queue.cpp

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

#include "pch.h"

#ifndef CRYPTOPP_IMPORTS

#include "queue.h"
#include "filters.h"
#include "misc.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)
        : m_buf(maxSize)
    {
        m_head = m_tail = 0;
        m_next = NULLPTR;
    }

    inline size_t MaxSize() const {return m_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)
    {
        // Avoid passing NULL to memcpy
        if (!begin || !length) return length;
        size_t l = STDMIN(length, MaxSize()-m_tail);
        if (m_buf+m_tail != begin)
            memcpy(m_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=m_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, m_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, m_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, m_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, m_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, m_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 m_buf[m_head+i];
    }

    ByteQueueNode* m_next;

    SecByteBlock m_buf;
    size_t m_head, m_tail;
};

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

ByteQueue::ByteQueue(size_t nodeSize)
    : Bufferless<BufferedTransformation>(), m_autoNodeSize(!nodeSize), m_nodeSize(nodeSize)
    , m_head(NULLPTR), m_tail(NULLPTR), m_lazyString(NULLPTR), m_lazyLength(0), m_lazyStringModifiable(false)
{
    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)
    : Bufferless<BufferedTransformation>(copy), m_lazyString(NULLPTR), m_lazyLength(0)
{
    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->m_next; current; current=current->m_next)
    {
        m_tail->m_next = new ByteQueueNode(*current);
        m_tail = m_tail->m_next;
    }

    m_tail->m_next = NULLPTR;

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

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

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

    m_tail = m_head;
    m_head->Clear();
    m_head->m_next = NULLPTR;
    m_lazyLength = 0;
}

size_t ByteQueue::Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
{
    CRYPTOPP_UNUSED(messageEnd), CRYPTOPP_UNUSED(blocking);

    if (m_lazyLength > 0)
        FinalizeLazyPut();

    size_t len;
    while ((len=m_tail->Put(inString, length)) < length)
    {
        inString = PtrAdd(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->m_next = new ByteQueueNode(STDMAX(m_nodeSize, length));
        m_tail = m_tail->m_next;
    }

    return 0;
}

void ByteQueue::CleanupUsedNodes()
{
    // Test for m_head due to Enterprise Anlysis finding
    while (m_head && m_head != m_tail && m_head->UsedUp())
    {
        ByteQueueNode *temp=m_head;
        m_head=m_head->m_next;
        delete temp;
    }

    // Test for m_head due to Enterprise Anlysis finding
    if (m_head && 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->m_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->m_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 = PtrAdd(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 = m_head->m_head - len;
    memcpy(m_head->m_buf + m_head->m_head, inString + length, len);

    if (length > 0)
    {
        ByteQueueNode *newHead = new ByteQueueNode(length);
        newHead->m_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->m_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->m_next = new ByteQueueNode(STDMAX(m_nodeSize, size));
        m_tail = m_tail->m_next;
    }

    size = m_tail->MaxSize() - m_tail->m_tail;
    return PtrAdd(m_tail->m_buf.begin(), 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->m_next)
    {
        if (i < current->CurrentSize())
            return (*current)[(size_t)i];

        i -= current->CurrentSize();
    }

    CRYPTOPP_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)
{
    CRYPTOPP_UNUSED(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->m_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->m_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 = PtrAdd(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