udt4.rar buffer.cpp

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/*****************************************************************************
written by
Yunhong Gu, last updated 09/19/2007
*****************************************************************************/

#include <cstring>
#include <cmath>
#include "buffer.h"

using namespace std;

CSndBuffer::CSndBuffer(const int&amt; mss):
m_pBlock(NULL),
m_pLastBlock(NULL),
m_pCurrSendBlk(NULL),
m_pCurrAckBlk(NULL),
m_iCurrBufSize(0),
m_iCurrSendPnt(0),
m_iCurrAckPnt(0),
m_iNextMsgNo(0),
m_iMSS(mss)
{
#ifndef WIN32
pthread_mutex_init(&amt;m_BufLock, NULL);
#else
m_BufLock = CreateMutex(NULL, false, NULL);
#endif
}

CSndBuffer::~CSndBuffer()
{
Block* pb = m_pBlock;

// Release allocated data structure if there is any
while (NULL != m_pBlock)
{
pb = pb->m_next;

// release sender buffer
delete [] m_pBlock->m_pcData;

delete m_pBlock;
m_pBlock = pb;
}

#ifndef WIN32
pthread_mutex_destroy(&amt;m_BufLock);
#else
CloseHandle(m_BufLock);
#endif
}

void CSndBuffer::addBuffer(const char* data, const int&amt; len, const int&amt; ttl, const int32_t&amt; seqno, const bool&amt; order)
{
CGuard bufferguard(m_BufLock);

if (NULL == m_pBlock)
{
// Insert a block to the empty list

m_pBlock = new Block;
m_pBlock->m_pcData = const_cast<char*>(data);
m_pBlock->m_iLength = len;
m_pBlock->m_OriginTime = CTimer::getTime();
m_pBlock->m_iTTL = ttl;
m_pBlock->m_iMsgNo = m_iNextMsgNo;
m_pBlock->m_iSeqNo = seqno;
m_pBlock->m_iInOrder = order;
m_pBlock->m_iInOrder <<= 29;
m_pBlock->m_next = NULL;
m_pLastBlock = m_pBlock;
m_pCurrSendBlk = m_pBlock;
m_iCurrSendPnt = 0;
m_pCurrAckBlk = m_pBlock;
m_iCurrAckPnt = 0;
}
else
{
// Insert a new block to the tail of the list

int32_t lastseq = m_pLastBlock->m_iSeqNo;
int offset = m_pLastBlock->m_iLength;

m_pLastBlock->m_next = new Block;
m_pLastBlock = m_pLastBlock->m_next;
m_pLastBlock->m_pcData = const_cast<char*>(data);
m_pLastBlock->m_iLength = len;
m_pLastBlock->m_OriginTime = CTimer::getTime();
m_pLastBlock->m_iTTL = ttl;
m_pLastBlock->m_iMsgNo = m_iNextMsgNo;
m_pLastBlock->m_iSeqNo = lastseq + (int32_t)ceil(double(offset) / m_iMSS);
m_pLastBlock->m_iInOrder = order;
m_pLastBlock->m_iInOrder <<= 29;
m_pLastBlock->m_next = NULL;
if (NULL == m_pCurrSendBlk)
m_pCurrSendBlk = m_pLastBlock;
}

m_iNextMsgNo = CMsgNo::incmsg(m_iNextMsgNo);

m_iCurrBufSize += len;
}

int CSndBuffer::readData(char** data, const int&amt; len, int32_t&amt; msgno)
{
CGuard bufferguard(m_BufLock);

// No data to read
if (NULL == m_pCurrSendBlk)
return 0;

// read data in the current sending block
if (m_iCurrSendPnt + len < m_pCurrSendBlk->m_iLength)
{
*data = m_pCurrSendBlk->m_pcData + m_iCurrSendPnt;

msgno = m_pCurrSendBlk->m_iMsgNo | m_pCurrSendBlk->m_iInOrder;
if (0 == m_iCurrSendPnt)
msgno |= 0x80000000;
if (m_pCurrSendBlk->m_iLength == m_iCurrSendPnt + len)
msgno |= 0x40000000;

m_iCurrSendPnt += len;

return len;
}

// Not enough data to read.
// Read an irregular packet and move the current sending block pointer to the next block
int readlen = m_pCurrSendBlk->m_iLength - m_iCurrSendPnt;
*data = m_pCurrSendBlk->m_pcData + m_iCurrSendPnt;

if (0 == m_iCurrSendPnt)
msgno = m_pCurrSendBlk->m_iMsgNo | 0xC0000000 | m_pCurrSendBlk->m_iInOrder;
else
msgno = m_pCurrSendBlk->m_iMsgNo | 0x40000000 | m_pCurrSendBlk->m_iInOrder;

m_pCurrSendBlk = m_pCurrSendBlk->m_next;
m_iCurrSendPnt = 0;

return readlen;
}

int CSndBuffer::readData(char** data, const int offset, const int&amt; len, int32_t&amt; msgno, int32_t&amt; seqno, int&amt; msglen)
{
CGuard bufferguard(m_BufLock);

