Increase use of bytearrays to improve loading speed

Author: radarhere

src/PIL/QoiImagePlugin.py

@@ -11,7 +11,6 @@
 
 from . import Image, ImageFile
 from ._binary import i32be as i32
-from ._binary import o8
 
 
 def _accept(prefix):
@@ -49,50 +48,55 @@ def _add_to_previous_pixels(self, value):
     def decode(self, buffer):
         self._previously_seen_pixels = {}
         self._previous_pixel = None
-        self._add_to_previous_pixels(b"".join(o8(i) for i in (0, 0, 0, 255)))
+        self._add_to_previous_pixels(bytearray((0, 0, 0, 255)))
 
         data = bytearray()
         bands = Image.getmodebands(self.mode)
         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:]
+                value = bytearray(self.fd.read(3)) + self._previous_pixel[3:]
             elif byte == 0b11111111:  # QOI_OP_RGBA
                 value = self.fd.read(4)
             else:
                 op = byte >> 6
                 if op == 0:  # QOI_OP_INDEX
                     op_index = byte & 0b00111111
-                    value = self._previously_seen_pixels.get(op_index, (0, 0, 0, 0))
+                    value = self._previously_seen_pixels.get(
+                        op_index, bytearray((0, 0, 0, 0))
+                    )
                 elif op == 1:  # QOI_OP_DIFF
-                    value = (
-                        (self._previous_pixel[0] + ((byte & 0b00110000) >> 4) - 2)
-                        % 256,
-                        (self._previous_pixel[1] + ((byte & 0b00001100) >> 2) - 2)
-                        % 256,
-                        (self._previous_pixel[2] + (byte & 0b00000011) - 2) % 256,
+                    value = bytearray(
+                        (
+                            (self._previous_pixel[0] + ((byte & 0b00110000) >> 4) - 2)
+                            % 256,
+                            (self._previous_pixel[1] + ((byte & 0b00001100) >> 2) - 2)
+                            % 256,
+                            (self._previous_pixel[2] + (byte & 0b00000011) - 2) % 256,
+                            self._previous_pixel[3],
+                        )
                     )
-                    value += (self._previous_pixel[3],)
                 elif op == 2:  # QOI_OP_LUMA
                     second_byte = self.fd.read(1)[0]
                     diff_green = (byte & 0b00111111) - 32
                     diff_red = ((second_byte & 0b11110000) >> 4) - 8
                     diff_blue = (second_byte & 0b00001111) - 8
 
-                    value = tuple(
-                        (self._previous_pixel[i] + diff_green + diff) % 256
-                        for i, diff in enumerate((diff_red, 0, diff_blue))
+                    value = bytearray(
+                        tuple(
+                            (self._previous_pixel[i] + diff_green + diff) % 256
+                            for i, diff in enumerate((diff_red, 0, diff_blue))
+                        )
                     )
-                    value += (self._previous_pixel[3],)
+                    value += self._previous_pixel[3:]
                 elif op == 3:  # QOI_OP_RUN
                     run_length = (byte & 0b00111111) + 1
                     value = self._previous_pixel
                     if bands == 3:
                         value = value[:3]
                     data += value * run_length
                     continue
-                value = b"".join(o8(i) for i in value)
             self._add_to_previous_pixels(value)
 
             if bands == 3: