change how we store Region data internally

We used to keep the bounds of the region as a
separate rectangle. Instead we now store it as the last
element of the Vector<> of Rects.

This has the benefit of being slightly more efficient when
copying regions and reduces the overhead of small regions,
but more importantly will allow us to export the underlaying
SharedBuffer (eventually).

Change-Id: I80790e4fb1a09a747a5616000cfef852ac4ce9e9

1 files changed, 30 insertions, 43 deletions

diff --git a/libs/ui/Region.cpp b/libs/ui/Region.cpp
index 2569ae1..cdc2894 100644
--- a/libs/ui/Region.cpp
+++ b/libs/ui/Region.cpp
@@ -48,22 +48,20 @@ enum {
 
 // ----------------------------------------------------------------------------
 
-Region::Region()
-    : mBounds(0,0)
-{
+Region::Region() {
+    mStorage.add(Rect(0,0));
 }
 
 Region::Region(const Region& rhs)
-    : mBounds(rhs.mBounds), mStorage(rhs.mStorage)
+    : mStorage(rhs.mStorage)
 {
 #if VALIDATE_REGIONS
     validate(rhs, "rhs copy-ctor");
 #endif
 }
 
-Region::Region(const Rect& rhs)
-    : mBounds(rhs)
-{
+Region::Region(const Rect& rhs) {
+    mStorage.add(rhs);
 }
 
 Region::~Region()
@@ -76,40 +74,46 @@ Region& Region::operator = (const Region& rhs)
     validate(*this, "this->operator=");
     validate(rhs, "rhs.operator=");
 #endif
-    mBounds = rhs.mBounds;
     mStorage = rhs.mStorage;
     return *this;
 }
 
 Region& Region::makeBoundsSelf()
 {
-    mStorage.clear();
+    if (mStorage.size() >= 2) {
+        const Rect bounds(getBounds());
+        mStorage.clear();
+        mStorage.add(bounds);
+    }
     return *this;
 }
 
 void Region::clear()
 {
-    mBounds.clear();
     mStorage.clear();
+    mStorage.add(Rect(0,0));
 }
 
 void Region::set(const Rect& r)
 {
-    mBounds = r;
     mStorage.clear();
+    mStorage.add(r);
 }
 
 void Region::set(uint32_t w, uint32_t h)
 {
-    mBounds = Rect(int(w), int(h));
     mStorage.clear();
+    mStorage.add(Rect(w,h));
 }
 
 // ----------------------------------------------------------------------------
 
 void Region::addRectUnchecked(int l, int t, int r, int b)
 {
-    mStorage.add(Rect(l,t,r,b));
+    Rect rect(l,t,r,b);
+    size_t where = mStorage.size() - 1;
+    mStorage.insertAt(rect, where, 1);
+
 #if VALIDATE_REGIONS
     validate(*this, "addRectUnchecked");
 #endif
@@ -252,7 +256,7 @@ const Region Region::operation(const Region& rhs, int dx, int dy, int op) const
 // to obtain an optimal region.
 class Region::rasterizer : public region_operator<Rect>::region_rasterizer 
 {
-    Rect& bounds;
+    Rect bounds;
     Vector<Rect>& storage;
     Rect* head;
     Rect* tail;
@@ -260,10 +264,7 @@ class Region::rasterizer : public region_operator<Rect>::region_rasterizer
     Rect* cur;
 public:
     rasterizer(Region& reg) 
-        : bounds(reg.mBounds), storage(reg.mStorage), head(), tail(), cur() {
-        bounds.top = bounds.bottom = 0;
-        bounds.left   = INT_MAX;
-        bounds.right  = INT_MIN;
+        : bounds(INT_MAX, 0, INT_MIN, 0), storage(reg.mStorage), head(), tail(), cur() {
         storage.clear();
     }
 
@@ -281,6 +282,7 @@ public:
             bounds.left  = 0;
             bounds.right = 0;
         }
+        storage.add(bounds);
     }
     
     virtual void operator()(const Rect& rect) {
@@ -372,6 +374,9 @@ bool Region::validate(const Region& reg, const char* name)
                 reg.getBounds().left, reg.getBounds().top, 
                 reg.getBounds().right, reg.getBounds().bottom);
     }
+    if (reg.mStorage.size() == 2) {
+        ALOGE("mStorage size is 2, which is never valid");
+    }
     if (result == false) {
         reg.dump(name);
     }
@@ -533,7 +538,6 @@ void Region::translate(Region& reg, int dx, int dy)
 #if VALIDATE_REGIONS
         validate(reg, "translate (before)");
 #endif
-        reg.mBounds.translate(dx, dy);
         size_t count = reg.mStorage.size();
         Rect* rects = reg.mStorage.editArray();
         while (count) {
@@ -556,12 +560,11 @@ void Region::translate(Region& dst, const Region& reg, int dx, int dy)
 // ----------------------------------------------------------------------------
 
 size_t Region::getSize() const {
-    return (mStorage.size() + 1) * sizeof(Rect);
+    return mStorage.size() * sizeof(Rect);
 }
 
 status_t Region::flatten(void* buffer) const {
     Rect* rects = reinterpret_cast<Rect*>(buffer);
-    *rects++ = mBounds;
     memcpy(rects, mStorage.array(), mStorage.size() * sizeof(Rect));
     return NO_ERROR;
 }
@@ -570,8 +573,6 @@ status_t Region::unflatten(void const* buffer, size_t size) {
     mStorage.clear();
     if (size >= sizeof(Rect)) {
         Rect const* rects = reinterpret_cast<Rect const*>(buffer);
-        mBounds = *rects++;
-        size -= sizeof(Rect);
         size_t count = size / sizeof(Rect);
         if (count > 0) {
             ssize_t err = mStorage.insertAt(0, count);
@@ -581,25 +582,21 @@ status_t Region::unflatten(void const* buffer, size_t size) {
             memcpy(mStorage.editArray(), rects, count*sizeof(Rect));
         }
     }
+#if VALIDATE_REGIONS
+    validate(*this, "Region::unflatten");
+#endif
     return NO_ERROR;
 }
 
 // ----------------------------------------------------------------------------
 
 Region::const_iterator Region::begin() const {
-    return isRect() ? &mBounds : mStorage.array();
+    return mStorage.array();
 }
 
 Region::const_iterator Region::end() const {
-    if (isRect()) {
-        if (isEmpty()) {
-            return &mBounds;
-        } else {
-            return &mBounds + 1;
-        }
-    } else {
-        return mStorage.array() + mStorage.size();
-    }
+    size_t numRects = isRect() ? 1 : mStorage.size() - 1;
+    return mStorage.array() + numRects;
 }
 
 Rect const* Region::getArray(size_t* count) const {
@@ -609,16 +606,6 @@ Rect const* Region::getArray(size_t* count) const {
     return b;
 }
 
-size_t Region::getRects(Vector<Rect>& rectList) const
-{
-    rectList = mStorage;
-    if (rectList.isEmpty()) {
-        rectList.clear();
-        rectList.add(mBounds);
-    }
-    return rectList.size();
-}
-
 // ----------------------------------------------------------------------------
 
 void Region::dump(String8& out, const char* what, uint32_t flags) const