10 files changed, 386 insertions, 244 deletions

diff --git a/qmake/Makefile.unix b/qmake/Makefile.unix
index 86f884fe20..520ae667e9 100644
--- a/qmake/Makefile.unix
+++ b/qmake/Makefile.unix
@@ -13,7 +13,7 @@ OBJS=project.o option.o property.o main.o ioutils.o proitems.o \
 
 #qt code
 QOBJS=qtextcodec.o qutfcodec.o qstring.o qstring_compat.o qstringbuilder.o qtextstream.o qiodevice.o \
-      qdebug.o qmalloc.o qglobal.o \
+      qringbuffer.o qdebug.o qmalloc.o qglobal.o \
       qarraydata.o qbytearray.o qbytearraymatcher.o qdatastream.o qbuffer.o qlist.o qfiledevice.o qfile.o \
       qfilesystementry.o qfilesystemengine.o qfsfileengine.o qfsfileengine_iterator.o qregexp.o qvector.o \
       qbitarray.o qdir.o qdiriterator.o quuid.o qhash.o qfileinfo.o qdatetime.o qstringlist.o \
@@ -44,6 +44,7 @@ DEPEND_SRC = \
 	   $(SOURCE_PATH)/src/corelib/tools/qstring_compat.cpp \
 	   $(SOURCE_PATH)/src/corelib/io/qfiledevice.cpp \
 	   $(SOURCE_PATH)/src/corelib/io/qtextstream.cpp $(SOURCE_PATH)/src/corelib/io/qiodevice.cpp \
+	   $(SOURCE_PATH)/src/corelib/tools/qringbuffer.cpp \
 	   $(SOURCE_PATH)/src/corelib/io/qdebug.cpp \
 	   $(SOURCE_PATH)/src/corelib/global/qmalloc.cpp \
 	   $(SOURCE_PATH)/src/corelib/global/qglobal.cpp $(SOURCE_PATH)/src/corelib/tools/qregexp.cpp \
@@ -242,6 +243,9 @@ qsettings_win.o: $(SOURCE_PATH)/src/corelib/io/qsettings_win.cpp
 qiodevice.o: $(SOURCE_PATH)/src/corelib/io/qiodevice.cpp
 	$(CXX) -c -o $@ $(CXXFLAGS) $(SOURCE_PATH)/src/corelib/io/qiodevice.cpp
 
+qringbuffer.o: $(SOURCE_PATH)/src/corelib/tools/qringbuffer.cpp
+	$(CXX) -c -o $@ $(CXXFLAGS) $(SOURCE_PATH)/src/corelib/tools/qringbuffer.cpp
+
 qdebug.o: $(SOURCE_PATH)/src/corelib/io/qdebug.cpp
 	$(CXX) -c -o $@ $(CXXFLAGS) $(SOURCE_PATH)/src/corelib/io/qdebug.cpp
 
diff --git a/qmake/Makefile.win32 b/qmake/Makefile.win32
index 9dda6ca1e7..272a0c09b1 100644
--- a/qmake/Makefile.win32
+++ b/qmake/Makefile.win32
@@ -88,6 +88,7 @@ QTOBJS= \
 	qglobal.obj \
 	qhash.obj \
 	qiodevice.obj \
+	qringbuffer.obj \
 	qdebug.obj \
 	qlist.obj \
 	qlinkedlist.obj \
diff --git a/src/corelib/tools/qringbuffer.cpp b/src/corelib/tools/qringbuffer.cpp
new file mode 100644
index 0000000000..d8becbe07d
--- /dev/null
+++ b/src/corelib/tools/qringbuffer.cpp
@@ -0,0 +1,327 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Copyright (C) 2015 Alex Trotsenko <alex1973tr@gmail.com>
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "private/qringbuffer_p.h"
+#include <string.h>
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \internal
+
+    Access the bytes at a specified position the out-variable length will
+    contain the amount of bytes readable from there, e.g. the amount still
+    the same QByteArray
+*/
+const char *QRingBuffer::readPointerAtPosition(qint64 pos, qint64 &length) const
+{
+    if (pos >= 0) {
+        pos += head;
+        for (int i = 0; i < buffers.size(); ++i) {
+            length = (i == tailBuffer ? tail : buffers[i].size());
+            if (length > pos) {
+                length -= pos;
+                return buffers[i].constData() + pos;
+            }
+            pos -= length;
+        }
+    }
+
+    length = 0;
+    return 0;
+}
+
+void QRingBuffer::free(qint64 bytes)
+{
+    while (bytes > 0) {
+        const qint64 blockSize = buffers.first().size() - head;
+
+        if (tailBuffer == 0 || blockSize > bytes) {
+            // keep a single block around if it does not exceed
+            // the basic block size, to avoid repeated allocations
+            // between uses of the buffer
+            if (bufferSize <= bytes) {
+                if (buffers.first().size() <= basicBlockSize) {
+                    bufferSize = 0;
+                    head = tail = 0;
+                } else {
+                    clear(); // try to minify/squeeze us
+                }
+            } else {
+                Q_ASSERT(quint64(bytes) < QByteArray::MaxSize);
+                head += int(bytes);
+                bufferSize -= bytes;
+            }
+            return;
+        }
+
+        bufferSize -= blockSize;
+        bytes -= blockSize;
+        buffers.removeFirst();
+        --tailBuffer;
+        head = 0;
+    }
+}
+
+char *QRingBuffer::reserve(qint64 bytes)
+{
+    if (bytes <= 0 || quint64(bytes) >= QByteArray::MaxSize)
+        return 0;
+
+    const qint64 newSize = bytes + tail;
+    // if need buffer reallocation
+    if (newSize > buffers.last().size()) {
+        if (newSize > buffers.last().capacity() && (tail >= basicBlockSize
+                || quint64(newSize) >= QByteArray::MaxSize)) {
+            // shrink this buffer to its current size
+            buffers.last().resize(tail);
+
+            // create a new QByteArray
+            buffers.append(QByteArray());
+            ++tailBuffer;
+            tail = 0;
+        }
+        buffers.last().resize(qMax(basicBlockSize, tail + int(bytes)));
+    }
+
+    char *writePtr = buffers.last().data() + tail;
+    bufferSize += bytes;
+    Q_ASSERT(quint64(bytes) < QByteArray::MaxSize);
+    tail += int(bytes);
+    return writePtr;
+}
+
+/*!
+    \internal
+
+    Allocate data at buffer head
+*/
+char *QRingBuffer::reserveFront(qint64 bytes)
+{
+    if (bytes <= 0 || quint64(bytes) >= QByteArray::MaxSize)
+        return 0;
+
+    if (head < bytes) {
+        buffers.first().remove(0, head);
+        if (tailBuffer == 0)
+            tail -= head;
+
+        buffers.prepend(QByteArray());
+        head = qMax(basicBlockSize, int(bytes));
+        buffers.first().resize(head);
+        ++tailBuffer;
+    }
+
+    head -= int(bytes);
+    bufferSize += bytes;
+    return buffers.first().data() + head;
+}
+
+void QRingBuffer::chop(qint64 bytes)
+{
+    while (bytes > 0) {
+        if (tailBuffer == 0 || tail > bytes) {
+            // keep a single block around if it does not exceed
+            // the basic block size, to avoid repeated allocations
+            // between uses of the buffer
+            if (bufferSize <= bytes) {
+                if (buffers.first().size() <= basicBlockSize) {
+                    bufferSize = 0;
+                    head = tail = 0;
+                } else {
