From 32cdd72192ccaf38ab46c34f2f66b0e1a26a7e71 Mon Sep 17 00:00:00 2001
From: Jonathan Behrens <fintelia@gmail.com>
Date: Sun, 19 Dec 2021 18:46:04 -0500
Subject: [PATCH] Optimize decoding of certain RGBA BMP files

---
 src/codecs/bmp/decoder.rs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/codecs/bmp/decoder.rs b/src/codecs/bmp/decoder.rs
index 1d88af47c6..7bd052100f 100644
--- a/src/codecs/bmp/decoder.rs
+++ b/src/codecs/bmp/decoder.rs
@@ -48,6 +48,12 @@ const R8_G8_B8_COLOR_MASK: Bitfields = Bitfields {
     b: Bitfield { len: 8, shift: 8 },
     a: Bitfield { len: 0, shift: 0 },
 };
+const R8_G8_B8_A8_COLOR_MASK: Bitfields = Bitfields {
+    r: Bitfield { len: 8, shift: 16 },
+    g: Bitfield { len: 8, shift: 8 },
+    b: Bitfield { len: 8, shift: 0 },
+    a: Bitfield { len: 8, shift: 24 },
+};
 
 const RLE_ESCAPE: u8 = 0;
 const RLE_ESCAPE_EOL: u8 = 0;
@@ -1428,6 +1434,9 @@ impl<R: Read + Seek> BmpDecoder<R> {
                 Some(R8_G8_B8_COLOR_MASK) => {
                     self.read_full_byte_pixel_data(&FormatFullBytes::Format888)
                 }
+                Some(R8_G8_B8_A8_COLOR_MASK) => {
+                    self.read_full_byte_pixel_data(&FormatFullBytes::RGBA32)
+                }
                 Some(_) => self.read_32_bit_pixel_data(),
                 None => Err(DecoderError::BitfieldMasksMissing(32).into()),
             },