Move qle_bitfield to qendian_p.h

Makes the qle_bitfield template more generic and moves it to qendian_p.h
It is also hardened to be more reliable.

Change-Id: I53214ec99cceee4f5e8934ae688c99e555a5fb42
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 85 insertions, 90 deletions

diff --git a/src/corelib/global/qendian_p.h b/src/corelib/global/qendian_p.h
index b279701a31..42d91cf735 100644
--- a/src/corelib/global/qendian_p.h
+++ b/src/corelib/global/qendian_p.h
@@ -51,7 +51,7 @@
 // We mean it.
 //
 
-#include "qendian.h"
+#include <QtCore/qendian.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -136,6 +136,88 @@ typedef QBEInteger<quint16> quint16_be;
 typedef QBEInteger<quint32> quint32_be;
 typedef QBEInteger<quint64> quint64_be;
 
+// Note if using multiple of these bitfields in a union; the underlying storage type must
+// match. Since we always use an unsigned storage type, unsigned and signed versions may
+// be used together, but different bit-widths may not.
+template<class S, int pos, int width>
+class QSpecialIntegerBitfield
+{
+protected:
+    typedef typename S::StorageType T;
+    typedef typename std::make_unsigned<T>::type UT;
+
+    static Q_DECL_CONSTEXPR UT mask()
+    {
+        return ((UT(1) << width) - 1) << pos;
+    }
+public:
+    // FIXME: val is public until qtdeclarative is fixed to not access it directly.
+    UT val;
+
+    QSpecialIntegerBitfield &operator =(T t)
+    {
+        UT i = S::fromSpecial(val);
+        i &= ~mask();
+        i |= (UT(t) << pos) & mask();
+        val  = S::toSpecial(i);
+        return *this;
+    }
+    operator T() const
+    {
+        if (std::is_signed<T>::value) {
+            UT i = S::fromSpecial(val);
+            i <<= (sizeof(T) * 8) - width - pos;
+            T t = T(i);
+            t >>= (sizeof(T) * 8) - width;
+            return t;
+        }
+        return (S::fromSpecial(val) & mask()) >> pos;
+    }
+
+    bool operator !() const { return !(val & S::toSpecial(mask())); }
+    bool operator ==(QSpecialIntegerBitfield<S, pos, width> i) const
+    {   return ((val ^ i.val) & S::toSpecial(mask())) == 0; }
+    bool operator !=(QSpecialIntegerBitfield<S, pos, width> i) const
+    {   return ((val ^ i.val) & S::toSpecial(mask())) != 0; }
+
+    QSpecialIntegerBitfield &operator +=(T i)
+    {   return (*this = (T(*this) + i)); }
+    QSpecialIntegerBitfield &operator -=(T i)
+    {   return (*this = (T(*this) - i)); }
+    QSpecialIntegerBitfield &operator *=(T i)
+    {   return (*this = (T(*this) * i)); }
+    QSpecialIntegerBitfield &operator /=(T i)
+    {   return (*this = (T(*this) / i)); }
+    QSpecialIntegerBitfield &operator %=(T i)
+    {   return (*this = (T(*this) % i)); }
+    QSpecialIntegerBitfield &operator |=(T i)
+    {   return (*this = (T(*this) | i)); }
+    QSpecialIntegerBitfield &operator &=(T i)
+    {   return (*this = (T(*this) & i)); }
+    QSpecialIntegerBitfield &operator ^=(T i)
+    {   return (*this = (T(*this) ^ i)); }
+    QSpecialIntegerBitfield &operator >>=(T i)
+    {   return (*this = (T(*this) >> i)); }
+    QSpecialIntegerBitfield &operator <<=(T i)
+    {   return (*this = (T(*this) << i)); }
+};
+
+template<typename T, int pos, int width>
+using QLEIntegerBitfield = QSpecialIntegerBitfield<QLittleEndianStorageType<T>, pos, width>;
+
+template<typename T, int pos, int width>
+using QBEIntegerBitfield = QSpecialIntegerBitfield<QBigEndianStorageType<T>, pos, width>;
+
+template<int pos, int width>
+using qint32_le_bitfield = QLEIntegerBitfield<int, pos, width>;
+template<int pos, int width>
+using quint32_le_bitfield = QLEIntegerBitfield<uint, pos, width>;
+template<int pos, int width>
+using qint32_be_bitfield = QBEIntegerBitfield<int, pos, width>;
+template<int pos, int width>
+using quint32_be_bitfield = QBEIntegerBitfield<uint, pos, width>;
+
+
 QT_END_NAMESPACE
 
