diff --git a/concore.hpp b/concore.hpp
index e109a5d..da2c792 100644
--- a/concore.hpp
+++ b/concore.hpp
@@ -24,6 +24,8 @@
 #include <cctype>
 #include <regex>
 
+#include "concore_base.hpp"
+
 using namespace std;
 
 /**
@@ -219,48 +221,13 @@ class Concore{
      */
     map<string,int> mapParser(string filename){
         map<string,int> ans;
-
-        ifstream portfile;
-        string portstr;
-        portfile.open(filename);
-        if(portfile){
-            ostringstream ss;
-            ss << portfile.rdbuf();
-            portstr = ss.str();
-            portfile.close();
-        }
-
-        if (portstr.empty()) {
-            return ans;
-        }
-
-        portstr[portstr.size()-1]=',';
-        portstr+='}';
-        int i=0;
-        string portname="";
-        string portnum="";
-
-        while(portstr[i]!='}'){
-            if(portstr[i]=='\''){
-                i++;
-                while(portstr[i]!='\''){
-                    portname+=portstr[i];
-                    i++;
-                }
-                ans.insert({portname,0});
+        auto str_map = concore_base::safe_literal_eval_dict(filename, {});
+        for (const auto& kv : str_map) {
+            try {
+                ans[kv.first] = std::stoi(kv.second);
+            } catch (...) {
+                ans[kv.first] = 0;
             }
-
-            if(portstr[i]==':'){
-                i++;
-                while(portstr[i]!=','){
-                    portnum+=portstr[i];
-                    i++;
-                }
-                ans[portname]=stoi(portnum);
-                portnum="";
-                portname="";
-            }  
-            i++;
         }
         return ans;
     }
@@ -286,25 +253,7 @@ class Concore{
      * @return A vector of double values extracted from the input string.
      */
     vector<double> parser(string f){
-        vector<double> temp;
-        if(f.empty()) return temp;
-        string value = "";
-    
-        //Changing last bracket to comma to use comma as a delimiter
-        f[f.length()-1]=',';
-
-        for(int i=1;i<f.length();i++){
-            if(f[i]!=',')
-                value+=f[i];
-            else{
-                if((int)value.size()!=0)
-                    temp.push_back(stod(value));
-                
-                //reset value
-                value = "";
-            }
-        }
-        return temp;
+        return concore_base::parselist_double(f);
     }
 
     /**
@@ -606,10 +555,7 @@ class Concore{
      * @return The stripped string.
      */
     string stripstr(string str){
-        size_t start = str.find_first_not_of(" \t\n\r");
-        if (start == string::npos) return "";
-        size_t end = str.find_last_not_of(" \t\n\r");
-        return str.substr(start, end - start + 1);
+        return concore_base::stripstr(str);
     }
 
     /**
@@ -618,9 +564,7 @@ class Concore{
      * @return The unquoted string.
      */
     string stripquotes(string str){
-        if (str.size() >= 2 && ((str.front() == '\'' && str.back() == '\'') || (str.front() == '"' && str.back() == '"')))
-            return str.substr(1, str.size() - 2);
-        return str;
+        return concore_base::stripquotes(str);
     }
 
     /**
@@ -629,21 +573,7 @@ class Concore{
      * @return A map of key-value string pairs.
      */
     map<string, string> parsedict(string str){
-        map<string, string> result;
-        string trimmed = stripstr(str);
-        if (trimmed.size() < 2 || trimmed.front() != '{' || trimmed.back() != '}')
-            return result;
-        string inner = trimmed.substr(1, trimmed.size() - 2);
-        stringstream ss(inner);
-        string token;
-        while (getline(ss, token, ',')) {
-            size_t colon = token.find(':');
-            if (colon == string::npos) continue;
-            string key = stripquotes(stripstr(token.substr(0, colon)));
-            string val = stripquotes(stripstr(token.substr(colon + 1)));
-            if (!key.empty()) result[key] = val;
-        }
-        return result;
+        return concore_base::parsedict(str);
     }
 
     /**
@@ -651,33 +581,15 @@ class Concore{
      * @param defaultValue The fallback value if the file is missing.
      */
     void default_maxtime(int defaultValue){
-        maxtime = defaultValue;
-        ifstream file(inpath + "/1/concore.maxtime");
-        if (file) {
-            file >> maxtime;
-        }
+        maxtime = (int)concore_base::load_maxtime(
+            inpath + "/1/concore.maxtime", (double)defaultValue);
     }
 
     /**
      * @brief Loads simulation parameters from concore.params into the params map.
      */
     void load_params(){
-        ifstream file(inpath + "/1/concore.params");
-        if (!file) return;
-        stringstream buffer;
-        buffer << file.rdbuf();
-        string sparams = buffer.str();
-
-        if (!sparams.empty() && sparams[0] == '"') {
-            sparams = sparams.substr(1, sparams.find('"', 1) - 1);
-        }
-
-        if (!sparams.empty() && sparams[0] != '{') {
-            sparams = "{\"" + regex_replace(regex_replace(regex_replace(sparams, regex(","), ",\""), regex("="), "\":"), regex(" "), "") + "}";
-        }
-        try {
-            params = parsedict(sparams);
-        } catch (...) {}
+        params = concore_base::load_params(inpath + "/1/concore.params");
     }
 
