qendian: Fix float conversions

Since Qt 5.10, qTo/FromBig/LittleEndian<float/double> stopped working.
It may be confusing, but big endian floats do exist, so not to break old
code, we should support them.

Change-Id: I21cdbc7f48ec030ce3d82f1cd1aad212f0fe5dd0
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/corelib/global/qendian.h b/src/corelib/global/qendian.h
index 1cc8a823d9..0e67a1ab8e 100644
--- a/src/corelib/global/qendian.h
+++ b/src/corelib/global/qendian.h
@@ -41,6 +41,7 @@
 #ifndef QENDIAN_H
 #define QENDIAN_H
 
+#include <QtCore/qfloat16.h>
 #include <QtCore/qglobal.h>
 
 // include stdlib.h and hope that it defines __GLIBC__ for glibc-based systems
@@ -151,6 +152,31 @@ template <> inline Q_DECL_CONSTEXPR qint8 qbswap<qint8>(qint8 source)
     return source;
 }
 
+// floating specializations
+template<typename Float>
+Float qbswapFloatHelper(Float source)
+{
+    // memcpy call in qFromUnaligned is recognized by optimizer as a correct way of type prunning
+    auto temp = qFromUnaligned<typename QIntegerForSizeof<Float>::Unsigned>(&source);
+    temp = qbswap(temp);
+    return qFromUnaligned<Float>(&temp);
+}
+
+template <> inline qfloat16 qbswap<qfloat16>(qfloat16 source)
+{
+    return qbswapFloatHelper(source);
+}
+
+template <> inline float qbswap<float>(float source)
+{
+    return qbswapFloatHelper(source);
+}
+
+template <> inline double qbswap<double>(double source)
+{
+    return qbswapFloatHelper(source);
+}
+
 /*
  * qbswap(const T src, const void *dest);
  * Changes the byte order of \a src from big endian to little endian or vice versa