/*
 Derived from source code of TrueCrypt 7.1a, which is
 Copyright (c) 2008-2012 TrueCrypt Developers Association and which is governed
 by the TrueCrypt License 3.0.

 Modifications and additions to the original source code (contained in this file)
 and all other portions of this file are Copyright (c) 2013-2017 IDRIX
 and are governed by the Apache License 2.0 the full text of which is
 contained in the file License.txt included in VeraCrypt binary and source
 code distribution packages.
*/

#ifndef TC_HEADER_Platform_Buffer
#define TC_HEADER_Platform_Buffer

#include "PlatformBase.h"
#include "Memory.h"

namespace VeraCrypt
{

	class ConstBufferPtr
	{
	public:
		ConstBufferPtr ()
			: DataPtr (nullptr), DataSize (0) { }
		ConstBufferPtr (const byte *data, size_t size)
			: DataPtr (data), DataSize (size) { }
		virtual ~ConstBufferPtr () { }

		operator const byte * () const { return DataPtr; }

		bool IsDataEqual (const ConstBufferPtr &other) const { return Memory::Compare (DataPtr, DataSize, other.DataPtr, other.DataSize) == 0; }
		const byte *Get () const { return DataPtr; }
		ConstBufferPtr GetRange (size_t offset, size_t size) const;
		void Set (const byte *data, size_t size) { DataPtr = data; DataSize = size; }
		size_t Size () const { return DataSize; }

	protected:
		const byte *DataPtr;
		size_t DataSize;
	};


	class BufferPtr
	{
	public:
		BufferPtr ()
			: DataPtr (nullptr), DataSize (0) { }
		BufferPtr (byte *data, size_t size)
			: DataPtr (data), DataSize (size) { }
		virtual ~BufferPtr () { }

		operator byte * () const { return DataPtr; }
		void CopyFrom (const ConstBufferPtr &bufferPtr) const;
		void Erase () const { Zero(); }
		byte *Get () const { return DataPtr; }
		BufferPtr GetRange (size_t offset, size_t size) const;
		void Set (byte *data, size_t size) { DataPtr = data; DataSize = size; }
		size_t Size () const { return DataSize; }
		void Zero () const { Memory::Zero (DataPtr, DataSize); }

		operator ConstBufferPtr () const { return ConstBufferPtr (DataPtr, DataSize); }

	protected:
		byte *DataPtr;
		size_t DataSize;
	};

	class Buffer
	{
	public:
		Buffer ();
		Buffer (size_t size, size_t alignment = 0);
		Buffer (const ConstBufferPtr &bufferPtr, size_t alignment = 0) { CopyFrom (bufferPtr, alignment); }
		virtual ~Buffer ();

		virtual void Allocate (size_t size, size_t alignment = 0);
		virtual void CopyFrom (const ConstBufferPtr &bufferPtr, size_t alignment = 0);
		virtual byte *Ptr () const { return DataPtr; }
		virtual void Erase ();
		virtual void Free ();
		virtual BufferPtr GetRange (size_t offset, size_t size) const;
		virtual size_t Size () const { return DataSize; }
		virtual size_t Alignment () const { return DataAlignment; }
		virtual bool IsAllocated () const { return DataSize != 0; }
		virtual void Zero ();

		virtual operator byte * () const { return DataPtr; }
		virtual operator BufferPtr () const { return BufferPtr (DataPtr, DataSize); }
		virtual operator ConstBufferPtr () const { return ConstBufferPtr (DataPtr, DataSize); }

	protected:
		byte *DataPtr;
		size_t DataSize;
		size_t DataAlignment;

	private:
		Buffer (const Buffer &);
		Buffer &operator= (const Buffer &);
	};

	class SecureBuffer : public Buffer
	{
	public:
		SecureBuffer () { }
		SecureBuffer (size_t size, size_t alignment = 0);
		SecureBuffer (const ConstBufferPtr &bufferPtr) { CopyFrom (bufferPtr); }
		virtual ~SecureBuffer ();

		virtual void Allocate (size_t size, size_t alignment = 0);
		virtual void Free ();

	private:
		SecureBuffer (const SecureBuffer &);
		SecureBuffer &operator= (const SecureBuffer &);
	};

}

#endif // TC_HEADER_Platform_Buffer