     /**
@@ -687,7 +599,7 @@ class Concore{
      * @return The parameter value or the default.
      */
     string tryparam(string n, string i){
-        return params.count(n) ? params[n] : i;
+        return concore_base::tryparam(params, n, i);
     }
 
     /**
diff --git a/concore_base.hpp b/concore_base.hpp
new file mode 100644
index 0000000..6479942
--- /dev/null
+++ b/concore_base.hpp
@@ -0,0 +1,183 @@
+// concore_base.hpp -- shared utilities for concore.hpp and concoredocker.hpp
+// Extracted to eliminate drift between local and Docker C++ implementations.
+#ifndef CONCORE_BASE_HPP
+#define CONCORE_BASE_HPP
+
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <string>
+#include <map>
+#include <vector>
+#include <chrono>
+#include <thread>
+#include <regex>
+#include <algorithm>
+#include <cstring>
+
+namespace concore_base {
+
+// ===================================================================
+// String Helpers
+// ===================================================================
+inline std::string stripstr(const std::string& str) {
+    size_t start = str.find_first_not_of(" \t\n\r");
+    if (start == std::string::npos) return "";
+    size_t end = str.find_last_not_of(" \t\n\r");
+    return str.substr(start, end - start + 1);
+}
+
+inline std::string stripquotes(const std::string& str) {
+    if (str.size() >= 2 &&
+        ((str.front() == '\'' && str.back() == '\'') ||
+         (str.front() == '"'  && str.back() == '"')))
+        return str.substr(1, str.size() - 2);
+    return str;
+}
+
+// ===================================================================
+// Parsing Utilities
+// ===================================================================
+
+/**
+ * Parses a Python-style dict string into a string→string map.
+ * Format: {'key1': val1, 'key2': val2}
+ * Handles both quoted and unquoted keys/values.
+ */
+inline std::map<std::string, std::string> parsedict(const std::string& str) {
+    std::map<std::string, std::string> result;
+    std::string trimmed = stripstr(str);
+    if (trimmed.size() < 2 || trimmed.front() != '{' || trimmed.back() != '}')
+        return result;
+    std::string inner = trimmed.substr(1, trimmed.size() - 2);
+    std::stringstream ss(inner);
+    std::string token;
+    while (std::getline(ss, token, ',')) {
+        size_t colon = token.find(':');
+        if (colon == std::string::npos) continue;
+        std::string key = stripquotes(stripstr(token.substr(0, colon)));
+        std::string val = stripquotes(stripstr(token.substr(colon + 1)));
+        if (!key.empty()) result[key] = val;
+    }
+    return result;
+}
+
+/**
+ * Parses a Python-style list string into a vector of strings.
+ * Format: [val1, val2, val3]
+ */
+inline std::vector<std::string> parselist(const std::string& str) {
+    std::vector<std::string> result;
+    std::string trimmed = stripstr(str);
+    if (trimmed.size() < 2 || trimmed.front() != '[' || trimmed.back() != ']')
+        return result;
+    std::string inner = trimmed.substr(1, trimmed.size() - 2);
+    std::stringstream ss(inner);
+    std::string token;
+    while (std::getline(ss, token, ',')) {
+        std::string val = stripstr(token);
+        if (!val.empty()) result.push_back(val);
+    }
+    return result;
+}
+
+/**
+ * Parses a double-valued list like "[0.0, 1.5, 2.3]" into a vector<double>.
+ * Used by concore.hpp's read/write which work with numeric data.
+ */
+inline std::vector<double> parselist_double(const std::string& str) {
+    std::vector<double> result;
+    std::vector<std::string> tokens = parselist(str);
+    for (const auto& tok : tokens) {
+        result.push_back(std::stod(tok));
+    }
+    return result;
+}
+
+/**
+ * Reads a file and parses its content as a dict.
+ * Returns defaultValue on any failure (matches Python safe_literal_eval).
+ */
+inline std::map<std::string, std::string> safe_literal_eval_dict(
+    const std::string& filename,
+    const std::map<std::string, std::string>& defaultValue)
+{
+    std::ifstream file(filename);
+    if (!file) return defaultValue;
+    std::stringstream buf;
+    buf << file.rdbuf();
+    std::string content = buf.str();
+    try {
+        return parsedict(content);
+    } catch (...) {
+        return defaultValue;
+    }
+}
+
+/**
+ * Loads simulation parameters from a concore.params file.
+ * Handles Windows quote wrapping, semicolon-separated key=value,
+ * and dict-literal format.
+ */
+inline std::map<std::string, std::string> load_params(const std::string& params_file) {
+    std::ifstream file(params_file);
+    if (!file) return {};
+    std::stringstream buffer;
+    buffer << file.rdbuf();
+    std::string sparams = buffer.str();
+
+    // Windows sometimes keeps surrounding quotes
+    if (!sparams.empty() && sparams[0] == '"') {
+        size_t closing = sparams.find('"', 1);
+        if (closing != std::string::npos)
+            sparams = sparams.substr(1, closing - 1);
+    }
+
+    sparams = stripstr(sparams);
+    if (sparams.empty()) return {};
+
+    // If already a dict literal, parse directly
+    if (sparams.front() == '{') {
+        try { return parsedict(sparams); } catch (...) {}
+    }
+
+    // Otherwise convert semicolon-separated key=value to dict format
+    // e.g. "a=1;b=2" -> {"a":"1","b":"2"}
+    std::string converted = "{\"" +
+        std::regex_replace(
+            std::regex_replace(
+                std::regex_replace(sparams, std::regex(","), ",\""),
+                std::regex("="), "\":"),
+            std::regex(" "), "") +
+        "}";
+    try { return parsedict(converted); } catch (...) {}
+
+    return {};
+}
+
+/**
+ * Reads maxtime from concore.maxtime file, falls back to defaultValue.
+ */
+inline double load_maxtime(const std::string& maxtime_file, double defaultValue) {
+    std::ifstream file(maxtime_file);
+    if (!file) return defaultValue;
+    double val;
+    if (file >> val) return val;
+    return defaultValue;
+}
+
+/**
+ * Returns param value by name, or default if not found.
+ */
+inline std::string tryparam(
+    const std::map<std::string, std::string>& params,
+    const std::string& name,
+    const std::string& defaultValue)
+{
+    auto it = params.find(name);
+    return (it != params.end()) ? it->second : defaultValue;
+}
+
+} // namespace concore_base
+
+#endif // CONCORE_BASE_HPP
diff --git a/concoredocker.hpp b/concoredocker.hpp
index 88a7ab6..593da87 100644
--- a/concoredocker.hpp
+++ b/concoredocker.hpp
@@ -1,5 +1,5 @@
-#ifndef CONCORE_HPP
-#define CONCORE_HPP
+#ifndef CONCOREDOCKER_HPP
+#define CONCOREDOCKER_HPP
 
