optimization/model:refactor LOTData class to optimize memory

As std::string uses short buffer optimization internally and because of
structure allignment the size of the LOTData was 32 byte.
by handling short buffer optimization ourself now size is reduced
from 32byte to 16 byte.

Change-Id: Icf7d43fb7f93d3dd9ee568130be7bf250809c98c

diff --git a/src/lottie/lottiemodel.h b/src/lottie/lottiemodel.h
index c8d38bbf73a853334d05020b15d12846204c6300..87cf59f22f4a63401b90b6e2cbd7b226bd263aa9 100644 (file)
--- a/src/lottie/lottiemodel.h
+++ b/src/lottie/lottiemodel.h
@@ -24,6 +24,7 @@
 #include<unordered_map>
 #include<algorithm>
 #include <cmath>
+#include <cstring>
 #include"vpoint.h"
 #include"vrect.h"
 #include"vinterpolator.h"
@@ -356,7 +357,7 @@ class LOTDataVisitor;
 class LOTData
 {
 public:
-    enum class Type :short {
+    enum class Type :unsigned char {
         Composition = 1,
         Layer,
         ShapeGroup,
@@ -372,19 +373,52 @@ public:
         Trim,
         Repeater
     };
-    explicit LOTData(LOTData::Type  type): mType(type){}
-    inline LOTData::Type type() const {return mType;}
-    bool isStatic() const{return mStatic;}
-    void setStatic(bool value) {mStatic = value;}
-    bool hidden() const {return mHidden;}
-    void setHidden(bool value) {mHidden = value;}
-    void setName(const char *str) {mName = str;}
-    const char* name() const{ return mName.c_str();}
+
+    explicit LOTData(LOTData::Type type):mPtr(nullptr)
+    {
+       mData._type = type;
+       mData._static = true;
+       mData._shortString = true;
+       mData._hidden = false;
+    }
+    ~LOTData() { if (!shortString() && mPtr) free(mPtr); }
+
+    void setStatic(bool value) { mData._static = value;}
+    bool isStatic() const {return mData._static;}
+    bool hidden() const {return mData._hidden;}
+    void setHidden(bool value) {mData._hidden = value;}
+    void setType(LOTData::Type type) {mData._type = type;}
+    LOTData::Type type() const { return mData._type;}
+    void setName(const char *name)
+    {
+        if (name) {
+            auto len = strlen(name);
+            if (len < maxShortStringLength) {
+                setShortString(true);
+                strncpy ( mData._buffer, name, len+1);
+            } else {
+                setShortString(false);
+                mPtr = strdup(name);
+            }
+
+        }
+    }
+    const char* name() const {return shortString() ? mData._buffer : mPtr;}
 private:
-    std::string               mName;
-    bool                      mStatic{true};
-    bool                      mHidden{false};
-    LOTData::Type             mType;
+    static constexpr unsigned char maxShortStringLength = 14;
+    void setShortString(bool value) {mData._shortString = value;}
+    bool shortString() const {return mData._shortString;}
+    struct Data{
+      char           _buffer[14];
+      LOTData::Type  _type;
+      bool           _static      : 1;
+      bool           _hidden      : 1;
+      bool           _shortString : 1;
+    };
+    union {
+        Data  mData;
+        char *mPtr;
+    };
 };
 
 class LOTGroupData: public LOTData
@@ -648,9 +682,9 @@ public:
     FillRule fillRule() const {return mFillRule;}
 public:
     FillRule                       mFillRule{FillRule::Winding}; /* "r" */
+    bool                           mEnabled{true}; /* "fillEnabled" */
     LOTAnimatable<LottieColor>     mColor;   /* "c" */
     LOTAnimatable<float>           mOpacity{100};  /* "o" */
-    bool                           mEnabled{true}; /* "fillEnabled" */
 };
 
 struct LOTDashProperty