From f04a878e557642cde8f853e2e2d90ef45ab1a261 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Mon, 19 Dec 2022 13:54:16 +0100
Subject: [PATCH] LibGfx/OpenType: Read "maxp" table using a C++ struct

---
 .../Libraries/LibGfx/Font/OpenType/Font.cpp   |  4 +--
 .../Libraries/LibGfx/Font/OpenType/Tables.h   | 32 ++++++++++++++++---
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/Userland/Libraries/LibGfx/Font/OpenType/Font.cpp b/Userland/Libraries/LibGfx/Font/OpenType/Font.cpp
index 4a67a39ba2..807aae833f 100644
--- a/Userland/Libraries/LibGfx/Font/OpenType/Font.cpp
+++ b/Userland/Libraries/LibGfx/Font/OpenType/Font.cpp
@@ -140,7 +140,7 @@ u16 Hhea::number_of_h_metrics() const
 
 Optional<Maxp> Maxp::from_slice(ReadonlyBytes slice)
 {
-    if (slice.size() < (size_t)Sizes::TableV0p5) {
+    if (slice.size() < sizeof(MaximumProfileVersion0_5)) {
         return {};
     }
     return Maxp(slice);
@@ -148,7 +148,7 @@ Optional<Maxp> Maxp::from_slice(ReadonlyBytes slice)
 
 u16 Maxp::num_glyphs() const
 {
-    return be_u16(m_slice.offset_pointer((u32)Offsets::NumGlyphs));
+    return header().num_glyphs;
 }
 
 Optional<Hmtx> Hmtx::from_slice(ReadonlyBytes slice, u32 num_glyphs, u32 number_of_h_metrics)
diff --git a/Userland/Libraries/LibGfx/Font/OpenType/Tables.h b/Userland/Libraries/LibGfx/Font/OpenType/Tables.h
index 4f83da55c2..728d1856f5 100644
--- a/Userland/Libraries/LibGfx/Font/OpenType/Tables.h
+++ b/Userland/Libraries/LibGfx/Font/OpenType/Tables.h
@@ -28,6 +28,11 @@ struct LongDateTime {
     BigEndian<u64> value;
 };
 
+struct Version16Dot16 {
+    BigEndian<u16> major;
+    BigEndian<u16> minor;
+};
+
 using FWord = BigEndian<i16>;
 using UFWord = BigEndian<u16>;
 
@@ -122,16 +127,35 @@ private:
 class Maxp {
 public:
     static Optional<Maxp> from_slice(ReadonlyBytes);
+
     u16 num_glyphs() const;
 
 private:
-    enum class Offsets {
-        NumGlyphs = 4
+    struct MaximumProfileVersion0_5 {
+        Version16Dot16 version;
+        BigEndian<u16> num_glyphs;
     };
-    enum class Sizes {
-        TableV0p5 = 6,
+
+    struct MaximumProfileVersion1_0 {
+        Version16Dot16 version;
+        BigEndian<u16> num_glyphs;
+        BigEndian<u16> max_points;
+        BigEndian<u16> max_contours;
+        BigEndian<u16> max_composite_points;
+        BigEndian<u16> max_composite_contours;
+        BigEndian<u16> max_zones;
+        BigEndian<u16> max_twilight_points;
+        BigEndian<u16> max_storage;
+        BigEndian<u16> max_function_defs;
+        BigEndian<u16> max_instruction_defs;
+        BigEndian<u16> max_stack_elements;
+        BigEndian<u16> max_size_of_instructions;
+        BigEndian<u16> max_component_elements;
+        BigEndian<u16> max_component_depths;
     };
 
+    MaximumProfileVersion0_5 const& header() const { return *bit_cast<MaximumProfileVersion0_5 const*>(m_slice.data()); }
+
     Maxp(ReadonlyBytes slice)
         : m_slice(slice)
     {