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Use maxval instead of unreliable 32-bit specific behaviour

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This commit is contained in:
Andrew Murray 2022-03-16 22:10:47 +11:00
parent e3b53dc7e0
commit edc6c3d2f0
1 changed files with 9 additions and 11 deletions
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20
src/PIL/PpmImagePlugin.py
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@ -100,6 +100,7 @@ class PpmImageFile(ImageFile.ImageFile):
elif magic_number in (b"P3", b"P6"):
self.custom_mimetype = "image/x-portable-pixmap"
maxval = None
for ix in range(3):
token = int(self._read_token())
if ix == 0: # token is the x size
@ -127,10 +128,9 @@ class PpmImageFile(ImageFile.ImageFile):
decoder_name = "raw"
if magic_number in (b"P1", b"P2", b"P3"):
decoder_name = "ppm_plain"
args = (rawmode, 0, 1) if decoder_name == "raw" else (rawmode, maxval)
self._size = xsize, ysize
self.tile = [
(decoder_name, (0, 0, xsize, ysize), self.fp.tell(), (rawmode, 0, 1))
]
self.tile = [(decoder_name, (0, 0, xsize, ysize), self.fp.tell(), args)]
#
@ -201,10 +201,8 @@ class PpmPlainDecoder(ImageFile.PyDecoder):
invert = bytes.maketrans(b"01", b"\xFF\x00")
return decoded_data.translate(invert)
def _decode_blocks(self, channels=1, depth=8):
def _decode_blocks(self, channels, depth, maxval):
decoded_data = bytearray()
# HACK: 32-bit grayscale uses signed int
maxval = 2 ** (31 if depth == 32 else depth) - 1
max_len = 10
bytes_per_sample = depth // 8
total_bytes = self.state.xsize * self.state.ysize * channels * bytes_per_sample
@ -256,20 +254,20 @@ class PpmPlainDecoder(ImageFile.PyDecoder):
return decoded_data
def decode(self, buffer):
rawmode = self.args[0]
rawmode, maxval = self.args
if self.mode == "1":
decoded_data = self._decode_bitonal()
rawmode = "1;8"
elif self.mode == "L":
decoded_data = self._decode_blocks(channels=1, depth=8)
decoded_data = self._decode_blocks(1, 8, maxval)
elif self.mode == "I":
if rawmode == "I;16B":
decoded_data = self._decode_blocks(channels=1, depth=16)
decoded_data = self._decode_blocks(1, 16, maxval)
elif rawmode == "I;32B":
decoded_data = self._decode_blocks(channels=1, depth=32)
decoded_data = self._decode_blocks(1, 32, maxval)
elif self.mode == "RGB":
decoded_data = self._decode_blocks(channels=3, depth=8)
decoded_data = self._decode_blocks(3, 8, maxval)
self.set_as_raw(bytes(decoded_data), rawmode)
return -1, 0