LibVideo/VP9: Move persistent context storage to a different header

Moving these to another header allows Parser.h to include less context
structs/classes that were previously in Context.h.

This change will also allow consolidating some common calculations into
Context.h, since we won't be polluting the VP9 namespace as much. There
are quite a few duplicate calculations for block size, transform size,
number of horizontal and vertical sub-blocks per block, all of which
could be moved to Context.h to allow for code deduplication and more
semantic code where those calculations are needed.

6 files changed, 271 insertions, 239 deletions

diff --git a/Userland/Libraries/LibVideo/VP9/Context.h b/Userland/Libraries/LibVideo/VP9/Context.h
index 31b68e1140..2a71a595a1 100644
--- a/Userland/Libraries/LibVideo/VP9/Context.h
+++ b/Userland/Libraries/LibVideo/VP9/Context.h
@@ -12,253 +12,19 @@
 #include <LibGfx/Size.h>
 #include <LibVideo/Color/CodingIndependentCodePoints.h>
 
+#include "ContextStorage.h"
 #include "Enums.h"
 #include "LookupTables.h"
 #include "MotionVector.h"
 
 namespace Video::VP9 {
 
-template<typename T>
-struct ReferencePair {
-    T primary;
-    T secondary;
-
-    T& operator[](ReferenceIndex index)
-    {
-        switch (index) {
-        case ReferenceIndex::Primary:
-            return primary;
-        case ReferenceIndex::Secondary:
-            return secondary;
-        default:
-            VERIFY_NOT_REACHED();
-        }
-    }
-
-    T const& operator[](ReferenceIndex index) const
-    {
-        return const_cast<ReferencePair<T>&>(*this)[index];
-    }
-};
-
-typedef ReferencePair<ReferenceFrameType> ReferenceFramePair;
-typedef ReferencePair<MotionVector> MotionVectorPair;
-
-template<typename T>
-class Vector2D;
-
-template<typename T>
-class Vector2DView {
-public:
-    u32 top() const { return m_top; }
-    u32 left() const { return m_left; }
-    u32 height() const { return m_height; }
-    u32 width() const { return m_width; }
-
-    T const& operator[](size_t index) const { return m_storage[index]; }
-    size_t size() const { return m_storage->size(); }
-
-    T& at(u32 relative_row, u32 relative_column)
-    {
-        VERIFY(relative_row < height());
-        VERIFY(relative_column < width());
-        return m_storage->at(top() + relative_row, left() + relative_column);
-    }
-    T const& at(u32 relative_row, u32 relative_column) const
-    {
-        VERIFY(relative_row < height());
-        VERIFY(relative_column < width());
-        return m_storage->at(top() + relative_row, left() + relative_column);
-    }
-
-    Vector2DView<T> view(u32 top, u32 left, u32 height, u32 width)
-    {
-        VERIFY(top + height <= this->height());
-        VERIFY(left + width <= this->width());
-        return Vector2DView<T>(m_storage, this->top() + top, this->left() + left, height, width);
-    }
-
-private:
-    friend class Vector2D<T>;
-
-    Vector2DView(Vector2D<T>* const storage, u32 top, u32 left, u32 height, u32 width)
-        : m_storage(storage)
-        , m_top(top)
-        , m_left(left)
-        , m_height(height)
-        , m_width(width)
-    {
-    }
-
-    Vector2D<T>* const m_storage;
-    u32 const m_top { 0 };
-    u32 const m_left { 0 };
-    u32 const m_height { 0 };
-    u32 const m_width { 0 };
-};
-
-template<typename T>
-class Vector2D {
-public:
-    ~Vector2D()
-    {
-        if (m_storage)
-            free(m_storage);
-        m_storage = nullptr;
-        m_width = 0;
-        m_height = 0;
-    }
-
-    ErrorOr<void> try_resize(u32 height, u32 width)
-    {
-        if (height != m_height && width != m_width) {
-            this->~Vector2D();
-            size_t size = height * width;
-            auto* new_storage = static_cast<T*>(malloc(size * sizeof(T)));
-            if (!new_storage)
-                return Error::from_errno(ENOMEM);
-            m_storage = new_storage;
-            m_height = height;
-            m_width = width;
-        }
-
-        return {};
