Json writer, support larger signed integers upto 2^53

Previously only 32bit signed integers were ensured to be supported by
JsonValue type via API but it is expected that a larger integer range
should be supported by a JSON implementation.

This commit brings the Qt implementation into parity with NodeJS
JSON.stringify() in respect of the JavaScript Number type.

Change-Id: If91153cb3b13ecc14c50da97055b35ce42f341e7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 13 insertions, 0 deletions

diff --git a/src/corelib/json/qjsonvalue.cpp b/src/corelib/json/qjsonvalue.cpp
index a540626579..d0b06c6924 100644
--- a/src/corelib/json/qjsonvalue.cpp
+++ b/src/corelib/json/qjsonvalue.cpp
@@ -156,6 +156,18 @@ QJsonValue::QJsonValue(int n)
 }
 
 /*!
+    \overload
+    Creates a value of type Double, with value \a n.
+    NOTE: the integer limits for IEEE 754 double precision data is 2^53 (-9007199254740992 to +9007199254740992).
+    If you pass in values outside this range expect a loss of precision to occur.
+ */
+QJsonValue::QJsonValue(qint64 n)
+    : d(0), t(Double)
+{
+    this->dbl = n;
+}
+
+/*!
     Creates a value of type String, with value \a s.
  */
 QJsonValue::QJsonValue(const QString &s)
diff --git a/src/corelib/json/qjsonvalue.h b/src/corelib/json/qjsonvalue.h
index b8bdf55aa3..c8efab5d5f 100644
--- a/src/corelib/json/qjsonvalue.h
+++ b/src/corelib/json/qjsonvalue.h
@@ -79,6 +79,7 @@ public:
     QJsonValue(bool b);
     QJsonValue(double n);
     QJsonValue(int n);
+    QJsonValue(qint64 n);
     QJsonValue(const QString &s);
     QJsonValue(QLatin1String s);
     QJsonValue(const QJsonArray &a);