optimize QImage comparison

Signed-off-by: Ivailo Monev <xakepa10@laimg.moc>

src/gui/image/qimage.cpp

@@ -4328,10 +4328,8 @@ QDataStream &operator<<(QDataStream &s, const QImage &image)
     if (image.isNull()) {
         s << (qint32) 0; // null image marker
         return s;
-    } else {
-        s << (qint32) 1;
-        // continue ...
     }
+    s << (qint32) 1;
     QImageWriter writer(s.device(), "png");
     writer.write(image);
     return s;
@@ -4378,51 +4376,12 @@ QDataStream &operator>>(QDataStream &s, QImage &image)
 bool QImage::operator==(const QImage & i) const
 {
     // same object, or shared?
-    if (i.d == d)
+    if (d == i.d)
         return true;
-    if (!i.d || !d)
-        return false;
 
-    // obviously different stuff?
-    if (i.d->height != d->height || i.d->width != d->width || i.d->format != d->format)
+    if (!d || !i.d || d->ser_no != i.d->ser_no || d->detach_no != i.d->detach_no)
         return false;
 
-    if (d->format != Format_RGB32) {
-        if (d->format >= Format_ARGB32) { // all bits defined
-            const int n = d->width * d->depth / 8;
-            if (n == d->bytes_per_line && n == i.d->bytes_per_line) {
-                if (memcmp(bits(), i.constBits(), d->nbytes))
-                    return false;
-            } else {
-                for (int y = 0; y < d->height; ++y) {
-                    if (memcmp(scanLine(y), i.scanLine(y), n))
-                        return false;
-                }
-            }
-        } else {
-            const int w = width();
-            const int h = height();
-            const QVector<QRgb> &colortable = d->colortable;
-            const QVector<QRgb> &icolortable = i.d->colortable;
-            for (int y=0; y<h; ++y) {
-                for (int x=0; x<w; ++x) {
-                    if (colortable[pixelIndex(x, y)] != icolortable[i.pixelIndex(x, y)])
-                        return false;
-                }
-            }
-        }
-    } else {
-        //alpha channel undefined, so we must mask it out
-        for(int l = 0; l < d->height; l++) {
-            int w = d->width;
-            const uint *p1 = reinterpret_cast<const uint*>(scanLine(l));
-            const uint *p2 = reinterpret_cast<const uint*>(i.scanLine(l));
-            while (w--) {
-                if ((*p1++ & 0x00ffffff) != (*p2++ & 0x00ffffff))
-                    return false;
-            }
-        }
-    }
     return true;
 }