-    }
-
-    u32 height() const { return m_height; }
-    u32 width() const { return m_width; }
-
-    size_t index_at(u32 row, u32 column) const
-    {
-        VERIFY(row < height());
-        VERIFY(column < width());
-        return row * width() + column;
-    }
-
-    T& operator[](size_t index) { return m_storage[index]; }
-    T const& operator[](size_t index) const { return m_storage[index]; }
-    size_t size() const { return m_height * m_width; }
-
-    T& at(u32 row, u32 column)
-    {
-        return m_storage[index_at(row, column)];
-    }
-    T const& at(u32 row, u32 column) const
-    {
-        return m_storage[index_at(row, column)];
-    }
-
-    template<typename OtherT>
-    ErrorOr<void> try_resize_to_match_other_vector2d(Vector2D<OtherT> const& other)
-    {
-        return try_resize(other.height(), other.width());
-    }
-
-    template<typename OtherT, typename Function>
-    void copy_to(Vector2D<OtherT>& other, Function function) const
-    {
-        VERIFY(width() <= other.width());
-        VERIFY(height() <= other.height());
-        for (u32 row = 0; row < height(); row++) {
-            for (u32 column = 0; column < width(); column++)
-                other.at(row, column) = function(at(row, column));
-        }
-    }
-
-    void copy_to(Vector2D<T>& other) const
-    {
-        VERIFY(width() <= other.width());
-        VERIFY(height() <= other.height());
-        for (u32 row = 0; row < height(); row++) {
-            auto other_index = other.index_at(row, 0);
-            AK::TypedTransfer<T>::copy(&m_storage[index_at(row, 0)], &other[other_index], width());
-        }
-    }
-
-    void reset()
-    {
-        for (size_t i = 0; i < size(); i++)
-            m_storage[i] = T();
-    }
-
-    Vector2DView<T> view(u32 top, u32 left, u32 height, u32 width)
-    {
-        VERIFY(top + height <= this->height());
-        VERIFY(left + width <= this->width());
-        return Vector2DView<T>(this, top, left, height, width);
-    }
-
-private:
-    u32 m_height { 0 };
-    u32 m_width { 0 };
-    T* m_storage { nullptr };
-};
-
-struct TokensContext {
-    TXSize m_tx_size;
-    bool m_is_uv_plane;
-    bool m_is_inter;
-    u8 m_band;
-    u8 m_context_index;
-};
-
-// Block context that is kept for the lifetime of a frame.
-struct FrameBlockContext {
-    bool is_intra_predicted() const { return ref_frames.primary == ReferenceFrameType::None; }
-    bool is_single_reference() const { return ref_frames.secondary == ReferenceFrameType::None; }
-    MotionVectorPair primary_motion_vector_pair() const { return sub_block_motion_vectors[3]; }
-
-    bool is_available { false };
-    bool skip_coefficients { false };
-    TXSize tx_size { TXSize::TX_4x4 };
-    PredictionMode y_mode { PredictionMode::DcPred };
-    Array<PredictionMode, 4> sub_modes { PredictionMode::DcPred, PredictionMode::DcPred, PredictionMode::DcPred, PredictionMode::DcPred };
-    InterpolationFilter interpolation_filter { InterpolationFilter::EightTap };
-    ReferenceFramePair ref_frames { ReferenceFrameType::None, ReferenceFrameType::None };
-    Array<MotionVectorPair, 4> sub_block_motion_vectors;
-    u8 segment_id { 0 };
-};
-
-// Block context that is kept between frames until explictly cleared.
-struct PersistentBlockContext {
-    PersistentBlockContext()
-        : available(false)
-    {
-    }
-
-    PersistentBlockContext(FrameBlockContext const& frame_context)
-        : available(frame_context.is_available)
-        , ref_frames(frame_context.ref_frames)
-        , primary_motion_vector_pair(frame_context.primary_motion_vector_pair())
-        , segment_id(frame_context.segment_id)
-    {
-    }
-
-    bool available { false };
-    ReferenceFramePair ref_frames { ReferenceFrameType::None, ReferenceFrameType::None };
-    MotionVectorPair primary_motion_vector_pair {};
-    u8 segment_id { 0 };
-};
-
 enum class FrameShowMode {
     CreateAndShowNewFrame,
     ShowExistingFrame,
     DoNotShowFrame,
 };
 
