preprocessor: avoid branches in tight code

Change-Id: I8dc0910f1cf11e506eb415a6f313b47ad2d41eae
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@nokia.com>

src/libs/cplusplus/PPToken.cpp

@@ -4,11 +4,7 @@
 
 using namespace CPlusPlus::Internal;
 
-ByteArrayRef::ByteArrayRef()
-    : m_ref(0)
-    , m_offset(0)
-    , m_length(0)
-{}
+const QByteArray ByteArrayRef::m_emptyByteArray;
 
 bool ByteArrayRef::startsWith(const char *s) const
 {
@@ -20,9 +16,6 @@ bool ByteArrayRef::startsWith(const char *s) const
 
 int ByteArrayRef::count(char ch) const
 {
-    if (!m_ref)
-        return 0;
-
     int num = 0;
     const char *b = start();
     const char *i = b + m_length;

src/libs/cplusplus/PPToken.h

@@ -12,7 +12,11 @@ namespace Internal {
 class CPLUSPLUS_EXPORT ByteArrayRef
 {
 public:
-    ByteArrayRef();
+    ByteArrayRef()
+        : m_ref(&m_emptyByteArray)
+        , m_offset(0)
+        , m_length(0)
+    {}
 
     ByteArrayRef(const QByteArray *ref)
         : m_ref(ref)
@@ -32,7 +36,7 @@ public:
     }
 
     inline const char *start() const
-    { return m_ref ? m_ref->constData() + m_offset : 0; }
+    { return m_ref->constData() + m_offset; }
 
     inline int length() const
     { return m_length; }
@@ -41,16 +45,16 @@ public:
     { return length(); }
 
     inline char at(int pos) const
-    { return m_ref && pos >= 0 && pos < m_length ? m_ref->at(m_offset + pos) : '\0'; }
+    { return pos >= 0 && pos < m_length ? m_ref->at(m_offset + pos) : '\0'; }
 
     inline char operator[](int pos) const
     { return at(pos); }
 
     QByteArray toByteArray() const
-    { return m_ref ? QByteArray(m_ref->constData() + m_offset, m_length) : QByteArray(); }
+    { return QByteArray(m_ref->constData() + m_offset, m_length); }
 
     bool operator==(const QByteArray &other) const
-    { return m_ref ? (m_length == other.length() && !qstrncmp(m_ref->constData() + m_offset, other.constData(), m_length)) : false; }
+    { return m_length == other.length() && !qstrncmp(m_ref->constData() + m_offset, other.constData(), m_length); }
     bool operator!=(const QByteArray &other) const
     { return !this->operator==(other); }
 
@@ -59,9 +63,10 @@ public:
     int count(char c) const;
 
 private:
-    const QByteArray *m_ref;
-    int m_offset;
-    int m_length;
+    const static QByteArray m_emptyByteArray;
+    const QByteArray * const m_ref;
+    const int m_offset;
+    const int m_length;
 };
 
 inline bool operator==(const QByteArray &other, const ByteArrayRef &ref)