C++ UnsignedMin函数代码示例

size_t StringStore::CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end, const std::string &channel, bool blocking) const
{
	size_t i = UnsignedMin(m_length, m_count+begin);
	size_t len = UnsignedMin(m_length-i, end-begin);
	size_t blockedBytes = target.ChannelPut2(channel, m_store+i, len, 0, blocking);
	if (!blockedBytes)
		begin += len;
	return blockedBytes;
}

bool WindowsPipeReceiver::Receive(byte* buf, size_t bufLen)
{
	CRYPTOPP_ASSERT(!m_resultPending && !m_eofReceived);

	HANDLE h = GetHandle();
	// don't queue too much at once, or we might use up non-paged memory
	if (ReadFile(h, buf, UnsignedMin((DWORD)128*1024, bufLen), &m_lastResult, &m_overlapped))
	{
		if (m_lastResult == 0)
			m_eofReceived = true;
	}
	else
	{
		switch (GetLastError())
		{
		default:
			CheckAndHandleError("ReadFile", false);
		case ERROR_BROKEN_PIPE:
		case ERROR_HANDLE_EOF:
			m_lastResult = 0;
			m_eofReceived = true;
			break;
		case ERROR_IO_PENDING:
			m_resultPending = true;
		}
	}
	return !m_resultPending;
}

	std::vector<word16> * operator()() const
	{
		const unsigned int maxPrimeTableSize = 3511;

		std::auto_ptr<std::vector<word16> > pPrimeTable(new std::vector<word16>);
		std::vector<word16> &primeTable = *pPrimeTable;
		primeTable.reserve(maxPrimeTableSize);

		primeTable.push_back(2);
		unsigned int testEntriesEnd = 1;
		
		for (unsigned int p=3; p<=s_lastSmallPrime; p+=2)
		{
			unsigned int j;
			for (j=1; j<testEntriesEnd; j++)
				if (p%primeTable[j] == 0)
					break;
			if (j == testEntriesEnd)
			{
				primeTable.push_back(p);
				testEntriesEnd = UnsignedMin(54U, primeTable.size());
			}
		}

		return pPrimeTable.release();
	}

	inline size_t TransferTo(BufferedTransformation &target, lword transferMax, const std::string &channel=DEFAULT_CHANNEL)
	{
		size_t len = UnsignedMin(m_tail-m_head, transferMax);
		target.ChannelPutModifiable(channel, buf+m_head, len);
		m_head += len;
		return len;
	}

bool SocketReceiver::Receive(byte* buf, size_t bufLen)
{
	CRYPTOPP_ASSERT(!m_resultPending && !m_eofReceived);

	DWORD flags = 0;
	// don't queue too much at once, or we might use up non-paged memory
	WSABUF wsabuf = {UnsignedMin((u_long)128*1024, bufLen), (char *)buf};
	if (WSARecv(m_s, &wsabuf, 1, &m_lastResult, &flags, &m_overlapped, NULL) == 0)
	{
		if (m_lastResult == 0)
			m_eofReceived = true;
	}
	else
	{
		switch (WSAGetLastError())
		{
		default:
			m_s.CheckAndHandleError_int("WSARecv", SOCKET_ERROR);
		case WSAEDISCON:
			m_lastResult = 0;
			m_eofReceived = true;
			break;
		case WSA_IO_PENDING:
			m_resultPending = true;
		}
	}
	return !m_resultPending;
}

lword NonblockingSink::TimedFlush(unsigned long maxTime, size_t targetSize)
{
	m_blockedBySpeedLimit = false;

	size_t curBufSize = GetCurrentBufferSize();
	if (curBufSize <= targetSize && (targetSize || !EofPending()))
		return 0;

	if (!GetMaxBytesPerSecond())
		return DoFlush(maxTime, targetSize);

	bool forever = (maxTime == INFINITE_TIME);
	unsigned long timeToGo = maxTime;
	Timer timer(Timer::MILLISECONDS, forever);
	lword totalFlushed = 0;

	timer.StartTimer();

	while (true)
	{	
		size_t flushSize = UnsignedMin(curBufSize - targetSize, ComputeCurrentTransceiveLimit());
		if (flushSize || EofPending())
		{
			if (!forever) timeToGo = SaturatingSubtract(maxTime, timer.ElapsedTime());
			size_t ret = (size_t)DoFlush(timeToGo, curBufSize - flushSize);
			if (ret)
			{
				NoteTransceive(ret);
				curBufSize -= ret;
				totalFlushed += ret;
			}
		}

		if (curBufSize <= targetSize && (targetSize || !EofPending()))
			break;

		if (!forever)
		{
			timeToGo = SaturatingSubtract(maxTime, timer.ElapsedTime());
			if (!timeToGo)
				break;
		}

		double waitTime = TimeToNextTransceive();
		if (!forever && waitTime > timeToGo)
		{
			m_blockedBySpeedLimit = true;
			break;
		}

		WaitObjectContainer container;
		LimitedBandwidth::GetWaitObjects(container, CallStack("NonblockingSink::TimedFlush() - speed limit", 0));
		container.Wait((unsigned long)waitTime);
	}

	return totalFlushed;
}

size_t NetworkSink::Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
{
	if (m_eofState == EOF_DONE)
	{
		if (length || messageEnd)
			throw Exception(Exception::OTHER_ERROR, "NetworkSink::Put2() being called after EOF had been sent");

		return 0;
	}

	if (m_eofState > EOF_NONE)
		goto EofSite;

