mqueue.h

Go to the documentation of this file.

// mqueue.h - originally written and placed in the public domain by Wei Dai
 
/// \file
/// \brief Classes for an unlimited queue to store messages
 
#ifndef CRYPTOPP_MQUEUE_H
#define CRYPTOPP_MQUEUE_H
 
#include "cryptlib.h"
#include "queue.h"
#include "filters.h"
#include "misc.h"
 
#include <deque>
 
NAMESPACE_BEGIN(CryptoPP)
 
/// \brief Data structure used to store messages
/// \details The queue is implemented with a ByteQueue.
/// \sa <A HREF="https://www.cryptopp.com/wiki/MessageQueue">MessageQueue</A>
///  on the Crypto++ wiki.
/// \since Crypto++ 2.0
class CRYPTOPP_DLL MessageQueue : public AutoSignaling<BufferedTransformation>
{
public:
    virtual ~MessageQueue() {}
 
    /// \brief Construct a MessageQueue
    /// \param nodeSize the initial node size
    MessageQueue(unsigned int nodeSize=256);
 
    // BufferedTransformation
    void IsolatedInitialize(const NameValuePairs &parameters)
        {m_queue.IsolatedInitialize(parameters); m_lengths.assign(1, 0U); m_messageCounts.assign(1, 0U);}
    size_t Put2(const byte *begin, size_t length, int messageEnd, bool blocking)
    {
        CRYPTOPP_UNUSED(blocking);
        m_queue.Put(begin, length);
        m_lengths.back() += length;
        if (messageEnd)
        {
            m_lengths.push_back(0);
            m_messageCounts.back()++;
        }
        return 0;
    }
    bool IsolatedFlush(bool hardFlush, bool blocking)
        {CRYPTOPP_UNUSED(hardFlush), CRYPTOPP_UNUSED(blocking); return false;}
    bool IsolatedMessageSeriesEnd(bool blocking)
        {CRYPTOPP_UNUSED(blocking); m_messageCounts.push_back(0); return false;}
 
    lword MaxRetrievable() const
        {return m_lengths.front();}
    bool AnyRetrievable() const
        {return m_lengths.front() > 0;}
 
    size_t TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true);
    size_t CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true) const;
 
    lword TotalBytesRetrievable() const
        {return m_queue.MaxRetrievable();}
    unsigned int NumberOfMessages() const
        {return (unsigned int)m_lengths.size()-1;}
    bool GetNextMessage();
 
    unsigned int NumberOfMessagesInThisSeries() const
        {return m_messageCounts[0];}
    unsigned int NumberOfMessageSeries() const
        {return (unsigned int)m_messageCounts.size()-1;}
 
    /// \brief Copy messages from this object to another BufferedTransformation.
    /// \param target the destination BufferedTransformation
    /// \param count the number of messages to copy
    /// \param channel the channel on which the transfer should occur
    /// \return the number of messages that remain in the copy (i.e., messages not copied)
    unsigned int CopyMessagesTo(BufferedTransformation &target, unsigned int count=UINT_MAX, const std::string &channel=DEFAULT_CHANNEL) const;
 
    /// \brief Peek data in the queue
    /// \param contiguousSize the size of the data
    /// \details Spy() peeks at data at the head of the queue. Spy() does
    ///  not remove data from the queue.
    /// \details The data's size is returned in <tt>contiguousSize</tt>.
    ///  Spy() returns the size of the first message in the list.
    const byte * Spy(size_t &contiguousSize) const;
 
    /// \brief Swap contents with another MessageQueue
    /// \param rhs the other MessageQueue
    void swap(MessageQueue &rhs);
 
private:
    ByteQueue m_queue;
    std::deque<lword> m_lengths;
    std::deque<unsigned int> m_messageCounts;
};
 
/// \brief Filter that checks messages on two channels for equality
class CRYPTOPP_DLL EqualityComparisonFilter : public Unflushable<Multichannel<Filter> >
{
public:
    /// \brief Different messages were detected
    struct MismatchDetected : public Exception
    {
        /// \brief Construct a MismatchDetected exception
        MismatchDetected() : Exception(DATA_INTEGRITY_CHECK_FAILED, "EqualityComparisonFilter: did not receive the same data on two channels") {}
    };
 
    /// \brief Construct an EqualityComparisonFilter
    /// \param attachment an attached transformation
    /// \param throwIfNotEqual flag indicating whether the objects throws
    /// \param firstChannel string naming the first channel
    /// \param secondChannel string naming the second channel
    /// \throw MismatchDetected if throwIfNotEqual is true and not equal
    /// \details If throwIfNotEqual is false, this filter will output a '\\0'
    ///  byte when it detects a mismatch, '\\1' otherwise.
    EqualityComparisonFilter(BufferedTransformation *attachment=NULLPTR, bool throwIfNotEqual=true, const std::string &firstChannel="0", const std::string &secondChannel="1")
        : m_throwIfNotEqual(throwIfNotEqual), m_mismatchDetected(false)
        , m_firstChannel(firstChannel), m_secondChannel(secondChannel)
        {Detach(attachment);}
 
    // BufferedTransformation
    size_t ChannelPut2(const std::string &channel, const byte *begin, size_t length, int messageEnd, bool blocking);
    bool ChannelMessageSeriesEnd(const std::string &channel, int propagation=-1, bool blocking=true);
 
protected:
    unsigned int MapChannel(const std::string &channel) const;
    bool HandleMismatchDetected(bool blocking);
 
private:
    bool m_throwIfNotEqual, m_mismatchDetected;
    std::string m_firstChannel, m_secondChannel;
    MessageQueue m_q[2];
};
 
NAMESPACE_END
 
#ifndef __BORLANDC__
NAMESPACE_BEGIN(std)
template<> inline void swap(CryptoPP::MessageQueue &a, CryptoPP::MessageQueue &b)
{
    a.swap(b);
}
NAMESPACE_END
#endif
 
#endif