QRingBuffer< T > Class Template Reference

#include <qringbuffer_p.h>

Public Functions
void	append (const QByteArray &qba)
bool	canReadLine () const
void	chop (int bytes)
void	clear ()
const T &	dequeue ()
void	enqueue (const T &x)
void	free (int bytes)
int	getChar ()
const T &	head () const
int	indexOf (char c) const
int	indexOf (char c, int maxLength) const
bool	isEmpty () const
bool	isEmpty () const
int	nextDataBlockSize () const
QByteArray	peek (int maxLength) const
void	putChar (char c)
	QRingBuffer (int growth=4096)
	QRingBuffer ()
int	read (char *data, int maxLength)
QByteArray	read (int maxLength)
QByteArray	read ()
QByteArray	readAll ()
int	readLine (char *data, int maxLength)
const char *	readPointer () const
const char *	readPointerAtPosition (qint64 pos, qint64 &length) const
bool	reallocate (int capacity)
char *	reserve (int bytes)
int	size () const
int	skip (int length)
void	truncate (int pos)
void	ungetChar (char c)
	~QRingBuffer ()

Properties
int	basicBlockSize
QList< QByteArray >	buffers
int	bufferSize
int	head
T *	m_array
int	m_capacity
int	m_head
int	m_size
int	tail
int	tailBuffer

Detailed Description

template<class T>
class QRingBuffer< T >

Definition at line 61 of file qringbuffer_p.h.

Constructors and Destructors

QRingBuffer() [1/2]

template<class T >

QRingBuffer< T >::QRingBuffer ( int  growth = 4096 )

inline

Definition at line 64 of file qringbuffer_p.h.

                                          : basicBlockSize(growth) {
        buffers << QByteArray();
        clear();
    }

QRingBuffer() [2/2]

template<class T >

QRingBuffer< T >::QRingBuffer ( )

inline

Definition at line 1246 of file qtriangulator.cpp.

: m_array(0), m_head(0), m_size(0), m_capacity(0) { }

~QRingBuffer()

template<class T >

QRingBuffer< T >::~QRingBuffer ( )

inline

Definition at line 1247 of file qtriangulator.cpp.

{if (m_array) delete[] m_array;}

Functions

append()

template<class T >

void QRingBuffer< T >::append ( const QByteArray &  qba )

inline

Definition at line 382 of file qringbuffer_p.h.

Referenced by QNetworkReplyImplPrivate::setup().

                                              {
        buffers[tailBuffer].resize(tail);
        buffers << qba;
        ++tailBuffer;
        tail = qba.length();
        bufferSize += qba.length();
    }

canReadLine()

template<class T >

bool QRingBuffer< T >::canReadLine ( ) const

inline

Definition at line 437 of file qringbuffer_p.h.

Referenced by QProcess::canReadLine().

                                    {
        return indexOf('\n') != -1;
    }

chop()

template<class T >

void QRingBuffer< T >::chop ( int  bytes )

inline

Definition at line 197 of file qringbuffer_p.h.

Referenced by QNetworkReplyImplPrivate::_q_bufferOutgoingData(), QAbstractSocketPrivate::readFromSocket(), and QRingBuffer< T >::truncate().

                                {
        bufferSize -= bytes;
        if (bufferSize < 0)
            bufferSize = 0;

        for (;;) {
            // special case: head and tail are in the same buffer
            if (tailBuffer == 0) {
                tail -= bytes;
                if (tail <= head)
                    tail = head = 0;
                return;
            }

            if (bytes <= tail) {
                tail -= bytes;
                return;
            }

            bytes -= tail;
            buffers.removeAt(tailBuffer);

            --tailBuffer;
            tail = buffers.at(tailBuffer).size();
        }

        if (isEmpty())
            clear(); // try to minify/squeeze us
    }

clear()

template<class T >

void QRingBuffer< T >::clear ( )

inline

Definition at line 260 of file qringbuffer_p.h.

Referenced by QRingBuffer< T >::chop(), QSslSocketPrivate::createPlainSocket(), QRingBuffer< T >::free(), QSslSocketPrivate::init(), and QRingBuffer< T >::QRingBuffer().

