Start C++ rewrite.

erow.h

@@ -0,0 +1,76 @@
+#ifndef EROW_HPP
+#define EROW_HPP
+
+#include <string>
+#include <memory>
+#include <cstddef>
+#include <cstdint>
+
+namespace ke {
+
+/**
+ * Editor row class representing a line of text with rendering information.
+ * C++17 implementation with RAII memory management.
+ */
+class erow {
+public:
+    // Constructors
+    erow() noexcept = default;
+    explicit erow(std::size_t initial_capacity);
+    erow(const char* text, std::size_t len);
+    
+    // Deleted copy constructor and assignment (use move semantics)
+    erow(const erow&) = delete;
+    erow& operator=(const erow&) = delete;
+    
+    // Move constructor and assignment
+    erow(erow&&) noexcept = default;
+    erow& operator=(erow&&) noexcept = default;
+    
+    // Destructor (automatic cleanup via std::string)
+    ~erow() = default;
+    
+    // Core operations
+    void update();
+    void insert_char(std::size_t at, char c);
+    void delete_char(std::size_t at);
+    void append_string(const char* s, std::size_t len);
+    
+    // Cursor/render position conversions
+    [[nodiscard]] int render_to_cursor(int cx) const;
+    [[nodiscard]] int cursor_to_render(int rx) const;
+    
+    // Accessors for line data
+    [[nodiscard]] const char* line_data() const noexcept { return line_.data(); }
+    [[nodiscard]] char* line_data() noexcept { return line_.data(); }
+    [[nodiscard]] std::size_t line_size() const noexcept { return line_.size(); }
+    [[nodiscard]] std::size_t line_capacity() const noexcept { return line_.capacity(); }
+    
+    // Accessors for render data
+    [[nodiscard]] const char* render_data() const noexcept { return render_.data(); }
+    [[nodiscard]] std::size_t render_size() const noexcept { return render_.size(); }
+    
+    // Direct access to strings (for compatibility)
+    [[nodiscard]] std::string& line() noexcept { return line_; }
+    [[nodiscard]] const std::string& line() const noexcept { return line_; }
+    [[nodiscard]] const std::string& render() const noexcept { return render_; }
+    
+    // Resize operations
+    void resize_line(std::size_t new_size) { line_.resize(new_size); }
+    void reserve_line(std::size_t new_cap) { line_.reserve(new_cap); }
+    
+    // Set line content
+    void set_line(const char* data, std::size_t len);
+    void set_line(std::string&& data) noexcept { line_ = std::move(data); }
+
+private:
+    std::string line_;    // The actual line content
+    std::string render_;  // The rendered version (with tabs expanded, etc.)
+    
+    // Helper for nibble to hex conversion
+    static char nibble_to_hex(char c);
+};
+
+} // namespace ke
+
+#endif // EROW_HPP