lottie: expressions compactness++

expressions is an optional feature,
do not prepare expressions if the engine doesn't support it.

src/loaders/lottie/tvgLottieBuilder.h

@@ -98,6 +98,11 @@ struct LottieBuilder
         LottieExpressions::retrieve(exps);
     }
 
+    bool expressions()
+    {
+        return exps ? true : false;
+    }
+
     bool update(LottieComposition* comp, float progress);
     void build(LottieComposition* comp);
 

src/loaders/lottie/tvgLottieLoader.cpp

@@ -37,7 +37,7 @@ void LottieLoader::run(unsigned tid)
         builder->update(comp, frameNo);
     //initial loading
     } else {
-        LottieParser parser(content, dirName);
+        LottieParser parser(content, dirName, builder->expressions());
         if (!parser.parse()) return;
         {
             ScopedLock lock(key);
@@ -300,7 +300,7 @@ bool LottieLoader::override(const char* slots, bool byDefault)
         auto temp = byDefault ? slots : strdup(slots);
 
         //parsing slot json
-        LottieParser parser(temp, dirName);
+        LottieParser parser(temp, dirName, builder->expressions());
         parser.comp = comp;
 
         auto idx = 0;

src/loaders/lottie/tvgLottieParser.cpp

@@ -34,8 +34,18 @@
 #define KEY_AS(name) !strcmp(key, name)
 
 
-static LottieExpression* _expression(char* code, LottieComposition* comp, LottieLayer* layer, LottieObject* object, LottieProperty* property)
+static unsigned long _int2str(int num)
 {
+    char str[20];
+    snprintf(str, 20, "%d", num);
+    return djb2Encode(str);
+}
+
+
+LottieExpression* LottieParser::getExpression(char* code, LottieComposition* comp, LottieLayer* layer, LottieObject* object, LottieProperty* property)
+{
+    if (!expressions) return nullptr;
+
     if (!comp->expressions) comp->expressions = true;
 
     auto inst = new LottieExpression;
@@ -49,14 +59,6 @@ static LottieExpression* _expression(char* code, LottieComposition* comp, Lottie
 }
 
 
-static unsigned long _int2str(int num)
-{
-    char str[20];
-    snprintf(str, 20, "%d", num);
-    return djb2Encode(str);
-}
-
-
 LottieEffect* LottieParser::getEffect(int type)
 {
     switch (type) {
@@ -477,7 +479,7 @@ void LottieParser::parseProperty(T& prop, LottieObject* obj)
     while (auto key = nextObjectKey()) {
         if (KEY_AS("k")) parsePropertyInternal(prop);
         else if (obj && KEY_AS("sid")) registerSlot<type>(obj, getString());
-        else if (KEY_AS("x")) prop.exp = _expression(getStringCopy(), comp, context.layer, context.parent, &prop);
+        else if (KEY_AS("x")) prop.exp = getExpression(getStringCopy(), comp, context.layer, context.parent, &prop);
         else if (KEY_AS("ix")) prop.ix = getInt();
         else skip();
     }
@@ -566,7 +568,7 @@ LottieTransform* LottieParser::parseTransform(bool ddd)
                 //check separateCoord to figure out whether "x(expression)" / "x(coord)"
                 else if (transform->coords && KEY_AS("x")) parseProperty<LottieProperty::Type::Float>(transform->coords->x);
                 else if (transform->coords && KEY_AS("y")) parseProperty<LottieProperty::Type::Float>(transform->coords->y);
-                else if (KEY_AS("x")) transform->position.exp = _expression(getStringCopy(), comp, context.layer, context.parent, &transform->position);
+                else if (KEY_AS("x")) transform->position.exp = getExpression(getStringCopy(), comp, context.layer, context.parent, &transform->position);
                 else if (KEY_AS("sid")) registerSlot<LottieProperty::Type::Position>(transform, getString());
                 else skip();
             }
@@ -659,7 +661,7 @@ void LottieParser::getPathSet(LottiePathSet& path)
                 getValue(path.value);
             }
         } else if (KEY_AS("x")) {
-            path.exp = _expression(getStringCopy(), comp, context.layer, context.parent, &path);
+            path.exp = getExpression(getStringCopy(), comp, context.layer, context.parent, &path);
         } else skip();
     }
     path.type = LottieProperty::Type::PathSet;

src/loaders/lottie/tvgLottieParser.h

@@ -30,9 +30,10 @@
 struct LottieParser : LookaheadParserHandler
 {
 public:
-    LottieParser(const char *str, const char* dirName) : LookaheadParserHandler(str)
+    LottieParser(const char *str, const char* dirName, bool expressions) : LookaheadParserHandler(str)
     {
         this->dirName = dirName;
+        this->expressions = expressions;
     }
 
     bool parse();
@@ -44,6 +45,7 @@ public:
     LottieComposition* comp = nullptr;
     const char* dirName = nullptr;       //base resource directory
     char* slots = nullptr;
+    bool expressions = false;            //support expressions?
 
 private:
     RGB24 getColor(const char *str);
@@ -51,6 +53,7 @@ private:
     MaskMethod getMaskMethod(bool inversed);
     LottieInterpolator* getInterpolator(const char* key, Point& in, Point& out);
     LottieEffect* getEffect(int type);
+    LottieExpression* getExpression(char* code, LottieComposition* comp, LottieLayer* layer, LottieObject* object, LottieProperty* property);
 
     void getInterpolatorPoint(Point& pt);
     void getPathSet(LottiePathSet& path);