                        {
        buffers.erase(buffers.begin() + 1, buffers.end());
        buffers[0].resize(0);
        buffers[0].squeeze();

        head = tail = 0;
        tailBuffer = 0;
        bufferSize = 0;
    }

dequeue()

template<class T >

const T & QRingBuffer< T >::dequeue ( )

inline

Definition at line 1285 of file qtriangulator.cpp.

{
    Q_ASSERT(m_size > 0);
    Q_ASSERT(m_array);
    Q_ASSERT(m_capacity >= m_size);
    int index = m_head;
    if (++m_head >= m_capacity)
        m_head -= m_capacity;
    --m_size;
    return m_array[index];
}

enqueue()

template<class T >

void QRingBuffer< T >::enqueue ( const T &  x )

inline

Definition at line 1298 of file qtriangulator.cpp.

{
    if (m_size == m_capacity)
        reallocate(qMax(2 * m_capacity, 64));
    int index = m_head + m_size;
    if (index >= m_capacity)
        index -= m_capacity;
    m_array[index] = x;
    ++m_size;
}

free()

template<class T >

void QRingBuffer< T >::free ( int  bytes )

inline

Definition at line 123 of file qringbuffer_p.h.

Referenced by _qfile_writeData(), QAbstractSocketPrivate::flush(), QRingBuffer< T >::getChar(), QRingBuffer< T >::read(), QProcess::readData(), QRingBuffer< T >::readLine(), and QSslSocketBackendPrivate::transmit().

                                {
        bufferSize -= bytes;
        if (bufferSize < 0)
            bufferSize = 0;

        for (;;) {
            int nextBlockSize = nextDataBlockSize();
            if (bytes < nextBlockSize) {
                head += bytes;
                if (head == tail && tailBuffer == 0)
                    head = tail = 0;
                break;
            }

            bytes -= nextBlockSize;
            if (buffers.count() == 1) {
                if (buffers.at(0).size() != basicBlockSize)
                    buffers[0].resize(basicBlockSize);
                head = tail = 0;
                tailBuffer = 0;
                break;
            }

            buffers.removeAt(0);
            --tailBuffer;
            head = 0;
        }

        if (isEmpty())
            clear(); // try to minify/squeeze us
    }

getChar()

template<class T >

int QRingBuffer< T >::getChar ( )

inline

Definition at line 231 of file qringbuffer_p.h.

Referenced by QProcess::readData().

                         {
        if (isEmpty())
            return -1;
        char c = *readPointer();
        free(1);
        return int(uchar(c));
    }

head()

template<class T >

const T& QRingBuffer< T >::head ( ) const

inline

Definition at line 1249 of file qtriangulator.cpp.

Referenced by QRingBuffer< T >::chop(), QRingBuffer< T >::clear(), QRingBuffer< T >::free(), QRingBuffer< T >::indexOf(), QRingBuffer< T >::nextDataBlockSize(), QRingBuffer< T >::peek(), QRingBuffer< T >::read(), QRingBuffer< T >::readPointer(), QRingBuffer< T >::readPointerAtPosition(), and QRingBuffer< T >::ungetChar().

{Q_ASSERT(m_size > 0); return m_array[m_head];}

indexOf() [1/2]

template<class T >

int QRingBuffer< T >::indexOf ( char  c ) const

inline

Definition at line 270 of file qringbuffer_p.h.

Referenced by QRingBuffer< T >::canReadLine(), and QRingBuffer< T >::readLine().

                                     {
        int index = 0;
        for (int i = 0; i < buffers.size(); ++i) {
            int start = 0;
            int end = buffers.at(i).size();

            if (i == 0)
                start = head;
            if (i == tailBuffer)
                end = tail;
            const char *ptr = buffers.at(i).data() + start;
            for (int j = start; j < end; ++j) {
                if (*ptr++ == c)
                    return index;
                ++index;
            }
        }
        return -1;
    }

indexOf() [2/2]

template<class T >

int QRingBuffer< T >::indexOf ( char  c, int  maxLength  ) const

inline

Definition at line 290 of file qringbuffer_p.h.