+                    clear(); // try to minify/squeeze us
+                }
+            } else {
+                Q_ASSERT(quint64(bytes) < QByteArray::MaxSize);
+                tail -= int(bytes);
+                bufferSize -= bytes;
+            }
+            return;
+        }
+
+        bufferSize -= tail;
+        bytes -= tail;
+        buffers.removeLast();
+        --tailBuffer;
+        tail = buffers.last().size();
+    }
+}
+
+void QRingBuffer::clear()
+{
+    buffers.erase(buffers.begin() + 1, buffers.end());
+    buffers.first().clear();
+
+    head = tail = 0;
+    tailBuffer = 0;
+    bufferSize = 0;
+}
+
+qint64 QRingBuffer::indexOf(char c) const
+{
+    qint64 index = 0;
+    qint64 j = head;
+    for (int i = 0; i < buffers.size(); ++i) {
+        const char *ptr = buffers[i].constData() + j;
+        j = index + (i == tailBuffer ? tail : buffers[i].size()) - j;
+
+        while (index < j) {
+            if (*ptr++ == c)
+                return index;
+            ++index;
+        }
+        j = 0;
+    }
+    return -1;
+}
+
+qint64 QRingBuffer::indexOf(char c, qint64 maxLength) const
+{
+    qint64 index = 0;
+    qint64 j = head;
+    for (int i = 0; index < maxLength && i < buffers.size(); ++i) {
+        const char *ptr = buffers[i].constData() + j;
+        j = qMin(index + (i == tailBuffer ? tail : buffers[i].size()) - j, maxLength);
+
+        while (index < j) {
+            if (*ptr++ == c)
+                return index;
+            ++index;
+        }
+        j = 0;
+    }
+    return -1;
+}
+
+qint64 QRingBuffer::read(char *data, qint64 maxLength)
+{
+    const qint64 bytesToRead = qMin(size(), maxLength);
+    qint64 readSoFar = 0;
+    while (readSoFar < bytesToRead) {
+        const qint64 bytesToReadFromThisBlock = qMin(bytesToRead - readSoFar,
+                                                     nextDataBlockSize());
+        if (data)
+            memcpy(data + readSoFar, readPointer(), bytesToReadFromThisBlock);
+        readSoFar += bytesToReadFromThisBlock;
+        free(bytesToReadFromThisBlock);
+    }
+    return readSoFar;
+}
+
+/*!
+    \internal
+
+    Read an unspecified amount (will read the first buffer)
+*/
+QByteArray QRingBuffer::read()
+{
+    if (bufferSize == 0)
+        return QByteArray();
+
+    QByteArray qba(buffers.takeFirst());
+
+    qba.reserve(0); // avoid that resizing needlessly reallocates
+    if (tailBuffer == 0) {
+        qba.resize(tail);
+        tail = 0;
+        buffers.append(QByteArray());
+    } else {
+        --tailBuffer;
+    }
+    qba.remove(0, head); // does nothing if head is 0
+    head = 0;
+    bufferSize -= qba.size();
+    return qba;
+}
+
+/*!
+    \internal
+
+    Peek the bytes from a specified position
+*/
+qint64 QRingBuffer::peek(char *data, qint64 maxLength, qint64 pos) const
+{
+    qint64 readSoFar = 0;
+
+    if (pos >= 0) {
+        pos += head;
+        for (int i = 0; readSoFar < maxLength && i < buffers.size(); ++i) {
+            qint64 blockLength = (i == tailBuffer ? tail : buffers[i].size());
+
+            if (pos < blockLength) {
+                blockLength = qMin(blockLength - pos, maxLength - readSoFar);
+                memcpy(data + readSoFar, buffers[i].constData() + pos, blockLength);
+                readSoFar += blockLength;
+                pos = 0;
+            } else {
+                pos -= blockLength;
+            }
+        }
+    }
+
+    return readSoFar;
+}
+
+/*!
+    \internal
+
+    Append a new buffer to the end
+*/
+void QRingBuffer::append(const QByteArray &qba)
+{
+    if (tail == 0) {
+        buffers.last() = qba;
+    } else {
+        buffers.last().resize(tail);
+        buffers.append(qba);
+        ++tailBuffer;
+    }
+    tail = qba.size();
+    bufferSize += tail;
+}
+
+qint64 QRingBuffer::readLine(char *data, qint64 maxLength)
+{
+    if (!data || --maxLength <= 0)
+        return -1;
+
+    qint64 i = indexOf('\n', maxLength);
+    i = read(data, i >= 0 ? (i + 1) : maxLength);
+
+    // Terminate it.
+    data[i] = '\0';
+    return i;
+}
+
+QT_END_NAMESPACE
diff --git a/src/corelib/tools/qringbuffer_p.h b/src/corelib/tools/qringbuffer_p.h
index 9ca14d2987..3a8cca46d8 100644
--- a/src/corelib/tools/qringbuffer_p.h
+++ b/src/corelib/tools/qringbuffer_p.h
@@ -66,117 +66,17 @@ public:
         return bufferSize == 0 ? Q_NULLPTR : (buffers.first().constData() + head);
     }
 
