Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89
Commit: 93712b24bf
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256
Reviewed-by: https://github.com/sideshowbarker

Libraries/LibGfx/ImageFormats/WebPSharedLossless.h

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2024, Nico Weber <thakis@chromium.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibCompress/Deflate.h>
+
+namespace Gfx {
+
+constexpr Array kCodeLengthCodeOrder = { 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
+
+// WebP-lossless's CanonicalCodes are almost identical to deflate's.
+// One difference is that codes with a single element in webp-lossless consume 0 bits to produce that single element,
+// while they consume 1 bit in Compress::CanonicalCode. This class wraps Compress::CanonicalCode to handle the case
+// where the codes contain just a single element, and dispatches to Compress::CanonicalCode else.
+class CanonicalCode {
+public:
+    CanonicalCode() = default;
+
+    static ErrorOr<CanonicalCode> from_bytes(ReadonlyBytes);
+    ErrorOr<u32> read_symbol(LittleEndianInputBitStream&) const;
+    ErrorOr<void> write_symbol(LittleEndianOutputBitStream&, u32) const;
+
+private:
+    explicit CanonicalCode(u32 single_symbol)
+        : m_code(single_symbol)
+    {
+    }
+
+    explicit CanonicalCode(Compress::CanonicalCode code)
+        : m_code(move(code))
+    {
+    }
+
+    Variant<u32, Compress::CanonicalCode> m_code { 0 };
+};
+
+ALWAYS_INLINE ErrorOr<void> CanonicalCode::write_symbol(LittleEndianOutputBitStream& bit_stream, u32 symbol) const
+{
+    TRY(m_code.visit(
+        [&](u32 single_code) __attribute__((always_inline))->ErrorOr<void> { VERIFY(symbol == single_code); return {}; },
+        [&](Compress::CanonicalCode const& code) __attribute__((always_inline)) { return code.write_symbol(bit_stream, symbol); }));
+    return {};
+}
+
+// https://developers.google.com/speed/webp/docs/webp_lossless_bitstream_specification#61_overview
+// "From here on, we refer to this set as a prefix code group."
+class PrefixCodeGroup {
+public:
+    PrefixCodeGroup() = default;
+    PrefixCodeGroup(PrefixCodeGroup&&) = default;
+    PrefixCodeGroup(PrefixCodeGroup const&) = delete;
+
+    CanonicalCode& operator[](int i) { return m_codes[i]; }
+    CanonicalCode const& operator[](int i) const { return m_codes[i]; }
+
+private:
+    Array<CanonicalCode, 5> m_codes;
+};
+
+enum class ImageKind {
+    SpatiallyCoded,
+    EntropyCoded,
+};
+
+enum TransformType {
+    // predictor-tx         =  %b00 predictor-image
+    PREDICTOR_TRANSFORM = 0,
+
+    // color-tx             =  %b01 color-image
+    COLOR_TRANSFORM = 1,
+
+    // subtract-green-tx    =  %b10
+    SUBTRACT_GREEN_TRANSFORM = 2,
+
+    // color-indexing-tx    =  %b11 color-indexing-image
+    COLOR_INDEXING_TRANSFORM = 3,
+};
+
+}