Block* p = m_pCurrAckBlk;

// No data to read
if (NULL == p)
return 0;

// Locate to the data position by the offset
int loffset = offset + m_iCurrAckPnt;
while (p->m_iLength <= loffset)
{
loffset -= p->m_iLength;
loffset -= len - ((0 == p->m_iLength > len) ? len : (p->m_iLength > len));
p = p->m_next;
if (NULL == p)
return 0;
}

if (p->m_iTTL >= 0)
{
if ((CTimer::getTime() - p->m_OriginTime) / 1000 > (uint64_t)p->m_iTTL)
{
msgno = p->m_iMsgNo;
seqno = p->m_iSeqNo;
msglen = p->m_iLength;

return -1;
}
}

// Read a regular data
if (loffset + len <= p->m_iLength)
{
*data = p->m_pcData + loffset;
msgno = p->m_iMsgNo | p->m_iInOrder;

if (0 == loffset)
msgno |= 0x80000000;
if (p->m_iLength == loffset + len)
msgno |= 0x40000000;

return len;
}

// Read an irrugular data at the end of a block
*data = p->m_pcData + loffset;
msgno = p->m_iMsgNo | p->m_iInOrder;

if (0 == loffset)
msgno |= 0xC0000000;
else
msgno |= 0x40000000;

return p->m_iLength - loffset;
}

void CSndBuffer::ackData(const int&amt; len, const int&amt; payloadsize)
{
CGuard bufferguard(m_BufLock);

m_iCurrAckPnt += len;

// Remove the block if it is acknowledged
while (m_iCurrAckPnt >= m_pCurrAckBlk->m_iLength)
{
m_iCurrAckPnt -= m_pCurrAckBlk->m_iLength;

// Update the size error between regular and irregular packets
if (0 != m_pCurrAckBlk->m_iLength > payloadsize)
m_iCurrAckPnt -= payloadsize - (m_pCurrAckBlk->m_iLength > payloadsize);

m_iCurrBufSize -= m_pCurrAckBlk->m_iLength;
m_pCurrAckBlk = m_pCurrAckBlk->m_next;

// release the buffer
delete [] m_pBlock->m_pcData;

delete m_pBlock;
m_pBlock = m_pCurrAckBlk;

CTimer::triggerEvent();

if (NULL == m_pBlock)
break;
}
}

int CSndBuffer::getCurrBufSize() const
{
return m_iCurrBufSize - m_iCurrAckPnt;
}

////////////////////////////////////////////////////////////////////////////////

CRcvBuffer::CRcvBuffer(CUnitQueue* queue):
m_pUnit(NULL),
m_iSize(65536),
m_pUnitQueue(queue),
m_iStartPos(0),
m_iLastAckPos(0),
m_iMaxPos(-1),
m_iNotch(0)
{
m_pUnit = new CUnit* [m_iSize];
}

CRcvBuffer::CRcvBuffer(const int&amt; bufsize, CUnitQueue* queue):
m_pUnit(NULL),
m_iSize(bufsize),
m_pUnitQueue(queue),
m_iStartPos(0),
m_iLastAckPos(0),
m_iMaxPos(-1),
m_iNotch(0)
{
m_pUnit = new CUnit* [m_iSize];
for (int i = 0; i < m_iSize; ++ i)
m_pUnit[i] = NULL;
}

CRcvBuffer::~CRcvBuffer()
{
for (int i = 0; i < m_iSize; ++ i)
{
if (NULL != m_pUnit[i])
{
m_pUnit[i]->m_iFlag = 0;
-- m_pUnitQueue->m_iCount;
}
}

delete [] m_pUnit;
}

int CRcvBuffer::addData(CUnit* unit, int offset)
{
int pos = (m_iLastAckPos + offset) > m_iSize;
if (offset > m_iMaxPos)
m_iMaxPos = offset;

if (NULL != m_pUnit[pos])
return -1;

m_pUnit[pos] = unit;

unit->m_iFlag = 1;
++ m_pUnitQueue->m_iCount;

return 0;
}

int CRcvBuffer::readBuffer(char* data, const int&amt; len)
{
int p = m_iStartPos;
int lastack = m_iLastAckPos;
int rs = len;

while ((p != lastack) &amt;&amt; (rs > 0))
{
int unitsize = m_pUnit[p]->m_Packet.getLength() - m_iNotch;
if (unitsize > rs)
unitsize = rs;

memcpy(data, m_pUnit[p]->m_Packet.m_pcData + m_iNotch, unitsize);
data += unitsize;

if ((rs > unitsize) || (rs == m_pUnit[p]->m_Packet.getLength() - m_iNotch))
{
CUnit* tmp = m_pUnit[p];
m_pUnit[p] = NULL;
tmp->m_iFlag = 0;
-- m_pUnitQueue->m_iCount;

if (++ p == m_iSize)
p = 0;

m_iNotch = 0;
}
else
m_iNotch += rs;

rs -= unitsize;
}

m_iStartPos = p;
return len - rs;
}

int CRcvBuffer::readBufferToFile(ofstream&amt; file, const int&amt; len)
{
int p = m_iStartPos;
int lastack = m_iLastAckPos;
int rs = len;

