x86_64/vga: split text implementation

1 files changed, 36 insertions, 28 deletions

diff --git a/arch/x86_64/src/vga/text.cpp b/arch/x86_64/src/vga/text.cpp
index 1249cc3..1ee69f6 100644
--- a/arch/x86_64/src/vga/text.cpp
+++ b/arch/x86_64/src/vga/text.cpp
@@ -19,30 +19,38 @@ namespace teachos::vga::x86_64::text
 {
   namespace
   {
-    constexpr auto BUFFER_BASE_ADDRESS = std::uintptr_t{0xb8000};
-    constexpr auto DEFAULT_TEXT_BUFFER_WIDTH = 80z;
-    constexpr auto DEFAULT_TEXT_BUFFER_HEIGHT = 25z;
-    constexpr auto CURSOR_ENABLED_BIT = 5U;
-  }  // namespace
+    constexpr auto default_buffer_address = std::uintptr_t{0xb8000};
+    constexpr auto default_buffer_width = 80z;
+    constexpr auto default_buffer_height = 25z;
 
-  std::span<device::glyph> const device::buffer =
-      std::span{std::bit_cast<device::glyph *>(BUFFER_BASE_ADDRESS +
-                                               std::bit_cast<std::uintptr_t>(&teachos::boot::x86_64::TEACHOS_VMA)),
-                DEFAULT_TEXT_BUFFER_WIDTH * DEFAULT_TEXT_BUFFER_HEIGHT};
+    constexpr auto bit_cursor_enabled = 5U;
+
+    [[maybe_unused]] constexpr auto black_on_black = attribute{.foreground_color = color::black,
+                                                               .foreground_flag = foreground_flag::none,
+                                                               .background_color = color::black,
+                                                               .background_flag = background_flag::none};
+  }  // namespace
 
   device::device()
-      : m_position{boot::bootstrap_information.vga_buffer_index}
-  {}
+      : m_width{default_buffer_width}
+      , m_height{default_buffer_height}
+      , m_buffer{std::bit_cast<device::cell *>(default_buffer_address +
+                                               std::bit_cast<std::uintptr_t>(&teachos::boot::x86_64::TEACHOS_VMA)),
+                 m_width * m_height}
+      , m_position{boot::bootstrap_information.vga_buffer_index}
+  {
+    clear();
+  }
 
-  auto device::clear(attribute attribute) -> void
+  auto device::clear() -> void
   {
     m_position = 0;
-    std::ranges::fill(buffer, std::pair{' ', std::bit_cast<std::byte>(attribute)});
+    std::ranges::fill(m_buffer, std::pair{' ', std::bit_cast<std::byte>(black_on_black)});
   }
 
   auto device::cursor(bool enabled) -> void
   {
-    auto cursor_disable_byte = std::byte{!enabled} << CURSOR_ENABLED_BIT;
+    auto cursor_disable_byte = std::byte{!enabled} << bit_cursor_enabled;
 
     crtc::address::write(crtc::registers::cursor_start);
     crtc::data::write(crtc::data::read() | cursor_disable_byte);
@@ -50,12 +58,12 @@ namespace teachos::vga::x86_64::text
 
   [[nodiscard]] auto device::column() const noexcept -> std::ptrdiff_t
   {
-    return m_position % DEFAULT_TEXT_BUFFER_WIDTH;
+    return m_position % m_width;
   }
 
   [[nodiscard]] auto device::line() const noexcept -> std::ptrdiff_t
   {
-    return m_position / DEFAULT_TEXT_BUFFER_WIDTH;
+    return m_position / m_width;
   }
 
   auto device::handle_special_code_point(char code_point, attribute attribute) -> bool
@@ -83,26 +91,26 @@ namespace teachos::vga::x86_64::text
 
   auto device::put(char code_point, attribute attribute) -> void
   {
-    buffer[m_position++] = std::pair{code_point, std::bit_cast<std::byte>(attribute)};
+    m_buffer[m_position++] = std::pair{code_point, std::bit_cast<std::byte>(attribute)};
   }
 
   auto device::newline() -> void
   {
-    auto free_glyphs_in_line = DEFAULT_TEXT_BUFFER_WIDTH - column();
+    auto free_glyphs_in_line = m_width - column();
     m_position += free_glyphs_in_line;
   }
 
-  auto device::scroll(std::ptrdiff_t nof_lines) -> void
+  auto device::scroll(std::size_t nof_lines) -> void
   {
-    auto scroll_count = std::min(nof_lines, DEFAULT_TEXT_BUFFER_HEIGHT);
+    auto scroll_count = std::min(nof_lines, m_height);
 
-    auto scroll_start = buffer.begin() + (scroll_count * DEFAULT_TEXT_BUFFER_WIDTH);
-    std::ranges::move(scroll_start, buffer.end(), buffer.begin());
+    auto scroll_start = m_buffer.begin() + (scroll_count * m_width);
+    std::ranges::move(scroll_start, m_buffer.end(), m_buffer.begin());
 
-    auto clear_start = buffer.begin() + (DEFAULT_TEXT_BUFFER_HEIGHT - scroll_count) * DEFAULT_TEXT_BUFFER_WIDTH;
-    std::ranges::fill(clear_start, buffer.end(), glyph{});
+    auto clear_start = m_buffer.begin() + (m_height - scroll_count) * m_width;
+    std::ranges::fill(clear_start, m_buffer.end(), cell{});
 
-    m_position = (line() - scroll_count) * DEFAULT_TEXT_BUFFER_WIDTH;
+    m_position = (line() - scroll_count) * m_width;
   }
 
   auto device::write(cio::output_stream stream, std::string_view text) -> void
@@ -111,9 +119,9 @@ namespace teachos::vga::x86_64::text
       switch (stream)
       {
         case cio::output_stream::stderr:
-          return common_attributes::red_on_black;
+          return red_on_black;
         default:
-          return common_attributes::green_on_black;
+          return green_on_black;
       }
     }();
     write(text, attributes);
@@ -126,7 +134,7 @@ namespace teachos::vga::x86_64::text
 
   auto device::write(char code_point, attribute attribute) -> void
   {
-    if (m_position + 1 > DEFAULT_TEXT_BUFFER_HEIGHT * DEFAULT_TEXT_BUFFER_WIDTH)
+    if (m_position + 1 > static_cast<std::ptrdiff_t>(m_height * m_width))
     {
       scroll();
     }