Initial import.

GapBuffer.h

@@ -0,0 +1,72 @@
+/*
+ * GapBuffer.h - C++ replacement for abuf append/prepend buffer utilities
+ */
+#ifndef KTE_GAPBUFFER_H
+#define KTE_GAPBUFFER_H
+
+#include <cstddef>
+
+class GapBuffer {
+public:
+	GapBuffer();
+
+	explicit GapBuffer(std::size_t initialCapacity);
+
+	GapBuffer(const GapBuffer &other);
+
+	GapBuffer &operator=(const GapBuffer &other);
+
+	GapBuffer(GapBuffer &&other) noexcept;
+
+	GapBuffer &operator=(GapBuffer &&other) noexcept;
+
+	~GapBuffer();
+
+	void Reserve(std::size_t newCapacity);
+
+
+	void AppendChar(char c);
+	void Append(const char *s, std::size_t len);
+	void Append(const GapBuffer &other);
+
+	void PrependChar(char c);
+	void Prepend(const char *s, std::size_t len);
+	void Prepend(const GapBuffer &other);
+
+	// Content management
+	void Clear();
+
+	// Accessors
+	char *Data()
+	{
+		return buffer_;
+	}
+
+	[[nodiscard]] const char *Data() const
+	{
+		return buffer_;
+	}
+
+	[[nodiscard]] std::size_t Size() const
+	{
+		return size_;
+	}
+
+	[[nodiscard]] std::size_t Capacity() const
+	{
+		return capacity_;
+	}
+
+private:
+	void ensureCapacityFor(std::size_t delta);
+
+	static std::size_t growCapacity(std::size_t current, std::size_t required);
+
+	void setTerminator() const;
+
+	char *buffer_         = nullptr;
+	std::size_t size_     = 0; // number of valid bytes (excluding terminator)
+	std::size_t capacity_ = 0; // capacity of buffer_ excluding space for terminator
+};
+
+#endif // KTE_GAPBUFFER_H