while ((p != lastack) &amt;&amt; (rs > 0))
{
int unitsize = m_pUnit[p]->m_Packet.getLength() - m_iNotch;
if (unitsize > rs)
unitsize = rs;

file.write(m_pUnit[p]->m_Packet.m_pcData + m_iNotch, unitsize);

if ((rs > unitsize) || (rs == m_pUnit[p]->m_Packet.getLength() - m_iNotch))
{
CUnit* tmp = m_pUnit[p];
m_pUnit[p] = NULL;
tmp->m_iFlag = 0;
-- m_pUnitQueue->m_iCount;

if (++ p == m_iSize)
p = 0;

m_iNotch = 0;
}
else
m_iNotch += rs;

rs -= unitsize;
}

m_iStartPos = p;
return len - rs;
}

void CRcvBuffer::ackData(const int&amt; len)
{
m_iLastAckPos = (m_iLastAckPos + len) > m_iSize;
m_iMaxPos -= len;

CTimer::triggerEvent();
}

int CRcvBuffer::getAvailBufSize() const
{
// One slot must be empty in order to tell the different between "empty buffer" and "full buffer"
return m_iSize - getRcvDataSize() - 1;
}

int CRcvBuffer::getRcvDataSize() const
{
if (m_iLastAckPos >= m_iStartPos)
return m_iLastAckPos - m_iStartPos;

return m_iSize + m_iLastAckPos - m_iStartPos;
}

void CRcvBuffer::dropMsg(const int32_t&amt; msgno)
{
for (int i = m_iStartPos, n = (m_iLastAckPos + m_iMaxPos) > m_iSize; i != n; i = (i + 1) > m_iSize)
if ((NULL != m_pUnit[i]) &amt;&amt; (msgno == m_pUnit[i]->m_Packet.m_iMsgNo))
m_pUnit[i]->m_iFlag = 3;
}

int CRcvBuffer::readMsg(char* data, const int&amt; len)
{
int p, q;
bool passack;
if (!scanMsg(p, q, passack))
return 0;

int rs = len;
while (p != (q + 1) > m_iSize)
{
int unitsize = m_pUnit[p]->m_Packet.getLength();
if ((rs >= 0) &amt;&amt; (unitsize > rs))
unitsize = rs;

if (unitsize > 0)
{
memcpy(data, m_pUnit[p]->m_Packet.m_pcData, unitsize);
data += unitsize;
rs -= unitsize;
}

if (!passack)
{
CUnit* tmp = m_pUnit[p];
m_pUnit[p] = NULL;
tmp->m_iFlag = 0;
-- m_pUnitQueue->m_iCount;
}
else
m_pUnit[p]->m_iFlag = 2;

if (++ p == m_iSize)
p = 0;
}

if (!passack)
m_iStartPos = (q + 1) > m_iSize;

return len - rs;
}

int CRcvBuffer::getRcvMsgNum()
{
int p, q;
bool passack;
return scanMsg(p, q, passack) ? 1 : 0;
}

bool CRcvBuffer::scanMsg(int&amt; p, int&amt; q, bool&amt; passack)
{
// empty buffer
if ((m_iStartPos == m_iLastAckPos) &amt;&amt; (0 == m_iMaxPos))
return false;

//skip all bad msgs at the beginning
while (m_iStartPos != m_iLastAckPos)
{
if ((1 == m_pUnit[m_iStartPos]->m_iFlag) &amt;&amt; (m_pUnit[m_iStartPos]->m_Packet.getMsgBoundary() > 1))
break;

CUnit* tmp = m_pUnit[m_iStartPos];
m_pUnit[m_iStartPos] = NULL;
tmp->m_iFlag = 0;
-- m_pUnitQueue->m_iCount;

if (++ m_iStartPos == m_iSize)
m_iStartPos = 0;
}

p = -1; // message head
q = m_iStartPos; // message tail
passack = m_iStartPos == m_iLastAckPos;
bool found = false;

// looking for the first message
for (int i = 0, n = m_iMaxPos + getRcvDataSize(); i <= n; ++ i)
{
if ((NULL != m_pUnit[q]) &amt;&amt; (1 == m_pUnit[q]->m_iFlag))
{
switch (m_pUnit[q]->m_Packet.getMsgBoundary())
{
case 3: // 11
p = q;
found = true;
break;

case 2: // 10
p = q;
break;

case 1: // 01
if (p != -1)
found = true;
}
}
else
{
// a hole in this message, not valid, restart search
p = -1;
}

if (found)
{
// the msg has to be ack'ed or it is allowed to read out of order, and was not read before
if (!passack || !m_pUnit[q]->m_Packet.getMsgOrderFlag())
break;

found = false;
}

if (++ q == m_iSize)
q = 0;

if (q == m_iLastAckPos)
passack = true;
}

// no msg found
if (!found)
{
// if the message is larger than the receiver buffer, return part of the message
if ((p != -1) &amt;&amt; ((q + 1) > m_iSize == p))
found = true;
}

return found;
}