resistancemonitor/7.Center/LNBuffer.cpp

#include "stdafx.h"
#include "LNBuffer.h"
#include <Simplelog.h>
#include <string>


CLNBuffer::CLNBuffer()
{
}


CLNBuffer::~CLNBuffer()
{
}

int CLNBuffer::HasPack()
{
	static DWORD64 headid = 0xABAAAAAAAAAAAAAA;
	int i, nStart = -1;

	//find pack head
	for (i = 0; i < m_nPos - 1 && m_nPos > 4; i++)
	{
		if (*(DWORD64*)(m_pBuffer + i) == headid)
		{
			nStart = i;
			break;
		}
	}

	if (nStart == -1)
	{
		m_nPos = 0;
		return 0;
	}
	else if (nStart > 0)
	{
		m_nPos -= nStart;
		memmove(m_pBuffer, m_pBuffer + nStart, m_nPos);
		nStart = 0;
	}

	int nlen = 0;
	//find pack tail
	DWORD nLen = htonl(*(DWORD*)(m_pBuffer + sizeof(headid)));
	if ((DWORD)m_nPos >= sizeof(HJDATAHEAD2) + nLen + 2)
	{
		if (m_pBuffer[sizeof(HJDATAHEAD2) + nLen] == 0x00 && m_pBuffer[sizeof(HJDATAHEAD2) + nLen + 1] == 0xab)
		{
			nlen = sizeof(HJDATAHEAD2) + nLen + 2;
		}
		else
		{
			ASSERT(0);
			m_nPos = 0;
		}
	}
	return nlen;
}