 #endif // QENDIAN_P_H
diff --git a/src/corelib/json/qjson_p.h b/src/corelib/json/qjson_p.h
index 5d600843aa..131528376b 100644
--- a/src/corelib/json/qjson_p.h
+++ b/src/corelib/json/qjson_p.h
@@ -140,97 +140,10 @@ typedef q_littleendian<int> qle_int;
 typedef q_littleendian<unsigned int> qle_uint;
 
 template<int pos, int width>
-class qle_bitfield
-{
-public:
-    uint val;
-
-    enum {
-        mask = ((1u << width) - 1) << pos
-    };
-
-    void operator =(uint t) {
-        uint i = qFromLittleEndian(val);
-        i &= ~mask;
-        i |= t << pos;
-        val = qToLittleEndian(i);
-    }
-    operator uint() const {
-        uint t = qFromLittleEndian(val);
-        t &= mask;
-        t >>= pos;
-        return t;
-    }
-    bool operator !() const {
-        return !operator uint();
-    }
-
-    bool operator ==(uint t) { return uint(*this) == t; }
-    bool operator !=(uint t) { return uint(*this) != t; }
-    bool operator <(uint t) { return uint(*this) < t; }
-    bool operator >(uint t) { return uint(*this) > t; }
-    bool operator <=(uint t) { return uint(*this) <= t; }
-    bool operator >=(uint t) { return uint(*this) >= t; }
-    qle_bitfield &operator +=(uint i) {
-        *this = (uint(*this) + i);
-        return *this;
-    }
-    qle_bitfield &operator -=(uint i) {
-        *this = (uint(*this) - i);
-        return *this;
-    }
-    qle_bitfield &operator |=(uint i) {
-        *this = (uint(*this) | i);
-        return *this;
-    }
-    qle_bitfield &operator &=(uint i) {
-        *this = (uint(*this) & i);
-        return *this;
-    }
-};
+using qle_bitfield = QLEIntegerBitfield<uint, pos, width>;
 
 template<int pos, int width>
-class qle_signedbitfield
-{
-public:
-    uint val;
-
-    enum {
-        mask = ((1u << width) - 1) << pos
-    };
-
-    void operator =(int t) {
-        uint i = qFromLittleEndian(val);
-        i &= ~mask;
-        i |= t << pos;
-        val = qToLittleEndian(i);
-    }
-    operator int() const {
-        uint i = qFromLittleEndian(val);
-        i <<= 32 - width - pos;
-        int t = (int) i;
-        t >>= 32 - width;
-        return t;
-    }
-    bool operator !() const {
-        return !operator int();
-    }
-
-    bool operator ==(int t) { return int(*this) == t; }
-    bool operator !=(int t) { return int(*this) != t; }
-    bool operator <(int t) { return int(*this) < t; }
-    bool operator >(int t) { return int(*this) > t; }
-    bool operator <=(int t) { return int(*this) <= t; }
-    bool operator >=(int t) { return int(*this) >= t; }
-    qle_signedbitfield &operator +=(int i) {
-        *this = (int(*this) + i);
-        return *this;
-    }
-    qle_signedbitfield &operator -=(int i) {
-        *this = (int(*this) - i);
-        return *this;
-    }
-};
+using qle_signedbitfield = QLEIntegerBitfield<int, pos, width>;
 
 typedef qle_uint offset;