Move endian integers to qendian_p.h

The endian integers have more use than just in QJson, and is already
used separately by QtDeclarative. This patch moves q_littleendian out
of qjson_p.h and matches it with a corresponding q_bigendian, and puts
it to use in simplifying endian handling in the ico image handler.

Change-Id: I975bb701a089256db8ced3cb53b4bd62cdfb02dd
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 142 insertions, 0 deletions

diff --git a/src/corelib/global/global.pri b/src/corelib/global/global.pri
index a087452d06..efc7f3cd22 100644
--- a/src/corelib/global/global.pri
+++ b/src/corelib/global/global.pri
@@ -9,6 +9,7 @@ HEADERS +=  \
         global/qprocessordetection.h \
 	global/qnamespace.h \
         global/qendian.h \
+        global/qendian_p.h \
         global/qnumeric_p.h \
         global/qnumeric.h \
         global/qfloat16_p.h \
diff --git a/src/corelib/global/qendian_p.h b/src/corelib/global/qendian_p.h
new file mode 100644
index 0000000000..b279701a31
--- /dev/null
+++ b/src/corelib/global/qendian_p.h
@@ -0,0 +1,141 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://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 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QENDIAN_P_H
+#define QENDIAN_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "qendian.h"
+
+QT_BEGIN_NAMESPACE
+
+template<class S>
+class QSpecialInteger
+{
+    typedef typename S::StorageType T;
+    T val;
+public:
+    QSpecialInteger() = default;
+    explicit Q_DECL_CONSTEXPR QSpecialInteger(T i) : val(S::toSpecial(i)) {}
+
+    QSpecialInteger &operator =(T i) { val = S::toSpecial(i); return *this; }
+    operator T() const { return S::fromSpecial(val); }
+
+    bool operator ==(QSpecialInteger<S> i) const { return val == i.val; }
+    bool operator !=(QSpecialInteger<S> i) const { return val != i.val; }
+
+    QSpecialInteger &operator +=(T i)
+    {   return (*this = S::fromSpecial(val) + i); }
+    QSpecialInteger &operator -=(T i)
+    {   return (*this = S::fromSpecial(val) - i); }
+    QSpecialInteger &operator *=(T i)
+    {   return (*this = S::fromSpecial(val) * i); }
+    QSpecialInteger &operator >>=(T i)
+    {   return (*this = S::fromSpecial(val) >> i); }
+    QSpecialInteger &operator <<=(T i)
+    {   return (*this = S::fromSpecial(val) << i); }
+    QSpecialInteger &operator /=(T i)
+    {   return (*this = S::fromSpecial(val) / i); }
+    QSpecialInteger &operator %=(T i)
+    {   return (*this = S::fromSpecial(val) % i); }
+    QSpecialInteger &operator |=(T i)
+    {   return (*this = S::fromSpecial(val) | i); }
+    QSpecialInteger &operator &=(T i)
+    {   return (*this = S::fromSpecial(val) & i); }
+    QSpecialInteger &operator ^=(T i)
+    {   return (*this = S::fromSpecial(val) ^ i); }
+};
+
+template<typename T>
+class QLittleEndianStorageType {
+public:
+    typedef T StorageType;
+    static Q_DECL_CONSTEXPR T toSpecial(T source) { return qToLittleEndian(source); }
+    static Q_DECL_CONSTEXPR T fromSpecial(T source) { return qFromLittleEndian(source); }
+};
+
+template<typename T>
+class QBigEndianStorageType {
+public:
+    typedef T StorageType;
+    static Q_DECL_CONSTEXPR T toSpecial(T source) { return qToBigEndian(source); }
+    static Q_DECL_CONSTEXPR T fromSpecial(T source) { return qFromBigEndian(source); }
+};
+
+template<typename T>
+using QLEInteger = QSpecialInteger<QLittleEndianStorageType<T>>;
+
+template<typename T>
+using QBEInteger = QSpecialInteger<QBigEndianStorageType<T>>;
+
+template <typename T>
+class QTypeInfo<QLEInteger<T> >
+    : public QTypeInfoMerger<QLEInteger<T>, T> {};
+
+template <typename T>
+class QTypeInfo<QBEInteger<T> >
+    : public QTypeInfoMerger<QBEInteger<T>, T> {};
+
+typedef QLEInteger<qint16> qint16_le;
+typedef QLEInteger<qint32> qint32_le;
+typedef QLEInteger<qint64> qint64_le;
+typedef QLEInteger<quint16> quint16_le;
+typedef QLEInteger<quint32> quint32_le;
+typedef QLEInteger<quint64> quint64_le;
+
+typedef QBEInteger<qint16> qint16_be;
+typedef QBEInteger<qint32> qint32_be;
+typedef QBEInteger<qint64> qint64_be;
+typedef QBEInteger<quint16> quint16_be;
+typedef QBEInteger<quint32> quint32_be;
+typedef QBEInteger<quint64> quint64_be;
+
+QT_END_NAMESPACE
+
+#endif // QENDIAN_P_H