1 files changed, 136 insertions, 0 deletions
diff --git a/src/zenhorde/hordecomputebuffer.h b/src/zenhorde/hordecomputebuffer.h
new file mode 100644
index 000000000..64ef91b7a
--- /dev/null
+++ b/src/zenhorde/hordecomputebuffer.h
@@ -0,0 +1,136 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zenbase/refcount.h>
+
+#include <cstddef>
+#include <cstdint>
+#include <mutex>
+#include <vector>
+
+namespace zen::horde {
+
+class ComputeBufferReader;
+class ComputeBufferWriter;
+
+/** Simplified in-process ring buffer for the Horde compute protocol.
+ *
+ *  Unlike the UE FComputeBuffer which supports shared-memory and memory-mapped files,
+ *  this implementation uses plain heap-allocated memory since we only need in-process
+ *  communication between channel and transport threads. The buffer is divided into
+ *  fixed-size chunks; readers and writers block when no space is available.
+ */
+class ComputeBuffer
+{
+public:
+	struct Params
+	{
+		size_t NumChunks   = 2;
+		size_t ChunkLength = 512 * 1024;
+	};
+
+	ComputeBuffer();
+	~ComputeBuffer();
+
+	ComputeBuffer(const ComputeBuffer&) = delete;
+	ComputeBuffer& operator=(const ComputeBuffer&) = delete;
+
+	bool CreateNew(const Params& InParams);
+	void Close();
+
+	bool IsValid() const;
+
+	ComputeBufferReader CreateReader();
+	ComputeBufferWriter CreateWriter();
+
+private:
+	struct Detail;
+	Ref<Detail> m_Detail;
+
+	friend class ComputeBufferReader;
+	friend class ComputeBufferWriter;
+};
+
+/** Read endpoint for a ComputeBuffer.
+ *
+ *  Provides blocking reads from the ring buffer. WaitToRead() returns a pointer
+ *  directly into the buffer memory (zero-copy); the caller must call
+ *  AdvanceReadPosition() after consuming the data.
+ */
+class ComputeBufferReader
+{
+public:
+	ComputeBufferReader();
+	ComputeBufferReader(const ComputeBufferReader&);
+	ComputeBufferReader(ComputeBufferReader&&) noexcept;
+	~ComputeBufferReader();
+
+	ComputeBufferReader& operator=(const ComputeBufferReader&);
+	ComputeBufferReader& operator=(ComputeBufferReader&&) noexcept;
+
+	void Close();
+	void Detach();
+	bool IsValid() const;
+	bool IsComplete() const;
+
+	void   AdvanceReadPosition(size_t Size);
+	size_t GetMaxReadSize() const;
+
+	/** Copy up to MaxSize bytes from the buffer into Buffer. Blocks until data is available. */
+	size_t Read(void* Buffer, size_t MaxSize, int TimeoutMs = -1, bool* OutTimedOut = nullptr);
+
+	/** Wait until at least MinSize bytes are available and return a direct pointer.
+	 *  Returns nullptr on timeout or if the writer has completed. */
+	const uint8_t* WaitToRead(size_t MinSize, int TimeoutMs = -1, bool* OutTimedOut = nullptr);
+
+private:
+	friend class ComputeBuffer;
+	explicit ComputeBufferReader(Ref<ComputeBuffer::Detail> InDetail);
+
+	Ref<ComputeBuffer::Detail> m_Detail;
+};
+
+/** Write endpoint for a ComputeBuffer.
+ *
+ *  Provides blocking writes into the ring buffer. WaitToWrite() returns a pointer
+ *  directly into the buffer memory (zero-copy); the caller must call
+ *  AdvanceWritePosition() after filling the data. Call MarkComplete() to signal
+ *  that no more data will be written.
+ */
+class ComputeBufferWriter
+{
+public:
+	ComputeBufferWriter();
+	ComputeBufferWriter(const ComputeBufferWriter&);
+	ComputeBufferWriter(ComputeBufferWriter&&) noexcept;
+	~ComputeBufferWriter();
+
+	ComputeBufferWriter& operator=(const ComputeBufferWriter&);
+	ComputeBufferWriter& operator=(ComputeBufferWriter&&) noexcept;
+
+	void Close();
+	bool IsValid() const;
+
+	/** Signal that no more data will be written. Unblocks any waiting readers. */
+	void MarkComplete();
+
+	void   AdvanceWritePosition(size_t Size);
+	size_t GetMaxWriteSize() const;
+	size_t GetChunkMaxLength() const;
+
+	/** Copy up to MaxSize bytes from Buffer into the ring buffer. Blocks until space is available. */
+	size_t Write(const void* Buffer, size_t MaxSize, int TimeoutMs = -1);
+
+	/** Wait until at least MinSize bytes of write space are available and return a direct pointer.
+	 *  Returns nullptr on timeout. */
+	uint8_t* WaitToWrite(size_t MinSize, int TimeoutMs = -1);
+
+private:
+	friend class ComputeBuffer;
+	explicit ComputeBufferWriter(Ref<ComputeBuffer::Detail> InDetail);
+
+	Ref<ComputeBuffer::Detail> m_Detail;
+};
+
+}  // namespace zen::horde