Do not calculate destination length each time

Author: radarhere

src/PIL/BmpImagePlugin.py

@@ -291,7 +291,8 @@ def decode(self, buffer):
         rle4 = self.args[1]
         data = bytearray()
         x = 0
-        while len(data) < self.state.xsize * self.state.ysize:
+        dest_length = self.state.xsize * self.state.ysize
+        while len(data) < dest_length:
             pixels = self.fd.read(1)
             byte = self.fd.read(1)
             if not pixels or not byte:

src/PIL/DdsImagePlugin.py

@@ -497,7 +497,8 @@ def decode(self, buffer):
 
         data = bytearray()
         bytecount = bitcount // 8
-        while len(data) < self.state.xsize * self.state.ysize * len(masks):
+        dest_length = self.state.xsize * self.state.ysize * len(masks)
+        while len(data) < dest_length:
             value = int.from_bytes(self.fd.read(bytecount), "little")
             for i, mask in enumerate(masks):
                 masked_value = value & mask

src/PIL/PpmImagePlugin.py

@@ -307,7 +307,8 @@ def decode(self, buffer: bytes) -> tuple[int, int]:
         out_byte_count = 4 if self.mode == "I" else 1
         out_max = 65535 if self.mode == "I" else 255
         bands = Image.getmodebands(self.mode)
-        while len(data) < self.state.xsize * self.state.ysize * bands * out_byte_count:
+        dest_length = self.state.xsize * self.state.ysize * bands * out_byte_count
+        while len(data) < dest_length:
             pixels = self.fd.read(in_byte_count * bands)
             if len(pixels) < in_byte_count * bands:
                 # eof

src/PIL/QoiImagePlugin.py

@@ -53,7 +53,8 @@ def decode(self, buffer):
 
         data = bytearray()
         bands = Image.getmodebands(self.mode)
-        while len(data) < self.state.xsize * self.state.ysize * bands:
+        dest_length = self.state.xsize * self.state.ysize * bands
+        while len(data) < dest_length:
             byte = self.fd.read(1)[0]
             if byte == 0b11111110:  # QOI_OP_RGB
                 value = self.fd.read(3) + self._previous_pixel[3:]