-    // access the bytes at a specified position
-    // the out-variable length will contain the amount of bytes readable
-    // from there, e.g. the amount still the same QByteArray
-    inline const char *readPointerAtPosition(qint64 pos, qint64 &length) const {
-        if (pos >= 0) {
-            pos += head;
-            for (int i = 0; i < buffers.size(); ++i) {
-                length = (i == tailBuffer ? tail : buffers[i].size());
-                if (length > pos) {
-                    length -= pos;
-                    return buffers[i].constData() + pos;
-                }
-                pos -= length;
-            }
-        }
-
-        length = 0;
-        return 0;
-    }
-
-    inline void free(qint64 bytes) {
-        while (bytes > 0) {
-            const qint64 blockSize = buffers.first().size() - head;
-
-            if (tailBuffer == 0 || blockSize > bytes) {
-                // keep a single block around if it does not exceed
-                // the basic block size, to avoid repeated allocations
-                // between uses of the buffer
-                if (bufferSize <= bytes) {
-                    if (buffers.first().size() <= basicBlockSize) {
-                        bufferSize = 0;
-                        head = tail = 0;
-                    } else {
-                        clear(); // try to minify/squeeze us
-                    }
-                } else {
-                    Q_ASSERT(quint64(bytes) < QByteArray::MaxSize);
-                    head += int(bytes);
-                    bufferSize -= bytes;
-                }
-                return;
-            }
-
-            bufferSize -= blockSize;
-            bytes -= blockSize;
-            buffers.removeFirst();
-            --tailBuffer;
-            head = 0;
-        }
-    }
-
-    inline char *reserve(qint64 bytes) {
-        if (bytes <= 0 || quint64(bytes) >= QByteArray::MaxSize)
-            return 0;
-
-        const qint64 newSize = bytes + tail;
-        // if need buffer reallocation
-        if (newSize > buffers.last().size()) {
-            if (newSize > buffers.last().capacity() && (tail >= basicBlockSize
-                    || quint64(newSize) >= QByteArray::MaxSize)) {
-                // shrink this buffer to its current size
-                buffers.last().resize(tail);
-
-                // create a new QByteArray
-                buffers.append(QByteArray());
-                ++tailBuffer;
-                tail = 0;
-            }
-            buffers.last().resize(qMax(basicBlockSize, tail + int(bytes)));
-        }
-
-        char *writePtr = buffers.last().data() + tail;
-        bufferSize += bytes;
-        Q_ASSERT(quint64(bytes) < QByteArray::MaxSize);
-        tail += int(bytes);
-        return writePtr;
-    }
+    Q_CORE_EXPORT const char *readPointerAtPosition(qint64 pos, qint64 &length) const;
+    Q_CORE_EXPORT void free(qint64 bytes);
+    Q_CORE_EXPORT char *reserve(qint64 bytes);
+    Q_CORE_EXPORT char *reserveFront(qint64 bytes);
 
