From b8ff139f9c25486b8b38ff703494d80fd84ad684 Mon Sep 17 00:00:00 2001
From: Tim Ledbetter <tim.ledbetter@ladybird.org>
Date: Fri, 12 Jun 2026 13:14:40 +0100
Subject: [PATCH] LibCompress: Remove `PackBitsDecoder`

This is no longer used.
---
 Libraries/LibCompress/CMakeLists.txt      |  1 -
 Libraries/LibCompress/PackBitsDecoder.cpp | 46 -----------------------
 Libraries/LibCompress/PackBitsDecoder.h   | 27 -------------
 Tests/LibCompress/CMakeLists.txt          |  1 -
 Tests/LibCompress/TestPackBits.cpp        | 25 ------------
 5 files changed, 100 deletions(-)
 delete mode 100644 Libraries/LibCompress/PackBitsDecoder.cpp
 delete mode 100644 Libraries/LibCompress/PackBitsDecoder.h
 delete mode 100644 Tests/LibCompress/TestPackBits.cpp

diff --git a/Libraries/LibCompress/CMakeLists.txt b/Libraries/LibCompress/CMakeLists.txt
index 6c593d6615..0e54758c1e 100644
--- a/Libraries/LibCompress/CMakeLists.txt
+++ b/Libraries/LibCompress/CMakeLists.txt
@@ -2,7 +2,6 @@ set(SOURCES
     Deflate.cpp
     GenericZlib.cpp
     Gzip.cpp
-    PackBitsDecoder.cpp
     Zlib.cpp
 )
 
diff --git a/Libraries/LibCompress/PackBitsDecoder.cpp b/Libraries/LibCompress/PackBitsDecoder.cpp
deleted file mode 100644
index 1e5567ed6e..0000000000
--- a/Libraries/LibCompress/PackBitsDecoder.cpp
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Copyright (c) 2023, Lucas Chollet <lucas.chollet@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include "PackBitsDecoder.h"
-#include <AK/MemoryStream.h>
-#include <AK/NonnullOwnPtr.h>
-
-namespace Compress::PackBits {
-
-ErrorOr<ByteBuffer> decode_all(ReadonlyBytes bytes, Optional<u64> expected_output_size, CompatibilityMode mode)
-{
-    // This implementation uses unsigned values for the selector, as described in the PDF spec.
-    // Note that this remains compatible with other implementations based on signed numbers.
-
-    auto memory_stream = make<FixedMemoryStream>(bytes);
-
-    ByteBuffer decoded_bytes;
-
-    if (expected_output_size.has_value())
-        TRY(decoded_bytes.try_ensure_capacity(*expected_output_size));
-
-    while (memory_stream->remaining() > 0 && decoded_bytes.size() < expected_output_size.value_or(NumericLimits<u64>::max())) {
-        auto const length = TRY(memory_stream->read_value<u8>());
-
-        if (length < 128) {
-            for (u8 i = 0; i <= length; ++i)
-                TRY(decoded_bytes.try_append(TRY(memory_stream->read_value<u8>())));
-        } else if (length > 128) {
-            auto const next_byte = TRY(memory_stream->read_value<u8>());
-
-            for (u8 i = 0; i < 257 - length; ++i)
-                TRY(decoded_bytes.try_append(next_byte));
-        } else {
-            VERIFY(length == 128);
-            if (mode == CompatibilityMode::PDF)
-                break;
-        }
-    }
-
-    return decoded_bytes;
-}
-
-}
diff --git a/Libraries/LibCompress/PackBitsDecoder.h b/Libraries/LibCompress/PackBitsDecoder.h
deleted file mode 100644
index 1badb8dc60..0000000000
--- a/Libraries/LibCompress/PackBitsDecoder.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Copyright (c) 2023, Lucas Chollet <lucas.chollet@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include <AK/ByteBuffer.h>
-#include <AK/Optional.h>
-
-namespace Compress::PackBits {
-
-// This implements the PackBits compression scheme, aka run-length compression
-// It is fairly simple and described here: https://web.archive.org/web/20080705155158/http://developer.apple.com/technotes/tn/tn1023.html
-// But also in section:
-//  - 7.4.5 RunLengthDecode Filter of the PDF specification
-//  - Section 9: PackBits Compression of the TIFF specification
-
-enum class CompatibilityMode {
-    Original, // 128 is defined as no-op
-    PDF,      // 128 is defined as end of stream
-};
-
-ErrorOr<ByteBuffer> decode_all(ReadonlyBytes bytes, Optional<u64> expected_output_size = {}, CompatibilityMode mode = CompatibilityMode::Original);
-
-}
diff --git a/Tests/LibCompress/CMakeLists.txt b/Tests/LibCompress/CMakeLists.txt
index 258f185eb5..75b3d0b8cd 100644
--- a/Tests/LibCompress/CMakeLists.txt
+++ b/Tests/LibCompress/CMakeLists.txt
@@ -2,7 +2,6 @@ set(TEST_SOURCES
     TestDeflate.cpp
     TestGzip.cpp
     TestLzw.cpp
-    TestPackBits.cpp
     TestZlib.cpp
 )
 
diff --git a/Tests/LibCompress/TestPackBits.cpp b/Tests/LibCompress/TestPackBits.cpp
deleted file mode 100644
index cd32339cc8..0000000000
--- a/Tests/LibCompress/TestPackBits.cpp
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Copyright (c) 2023, Lucas Chollet <lucas.chollet@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include <LibTest/TestCase.h>
-
-#include <AK/Array.h>
-#include <LibCompress/PackBitsDecoder.h>
-
-TEST_CASE(pack_bits)
-{
-    Array<u8, 15> const compressed {
-        0xFE, 0xAA, 0x02, 0x80, 0x00, 0x2A, 0xFD, 0xAA, 0x03, 0x80, 0x00, 0x2A, 0x22, 0xF7, 0xAA
-    };
-
-    Array<u8, 24> const raw {
-        0xAA, 0xAA, 0xAA, 0x80, 0x00, 0x2A, 0xAA, 0xAA, 0xAA, 0xAA, 0x80, 0x00,
-        0x2A, 0x22, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA
-    };
-
-    auto unpacked = TRY_OR_FAIL(Compress::PackBits::decode_all(compressed));
-    EXPECT_EQ(unpacked.bytes(), raw);
-}