                                                    {
        int index = 0;
        int remain = qMin(size(), maxLength);
        for (int i = 0; remain && i < buffers.size(); ++i) {
            int start = 0;
            int end = buffers.at(i).size();

            if (i == 0)
                start = head;
            if (i == tailBuffer)
                end = tail;
            if (remain < end - start) {
                end = start + remain;
                remain = 0;
            } else {
                remain -= end - start;
            }
            const char *ptr = buffers.at(i).data() + start;
            for (int j = start; j < end; ++j) {
                if (*ptr++ == c)
                    return index;
                ++index;
            }
        }
        return -1;
    }

isEmpty() [1/2]

template<class T >

bool QRingBuffer< T >::isEmpty ( ) const

inline

Definition at line 227 of file qringbuffer_p.h.

Referenced by QSslSocketPrivate::_q_bytesWrittenSlot(), QSslSocketPrivate::_q_flushWriteBuffer(), QProcess::atEnd(), QAbstractSocketPrivate::canWriteNotification(), QRingBuffer< T >::chop(), QAbstractSocketPrivate::flush(), QRingBuffer< T >::free(), QRingBuffer< T >::getChar(), QProcessPrivate::pipeWriterBytesToWrite(), qt_terminateApp(), QProcess::readData(), and QSslSocketBackendPrivate::transmit().

                                {
        return tailBuffer == 0 && tail == 0;
    }

isEmpty() [2/2]

template<class T >

bool QRingBuffer< T >::isEmpty ( ) const

inline

Definition at line 1252 of file qtriangulator.cpp.

{return m_size == 0;}

nextDataBlockSize()

template<class T >

int QRingBuffer< T >::nextDataBlockSize ( ) const

inline

Definition at line 69 of file qringbuffer_p.h.

Referenced by _qfile_writeData(), QAbstractSocketPrivate::flush(), QRingBuffer< T >::free(), QRingBuffer< T >::read(), QProcess::readData(), QRingBuffer< T >::readLine(), QRingBuffer< T >::readPointerAtPosition(), and QSslSocketBackendPrivate::transmit().

                                         {
        return (tailBuffer == 0 ? tail : buffers.first().size()) - head;
    }

peek()

template<class T >

QByteArray QRingBuffer< T >::peek ( int  maxLength ) const

inline

Definition at line 390 of file qringbuffer_p.h.

                                                {
        int bytesToRead = qMin(size(), maxLength);
        if(maxLength <= 0)
            return QByteArray();
        QByteArray ret;
        ret.resize(bytesToRead);
        int readSoFar = 0;
        for (int i = 0; readSoFar < bytesToRead && i < buffers.size(); ++i) {
            int start = 0;
            int end = buffers.at(i).size();
            if (i == 0)
                start = head;
            if (i == tailBuffer)
                end = tail;
            const int len = qMin(ret.size()-readSoFar, end-start);
            memcpy(ret.data()+readSoFar, buffers.at(i).constData()+start, len);
            readSoFar += len;
        }
        Q_ASSERT(readSoFar == ret.size());
        return ret;
    }

putChar()

template<class T >

void QRingBuffer< T >::putChar ( char  c )

inline

Definition at line 239 of file qringbuffer_p.h.

                                {
        char *ptr = reserve(1);
        *ptr = c;
    }

read() [1/3]

template<class T >

int QRingBuffer< T >::read ( char *  data, int  maxLength  )

inline

Definition at line 317 of file qringbuffer_p.h.

                                               {
        int bytesToRead = qMin(size(), maxLength);
        int readSoFar = 0;
        while (readSoFar < bytesToRead) {
            const char *ptr = readPointer();
            int bytesToReadFromThisBlock = qMin(bytesToRead - readSoFar, nextDataBlockSize());
            if (data)
                memcpy(data + readSoFar, ptr, bytesToReadFromThisBlock);
            readSoFar += bytesToReadFromThisBlock;
            free(bytesToReadFromThisBlock);
        }
        return readSoFar;
    }

read() [2/3]

template<class T >

QByteArray QRingBuffer< T >::read ( int  maxLength )

inline

Definition at line 331 of file qringbuffer_p.h.

