// ByteStream.h
// Interfaces to the cByteBuffer class representing a ringbuffer of bytes
#pragma once
/** An object that can store incoming bytes and lets its clients read the bytes sequentially
The bytes are stored in a ringbuffer of constant size; if more than that size
is requested, the write operation fails.
The bytes stored can be retrieved using various ReadXXX functions; these assume that the needed
number of bytes are present in the buffer (ASSERT; for performance reasons).
The reading doesn't actually remove the bytes, it only moves the internal read ptr.
To remove the bytes, call CommitRead().
To re-start reading from the beginning, call ResetRead().
This class doesn't implement thread safety, the clients of this class need to provide
their own synchronization.
*/
class cByteBuffer
{
public:
cByteBuffer(size_t a_BufferSize);
~cByteBuffer();
/** Writes the bytes specified to the ringbuffer. Returns true if successful, false if not */
bool Write(const void * a_Bytes, size_t a_Count);
/** Returns the number of bytes that can be successfully written to the ringbuffer */
size_t GetFreeSpace(void) const;
/** Returns the number of bytes that are currently in the ringbuffer. Note GetReadableBytes() */
size_t GetUsedSpace(void) const;
/** Returns the number of bytes that are currently available for reading (may be less than UsedSpace due to some data having been read already) */
size_t GetReadableSpace(void) const;
/** Returns the current data start index. For debugging purposes. */
size_t GetDataStart(void) const { return m_DataStart; }
/** Returns true if the specified amount of bytes are available for reading */
bool CanReadBytes(size_t a_Count) const;
/** Returns true if the specified amount of bytes are available for writing */
bool CanWriteBytes(size_t a_Count) const;
// Read the specified datatype and advance the read pointer; return true if successfully read:
bool ReadBEInt8 (Int8 & a_Value);
bool ReadBEInt16 (Int16 & a_Value);
bool ReadBEInt32 (Int32 & a_Value);
bool ReadBEInt64 (Int64 & a_Value);
bool ReadBEUInt8 (UInt8 & a_Value);
bool ReadBEUInt16 (UInt16 & a_Value);
bool ReadBEUInt32 (UInt32 & a_Value);
bool ReadBEUInt64 (UInt64 & a_Value);
bool ReadBEFloat (float & a_Value);
bool ReadBEDouble (double & a_Value);
bool ReadBool (bool & a_Value);
bool ReadVarInt32 (UInt32 & a_Value);
bool ReadVarInt64 (UInt64 & a_Value);
bool ReadVarUTF8String (AString & a_Value); // string length as VarInt, then string as UTF-8
bool ReadLEInt (int & a_Value);
bool ReadPosition64 (int & a_BlockX, int & a_BlockY, int & a_BlockZ);
/** Reads VarInt, assigns it to anything that can be assigned from an UInt64 (unsigned short, char, Byte, double, ...) */
template <typename T> bool ReadVarInt(T & a_Value)
{
UInt64 v;
bool res = ReadVarInt64(v);
if (res)
{
a_Value = static_cast<T>(v);
}
return res;
}
// Write the specified datatype; return true if successfully written
bool WriteBEInt8 (Int8 a_Value);
bool WriteBEInt16 (Int16 a_Value);
bool WriteBEInt32 (Int32 a_Value);
bool WriteBEInt64 (Int64 a_Value);
bool WriteBEUInt8 (UInt8 a_Value);
bool WriteBEUInt16 (UInt16 a_Value);
bool WriteBEUInt32 (UInt32 a_Value);
bool WriteBEUInt64 (UInt64 a_Value);
bool WriteBEFloat (float a_Value);
bool WriteBEDouble (double a_Value);
bool WriteBool (bool a_Value);
bool WriteVarInt32 (UInt32 a_Value);
bool WriteVarInt64 (UInt64 a_Value);
bool WriteVarUTF8String (const AString & a_Value); // string length as VarInt, then string as UTF-8
bool WriteLEInt32 (Int32 a_Value);
bool WritePosition64 (Int32 a_BlockX, Int32 a_BlockY, Int32 a_BlockZ);
/** Reads a_Count bytes into a_Buffer; returns true if successful */
bool ReadBuf(void * a_Buffer, size_t a_Count);
/** Writes a_Count bytes into a_Buffer; returns true if successful */
bool WriteBuf(const void * a_Buffer, size_t a_Count);
/** Reads a_Count bytes into a_String; returns true if successful */
bool ReadString(AString & a_String, size_t a_Count);
/** Skips reading by a_Count bytes; returns false if not enough bytes in the ringbuffer */
bool SkipRead(size_t a_Count);
/** Reads all available data into a_Data */
void ReadAll(AString & a_Data);
/** Reads the specified number of bytes and writes it into the destinatio bytebuffer. Returns true on success. */
bool ReadToByteBuffer(cByteBuffer & a_Dst, size_t a_NumBytes);
/** Removes the bytes that have been read from the ringbuffer */
void CommitRead(void);
/** Restarts next reading operation at the start of the ringbuffer */
void ResetRead(void);
/** Re-reads the data that has been read since the last commit to the current readpos. Used by ProtoProxy to duplicate communication */
void ReadAgain(AString & a_Out);
/** Checks if the internal state is valid (read and write positions in the correct bounds) using ASSERTs */
void CheckValid(void) const;
/** Gets the number of bytes that are needed to represent the given VarInt */
static size_t GetVarIntSize(UInt32 a_Value);
protected:
char * m_Buffer;
size_t m_BufferSize; // Total size of the ringbuffer
size_t m_DataStart; // Where the data starts in the ringbuffer
size_t m_WritePos; // Where the data ends in the ringbuffer
size_t m_ReadPos; // Where the next read will start in the ringbuffer
#ifdef _DEBUG
/** The ID of the thread currently accessing the object.
Used for checking that only one thread accesses the object at a time, via cSingleThreadAccessChecker. */
mutable std::thread::id m_ThreadID;
#endif
/** Advances the m_ReadPos by a_Count bytes */
void AdvanceReadPos(size_t a_Count);
} ;
