From 9ae17e3a7acec196cafdfba8a7e21cd1cb85bc58 Mon Sep 17 00:00:00 2001
From: Lucas CHOLLET <lucas.chollet@free.fr>
Date: Sat, 10 Feb 2024 00:57:25 -0500
Subject: [PATCH] LibGfx/CCITT: Align the output stream on byte-boundary after
 each line

This makes the CCITT decoder in line with what the TIFF decoder is
expecting.
---
 Userland/Libraries/LibGfx/ImageFormats/CCITTDecoder.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/Userland/Libraries/LibGfx/ImageFormats/CCITTDecoder.cpp b/Userland/Libraries/LibGfx/ImageFormats/CCITTDecoder.cpp
index ace6134fd8..9c52911fc1 100644
--- a/Userland/Libraries/LibGfx/ImageFormats/CCITTDecoder.cpp
+++ b/Userland/Libraries/LibGfx/ImageFormats/CCITTDecoder.cpp
@@ -313,6 +313,8 @@ ErrorOr<void> decode_single_ccitt3_1d_line(BigEndianInputBitStream& input_bit_st
             return Error::from_string_literal("TIFFImageDecoderPlugin: CCITT codes encode for more that a line");
     }
 
+    TRY(decoded_bits.align_to_byte_boundary());
+
     return {};
 }
 
@@ -333,7 +335,8 @@ ErrorOr<ByteBuffer> decode_ccitt_rle(ReadonlyBytes bytes, u32 image_width, u32 i
     auto strip_stream = make<FixedMemoryStream>(bytes);
     auto bit_stream = make<BigEndianInputBitStream>(MaybeOwned<Stream>(*strip_stream));
 
-    ByteBuffer decoded_bytes = TRY(ByteBuffer::create_zeroed(ceil_div(image_width * image_height, 8)));
+    // Note: We put image_height extra-space to handle at most one alignment to byte boundary per line.
+    ByteBuffer decoded_bytes = TRY(ByteBuffer::create_zeroed(ceil_div(image_width * image_height, 8) + image_height));
     auto output_stream = make<FixedMemoryStream>(decoded_bytes.bytes());
     auto decoded_bits = make<BigEndianOutputBitStream>(MaybeOwned<Stream>(*output_stream));
 
@@ -341,7 +344,6 @@ ErrorOr<ByteBuffer> decode_ccitt_rle(ReadonlyBytes bytes, u32 image_width, u32 i
         TRY(decode_single_ccitt3_1d_line(*bit_stream, *decoded_bits, image_width));
 
         bit_stream->align_to_byte_boundary();
-        TRY(decoded_bits->align_to_byte_boundary());
     }
 
     return decoded_bytes;
@@ -352,7 +354,8 @@ ErrorOr<ByteBuffer> decode_ccitt_group3(ReadonlyBytes bytes, u32 image_width, u3
     auto strip_stream = make<FixedMemoryStream>(bytes);
     auto bit_stream = make<BigEndianInputBitStream>(MaybeOwned<Stream>(*strip_stream));
 
-    ByteBuffer decoded_bytes = TRY(ByteBuffer::create_zeroed(ceil_div(image_width * image_height, 8)));
+    // Note: We put image_height extra-space to handle at most one alignment to byte boundary per line.
+    ByteBuffer decoded_bytes = TRY(ByteBuffer::create_zeroed(ceil_div(image_width * image_height, 8) + image_height));
     auto output_stream = make<FixedMemoryStream>(decoded_bytes.bytes());
     auto decoded_bits = make<BigEndianOutputBitStream>(MaybeOwned<Stream>(*output_stream));