                                          {
        QByteArray tmp;
        tmp.resize(qMin(maxLength, size()));
        read(tmp.data(), tmp.size());
        return tmp;
    }

read() [3/3]

template<class T >

QByteArray QRingBuffer< T >::read ( )

inline

Definition at line 343 of file qringbuffer_p.h.

Referenced by QRingBuffer< T >::read(), QRingBuffer< T >::readAll(), QRingBuffer< T >::readLine(), and QRingBuffer< T >::skip().

                             {
        if (bufferSize == 0)
            return QByteArray();

        // multiple buffers, just take the first one
        if (head == 0 && tailBuffer != 0) {
            QByteArray qba = buffers.takeFirst();
            --tailBuffer;
            bufferSize -= qba.length();
            return qba;
        }

        // one buffer with good value for head. Just take it.
        if (head == 0 && tailBuffer == 0) {
            QByteArray qba = buffers.takeFirst();
            qba.resize(tail);
            buffers << QByteArray();
            bufferSize = 0;
            tail = 0;
            return qba;
        }

        // Bad case: We have to memcpy.
        // We can avoid by initializing the QRingBuffer with basicBlockSize of 0
        // and only using this read() function.
        QByteArray qba(readPointer(), nextDataBlockSize());
        buffers.removeFirst();
        head = 0;
        if (tailBuffer == 0) {
            buffers << QByteArray();
            tail = 0;
        } else {
            --tailBuffer;
        }
        bufferSize -= qba.length();
        return qba;        
    }

readAll()

template<class T >

QByteArray QRingBuffer< T >::readAll ( )

inline

Definition at line 338 of file qringbuffer_p.h.

                                {
        return read(size());
    }

readLine()

template<class T >

int QRingBuffer< T >::readLine ( char *  data, int  maxLength  )

inline

Definition at line 416 of file qringbuffer_p.h.

                                                   {
        int index = indexOf('\n');
        if (index == -1)
            return read(data, maxLength);
        if (maxLength <= 0)
            return -1;

        int readSoFar = 0;
        while (readSoFar < index + 1 && readSoFar < maxLength - 1) {
            int bytesToRead = qMin((index + 1) - readSoFar, nextDataBlockSize());
            bytesToRead = qMin(bytesToRead, (maxLength - 1) - readSoFar);
            memcpy(data + readSoFar, readPointer(), bytesToRead);
            readSoFar += bytesToRead;
            free(bytesToRead);
        }

        // Terminate it.
        data[readSoFar] = '\0';
        return readSoFar;
    }

readPointer()

template<class T >

const char* QRingBuffer< T >::readPointer ( ) const

inline

Definition at line 73 of file qringbuffer_p.h.

Referenced by _qfile_writeData(), QAbstractSocketPrivate::flush(), QRingBuffer< T >::getChar(), QRingBuffer< T >::read(), QProcess::readData(), QRingBuffer< T >::readLine(), and QSslSocketBackendPrivate::transmit().

                                           {
        return buffers.isEmpty() ? 0 : (buffers.first().constData() + head);
    }

readPointerAtPosition()

template<class T >

const char* QRingBuffer< T >::readPointerAtPosition ( qint64  pos, qint64 &  length  ) const

inline

Definition at line 80 of file qringbuffer_p.h.

Referenced by QNonContiguousByteDeviceRingBufferImpl::readPointer().

                                                                               {
        if (buffers.isEmpty()) {
            length = 0;
            return 0;
        }

        if (pos >= bufferSize) {
            length = 0;
            return 0;
        }

        // special case: it is in the first buffer
        int nextDataBlockSizeValue = nextDataBlockSize();
        if (pos - head < nextDataBlockSizeValue) {
            length = nextDataBlockSizeValue - pos;
            return buffers.at(0).constData() + head + pos;
        }

        // special case: we only had one buffer and tried to read over it
        if (buffers.length() == 1) {
            length = 0;
            return 0;
        }

        // skip the first
        pos -= nextDataBlockSizeValue;

        // normal case: it is somewhere in the second to the-one-before-the-tailBuffer
        for (int i = 1; i < tailBuffer; i++) {
            if (pos >= buffers[i].size()) {
                pos -= buffers[i].size();
                continue;
            }

            length = buffers[i].length() - pos;
            return buffers[i].constData() + pos;
        }

        // it is in the tail buffer
        length = tail - pos;
        return buffers[tailBuffer].constData() + pos;
    }

reallocate()

template<class T >

bool QRingBuffer< T >::reallocate

(

int

capacity

)

Definition at line 1261 of file qtriangulator.cpp.

