mqueue.cpp

// mqueue.cpp - originally written and placed in the public domain by Wei Dai

#include "pch.h"

#ifndef CRYPTOPP_IMPORTS

#include "mqueue.h"

NAMESPACE_BEGIN(CryptoPP)

MessageQueue::MessageQueue(unsigned int nodeSize)
    : m_queue(nodeSize), m_lengths(1, 0U), m_messageCounts(1, 0U)
{
}

size_t MessageQueue::CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end, const std::string &channel, bool blocking) const
{
    if (begin >= MaxRetrievable())
        return 0;

    return m_queue.CopyRangeTo2(target, begin, STDMIN(MaxRetrievable(), end), channel, blocking);
}

size_t MessageQueue::TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel, bool blocking)
{
    transferBytes = STDMIN(MaxRetrievable(), transferBytes);
    size_t blockedBytes = m_queue.TransferTo2(target, transferBytes, channel, blocking);
    m_lengths.front() -= transferBytes;
    return blockedBytes;
}

bool MessageQueue::GetNextMessage()
{
    if (NumberOfMessages() > 0 && !AnyRetrievable())
    {
        m_lengths.pop_front();
        if (m_messageCounts[0] == 0 && m_messageCounts.size() > 1)
            m_messageCounts.pop_front();
        return true;
    }
    else
        return false;
}

unsigned int MessageQueue::CopyMessagesTo(BufferedTransformation &target, unsigned int count, const std::string &channel) const
{
    ByteQueue::Walker walker(m_queue);
    std::deque<lword>::const_iterator it = m_lengths.begin();
    unsigned int i;
    for (i=0; i<count && it != --m_lengths.end(); ++i, ++it)
    {
        walker.TransferTo(target, *it, channel);
        if (GetAutoSignalPropagation())
            target.ChannelMessageEnd(channel, GetAutoSignalPropagation()-1);
    }
    return i;
}

void MessageQueue::swap(MessageQueue &rhs)
{
    m_queue.swap(rhs.m_queue);
    m_lengths.swap(rhs.m_lengths);
}

const byte * MessageQueue::Spy(size_t &contiguousSize) const
{
    const byte *result = m_queue.Spy(contiguousSize);
    contiguousSize = UnsignedMin(contiguousSize, MaxRetrievable());
    return result;
}

// *************************************************************

unsigned int EqualityComparisonFilter::MapChannel(const std::string &channel) const
{
    if (channel == m_firstChannel)
        return 0;
    else if (channel == m_secondChannel)
        return 1;
    else
        return 2;
}

size_t EqualityComparisonFilter::ChannelPut2(const std::string &channel, const byte *inString, size_t length, int messageEnd, bool blocking)
{
    if (!blocking)
        throw BlockingInputOnly("EqualityComparisonFilter");

    unsigned int i = MapChannel(channel);

    if (i == 2)
        return Output(3, inString, length, messageEnd, blocking, channel);
    else if (m_mismatchDetected)
        return 0;
    else
    {
        MessageQueue &q1 = m_q[i], &q2 = m_q[1-i];

        if (q2.AnyMessages() && q2.MaxRetrievable() < length)
            goto mismatch;

        while (length > 0 && q2.AnyRetrievable())
        {
            size_t len = length;
            const byte *data = q2.Spy(len);
            len = STDMIN(len, length);
            if (memcmp(inString, data, len) != 0)
                goto mismatch;
            inString += len;
            length -= len;
            q2.Skip(len);
        }

        q1.Put(inString, length);

        if (messageEnd)
        {
            if (q2.AnyRetrievable())
                goto mismatch;
            else if (q2.AnyMessages())
                q2.GetNextMessage();
            else if (q2.NumberOfMessageSeries() > 0)
                goto mismatch;
            else
                q1.MessageEnd();
        }

        return 0;

mismatch:
        return HandleMismatchDetected(blocking);
    }
}

bool EqualityComparisonFilter::ChannelMessageSeriesEnd(const std::string &channel, int propagation, bool blocking)
{
    unsigned int i = MapChannel(channel);

    if (i == 2)
    {
        OutputMessageSeriesEnd(4, propagation, blocking, channel);
        return false;
    }
    else if (m_mismatchDetected)
        return false;
    else
    {
        MessageQueue &q1 = m_q[i], &q2 = m_q[1-i];

        if (q2.AnyRetrievable() || q2.AnyMessages())
            goto mismatch;
        else if (q2.NumberOfMessageSeries() > 0)
            return Output(2, (const byte *)"\1", 1, 0, blocking) != 0;
        else
            q1.MessageSeriesEnd();

        return false;

mismatch:
        return HandleMismatchDetected(blocking);
    }
}

bool EqualityComparisonFilter::HandleMismatchDetected(bool blocking)
{
    m_mismatchDetected = true;
    if (m_throwIfNotEqual)
        throw MismatchDetected();
    const byte b[1] = {0};
    return Output(1, b, 1, 0, blocking) != 0;
}

NAMESPACE_END

#endif