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+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the Qt Mobility Components.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QPRIVATELINEARBUFFER_P_H
+#define QPRIVATELINEARBUFFER_P_H
+
+// This is QIODevice's read buffer, optimised for read(), isEmpty() and getChar()
+class QPrivateLinearBuffer
+{
+public:
+    QPrivateLinearBuffer() : len(0), first(0), buf(0), capacity(0) {
+    }
+    ~QPrivateLinearBuffer() {
+        delete [] buf;
+    }
+    void clear() {
+        first = buf;
+        len = 0;
+    }
+    int size() const {
+        return len;
+    }
+    bool isEmpty() const {
+        return len == 0;
+    }
+    void skip(int n) {
+        if (n >= len) {
+            clear();
+        } else {
+            len -= n;
+            first += n;
+        }
+    }
+    int getChar() {
+        if (len == 0)
+            return -1;
+        int ch = uchar(*first);
+        len--;
+        first++;
+        return ch;
+    }
+    int read(char* target, int size) {
+        int r = qMin(size, len);
+        memcpy(target, first, r);
+        len -= r;
+        first += r;
+        return r;
+    }
+    char* reserve(int size) {
+        makeSpace(size + len, freeSpaceAtEnd);
+        char* writePtr = first + len;
+        len += size;
+        return writePtr;
+    }
+    void chop(int size) {
+        if (size >= len) {
+            clear();
+        } else {
+            len -= size;
+        }
+    }
+    QByteArray readAll() {
+        char* f = first;
+        int l = len;
+        clear();
+        return QByteArray(f, l);
+    }
+    int readLine(char* target, int size) {
+        int r = qMin(size, len);
+        char* eol = static_cast<char*>(memchr(first, '\n', r));
+        if (eol)
+            r = 1+(eol-first);
+        memcpy(target, first, r);
+        len -= r;
+        first += r;
+        return int(r);
+        }
+    bool canReadLine() const {
+        return memchr(first, '\n', len);
+    }
+    void ungetChar(char c) {
+        if (first == buf) {
+            // underflow, the existing valid data needs to move to the end of the (potentially bigger) buffer
+            makeSpace(len+1, freeSpaceAtStart);
+        }
+        first--;
+        len++;
+        *first = c;
+    }
+    void ungetBlock(const char* block, int size) {
+        if ((first - buf) < size) {
+            // underflow, the existing valid data needs to move to the end of the (potentially bigger) buffer
+            makeSpace(len + size, freeSpaceAtStart);
+        }
+        first -= size;
+        len += size;
+        memcpy(first, block, size);
+    }
+
+private:
+    enum FreeSpacePos {freeSpaceAtStart, freeSpaceAtEnd};
+    void makeSpace(size_t required, FreeSpacePos where) {
+        size_t newCapacity = qMax(capacity, size_t(QPRIVATELINEARBUFFER_BUFFERSIZE));
+        while (newCapacity < required)
+            newCapacity *= 2;
+        int moveOffset = (where == freeSpaceAtEnd) ? 0 : newCapacity - len;
+        if (newCapacity > capacity) {
+            // allocate more space
+            char* newBuf = new char[newCapacity];
+            memmove(newBuf + moveOffset, first, len);
+            delete [] buf;
+            buf = newBuf;
+            capacity = newCapacity;
+        } else {
+            // shift any existing data to make space
+            memmove(buf + moveOffset, first, len);
+        }
+        first = buf + moveOffset;
+    }
+
+private:
+    // length of the unread data
+    int len;
+    // start of the unread data
+    char* first;
+    // the allocated buffer
+    char* buf;
+    // allocated buffer size
+    size_t capacity;
+};
+
+#endif // QPRIVATELINEARBUFFER_P_H