140 lines
5.0 KiB
C++
140 lines
5.0 KiB
C++
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// ByteStream.h
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// Interfaces to the cByteBuffer class representing a ringbuffer of bytes
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#pragma once
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/** An object that can store incoming bytes and lets its clients read the bytes sequentially
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The bytes are stored in a ringbuffer of constant size; if more than that size
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is requested, the write operation fails.
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The bytes stored can be retrieved using various ReadXXX functions; these assume that the needed
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number of bytes are present in the buffer (ASSERT; for performance reasons).
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The reading doesn't actually remove the bytes, it only moves the internal read ptr.
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To remove the bytes, call CommitRead().
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To re-start reading from the beginning, call ResetRead().
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This class doesn't implement thread safety, the clients of this class need to provide
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their own synchronization.
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*/
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class cByteBuffer
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{
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public:
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cByteBuffer(int a_BufferSize);
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~cByteBuffer();
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/// Writes the bytes specified to the ringbuffer. Returns true if successful, false if not
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bool Write(const char * a_Bytes, int a_Count);
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/// Returns the number of bytes that can be successfully written to the ringbuffer
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int GetFreeSpace(void) const;
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/// Returns the number of bytes that are currently in the ringbuffer. Note GetReadableBytes()
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int GetUsedSpace(void) const;
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/// Returns the number of bytes that are currently available for reading (may be less than UsedSpace due to some data having been read already)
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int GetReadableSpace(void) const;
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/// Returns true if the specified amount of bytes are available for reading
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bool CanReadBytes(int a_Count) const;
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/// Returns true if the specified amount of bytes are available for writing
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bool CanWriteBytes(int a_Count) const;
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// Read the specified datatype and advance the read pointer; return true if successfully read:
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bool ReadChar (char & a_Value);
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bool ReadByte (unsigned char & a_Value);
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bool ReadBEShort (short & a_Value);
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bool ReadBEInt (int & a_Value);
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bool ReadBEInt64 (Int64 & a_Value);
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bool ReadBEFloat (float & a_Value);
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bool ReadBEDouble (double & a_Value);
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bool ReadBool (bool & a_Value);
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bool ReadBEUTF16String16(AString & a_Value); // string length as BE short, then string as UTF-16BE
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bool ReadVarInt (UInt32 & a_Value);
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bool ReadVarUTF8String (AString & a_Value); // string length as VarInt, then string as UTF-8
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bool ReadLEInt (int & a_Value);
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/// Reads VarInt, assigns it to anything that can be assigned from an UInt32 (unsigned short, char, Byte, double, ...)
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template <typename T> bool ReadVarInt(T & a_Value)
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{
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UInt32 v;
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bool res = ReadVarInt(v);
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if (res)
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{
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a_Value = v;
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}
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return res;
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}
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// Write the specified datatype; return true if successfully written
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bool WriteChar (char a_Value);
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bool WriteByte (unsigned char a_Value);
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bool WriteBEShort (short a_Value);
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bool WriteBEInt (int a_Value);
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bool WriteBEInt64 (Int64 a_Value);
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bool WriteBEFloat (float a_Value);
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bool WriteBEDouble (double a_Value);
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bool WriteBool (bool a_Value);
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bool WriteBEUTF16String16(const AString & a_Value); // string length as BE short, then string as UTF-16BE
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bool WriteVarInt (UInt32 a_Value);
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bool WriteVarUTF8String (const AString & a_Value); // string length as VarInt, then string as UTF-8
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bool WriteLEInt (int a_Value);
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/// Reads a_Count bytes into a_Buffer; returns true if successful
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bool ReadBuf(void * a_Buffer, int a_Count);
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/// Writes a_Count bytes into a_Buffer; returns true if successful
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bool WriteBuf(const void * a_Buffer, int a_Count);
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/// Reads a_Count bytes into a_String; returns true if successful
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bool ReadString(AString & a_String, int a_Count);
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/// Reads 2 * a_NumChars bytes and interprets it as a UTF16-BE string, converting it into UTF8 string a_String
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bool ReadUTF16String(AString & a_String, int a_NumChars);
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/// Skips reading by a_Count bytes; returns false if not enough bytes in the ringbuffer
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bool SkipRead(int a_Count);
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/// Reads all available data into a_Data
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void ReadAll(AString & a_Data);
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/// Removes the bytes that have been read from the ringbuffer
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void CommitRead(void);
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/// Restarts next reading operation at the start of the ringbuffer
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void ResetRead(void);
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/// Re-reads the data that has been read since the last commit to the current readpos. Used by ProtoProxy to duplicate communication
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void ReadAgain(AString & a_Out);
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/// Checks if the internal state is valid (read and write positions in the correct bounds) using ASSERTs
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void CheckValid(void) const;
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protected:
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char * m_Buffer;
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int m_BufferSize; // Total size of the ringbuffer
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#ifdef _DEBUG
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unsigned long m_ThreadID; // Thread that is currently accessing the object, checked via cSingleThreadAccessChecker
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#endif // _DEBUG
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int m_DataStart; // Where the data starts in the ringbuffer
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int m_WritePos; // Where the data ends in the ringbuffer
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int m_ReadPos; // Where the next read will start in the ringbuffer
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/// Advances the m_ReadPos by a_Count bytes
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void AdvanceReadPos(int a_Count);
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} ;
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