New qfloat16 class

This constitutes a fairly complete submission of an entirely new
floating point type which conforms to IEEE 754 as a 16-bit storage
class.  Conversion between qfloat16 and float is currently performed
through a sequence of lookup tables.  Global-level functions
qRound(), qRound64(), qFuzzyCompare(), qFuzzyIsNull(), and
qIsNull() each with a qfloat16 parameter have been included
for completeness.

[ChangeLog][QtCore] Added new qfloat16 class.

Change-Id: Ia52eb27846965c14f8140c00faf5ba33c9443976
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 31 insertions, 1 deletions

diff --git a/src/corelib/io/qdatastream.cpp b/src/corelib/io/qdatastream.cpp
index 2730fd7f11..cac5152e87 100644
--- a/src/corelib/io/qdatastream.cpp
+++ b/src/corelib/io/qdatastream.cpp
@@ -448,6 +448,9 @@ QDataStream::FloatingPointPrecision QDataStream::floatingPointPrecision() const
 
     The default is DoublePrecision.
 
+    Note that this property does not affect the serialization or deserialization of \c qfloat16
+    instances.
+
     \warning This property must be set to the same value on the object that writes and the object
     that reads the data stream.
 
@@ -972,6 +975,16 @@ QDataStream &QDataStream::operator>>(double &f)
 
 
 /*!
+    \fn QDataStream &QDataStream::operator>>(qfloat16 &f)
+    \overload
+    \since 5.9
+
+    Reads a floating point number from the stream into \a f,
+    using the standard IEEE 754 format. Returns a reference to the
+    stream.
+*/
+
+/*!
     \overload
 
     Reads the '\\0'-terminated string \a s from the stream and returns
@@ -1260,6 +1273,15 @@ QDataStream &QDataStream::operator<<(double f)
 
 
 /*!
+    \fn QDataStream &QDataStream::operator<<(qfloat16 f)
+    \overload
+    \since 5.9
+
+    Writes a floating point number, \a f, to the stream using
+    the standard IEEE 754 format. Returns a reference to the stream.
+*/
+
+/*!
     \overload
 
     Writes the '\\0'-terminated string \a s to the stream and returns a
@@ -1282,7 +1304,6 @@ QDataStream &QDataStream::operator<<(const char *s)
     return *this;
 }
 
-
 /*!
     Writes the length specifier \a len and the buffer \a s to the
     stream and returns a reference to the stream.
diff --git a/src/corelib/io/qdatastream.h b/src/corelib/io/qdatastream.h
index 994ed88791..9a7d7e275d 100644
--- a/src/corelib/io/qdatastream.h
+++ b/src/corelib/io/qdatastream.h
@@ -43,6 +43,7 @@
 #include <QtCore/qscopedpointer.h>
 #include <QtCore/qiodevice.h>
 #include <QtCore/qpair.h>
+#include <QtCore/qfloat16.h>
 
 #ifdef Status
 #error qdatastream.h must be included before any header file that defines Status
@@ -154,6 +155,7 @@ public:
     QDataStream &operator>>(quint64 &i);
 
     QDataStream &operator>>(bool &i);
+    QDataStream &operator>>(qfloat16 &f);
     QDataStream &operator>>(float &f);
     QDataStream &operator>>(double &f);
     QDataStream &operator>>(char *&str);
@@ -167,6 +169,7 @@ public:
     QDataStream &operator<<(qint64 i);
     QDataStream &operator<<(quint64 i);
     QDataStream &operator<<(bool i);
+    QDataStream &operator<<(qfloat16 f);
     QDataStream &operator<<(float f);
     QDataStream &operator<<(double f);
     QDataStream &operator<<(const char *str);
@@ -345,6 +348,9 @@ inline QDataStream &QDataStream::operator>>(quint32 &i)
 inline QDataStream &QDataStream::operator>>(quint64 &i)
 { return *this >> reinterpret_cast<qint64&>(i); }
 
+inline QDataStream &QDataStream::operator>>(qfloat16 &f)
+{ return *this >> reinterpret_cast<qint16&>(f); }
+
 inline QDataStream &QDataStream::operator<<(quint8 i)
 { return *this << qint8(i); }
 
@@ -357,6 +363,9 @@ inline QDataStream &QDataStream::operator<<(quint32 i)
 inline QDataStream &QDataStream::operator<<(quint64 i)
 { return *this << qint64(i); }
 
+inline QDataStream &QDataStream::operator<<(qfloat16 f)
+{ return *this << reinterpret_cast<qint16&>(f); }
+
 template <typename T>
 inline QDataStream &operator>>(QDataStream &s, QList<T> &l)
 {