-struct ColorConfig {
-    u8 bit_depth { 8 };
-    ColorSpace color_space { ColorSpace::Bt601 };
-    ColorRange color_range { ColorRange::Studio };
-    bool subsampling_x { true };
-    bool subsampling_y { true };
-};
-
-struct SegmentFeature {
-    bool enabled { false };
-    u8 value { 0 };
-};
-
 struct FrameContext {
 public:
     FrameContext(Vector2D<FrameBlockContext>& contexts)
@@ -445,8 +211,6 @@ struct BlockMotionVectorCandidateSet {
     MotionVector best_vector;
 };
 
-using BlockMotionVectorCandidates = ReferencePair<BlockMotionVectorCandidateSet>;
-
 struct MotionVectorCandidate {
     ReferenceFrameType type;
     MotionVector vector;
diff --git a/Userland/Libraries/LibVideo/VP9/ContextStorage.h b/Userland/Libraries/LibVideo/VP9/ContextStorage.h
new file mode 100644
index 0000000000..30156f5f60
--- /dev/null
+++ b/Userland/Libraries/LibVideo/VP9/ContextStorage.h
@@ -0,0 +1,251 @@
+/*
+ * Copyright (c) 2021, Hunter Salyer <thefalsehonesty@gmail.com>
+ * Copyright (c) 2022, Gregory Bertilson <zaggy1024@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Array.h>
+#include <AK/Error.h>
+#include <LibGfx/Size.h>
+#include <LibVideo/Color/CodingIndependentCodePoints.h>
+
+#include "Enums.h"
+#include "LookupTables.h"
+#include "MotionVector.h"
+
+namespace Video::VP9 {
+
+template<typename T>
+struct ReferencePair {
+    T primary;
+    T secondary;
+
+    T& operator[](ReferenceIndex index)
+    {
+        switch (index) {
+        case ReferenceIndex::Primary:
+            return primary;
+        case ReferenceIndex::Secondary:
+            return secondary;
+        default:
+            VERIFY_NOT_REACHED();
+        }
+    }
+
+    T const& operator[](ReferenceIndex index) const
+    {
+        return const_cast<ReferencePair<T>&>(*this)[index];
+    }
+};
+
+typedef ReferencePair<ReferenceFrameType> ReferenceFramePair;
+typedef ReferencePair<MotionVector> MotionVectorPair;
+
+template<typename T>
+class Vector2D;
+
+template<typename T>
+class Vector2DView {
+public:
+    u32 top() const { return m_top; }
+    u32 left() const { return m_left; }
+    u32 height() const { return m_height; }
+    u32 width() const { return m_width; }
+
+    T const& operator[](size_t index) const { return m_storage[index]; }
+    size_t size() const { return m_storage->size(); }
+
+    T& at(u32 relative_row, u32 relative_column)
+    {
+        VERIFY(relative_row < height());
+        VERIFY(relative_column < width());
+        return m_storage->at(top() + relative_row, left() + relative_column);
+    }
+    T const& at(u32 relative_row, u32 relative_column) const
+    {
+        VERIFY(relative_row < height());
+        VERIFY(relative_column < width());
+        return m_storage->at(top() + relative_row, left() + relative_column);
+    }
+
+    Vector2DView<T> view(u32 top, u32 left, u32 height, u32 width)
+    {
+        VERIFY(top + height <= this->height());
+        VERIFY(left + width <= this->width());
+        return Vector2DView<T>(m_storage, this->top() + top, this->left() + left, height, width);
+    }
+
+private:
+    friend class Vector2D<T>;
+
+    Vector2DView(Vector2D<T>* const storage, u32 top, u32 left, u32 height, u32 width)
+        : m_storage(storage)
+        , m_top(top)
+        , m_left(left)
+        , m_height(height)
+        , m_width(width)
+    {
+    }
+
+    Vector2D<T>* const m_storage;
+    u32 const m_top { 0 };
+    u32 const m_left { 0 };
+    u32 const m_height { 0 };
+    u32 const m_width { 0 };
+};
+
+template<typename T>
+class Vector2D {
+public:
+    ~Vector2D()
+    {
+        if (m_storage)
+            free(m_storage);
+        m_storage = nullptr;
+        m_width = 0;
+        m_height = 0;
+    }
+
+    ErrorOr<void> try_resize(u32 height, u32 width)
+    {
+        if (height != m_height && width != m_width) {
+            this->~Vector2D();
+            size_t size = height * width;
+            auto* new_storage = static_cast<T*>(malloc(size * sizeof(T)));
+            if (!new_storage)
+                return Error::from_errno(ENOMEM);
+            m_storage = new_storage;
+            m_height = height;
+            m_width = width;
+        }
+
+        return {};
+    }
+
+    u32 height() const { return m_height; }
+    u32 width() const { return m_width; }
+
+    size_t index_at(u32 row, u32 column) const
+    {
