queue.cpp

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

#include "pch.h"

#ifndef CRYPTOPP_IMPORTS

#include "queue.h"
#include "filters.h"

NAMESPACE_BEGIN(CryptoPP)

static const unsigned int s_maxAutoNodeSize = 16*1024;

// this class for use by ByteQueue only
class ByteQueueNode
{
public:
        ByteQueueNode(size_t maxSize)
                : buf(maxSize)
        {
                m_head = m_tail = 0;
                next = 0;
        }

        inline size_t MaxSize() const {return buf.size();}

        inline size_t CurrentSize() const
        {
                return m_tail-m_head;
        }

        inline bool UsedUp() const
        {
                return (m_head==MaxSize());
        }

        inline void Clear()
        {
                m_head = m_tail = 0;
        }

        inline size_t Put(const byte *begin, size_t length)
        {
                size_t l = STDMIN(length, MaxSize()-m_tail);
                if (buf+m_tail != begin)
                        memcpy(buf+m_tail, begin, l);
                m_tail += l;
                return l;
        }

        inline size_t Peek(byte &outByte) const
        {
                if (m_tail==m_head)
                        return 0;

                outByte=buf[m_head];
                return 1;
        }

        inline size_t Peek(byte *target, size_t copyMax) const
        {
                size_t len = STDMIN(copyMax, m_tail-m_head);
                memcpy(target, buf+m_head, len);
                return len;
        }

        inline size_t CopyTo(BufferedTransformation &target, const std::string &channel=DEFAULT_CHANNEL) const
        {
                size_t len = m_tail-m_head;
                target.ChannelPut(channel, buf+m_head, len);
                return len;
        }

        inline size_t CopyTo(BufferedTransformation &target, size_t copyMax, const std::string &channel=DEFAULT_CHANNEL) const
        {
                size_t len = STDMIN(copyMax, m_tail-m_head);
                target.ChannelPut(channel, buf+m_head, len);
                return len;
        }

        inline size_t Get(byte &outByte)
        {
                size_t len = Peek(outByte);
                m_head += len;
                return len;
        }

        inline size_t Get(byte *outString, size_t getMax)
        {
                size_t len = Peek(outString, getMax);
                m_head += len;
                return len;
        }

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

        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;
        }

        inline size_t Skip(size_t skipMax)
        {
                size_t len = STDMIN(skipMax, m_tail-m_head);
                m_head += len;
                return len;
        }

        inline byte operator[](size_t i) const
        {
                return buf[m_head+i];
        }

        ByteQueueNode *next;

        SecByteBlock buf;
        size_t m_head, m_tail;
};

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

ByteQueue::ByteQueue(size_t nodeSize)
        : m_lazyString(NULL), m_lazyLength(0)
{
        SetNodeSize(nodeSize);
        m_head = m_tail = new ByteQueueNode(m_nodeSize);
}

void ByteQueue::SetNodeSize(size_t nodeSize)
{
        m_autoNodeSize = !nodeSize;
        m_nodeSize = m_autoNodeSize ? 256 : nodeSize;
}

ByteQueue::ByteQueue(const ByteQueue &copy)
        : m_lazyString(NULL)
{
        CopyFrom(copy);
}

void ByteQueue::CopyFrom(const ByteQueue &copy)
{
        m_lazyLength = 0;
        m_autoNodeSize = copy.m_autoNodeSize;
        m_nodeSize = copy.m_nodeSize;
        m_head = m_tail = new ByteQueueNode(*copy.m_head);

        for (ByteQueueNode *current=copy.m_head->next; current; current=current->next)
        {
                m_tail->next = new ByteQueueNode(*current);
                m_tail = m_tail->next;
        }

        m_tail->next = NULL;

        Put(copy.m_lazyString, copy.m_lazyLength);
}

ByteQueue::~ByteQueue()
{
        Destroy();
}

void ByteQueue::Destroy()
{
        for (ByteQueueNode *next, *current=m_head; current; current=next)
        {
                next=current->next;
                delete current;
        }
}

void ByteQueue::IsolatedInitialize(const NameValuePairs &parameters)
{
        m_nodeSize = parameters.GetIntValueWithDefault("NodeSize", 256);
        Clear();
}

lword ByteQueue::CurrentSize() const
{
        lword size=0;

        for (ByteQueueNode *current=m_head; current; current=current->next)
                size += current->CurrentSize();

        return size + m_lazyLength;
}

bool ByteQueue::IsEmpty() const
{
        return m_head==m_tail && m_head->CurrentSize()==0 && m_lazyLength==0;
}

void ByteQueue::Clear()
{
        for (ByteQueueNode *next, *current=m_head->next; current; current=next)
        {
                next=current->next;
                delete current;
        }

        m_tail = m_head;
        m_head->Clear();
        m_head->next = NULL;
        m_lazyLength = 0;
}