     inline void truncate(qint64 pos) {
         if (pos < size())
             chop(size() - pos);
     }
 
-    inline void chop(qint64 bytes) {
-        while (bytes > 0) {
-            if (tailBuffer == 0 || tail > bytes) {
-                // keep a single block around if it does not exceed
-                // the basic block size, to avoid repeated allocations
-                // between uses of the buffer
-                if (bufferSize <= bytes) {
-                    if (buffers.first().size() <= basicBlockSize) {
-                        bufferSize = 0;
-                        head = tail = 0;
-                    } else {
-                        clear(); // try to minify/squeeze us
-                    }
-                } else {
-                    Q_ASSERT(quint64(bytes) < QByteArray::MaxSize);
-                    tail -= int(bytes);
-                    bufferSize -= bytes;
-                }
-                return;
-            }
-
-            bufferSize -= tail;
-            bytes -= tail;
-            buffers.removeLast();
-            --tailBuffer;
-            tail = buffers.last().size();
-        }
-    }
+    Q_CORE_EXPORT void chop(qint64 bytes);
 
     inline bool isEmpty() const {
         return bufferSize == 0;
@@ -195,156 +95,36 @@ public:
         *ptr = c;
     }
 
-    inline void ungetChar(char c) {
-        --head;
-        if (head < 0) {
-            if (bufferSize != 0) {
-                buffers.prepend(QByteArray());
-                ++tailBuffer;
-            } else {
-                tail = basicBlockSize;
-            }
-            buffers.first().resize(basicBlockSize);
-            head = basicBlockSize - 1;
-        }
-        buffers.first()[head] = c;
-        ++bufferSize;
-    }
-
-    inline qint64 size() const {
-        return bufferSize;
-    }
-
-    inline void clear() {
-        buffers.erase(buffers.begin() + 1, buffers.end());
-        buffers.first().clear();
-
-        head = tail = 0;
-        tailBuffer = 0;
-        bufferSize = 0;
-    }
-
-    inline qint64 indexOf(char c) const {
-        qint64 index = 0;
-        qint64 j = head;
-        for (int i = 0; i < buffers.size(); ++i) {
-            const char *ptr = buffers[i].constData() + j;
-            j = index + (i == tailBuffer ? tail : buffers[i].size()) - j;
-
-            while (index < j) {
-                if (*ptr++ == c)
-                    return index;
-                ++index;
-            }
-            j = 0;
-        }
-        return -1;
-    }
-
-    inline qint64 indexOf(char c, qint64 maxLength) const {
-        qint64 index = 0;
-        qint64 j = head;
-        for (int i = 0; index < maxLength && i < buffers.size(); ++i) {
-            const char *ptr = buffers[i].constData() + j;
-            j = qMin(index + (i == tailBuffer ? tail : buffers[i].size()) - j, maxLength);
-
-            while (index < j) {
-                if (*ptr++ == c)
-                    return index;
-                ++index;
-            }
-            j = 0;
-        }
-        return -1;
-    }
-
-    inline qint64 read(char *data, qint64 maxLength) {
-        const qint64 bytesToRead = qMin(size(), maxLength);
-        qint64 readSoFar = 0;
-        while (readSoFar < bytesToRead) {
-            const qint64 bytesToReadFromThisBlock = qMin(bytesToRead - readSoFar,
-                                                         nextDataBlockSize());
-            if (data)
-                memcpy(data + readSoFar, readPointer(), bytesToReadFromThisBlock);
-            readSoFar += bytesToReadFromThisBlock;
-            free(bytesToReadFromThisBlock);
-        }
-        return readSoFar;
-    }
-
-    // read an unspecified amount (will read the first buffer)
-    inline QByteArray read() {
-        if (bufferSize == 0)
-            return QByteArray();
-
-        QByteArray qba(buffers.takeFirst());
-
-        qba.reserve(0); // avoid that resizing needlessly reallocates
-        if (tailBuffer == 0) {
-            qba.resize(tail);
-            tail = 0;
-            buffers.append(QByteArray());
+    void ungetChar(char c)
+    {
+        if (head > 0) {
+            --head;
+            buffers.first()[head] = c;
+            ++bufferSize;
         } else {
-            --tailBuffer;
+            char *ptr = reserveFront(1);
+            *ptr = c;
         }
-        qba.remove(0, head); // does nothing if head is 0
-        head = 0;
-        bufferSize -= qba.size();
-        return qba;
     }
 
-    // peek the bytes from a specified position
-    inline qint64 peek(char *data, qint64 maxLength, qint64 pos = 0) const
-    {
-        qint64 readSoFar = 0;
-
-        if (pos >= 0) {
-            pos += head;
-            for (int i = 0; readSoFar < maxLength && i < buffers.size(); ++i) {
-                qint64 blockLength = (i == tailBuffer ? tail : buffers[i].size());
-
-                if (pos < blockLength) {
-                    blockLength = qMin(blockLength - pos, maxLength - readSoFar);
-                    memcpy(data + readSoFar, buffers[i].constData() + pos, blockLength);
-                    readSoFar += blockLength;
-                    pos = 0;
-                } else {
-                    pos -= blockLength;
-                }
-            }
-        }
 
