7 @@
from __future__ import annotations

import sys

# mode descriptor cache
_modes = None
from functools import lru_cache


class ModeDescriptor:
Expand All @@ -41,58 +39,58 @@ def __str__(self) -> str:
return self.mode


@lru_cache
def getmode(mode: str) -> ModeDescriptor:
"""Gets a mode descriptor for the given mode."""
global _modes
if not _modes:
# initialize mode cache
modes = {}
endian = "<" if sys.byteorder == "little" else ">"
for m, (basemode, basetype, bands, typestr) in {
# core modes
# Bits need to be extended to bytes
"1": ("L", "L", ("1",), "|b1"),
"L": ("L", "L", ("L",), "|u1"),
"I": ("L", "I", ("I",), endian + "i4"),
"F": ("L", "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"),
}.items():
modes[m] = ModeDescriptor(m, bands, basemode, basetype, typestr)
# mapping modes
for i16mode, typestr in {
# 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": endian + "u2",
"I;16NS": endian + "i2",
"I;32": "<u4",
"I;32B": ">u4",
"I;32L": "<u4",
"I;32S": "<i4",
"I;32BS": ">i4",
"I;32LS": "<i4",
}.items():
modes[i16mode] = ModeDescriptor(i16mode, ("I",), "L", "L", typestr)
# set global mode cache atomically
_modes = modes
return _modes[mode]
# initialize mode cache
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",), endian + "i4"),
"F": ("L", "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:
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": endian + "u2",
"I;16NS": 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)