	{
		if (m_skipBytes)
		{
			assert(length >= m_skipBytes);
			inString += m_skipBytes;
			length -= m_skipBytes;
		}

		m_buffer.Put(inString, length);

		if (!blocking || m_buffer.CurrentSize() > m_autoFlushBound)
			TimedFlush(0, 0);

		size_t targetSize = messageEnd ? 0 : m_maxBufferSize;
		if (blocking)
			TimedFlush(INFINITE_TIME, targetSize);

		if (m_buffer.CurrentSize() > targetSize)
		{
			assert(!blocking);
			m_wasBlocked = true;
			m_skipBytes += length;
			size_t blockedBytes = UnsignedMin(length, m_buffer.CurrentSize() - targetSize);
			return STDMAX<size_t>(blockedBytes, 1);
		}

		m_wasBlocked = false;
		m_skipBytes = 0;
	}

	if (messageEnd)
	{
		m_eofState = EOF_PENDING_SEND;

	EofSite:
		TimedFlush(blocking ? INFINITE_TIME : 0, 0);
		if (m_eofState != EOF_DONE)
			return 1;
	}

	return 0;
}

void RandomizedTransfer(BufferedTransformation &source, BufferedTransformation &target, bool finish, const std::string &channel=DEFAULT_CHANNEL)
{
	while (source.MaxRetrievable() > (finish ? 0 : 4096))
	{
		byte buf[4096+64];
		size_t start = GlobalRNG().GenerateWord32(0, 63);
		size_t len = GlobalRNG().GenerateWord32(1, UnsignedMin(4096U, 3*source.MaxRetrievable()/2));
		len = source.Get(buf+start, len);
		target.ChannelPut(channel, buf+start, len);
	}
}

void OldRandomPool::GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size)
{
	while (size > 0)
	{
		if (getPos == pool.size())
				Stir();
		size_t t = UnsignedMin(pool.size() - getPos, size);
		target.ChannelPut(channel, pool+getPos, t);
		size -= t;
		getPos += t;
	}}

void RandomNumberGenerator::GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword length)
{
	FixedSizeSecBlock<byte, 256> buffer;
	while (length)
	{
		size_t len = UnsignedMin(buffer.size(), length);
		GenerateBlock(buffer, len);
		target.ChannelPut(channel, buffer, len);
		length -= len;
	}
}

size_t RandomNumberStore::TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel, bool blocking)
{
	if (!blocking)
		throw NotImplemented("RandomNumberStore: nonblocking transfer is not implemented by this object");

	transferBytes = UnsignedMin(transferBytes, m_length - m_count);
	m_rng->GenerateIntoBufferedTransformation(target, channel, transferBytes);
	m_count += transferBytes;

	return 0;
}

inline unsigned int GetAlignmentOf(T *dummy=NULL)	// VC60 workaround
{
#ifdef CRYPTOPP_ALLOW_UNALIGNED_DATA_ACCESS
	if (sizeof(T) < 16)
		return 1;
#endif

#if (_MSC_VER >= 1300)
	return __alignof(T);
#elif defined(__GNUC__)
	return __alignof__(T);
#elif CRYPTOPP_BOOL_SLOW_WORD64
	return UnsignedMin(4U, sizeof(T));
#else
	return sizeof(T);
#endif
}

void Inflator::OutputString(const byte *string, size_t length)
{
    while (length)
    {
        size_t len = UnsignedMin(length, m_window.size() - m_current);
        memcpy(m_window + m_current, string, len);
        m_current += len;
        if (m_current == m_window.size())
        {
            ProcessDecompressedData(m_window + m_lastFlush, m_window.size() - m_lastFlush);
            m_lastFlush = 0;
            m_current = 0;
            m_wrappedAround = true;
        }
        string += len;
        length -= len;
    }
}

void WindowsPipeSender::Send(const byte* buf, size_t bufLen)
{
	DWORD written = 0;
	HANDLE h = GetHandle();
	// don't queue too much at once, or we might use up non-paged memory
	if (WriteFile(h, buf, UnsignedMin((DWORD)128*1024, bufLen), &written, &m_overlapped))
	{
		m_resultPending = false;
		m_lastResult = written;
	}
	else
	{
		if (GetLastError() != ERROR_IO_PENDING)
			CheckAndHandleError("WriteFile", false);

		m_resultPending = true;
	}
}

void CMAC_Base::Update(const byte *input, size_t length)
{
	assert((input && length) || !(input || length));
	if (!length)
		return;

	BlockCipher &cipher = AccessCipher();
	unsigned int blockSize = cipher.BlockSize();

	if (m_counter > 0)
	{
		const unsigned int len = UnsignedMin(blockSize - m_counter, length);
		if (len)
		{
			xorbuf(m_reg+m_counter, input, len);
			length -= len;
			input += len;
			m_counter += len;
		}

		if (m_counter == blockSize && length > 0)
		{
			cipher.ProcessBlock(m_reg);
			m_counter = 0;
		}
	}

	if (length > blockSize)
	{
		assert(m_counter == 0);
		size_t leftOver = 1 + cipher.AdvancedProcessBlocks(m_reg, input, m_reg, length-1, BlockTransformation::BT_DontIncrementInOutPointers|BlockTransformation::BT_XorInput);
		input += (length - leftOver);
		length = leftOver;
	}

	if (length > 0)
	{
		assert(m_counter + length <= blockSize);
		xorbuf(m_reg+m_counter, input, length);
		m_counter += (unsigned int)length;
	}

	assert(m_counter > 0);
}