Use value stack for checking maximum depth.

As we now have an explicit stack, we don't need the depth variable argument to
count the recursion levels. We can simply use the value stack size instead.

Author: canatella

json11.cpp

@@ -717,8 +717,8 @@ struct JsonParserPriv final {
      *
      * Parse a JSON object.
      */
-    void parse_json(int depth) {
-        if (depth > max_depth) {
+    void parse_json() {
+        if (values.size() > max_depth) {
             return fail("exceeded maximum nesting depth");
         }
 
@@ -773,7 +773,7 @@ struct JsonParserPriv final {
                 if (ch != ':')
                     return fail("expected ':' in object, got " + esc(ch));
 
-                parse_json(depth + 1);
+                parse_json();
                 if (need_data)
                     return;
 
@@ -813,7 +813,7 @@ struct JsonParserPriv final {
                     return;
 
                 i--;
-                parse_json(depth + 1);
+                parse_json();
                 if (need_data)
                     return;
 
@@ -860,7 +860,7 @@ JsonParser::~JsonParser() {
 void JsonParser::consume(const std::string &in) {
     parser->str = in;
     parser->eof = true;
-    parser->parse_json(0);
+    parser->parse_json();
 }
 
 Json JsonParser::json() const {
@@ -870,7 +870,7 @@ Json JsonParser::json() const {
 Json Json::parse(const string &in, string &err, JsonParse strategy) {
     JsonParserPriv parser { in, err, strategy };
     parser.eof = true;
-    parser.parse_json(0);
+    parser.parse_json();
 
     // Check for any trailing garbage
     parser.consume_garbage();
@@ -902,7 +902,7 @@ vector<Json> Json::parse_multi(const string &in,
     parser_stop_pos = 0;
     vector<Json> json_vec;
     while (parser.i != in.size() && !parser.failed && !parser.need_data) {
-        parser.parse_json(0);
+        parser.parse_json();
         if (parser.need_data) {
             parser.failed = true;
             parser.values.push(Json());