-        return readSoFar;
+    inline qint64 size() const {
+        return bufferSize;
     }
 
-    // append a new buffer to the end
-    inline void append(const QByteArray &qba) {
-        if (tail == 0) {
-            buffers.last() = qba;
-        } else {
-            buffers.last().resize(tail);
-            buffers.append(qba);
-            ++tailBuffer;
-        }
-        tail = qba.size();
-        bufferSize += tail;
-    }
+    Q_CORE_EXPORT void clear();
+    Q_CORE_EXPORT qint64 indexOf(char c) const;
+    Q_CORE_EXPORT qint64 indexOf(char c, qint64 maxLength) const;
+    Q_CORE_EXPORT qint64 read(char *data, qint64 maxLength);
+    Q_CORE_EXPORT QByteArray read();
+    Q_CORE_EXPORT qint64 peek(char *data, qint64 maxLength, qint64 pos = 0) const;
+    Q_CORE_EXPORT void append(const QByteArray &qba);
 
     inline qint64 skip(qint64 length) {
         return read(0, length);
     }
 
-    inline qint64 readLine(char *data, qint64 maxLength) {
-        if (!data || --maxLength <= 0)
-            return -1;
-
-        qint64 i = indexOf('\n', maxLength);
-        i = read(data, i >= 0 ? (i + 1) : maxLength);
-
-        // Terminate it.
-        data[i] = '\0';
-        return i;
-    }
+    Q_CORE_EXPORT qint64 readLine(char *data, qint64 maxLength);
 
     inline bool canReadLine() const {
         return indexOf('\n') >= 0;
diff --git a/src/corelib/tools/tools.pri b/src/corelib/tools/tools.pri
index 5e4a22e283..1dba6784b6 100644
--- a/src/corelib/tools/tools.pri
+++ b/src/corelib/tools/tools.pri
@@ -106,6 +106,7 @@ SOURCES += \
         tools/qrect.cpp \
         tools/qregexp.cpp \
         tools/qrefcount.cpp \
+        tools/qringbuffer.cpp \
         tools/qshareddata.cpp \
         tools/qsharedpointer.cpp \
         tools/qsimd.cpp \
diff --git a/src/tools/bootstrap/bootstrap.pro b/src/tools/bootstrap/bootstrap.pro
index a92e5b8f3d..be6bcadacb 100644
--- a/src/tools/bootstrap/bootstrap.pro
+++ b/src/tools/bootstrap/bootstrap.pro
@@ -97,6 +97,7 @@ SOURCES += \
            ../../corelib/tools/qlocale_tools.cpp \
            ../../corelib/tools/qmap.cpp \
            ../../corelib/tools/qregexp.cpp \
+           ../../corelib/tools/qringbuffer.cpp \
            ../../corelib/tools/qpoint.cpp \
            ../../corelib/tools/qrect.cpp \
            ../../corelib/tools/qsize.cpp \
diff --git a/tests/auto/corelib/tools/qringbuffer/tst_qringbuffer.cpp b/tests/auto/corelib/tools/qringbuffer/tst_qringbuffer.cpp
index 044fdbdee5..f9bca77ed3 100644
--- a/tests/auto/corelib/tools/qringbuffer/tst_qringbuffer.cpp
+++ b/tests/auto/corelib/tools/qringbuffer/tst_qringbuffer.cpp
@@ -48,6 +48,7 @@ private slots:
     void sizeWhenReserved();
     void free();
     void reserveAndRead();
+    void reserveFrontAndRead();
     void chop();
     void ungetChar();
     void indexOf();
@@ -219,6 +220,28 @@ void tst_QRingBuffer::reserveAndRead()
     QVERIFY(ringBuffer.size() == 0);
 }
 