size_t ByteQueue::Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
{
        if (m_lazyLength > 0)
                FinalizeLazyPut();

        size_t len;
        while ((len=m_tail->Put(inString, length)) < length)
        {
                inString += len;
                length -= len;
                if (m_autoNodeSize && m_nodeSize < s_maxAutoNodeSize)
                        do
                        {
                                m_nodeSize *= 2;
                        }
                        while (m_nodeSize < length && m_nodeSize < s_maxAutoNodeSize);
                m_tail->next = new ByteQueueNode(STDMAX(m_nodeSize, length));
                m_tail = m_tail->next;
        }

        return 0;
}

void ByteQueue::CleanupUsedNodes()
{
        while (m_head != m_tail && m_head->UsedUp())
        {
                ByteQueueNode *temp=m_head;
                m_head=m_head->next;
                delete temp;
        }

        if (m_head->CurrentSize() == 0)
                m_head->Clear();
}

void ByteQueue::LazyPut(const byte *inString, size_t size)
{
        if (m_lazyLength > 0)
                FinalizeLazyPut();

        if (inString == m_tail->buf+m_tail->m_tail)
                Put(inString, size);
        else
        {
                m_lazyString = const_cast<byte *>(inString);
                m_lazyLength = size;
                m_lazyStringModifiable = false;
        }
}

void ByteQueue::LazyPutModifiable(byte *inString, size_t size)
{
        if (m_lazyLength > 0)
                FinalizeLazyPut();
        m_lazyString = inString;
        m_lazyLength = size;
        m_lazyStringModifiable = true;
}

void ByteQueue::UndoLazyPut(size_t size)
{
        if (m_lazyLength < size)
                throw InvalidArgument("ByteQueue: size specified for UndoLazyPut is too large");

        m_lazyLength -= size;
}

void ByteQueue::FinalizeLazyPut()
{
        size_t len = m_lazyLength;
        m_lazyLength = 0;
        if (len)
                Put(m_lazyString, len);
}

size_t ByteQueue::Get(byte &outByte)
{
        if (m_head->Get(outByte))
        {
                if (m_head->UsedUp())
                        CleanupUsedNodes();
                return 1;
        }
        else if (m_lazyLength > 0)
        {
                outByte = *m_lazyString++;
                m_lazyLength--;
                return 1;
        }
        else
                return 0;
}

size_t ByteQueue::Get(byte *outString, size_t getMax)
{
        ArraySink sink(outString, getMax);
        return (size_t)TransferTo(sink, getMax);
}

size_t ByteQueue::Peek(byte &outByte) const
{
        if (m_head->Peek(outByte))
                return 1;
        else if (m_lazyLength > 0)
        {
                outByte = *m_lazyString;
                return 1;
        }
        else
                return 0;
}

size_t ByteQueue::Peek(byte *outString, size_t peekMax) const
{
        ArraySink sink(outString, peekMax);
        return (size_t)CopyTo(sink, peekMax);
}

size_t ByteQueue::TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel, bool blocking)
{
        if (blocking)
        {
                lword bytesLeft = transferBytes;
                for (ByteQueueNode *current=m_head; bytesLeft && current; current=current->next)
                        bytesLeft -= current->TransferTo(target, bytesLeft, channel);
                CleanupUsedNodes();

                size_t len = (size_t)STDMIN(bytesLeft, (lword)m_lazyLength);
                if (len)
                {
                        if (m_lazyStringModifiable)
                                target.ChannelPutModifiable(channel, m_lazyString, len);
                        else
                                target.ChannelPut(channel, m_lazyString, len);
                        m_lazyString += len;
                        m_lazyLength -= len;
                        bytesLeft -= len;
                }
                transferBytes -= bytesLeft;
                return 0;
        }
        else
        {
                Walker walker(*this);
                size_t blockedBytes = walker.TransferTo2(target, transferBytes, channel, blocking);
                Skip(transferBytes);
                return blockedBytes;
        }
}

size_t ByteQueue::CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end, const std::string &channel, bool blocking) const
{
        Walker walker(*this);
        walker.Skip(begin);
        lword transferBytes = end-begin;
        size_t blockedBytes = walker.TransferTo2(target, transferBytes, channel, blocking);
        begin += transferBytes;
        return blockedBytes;
}

void ByteQueue::Unget(byte inByte)
{
        Unget(&inByte, 1);
}

void ByteQueue::Unget(const byte *inString, size_t length)
{
        size_t len = STDMIN(length, m_head->m_head);
        length -= len;
        m_head->m_head -= len;
        memcpy(m_head->buf + m_head->m_head, inString + length, len);

        if (length > 0)
        {
                ByteQueueNode *newHead = new ByteQueueNode(length);
                newHead->next = m_head;
                m_head = newHead;
                m_head->Put(inString, length);
        }
}

