From 70a4ca5bc196676e8926028b2187fe7bd2874d42 Mon Sep 17 00:00:00 2001
From: "madmaxoft@gmail.com"
 <madmaxoft@gmail.com@0a769ca7-a7f5-676a-18bf-c427514a06d6>
Date: Fri, 17 Aug 2012 10:18:07 +0000
Subject: Packets now parse themselves from a cByteBuffer object (1st part of
 packeting rewrite, http://forum.mc-server.org/showthread.php?tid=524 )

git-svn-id: http://mc-server.googlecode.com/svn/trunk@744 0a769ca7-a7f5-676a-18bf-c427514a06d6
---
 source/ByteBuffer.cpp | 324 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 324 insertions(+)
 create mode 100644 source/ByteBuffer.cpp

(limited to 'source/ByteBuffer.cpp')

diff --git a/source/ByteBuffer.cpp b/source/ByteBuffer.cpp
new file mode 100644
index 000000000..d25eb8e0b
--- /dev/null
+++ b/source/ByteBuffer.cpp
@@ -0,0 +1,324 @@
+
+// ByteBuffer.cpp
+
+// Implements the cByteBuffer class representing a ringbuffer of bytes
+
+#include "Globals.h"
+
+#include "ByteBuffer.h"
+#include "Endianness.h"
+
+
+
+
+
+#define NEEDBYTES(Num) if (!CanReadBytes(Num)) return false;
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cByteBuffer:
+
+cByteBuffer::cByteBuffer(int a_BufferSize) :
+	m_Buffer(new char[a_BufferSize + 1]),
+	m_BufferSize(a_BufferSize + 1),
+	m_DataStart(0),
+	m_WritePos(0),
+	m_ReadPos(0)
+{
+	// Allocating one byte more than the buffer size requested, so that we can distinguish between
+	// completely-full and completely-empty states
+}
+
+
+
+
+
+cByteBuffer::~cByteBuffer()
+{
+	delete m_Buffer;
+}
+
+
+
+
+
+bool cByteBuffer::Write(const char * a_Bytes, int a_Count)
+{
+	if (GetFreeSpace() < a_Count)
+	{
+		return false;
+	}
+	int TillEnd = m_BufferSize - m_WritePos;
+	if (TillEnd < a_Count)
+	{
+		// Need to wrap around the ringbuffer end
+		memcpy(m_Buffer + m_WritePos, a_Bytes, TillEnd);
+		m_WritePos = 0;
+		a_Bytes += TillEnd;
+		a_Count -= TillEnd;
+	}
+	
+	// We're guaranteed that we'll fit in a single write op
+	memcpy(m_Buffer + m_WritePos, a_Bytes, a_Count);
+	m_WritePos += a_Count;
+	return true;
+}
+
+
+
+
+
+int cByteBuffer::GetFreeSpace(void) const
+{
+	if (m_WritePos >= m_DataStart)
+	{
+		// Wrap around the buffer end:
+		return m_BufferSize - m_WritePos + m_DataStart - 1;
+	}
+	// Single free space partition:
+	return m_DataStart - m_WritePos - 1;
+}
+
+
+
+
+
+/// Returns the number of bytes that are currently in the ringbuffer. Note GetReadableBytes()
+int cByteBuffer::GetUsedSpace(void) const
+{
+	return m_BufferSize - GetFreeSpace();
+}
+
+
+
+
+
+/// Returns the number of bytes that are currently available for reading (may be less than UsedSpace due to some data having been read already)
+int cByteBuffer::GetReadableSpace(void) const
+{
+	if (m_ReadPos > m_WritePos)
+	{
+		// Wrap around the buffer end:
+		return m_BufferSize - m_ReadPos + m_WritePos;
+	}
+	// Single readable space partition:
+	return m_WritePos - m_ReadPos ;
+}
+
+
+
+
+
+bool cByteBuffer::CanReadBytes(int a_Count) const
+{
+	return (a_Count <= GetReadableSpace());
+}
+
+
+
+
+
+bool cByteBuffer::ReadChar(char & a_Value)
+{
+	NEEDBYTES(1);
+	a_Value = m_Buffer[m_ReadPos++];
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadByte(unsigned char & a_Value)
+{
+	NEEDBYTES(1);
