Merge pull request open-source-parsers#599 from pavel-pimenov/fix-v815

Fix V815:Decreased performance

Author: cdunn2001

src/lib_json/json_reader.cpp

@@ -137,7 +137,7 @@ bool Reader::parse(const char* beginDoc,
   current_ = begin_;
   lastValueEnd_ = 0;
   lastValue_ = 0;
-  commentsBefore_ = "";
+  commentsBefore_.clear();
   errors_.clear();
   while (!nodes_.empty())
     nodes_.pop();
@@ -176,7 +176,7 @@ bool Reader::readValue() {
 
   if (collectComments_ && !commentsBefore_.empty()) {
     currentValue().setComment(commentsBefore_, commentBefore);
-    commentsBefore_ = "";
+    commentsBefore_.clear();
   }
 
   switch (token.type_) {
@@ -474,7 +474,7 @@ bool Reader::readObject(Token& tokenStart) {
       break;
     if (tokenName.type_ == tokenObjectEnd && name.empty()) // empty object
       return true;
-    name = "";
+    name.clear();
     if (tokenName.type_ == tokenString) {
       if (!decodeString(tokenName, name))
         return recoverFromError(tokenObjectEnd);
@@ -1056,7 +1056,7 @@ bool OurReader::parse(const char* beginDoc,
   current_ = begin_;
   lastValueEnd_ = 0;
   lastValue_ = 0;
-  commentsBefore_ = "";
+  commentsBefore_.clear();
   errors_.clear();
   while (!nodes_.empty())
     nodes_.pop();
@@ -1098,7 +1098,7 @@ bool OurReader::readValue() {
 
   if (collectComments_ && !commentsBefore_.empty()) {
     currentValue().setComment(commentsBefore_, commentBefore);
-    commentsBefore_ = "";
+    commentsBefore_.clear();
   }
 
   switch (token.type_) {
@@ -1447,7 +1447,7 @@ bool OurReader::readObject(Token& tokenStart) {
       break;
     if (tokenName.type_ == tokenObjectEnd && name.empty()) // empty object
       return true;
-    name = "";
+    name.clear();
     if (tokenName.type_ == tokenString) {
       if (!decodeString(tokenName, name))
         return recoverFromError(tokenObjectEnd);

src/lib_json/json_value.cpp

@@ -880,7 +880,7 @@ bool Value::isConvertibleTo(ValueType other) const {
   case nullValue:
     return (isNumeric() && asDouble() == 0.0) ||
            (type_ == booleanValue && value_.bool_ == false) ||
-           (type_ == stringValue && asString() == "") ||
+           (type_ == stringValue && asString().empty()) ||
            (type_ == arrayValue && value_.map_->size() == 0) ||
            (type_ == objectValue && value_.map_->size() == 0) ||
            type_ == nullValue;
@@ -1506,6 +1506,7 @@ Path::Path(const JSONCPP_STRING& path,
            const PathArgument& a4,
            const PathArgument& a5) {
   InArgs in;
+  in.reserve(5);
   in.push_back(&a1);
   in.push_back(&a2);
   in.push_back(&a3);

src/lib_json/json_writer.cpp

@@ -335,7 +335,7 @@ void FastWriter::dropNullPlaceholders() { dropNullPlaceholders_ = true; }
 void FastWriter::omitEndingLineFeed() { omitEndingLineFeed_ = true; }
 
 JSONCPP_STRING FastWriter::write(const Value& root) {
-  document_ = "";
+  document_.clear();
   writeValue(root);
   if (!omitEndingLineFeed_)
     document_ += "\n";
@@ -403,9 +403,9 @@ StyledWriter::StyledWriter()
     : rightMargin_(74), indentSize_(3), addChildValues_() {}
 
 JSONCPP_STRING StyledWriter::write(const Value& root) {
-  document_ = "";
+  document_.clear();
   addChildValues_ = false;
-  indentString_ = "";
+  indentString_.clear();
   writeCommentBeforeValue(root);
   writeValue(root);
   writeCommentAfterValueOnSameLine(root);
@@ -619,7 +619,7 @@ StyledStreamWriter::StyledStreamWriter(JSONCPP_STRING indentation)
 void StyledStreamWriter::write(JSONCPP_OSTREAM& out, const Value& root) {
   document_ = &out;
   addChildValues_ = false;
-  indentString_ = "";
+  indentString_.clear();
   indented_ = true;
   writeCommentBeforeValue(root);
   if (!indented_) writeIndent();
@@ -901,7 +901,7 @@ int BuiltStyledStreamWriter::write(Value const& root, JSONCPP_OSTREAM* sout)
   sout_ = sout;
   addChildValues_ = false;
   indented_ = true;
-  indentString_ = "";
+  indentString_.clear();
   writeCommentBeforeValue(root);
   if (!indented_) writeIndent();
   indented_ = true;
@@ -1155,10 +1155,10 @@ StreamWriter* StreamWriterBuilder::newStreamWriter() const
   }
   JSONCPP_STRING nullSymbol = "null";
   if (dnp) {
-    nullSymbol = "";
+    nullSymbol.clear();
   }
   if (pre > 17) pre = 17;
-  JSONCPP_STRING endingLineFeedSymbol = "";
+  JSONCPP_STRING endingLineFeedSymbol;
   return new BuiltStyledStreamWriter(
       indentation, cs,
       colonSymbol, nullSymbol, endingLineFeedSymbol, usf, pre);