+void tst_QRingBuffer::reserveFrontAndRead()
+{
+    QRingBuffer ringBuffer;
+    // fill buffer with an arithmetic progression
+    for (int i = 1; i < 256; ++i) {
+        QByteArray ba(i, char(i));
+        char *ringPos = ringBuffer.reserveFront(i);
+        QVERIFY(ringPos);
+        memcpy(ringPos, ba.constData(), i);
+    }
+
+    // readback and check stored data
+    for (int i = 255; i > 0; --i) {
+        QByteArray ba;
+        ba.resize(i);
+        qint64 thisRead = ringBuffer.read(ba.data(), i);
+        QCOMPARE(thisRead, qint64(i));
+        QVERIFY(ba.count(char(i)) == i);
+    }
+    QVERIFY(ringBuffer.size() == 0);
+}
+
 void tst_QRingBuffer::chop()
 {
     QRingBuffer ringBuffer;
diff --git a/tools/configure/Makefile.mingw b/tools/configure/Makefile.mingw
index 40c2112132..a626bd6052 100644
--- a/tools/configure/Makefile.mingw
+++ b/tools/configure/Makefile.mingw
@@ -48,6 +48,7 @@ OBJECTS = \
     qfsfileengine_win.o \
     qfsfileengine_iterator.o \
     qiodevice.o \
+    qringbuffer.o \
     qdebug.o \
     qtextstream.o \
     qlogging.o \
diff --git a/tools/configure/Makefile.win32 b/tools/configure/Makefile.win32
index b74b0bc82d..148872525a 100644
--- a/tools/configure/Makefile.win32
+++ b/tools/configure/Makefile.win32
@@ -47,6 +47,7 @@ OBJECTS = \
     qfsfileengine_win.obj \
     qfsfileengine_iterator.obj \
     qiodevice.obj \
+    qringbuffer.obj \
     qdebug.obj \
     qtextstream.obj \
     qlogging.obj \
@@ -122,6 +123,7 @@ qfsfileengine.obj: $(CORESRC)\io\qfsfileengine.cpp $(PCH)
 qfsfileengine_win.obj: $(CORESRC)\io\qfsfileengine_win.cpp $(PCH)
 qfsfileengine_iterator.obj: $(CORESRC)\io\qfsfileengine_iterator.cpp $(PCH)
 qiodevice.obj: $(CORESRC)\io\qiodevice.cpp $(PCH)
+qringbuffer.obj: $(CORESRC)\tools\qringbuffer.cpp $(PCH)
 qdebug.obj: $(CORESRC)\io\qdebug.cpp $(PCH)
 qtextstream.obj: $(CORESRC)\io\qtextstream.cpp $(PCH)
 qtemporaryfile.obj: $(CORESRC)\io\qtemporaryfile.cpp $(PCH)
diff --git a/tools/configure/configure.pro b/tools/configure/configure.pro
index d3237d472b..13ab3746ed 100644
--- a/tools/configure/configure.pro
+++ b/tools/configure/configure.pro
@@ -68,6 +68,7 @@ HEADERS  = configureapp.h environment.h tools.h\
            $$QT_SOURCE_TREE/src/corelib/tools/qdatetime.h \
            $$QT_SOURCE_TREE/src/corelib/tools/qmap.h \
            $$QT_SOURCE_TREE/src/corelib/tools/qregexp.h \
+           $$QT_SOURCE_TREE/src/corelib/tools/qringbuffer_p.h \
            $$QT_SOURCE_TREE/src/corelib/tools/qstring.h \
            $$QT_SOURCE_TREE/src/corelib/tools/qstringlist.h \
            $$QT_SOURCE_TREE/src/corelib/tools/qstringmatcher.h \
@@ -119,6 +120,7 @@ SOURCES  = main.cpp configureapp.cpp environment.cpp tools.cpp \
            $$QT_SOURCE_TREE/src/corelib/tools/qdatetime.cpp \
            $$QT_SOURCE_TREE/src/corelib/tools/qmap.cpp \
            $$QT_SOURCE_TREE/src/corelib/tools/qregexp.cpp \
+           $$QT_SOURCE_TREE/src/corelib/tools/qringbuffer.cpp \
            $$QT_SOURCE_TREE/src/corelib/tools/qstring.cpp \
            $$QT_SOURCE_TREE/src/corelib/tools/qstring_compat.cpp \
            $$QT_SOURCE_TREE/src/corelib/tools/qstringlist.cpp \