QTextBoundaryFinder: squash the bitfield member

This is in the way of adding an inline member-swap() (can't take
references to bit-fields), and therefore move-assignment.

We can always redistribute the bits in freeBuffer later, if needed:
there are (and, since 6.0, were) no inline users of this member.

This should even improve codegen, as the compiler doesn't have to deal
with bit-fields anymore. There's no need to pessimize the code for
that kind of flexibility until another user actually surfaces.

Amends the start of the public history.

Task-number: QTBUG-138659
Pick-to: 6.10 6.9 6.8 6.5
Change-Id: I47eb96da87bf4e3f1052e9f455943d9dea3121d1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/text/qtextboundaryfinder.cpp

@@ -104,7 +104,6 @@ static void init(QTextBoundaryFinder::BoundaryType type, QStringView str, QCharA
 */
 QTextBoundaryFinder::QTextBoundaryFinder()
     : freeBuffer(true)
-    , unused{0}
 {
 }
 
@@ -117,7 +116,6 @@ QTextBoundaryFinder::QTextBoundaryFinder(const QTextBoundaryFinder &other)
     , sv(other.sv)
     , pos(other.pos)
     , freeBuffer(true)
-    , unused{0}
 {
     if (other.attributes) {
         Q_ASSERT(sv.size() > 0);
@@ -165,7 +163,6 @@ QTextBoundaryFinder &QTextBoundaryFinder::operator=(const QTextBoundaryFinder &o
 */
 QTextBoundaryFinder::~QTextBoundaryFinder()
 {
-    Q_UNUSED(unused);
     if (freeBuffer)
         free(attributes);
 }
@@ -178,7 +175,6 @@ QTextBoundaryFinder::QTextBoundaryFinder(BoundaryType type, const QString &strin
     , s(string)
     , sv(s)
     , freeBuffer(true)
-    , unused{0}
 {
     if (sv.size() > 0) {
         attributes = (QCharAttributes *) malloc((sv.size() + 1) * sizeof(QCharAttributes));
@@ -212,7 +208,6 @@ QTextBoundaryFinder::QTextBoundaryFinder(BoundaryType type, QStringView string,
     : t(type)
     , sv(string)
     , freeBuffer(true)
-    , unused{0}
 {
     if (!sv.isEmpty()) {
         if (buffer && bufferSize / int(sizeof(QCharAttributes)) >= sv.size() + 1) {

src/corelib/text/qtextboundaryfinder.h

@@ -65,8 +65,7 @@ private:
     QString s;
     QStringView sv;
     qsizetype pos = 0;
-    uint freeBuffer : 1;
-    uint unused : 31;
+    uint freeBuffer; // this may be used to store another 31 bit of data in the future
     QCharAttributes *attributes = nullptr;
 };