{
    T *oldArray = m_array;
    m_array = new T[capacity];
    if (m_array) {
        if (oldArray) {
            if (m_head + m_size > m_capacity) {
                memcpy(m_array, oldArray + m_head, (m_capacity - m_head) * sizeof(T));
                memcpy(m_array + (m_capacity - m_head), oldArray, (m_head + m_size - m_capacity) * sizeof(T));
            } else {
                memcpy(m_array, oldArray + m_head, m_size * sizeof(T));
            }
            delete[] oldArray;
        }
        m_capacity = capacity;
        m_head = 0;
        return true;
    } else {
        m_array = oldArray;
        return false;
    }
}

reserve()

template<class T >

char* QRingBuffer< T >::reserve ( int  bytes )

inline

Definition at line 155 of file qringbuffer_p.h.

Referenced by QNetworkReplyImplPrivate::_q_bufferOutgoingData(), QHttpPrivate::_q_slotReadyRead(), QRingBuffer< T >::putChar(), QAbstractSocketPrivate::readFromSocket(), QLocalSocketPrivate::startAsyncRead(), and QSslSocketBackendPrivate::transmit().

                                    {
        // if this is a fresh empty QRingBuffer
        if (bufferSize == 0) {
            buffers[0].resize(qMax(basicBlockSize, bytes));
            bufferSize += bytes;
            tail = bytes;
            return buffers[tailBuffer].data();
        }

        bufferSize += bytes;

        // if there is already enough space, simply return.
        if (tail + bytes <= buffers.at(tailBuffer).size()) {
            char *writePtr = buffers[tailBuffer].data() + tail;
            tail += bytes;
            return writePtr;
        }

        // if our buffer isn't half full yet, simply resize it.
        if (tail < buffers.at(tailBuffer).size() / 2) {
            buffers[tailBuffer].resize(tail + bytes);
            char *writePtr = buffers[tailBuffer].data() + tail;
            tail += bytes;
            return writePtr;
        }

        // shrink this buffer to its current size
        buffers[tailBuffer].resize(tail);

        // create a new QByteArray with the right size
        buffers << QByteArray();
        ++tailBuffer;
        buffers[tailBuffer].resize(qMax(basicBlockSize, bytes));
        tail = bytes;
        return buffers[tailBuffer].data();
    }

size()

template<class T >

int QRingBuffer< T >::size ( ) const

inline

Definition at line 256 of file qringbuffer_p.h.

Referenced by QProcess::bytesAvailable(), QAbstractSocketPrivate::canReadNotification(), QAbstractSocketPrivate::canWriteNotification(), QRingBuffer< T >::indexOf(), QRingBuffer< T >::peek(), QRingBuffer< T >::read(), QRingBuffer< T >::readAll(), QProcess::readData(), QAbstractSocketPrivate::readFromSocket(), QRingBuffer< T >::readPointerAtPosition(), QNetworkReplyImplPrivate::setup(), QNonContiguousByteDeviceRingBufferImpl::size(), QLocalSocketPrivate::startAsyncRead(), QSslSocketBackendPrivate::transmit(), and QRingBuffer< T >::truncate().

                            {
        return bufferSize;
    }

skip()

template<class T >

int QRingBuffer< T >::skip ( int  length )

inline

Definition at line 412 of file qringbuffer_p.h.

                                {
        return read(0, length);
    }

truncate()

template<class T >

void QRingBuffer< T >::truncate ( int  pos )

inline

Definition at line 192 of file qringbuffer_p.h.

Referenced by QLocalSocketPrivate::completeAsyncRead().

