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tracker/common/UtlMsgBuffer.h

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: Generic named data buffer, declaration and implementation
+//
+//=============================================================================
+
+#ifndef UTLMSGBUFFER_H
+#define UTLMSGBUFFER_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+#include "UtlMemory.h"
+
+#pragma warning(disable: 4244) // warning C4244: '=' : conversion from 'int' to 'short', possible loss of data
+
+//-----------------------------------------------------------------------------
+// Purpose: Generic named data buffer
+//-----------------------------------------------------------------------------
+class CUtlMsgBuffer
+{
+public:
+	CUtlMsgBuffer(unsigned short msgID, int initialSize);
+	CUtlMsgBuffer(unsigned short msgID, void const *data, int dataSize);
+	~CUtlMsgBuffer();
+
+	unsigned short GetMsgID() const				{ return m_iMsgID; }
+	void SetMsgID(unsigned short msgID)			{ m_iMsgID = msgID; }
+
+	// read functions
+	bool ReadInt(const char *name, int &data);
+	bool ReadUInt(const char *name, unsigned int &data);
+	bool ReadString(const char *name, char *data, int dataBufferSize);
+	bool ReadBuffer(const char *name, CUtlMsgBuffer &buffer);
+	// returns number of bytes read, 0 on failure
+	int ReadBlob(const char *name, void *data, int dataBufferSize);	
+
+	// reads out the next variable available in the buffer
+	// fills out parameters with var details and data
+	// returns false if no more vars available
+	bool ReadNextVar(char name[32], bool &stringData, void *data, int &dataSize);
+
+	// write functions
+	void WriteInt(const char *name, int data);
+	void WriteUInt(const char *name, unsigned int data);
+	void WriteString(const char *name, const char *data);
+	void WriteBlob(const char *name, const void *data, int dataSize);
+	void WriteBuffer(const char *name, const CUtlMsgBuffer *buffer);
+
+	// returns a pointer to the data buffer, and its size, of the specified variable
+	void *FindVar(const char *name, int &dataSizeOut);
+
+	// pads the buffer to the specified boundary (in bytes)
+	void PadBuffer(int boundary);
+
+    // makes sure the message has this much space allocated
+    void EnsureCapacity(int dataSize);
+
+	// returns the number of bytes used by the message
+	int DataSize() const;
+
+	// returns a pointer to the base data
+	void *Base();
+
+	// returns a const pointer to the base data
+	const void *Base() const;
+
+    // advances the write pointer - used when you write directly into the buffer
+    void SetWritePos(int size);
+
+    CUtlMsgBuffer& Copy(const CUtlMsgBuffer &rhs);
+
+	// copy constructor
+	CUtlMsgBuffer(const CUtlMsgBuffer &rhs)
+	{
+		m_iMsgID = rhs.m_iMsgID;
+		m_iWritePos = rhs.m_iWritePos;
+		m_iReadPos = rhs.m_iReadPos;
+		m_iNextVarPos = rhs.m_iNextVarPos;
+
+		m_Memory.EnsureCapacity(rhs.m_Memory.NumAllocated());
+		if ( rhs.m_Memory.NumAllocated() > 0 )
+		{
+			memcpy(Base(), rhs.Base(), rhs.m_Memory.NumAllocated());
+		}
+	}
+
+private:
+
+	bool Read(void *buffer, int readAmount);
+	bool ReadUntilNull(void *buffer, int bufferSize);
+	void Write(void const *data, int size);
+
+	CUtlMemory<char> m_Memory;
+
+	unsigned short m_iMsgID;
+	short m_iWritePos;		// position in buffer we are currently writing to
+	short m_iReadPos;			// current reading position
+	short m_iNextVarPos;		// a guess at which variable is most likely to be read next
+};
+
+//-----------------------------------------------------------------------------
+// Purpose: returns the number of bytes used by the message
+//-----------------------------------------------------------------------------
+inline int CUtlMsgBuffer::DataSize() const
+{
+	// return the highest read/write mark
+	if (m_iWritePos > m_iReadPos)
+		return m_iWritePos;
+
+	return m_iReadPos;
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: returns a pointer to the base data
+//-----------------------------------------------------------------------------
+inline void *CUtlMsgBuffer::Base()
+{
+	return &m_Memory[0];
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: returns a pointer to the base data
+//-----------------------------------------------------------------------------
+inline const void *CUtlMsgBuffer::Base() const
+{
+	return &m_Memory[0];
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: ensures capacity
+//-----------------------------------------------------------------------------
+inline void CUtlMsgBuffer::EnsureCapacity(int dataSize)
+{
+    m_Memory.EnsureCapacity(dataSize);
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: pads the buffer to the specified boundary (in bytes)
+//-----------------------------------------------------------------------------
+inline void CUtlMsgBuffer::PadBuffer(int boundary)
+{
+	// pad the buffer to be the right size for encryption
+	int pad = (boundary - (DataSize() % boundary));	
+	Write("\0\0\0\0\0\0\0\0\0\0\0\0", pad);
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: Reads in a named 4-byte int, returns true on sucess, false on failure
+//-----------------------------------------------------------------------------
+inline bool CUtlMsgBuffer::ReadInt(const char *name, int &data)
+{
+	return (ReadBlob(name, &data, 4) == 4);
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: Reads in a named 4-byte unsigned int, returns true on sucess, false on failure
+//-----------------------------------------------------------------------------
+inline bool CUtlMsgBuffer::ReadUInt(const char *name, unsigned int &data)
+{
+	return (ReadBlob(name, &data, 4) == 4);
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: Reads in a named variable length character string
+//			returns true on sucess, false on failure
+//-----------------------------------------------------------------------------
+inline bool CUtlMsgBuffer::ReadString(const char *name, char *data, int dataBufferSize)
+{
+	return (ReadBlob(name, data, dataBufferSize) > 0);
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: Writes out an integer to the message
+//-----------------------------------------------------------------------------
+inline void CUtlMsgBuffer::WriteInt(const char *name, int data)
+{
+	WriteBlob(name, &data, 4);
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: Writes out an unsigned integer to the message
+//-----------------------------------------------------------------------------
+inline void CUtlMsgBuffer::WriteUInt(const char *name, unsigned int data)
+{
+	WriteBlob(name, &data, 4);
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: 
+//-----------------------------------------------------------------------------
+inline void CUtlMsgBuffer::SetWritePos(int size)
+{
+    m_iWritePos = size;
+}
+
+
+#endif // UTLMSGBUFFER_H