const byte * ByteQueue::Spy(size_t &contiguousSize) const
{
        contiguousSize = m_head->m_tail - m_head->m_head;
        if (contiguousSize == 0 && m_lazyLength > 0)
        {
                contiguousSize = m_lazyLength;
                return m_lazyString;
        }
        else
                return m_head->buf + m_head->m_head;
}

byte * ByteQueue::CreatePutSpace(size_t &size)
{
        if (m_lazyLength > 0)
                FinalizeLazyPut();

        if (m_tail->m_tail == m_tail->MaxSize())
        {
                m_tail->next = new ByteQueueNode(STDMAX(m_nodeSize, size));
                m_tail = m_tail->next;
        }

        size = m_tail->MaxSize() - m_tail->m_tail;
        return m_tail->buf + m_tail->m_tail;
}

ByteQueue & ByteQueue::operator=(const ByteQueue &rhs)
{
        Destroy();
        CopyFrom(rhs);
        return *this;
}

bool ByteQueue::operator==(const ByteQueue &rhs) const
{
        const lword currentSize = CurrentSize();

        if (currentSize != rhs.CurrentSize())
                return false;

        Walker walker1(*this), walker2(rhs);
        byte b1, b2;

        while (walker1.Get(b1) && walker2.Get(b2))
                if (b1 != b2)
                        return false;

        return true;
}

byte ByteQueue::operator[](lword i) const
{
        for (ByteQueueNode *current=m_head; current; current=current->next)
        {
                if (i < current->CurrentSize())
                        return (*current)[(size_t)i];
                
                i -= current->CurrentSize();
        }

        assert(i < m_lazyLength);
        return m_lazyString[i];
}

void ByteQueue::swap(ByteQueue &rhs)
{
        std::swap(m_autoNodeSize, rhs.m_autoNodeSize);
        std::swap(m_nodeSize, rhs.m_nodeSize);
        std::swap(m_head, rhs.m_head);
        std::swap(m_tail, rhs.m_tail);
        std::swap(m_lazyString, rhs.m_lazyString);
        std::swap(m_lazyLength, rhs.m_lazyLength);
        std::swap(m_lazyStringModifiable, rhs.m_lazyStringModifiable);
}

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

void ByteQueue::Walker::IsolatedInitialize(const NameValuePairs &parameters)
{
        m_node = m_queue.m_head;
        m_position = 0;
        m_offset = 0;
        m_lazyString = m_queue.m_lazyString;
        m_lazyLength = m_queue.m_lazyLength;
}

size_t ByteQueue::Walker::Get(byte &outByte)
{
        ArraySink sink(&outByte, 1);
        return (size_t)TransferTo(sink, 1);
}

size_t ByteQueue::Walker::Get(byte *outString, size_t getMax)
{
        ArraySink sink(outString, getMax);
        return (size_t)TransferTo(sink, getMax);
}

size_t ByteQueue::Walker::Peek(byte &outByte) const
{
        ArraySink sink(&outByte, 1);
        return (size_t)CopyTo(sink, 1);
}

size_t ByteQueue::Walker::Peek(byte *outString, size_t peekMax) const
{
        ArraySink sink(outString, peekMax);
        return (size_t)CopyTo(sink, peekMax);
}

size_t ByteQueue::Walker::TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel, bool blocking)
{
        lword bytesLeft = transferBytes;
        size_t blockedBytes = 0;

        while (m_node)
        {
                size_t len = (size_t)STDMIN(bytesLeft, (lword)m_node->CurrentSize()-m_offset);
                blockedBytes = target.ChannelPut2(channel, m_node->buf+m_node->m_head+m_offset, len, 0, blocking);

                if (blockedBytes)
                        goto done;

                m_position += len;
                bytesLeft -= len;

                if (!bytesLeft)
                {
                        m_offset += len;
                        goto done;
                }

                m_node = m_node->next;
                m_offset = 0;
        }

        if (bytesLeft && m_lazyLength)
        {
                size_t len = (size_t)STDMIN(bytesLeft, (lword)m_lazyLength);
                blockedBytes = target.ChannelPut2(channel, m_lazyString, len, 0, blocking);
                if (blockedBytes)
                        goto done;

                m_lazyString += len;
                m_lazyLength -= len;
                bytesLeft -= len;
        }

done:
        transferBytes -= bytesLeft;
        return blockedBytes;
}

size_t ByteQueue::Walker::CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end, const std::string &channel, bool blocking) const
{
        Walker walker(*this);
        walker.Skip(begin);
        lword transferBytes = end-begin;
        size_t blockedBytes = walker.TransferTo2(target, transferBytes, channel, blocking);
        begin += transferBytes;
        return blockedBytes;
}

NAMESPACE_END

#endif