+        VERIFY(row < height());
+        VERIFY(column < width());
+        return row * width() + column;
+    }
+
+    T& operator[](size_t index) { return m_storage[index]; }
+    T const& operator[](size_t index) const { return m_storage[index]; }
+    size_t size() const { return m_height * m_width; }
+
+    T& at(u32 row, u32 column)
+    {
+        return m_storage[index_at(row, column)];
+    }
+    T const& at(u32 row, u32 column) const
+    {
+        return m_storage[index_at(row, column)];
+    }
+
+    template<typename OtherT, typename Function>
+    void copy_to(Vector2D<OtherT>& other, Function function) const
+    {
+        VERIFY(width() <= other.width());
+        VERIFY(height() <= other.height());
+        for (u32 row = 0; row < height(); row++) {
+            for (u32 column = 0; column < width(); column++)
+                other.at(row, column) = function(at(row, column));
+        }
+    }
+
+    void copy_to(Vector2D<T>& other) const
+    {
+        VERIFY(width() <= other.width());
+        VERIFY(height() <= other.height());
+        for (u32 row = 0; row < height(); row++) {
+            auto other_index = other.index_at(row, 0);
+            AK::TypedTransfer<T>::copy(&m_storage[index_at(row, 0)], &other[other_index], width());
+        }
+    }
+
+    template<typename OtherT>
+    ErrorOr<void> try_resize_to_match_other_vector2d(Vector2D<OtherT> const& other)
+    {
+        return try_resize(other.height(), other.width());
+    }
+
+    void reset()
+    {
+        for (size_t i = 0; i < size(); i++)
+            m_storage[i] = T();
+    }
+
+    Vector2DView<T> view(u32 top, u32 left, u32 height, u32 width)
+    {
+        VERIFY(top + height <= this->height());
+        VERIFY(left + width <= this->width());
+        return Vector2DView<T>(this, top, left, height, width);
+    }
+
+private:
+    u32 m_height { 0 };
+    u32 m_width { 0 };
+    T* m_storage { nullptr };
+};
+
+// Block context that is kept for the lifetime of a frame.
+struct FrameBlockContext {
+    bool is_intra_predicted() const { return ref_frames.primary == ReferenceFrameType::None; }
+    bool is_single_reference() const { return ref_frames.secondary == ReferenceFrameType::None; }
+    MotionVectorPair primary_motion_vector_pair() const { return sub_block_motion_vectors[3]; }
+
+    bool is_available { false };
+    bool skip_coefficients { false };
+    TXSize tx_size { TXSize::TX_4x4 };
+    PredictionMode y_mode { PredictionMode::DcPred };
+    Array<PredictionMode, 4> sub_modes { PredictionMode::DcPred, PredictionMode::DcPred, PredictionMode::DcPred, PredictionMode::DcPred };
+    InterpolationFilter interpolation_filter { InterpolationFilter::EightTap };
+    ReferenceFramePair ref_frames { ReferenceFrameType::None, ReferenceFrameType::None };
+    Array<MotionVectorPair, 4> sub_block_motion_vectors;
+    u8 segment_id { 0 };
+};
+
+// Block context that is kept between frames until explictly cleared.
+struct PersistentBlockContext {
+    PersistentBlockContext()
+        : available(false)
+    {
+    }
+
+    PersistentBlockContext(FrameBlockContext const& frame_context)
+        : available(frame_context.is_available)
+        , ref_frames(frame_context.ref_frames)
+        , primary_motion_vector_pair(frame_context.primary_motion_vector_pair())
+        , segment_id(frame_context.segment_id)
+    {
+    }
+
+    bool available { false };
+    ReferenceFramePair ref_frames { ReferenceFrameType::None, ReferenceFrameType::None };
+    MotionVectorPair primary_motion_vector_pair {};
+    u8 segment_id { 0 };
+};
+
+struct SegmentFeature {
+    bool enabled { false };
+    u8 value { 0 };
+};
+
+struct ColorConfig {
+    u8 bit_depth { 8 };
+    ColorSpace color_space { ColorSpace::Bt601 };
+    ColorRange color_range { ColorRange::Studio };
+    bool subsampling_x { true };
+    bool subsampling_y { true };
+};
+
+struct BlockMotionVectorCandidateSet;
+using BlockMotionVectorCandidates = ReferencePair<BlockMotionVectorCandidateSet>;
+
+}
diff --git a/Userland/Libraries/LibVideo/VP9/Decoder.cpp b/Userland/Libraries/LibVideo/VP9/Decoder.cpp
index 252618254b..c0fe2c4cd5 100644
--- a/Userland/Libraries/LibVideo/VP9/Decoder.cpp
+++ b/Userland/Libraries/LibVideo/VP9/Decoder.cpp
@@ -9,6 +9,7 @@
 #include <LibGfx/Size.h>
 #include <LibVideo/Color/CodingIndependentCodePoints.h>
 
