.

json/json_functions.h

@@ -364,6 +364,39 @@ static bool loadjson(const jsonval& parent, const std::string& key, int& value,
     return true;
 }
 
+static bool loadjson(const jsonval& parent, const std::string& key, size_t& value, const bool exist = true, bool* loaded = nullptr)
+{
+    jsonval::ConstMemberIterator itr;
+    if (!extract_value(parent, key, exist, loaded, itr)) {
+        return false;
+    }
+
+    const jsonval& a = itr->value;
+
+    if (a.IsNumber()) {
+        value = a.GetInt();
+    }
+    else if (a.IsString()) {
+
+        std::string str = a.GetString();
+        if (str.empty() && !exist) {
+            if (loaded) {
+                *loaded = false;
+            }
+            return false;
+        }
+
+        if (!Converter::ToNumber(str, value)) {
+            throw (Exp() << "bad value format '" << str << "'" << " in container '");
+        }
+    }
+    else {
+        throw (Exp() << "element '" << key << "'" << " has unexpected format '");
+    }
+
+    return true;
+}
+
 static bool loadjson(const jsonval& parent, const std::string& key, bool& value, const bool exist = true, bool* loaded = nullptr)
 {
     jsonval::ConstMemberIterator itr;