+	a_Value = (unsigned char)(m_Buffer[m_ReadPos++]);
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEShort(short & a_Value)
+{
+	NEEDBYTES(2);
+	ReadBuf(&a_Value, 2);
+	a_Value = ntohs(a_Value);
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEInt(int & a_Value)
+{
+	NEEDBYTES(4);
+	ReadBuf(&a_Value, 4);
+	a_Value = ntohl(a_Value);
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEInt64(Int64 & a_Value)
+{
+	NEEDBYTES(8);
+	ReadBuf(&a_Value, 8);
+	a_Value = NetworkToHostLong8(&a_Value);
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEFloat(float & a_Value)
+{
+	NEEDBYTES(4);
+	ReadBuf(&a_Value, 4);
+	a_Value = NetworkToHostFloat4(&a_Value);
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEDouble(double & a_Value)
+{
+	NEEDBYTES(8);
+	ReadBuf(&a_Value, 8);
+	a_Value = NetworkToHostDouble8(&a_Value);
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBool(bool & a_Value)
+{
+	NEEDBYTES(1);
+	a_Value = (m_Buffer[m_ReadPos++] != 0);
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEUTF16String16(AString & a_Value)
+{
+	short Length;
+	if (!ReadBEShort(Length))
+	{
+		return false;
+	}
+	return ReadUTF16String(a_Value, Length);
+}
+
+
+
+
+
+bool cByteBuffer::ReadBuf(void * a_Buffer, int a_Count)
+{
+	NEEDBYTES(a_Count);
+	char * Dst = (char *)a_Buffer;  // So that we can do byte math
+	int BytesToEndOfBuffer = m_BufferSize - m_ReadPos;
+	if (BytesToEndOfBuffer < a_Count)
+	{
+		// Reading across the ringbuffer end, read the first part and adjust parameters:
+		memcpy(Dst, m_Buffer + m_ReadPos, BytesToEndOfBuffer);
+		Dst += BytesToEndOfBuffer;
+		a_Count -= BytesToEndOfBuffer;
+		m_ReadPos = 0;
+	}
+	
+	// Read the rest of the bytes in a single read (guaranteed to fit):
+	memcpy(Dst, m_Buffer + m_ReadPos, a_Count);
+	m_ReadPos += a_Count;
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadString(AString & a_String, int a_Count)
+{
+	NEEDBYTES(a_Count);
+	a_String.clear();
+	a_String.reserve(a_Count);
+	int BytesToEndOfBuffer = m_BufferSize - m_ReadPos;
+	if (BytesToEndOfBuffer < a_Count)
+	{
+		// Reading across the ringbuffer end, read the first part and adjust parameters:
+		a_String.assign(m_Buffer + m_ReadPos, BytesToEndOfBuffer);
+		a_Count -= BytesToEndOfBuffer;
+		m_ReadPos = 0;
+	}
+	
+	// Read the rest of the bytes in a single read (guaranteed to fit):
+	a_String.append(m_Buffer + m_ReadPos, a_Count);
+	m_ReadPos += a_Count;
+	return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadUTF16String(AString & a_String, int a_NumChars)
+{
+	// Reads 2 * a_NumChars bytes and interprets it as a UTF16 string, converting it into UTF8 string a_String
+	AString RawData;
+	if (!ReadString(RawData, a_NumChars * 2))
+	{
+		return false;
+	}
+	RawBEToUTF8((short *)(RawData.data()), a_NumChars, a_String);
+	return true;
+}
+
+
+
+
+
+void cByteBuffer::CommitRead(void)
+{
+	m_DataStart = m_ReadPos;
+}
+
+
+
+
+
+void cByteBuffer::ResetRead(void)
+{
+	m_ReadPos = m_DataStart;
+}
+
+
+
+
+
+void cByteBuffer::AdvanceReadPos(int a_Count)
+{
+	m_ReadPos += a_Count;
+	if (m_ReadPos > m_BufferSize)
+	{
+		m_ReadPos -= m_BufferSize;
+	}
+}
+
+
+
+
-- 
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