+#include "Context.h"
 #include "Decoder.h"
 #include "Utilities.h"
 
diff --git a/Userland/Libraries/LibVideo/VP9/Parser.cpp b/Userland/Libraries/LibVideo/VP9/Parser.cpp
index ca31c6731a..374cea9fb0 100644
--- a/Userland/Libraries/LibVideo/VP9/Parser.cpp
+++ b/Userland/Libraries/LibVideo/VP9/Parser.cpp
@@ -9,6 +9,7 @@
 #include <LibGfx/Point.h>
 #include <LibGfx/Size.h>
 
+#include "Context.h"
 #include "Decoder.h"
 #include "Parser.h"
 #include "Utilities.h"
diff --git a/Userland/Libraries/LibVideo/VP9/Parser.h b/Userland/Libraries/LibVideo/VP9/Parser.h
index 3dc86578d1..47db261b1a 100644
--- a/Userland/Libraries/LibVideo/VP9/Parser.h
+++ b/Userland/Libraries/LibVideo/VP9/Parser.h
@@ -16,7 +16,7 @@
 #include <LibVideo/DecoderError.h>
 
 #include "BitStream.h"
-#include "Context.h"
+#include "ContextStorage.h"
 #include "LookupTables.h"
 #include "MotionVector.h"
 #include "ProbabilityTables.h"
@@ -27,6 +27,11 @@ namespace Video::VP9 {
 
 class Decoder;
 
+struct FrameContext;
+struct TileContext;
+struct BlockContext;
+struct MotionVectorCandidate;
+
 class Parser {
     friend class TreeParser;
     friend class Decoder;
diff --git a/Userland/Libraries/LibVideo/VP9/TreeParser.h b/Userland/Libraries/LibVideo/VP9/TreeParser.h
index 4002402a69..02400bd093 100644
--- a/Userland/Libraries/LibVideo/VP9/TreeParser.h
+++ b/Userland/Libraries/LibVideo/VP9/TreeParser.h
@@ -8,7 +8,7 @@
 #pragma once
 
 #include "BitStream.h"
-#include "Context.h"
+#include "ContextStorage.h"
 #include "Enums.h"
 #include "ProbabilityTables.h"
 #include "SyntaxElementCounter.h"
@@ -17,6 +17,16 @@ namespace Video::VP9 {
 
 class Parser;
 
+struct FrameBlockContext;
+
+struct TokensContext {
+    TXSize m_tx_size;
+    bool m_is_uv_plane;
+    bool m_is_inter;
+    u8 m_band;
+    u8 m_context_index;
+};
+
 class TreeParser {
 public:
     // FIXME: Move or remove this class once it is unused in the header.