myvtm/Common/Blob.h

#ifndef _RVC_COMM_CBLOB_H_
#define _RVC_COMM_CBLOB_H_

#pragma once

struct CBlob
{
	void *m_pData;
	int m_iLength;
	bool m_bManaged;
	CBlob() : m_bManaged(false), m_pData(NULL), m_iLength(0) {}
	~CBlob() { Clear(); }
	CBlob(const CBlob &t)
		: m_bManaged(false), m_pData(NULL), m_iLength(0)
	{
		m_bManaged = t.m_bManaged;
		m_iLength = t.m_iLength;
		if (m_bManaged) {
			if (m_iLength) {
				m_pData = new char[m_iLength];
				memcpy(m_pData, t.m_pData, m_iLength);
			}
		} else {
			m_pData = t.m_pData;
		}
	}
	void Clear() 
	{ 
		if (m_bManaged) {
			delete m_pData;
			m_bManaged = false;
		}
		m_iLength = 0;
		m_pData = NULL;
	}

	const CBlob &operator =(const CBlob &t) {
		Clear();
		m_bManaged = t.m_bManaged;
		m_iLength = t.m_iLength;
		if (m_bManaged) {
			if (m_iLength) {
				m_pData = new char[m_iLength];
				memcpy(m_pData, t.m_pData, m_iLength);
			}
		} else {
			m_pData = t.m_pData;
		}
		return *this;
	}

	void Alloc(int len) {
		if (m_bManaged) {
			delete m_pData;
		} else {
			m_bManaged = true;
		}
		m_pData = new char[len];
		memset(m_pData, 0, len);
		m_iLength = len;
	}
	
	void Attach(void *pData, int nLen)
	{
		Clear();

		m_pData = pData;
		m_iLength = nLen;
		m_bManaged = true;
	}

	// resize buffer size, if smaller, only change m_iLength;  if larger, realloc memory and copy current data
	void Resize(int len)
	{
		if (len == 0)
		{
			Clear();
			return;
		}

		if (len <= m_iLength)
		{
			// smaller size only change m_iLength
			m_iLength = len;
			return;
		}

		// new size is larger
		char *pNewBuf = new char[len];
		memset(pNewBuf, 0, len);
		
		if (m_iLength >0)		// copy original data
			memcpy(pNewBuf, m_pData, m_iLength);

		if (m_bManaged)
			delete m_pData;

		m_bManaged = true;
		m_pData = pNewBuf;
		m_iLength = len;
	}

	// dont release memory when destruct
	void Refer(void *pData, int nLen)
	{
		Clear();

		m_pData = pData;
		m_iLength = nLen;
		m_bManaged = false;
	}

	void AssignAndClear(CBlob &toBlob) {
		toBlob.Clear();
		toBlob.m_pData = m_pData;
		toBlob.m_iLength = m_iLength;
		toBlob.m_bManaged = m_bManaged;
		if (m_bManaged) {
			m_bManaged = false;
			Clear();				
		}
	}
};

#endif //_RVC_COMM_CBLOB_H_