                                  {
        if (pos < size())
            chop(size() - pos);
    }

ungetChar()

template<class T >

void QRingBuffer< T >::ungetChar ( char  c )

inline

Definition at line 244 of file qringbuffer_p.h.

                                  {
        --head;
        if (head < 0) {
            buffers.prepend(QByteArray());
            buffers[0].resize(basicBlockSize);
            head = basicBlockSize - 1;
            ++tailBuffer;
        }
        buffers[0][head] = c;
        ++bufferSize;
    }

Properties

basicBlockSize

template<class T >

int QRingBuffer< T >::basicBlockSize

private

Definition at line 445 of file qringbuffer_p.h.

Referenced by QRingBuffer< T >::free(), QRingBuffer< T >::reserve(), and QRingBuffer< T >::ungetChar().

buffers

template<class T >

QList<QByteArray> QRingBuffer< T >::buffers

private

Definition at line 442 of file qringbuffer_p.h.

Referenced by QRingBuffer< T >::append(), QRingBuffer< T >::chop(), QRingBuffer< T >::clear(), QRingBuffer< T >::free(), QRingBuffer< T >::indexOf(), QRingBuffer< T >::nextDataBlockSize(), QRingBuffer< T >::peek(), QRingBuffer< T >::QRingBuffer(), QRingBuffer< T >::read(), QRingBuffer< T >::readPointer(), QRingBuffer< T >::readPointerAtPosition(), QRingBuffer< T >::reserve(), and QRingBuffer< T >::ungetChar().

bufferSize

template<class T >

int QRingBuffer< T >::bufferSize

private

Definition at line 446 of file qringbuffer_p.h.

Referenced by QRingBuffer< T >::append(), QRingBuffer< T >::chop(), QRingBuffer< T >::clear(), QRingBuffer< T >::free(), QRingBuffer< T >::read(), QRingBuffer< T >::readPointerAtPosition(), QRingBuffer< T >::reserve(), QRingBuffer< T >::size(), and QRingBuffer< T >::ungetChar().

head

template<class T >

int QRingBuffer< T >::head

private

Definition at line 443 of file qringbuffer_p.h.

m_array

template<class T >

T* QRingBuffer< T >::m_array

private

Definition at line 1254 of file qtriangulator.cpp.

m_capacity

template<class T >

int QRingBuffer< T >::m_capacity

private

Definition at line 1257 of file qtriangulator.cpp.

m_head

template<class T >

int QRingBuffer< T >::m_head

private

Definition at line 1255 of file qtriangulator.cpp.

m_size

template<class T >

int QRingBuffer< T >::m_size

private

Definition at line 1256 of file qtriangulator.cpp.

tail

template<class T >

int QRingBuffer< T >::tail

private

Definition at line 443 of file qringbuffer_p.h.

Referenced by QRingBuffer< T >::append(), QRingBuffer< T >::chop(), QRingBuffer< T >::clear(), QRingBuffer< T >::free(), QRingBuffer< T >::indexOf(), QRingBuffer< T >::isEmpty(), QRingBuffer< T >::nextDataBlockSize(), QRingBuffer< T >::peek(), QRingBuffer< T >::read(), QRingBuffer< T >::readPointerAtPosition(), and QRingBuffer< T >::reserve().

tailBuffer

template<class T >

int QRingBuffer< T >::tailBuffer

private

Definition at line 444 of file qringbuffer_p.h.

Referenced by QRingBuffer< T >::append(), QRingBuffer< T >::chop(), QRingBuffer< T >::clear(), QRingBuffer< T >::free(), QRingBuffer< T >::indexOf(), QRingBuffer< T >::isEmpty(), QRingBuffer< T >::nextDataBlockSize(), QRingBuffer< T >::peek(), QRingBuffer< T >::read(), QRingBuffer< T >::readPointerAtPosition(), QRingBuffer< T >::reserve(), and QRingBuffer< T >::ungetChar().

---

The documentation for this class was generated from the following files:

• /src/corelib/tools/qringbuffer_p.h
• /src/opengl/gl2paintengineex/qtriangulator.cpp