 #include <iostream>
 #include <fstream>
@@ -14,6 +14,8 @@
 #include <regex>
 #include <algorithm>
 
+#include "concore_base.hpp"
+
 class Concore {
 public:
     std::unordered_map<std::string, std::string> iport;
@@ -28,49 +30,20 @@ class Concore {
     std::unordered_map<std::string, std::string> params;
 
     std::string stripstr(const std::string& str) {
-        size_t start = str.find_first_not_of(" \t\n\r");
-        if (start == std::string::npos) return "";
-        size_t end = str.find_last_not_of(" \t\n\r");
-        return str.substr(start, end - start + 1);
+        return concore_base::stripstr(str);
     }
 
     std::string stripquotes(const std::string& str) {
-        if (str.size() >= 2 && ((str.front() == '\'' && str.back() == '\'') || (str.front() == '"' && str.back() == '"')))
-            return str.substr(1, str.size() - 2);
-        return str;
+        return concore_base::stripquotes(str);
     }
 
     std::unordered_map<std::string, std::string> parsedict(const std::string& str) {
-        std::unordered_map<std::string, std::string> result;
-        std::string trimmed = stripstr(str);
-        if (trimmed.size() < 2 || trimmed.front() != '{' || trimmed.back() != '}')
-            return result;
-        std::string inner = trimmed.substr(1, trimmed.size() - 2);
-        std::stringstream ss(inner);
-        std::string token;
-        while (std::getline(ss, token, ',')) {
-            size_t colon = token.find(':');
-            if (colon == std::string::npos) continue;
-            std::string key = stripquotes(stripstr(token.substr(0, colon)));
-            std::string val = stripquotes(stripstr(token.substr(colon + 1)));
-            if (!key.empty()) result[key] = val;
-        }
-        return result;
+        auto ordered = concore_base::parsedict(str);
+        return std::unordered_map<std::string, std::string>(ordered.begin(), ordered.end());
     }
 
     std::vector<std::string> parselist(const std::string& str) {
-        std::vector<std::string> result;
-        std::string trimmed = stripstr(str);
-        if (trimmed.size() < 2 || trimmed.front() != '[' || trimmed.back() != ']')
-            return result;
-        std::string inner = trimmed.substr(1, trimmed.size() - 2);
-        std::stringstream ss(inner);
-        std::string token;
-        while (std::getline(ss, token, ',')) {
-            std::string val = stripstr(token);
-            if (!val.empty()) result.push_back(val);
-        }
-        return result;
+        return concore_base::parselist(str);
     }
 
     Concore() {
@@ -82,37 +55,17 @@ class Concore {
 
     std::unordered_map<std::string, std::string> safe_literal_eval(const std::string& filename, std::unordered_map<std::string, std::string> defaultValue) {
         std::ifstream file(filename);
-        if (!file) {
-            std::cerr << "Error reading " << filename << "\n";
-            return defaultValue;
-        }
+        if (!file) return defaultValue;
         std::stringstream buf;
         buf << file.rdbuf();
-        std::string content = buf.str();
-        try {
-            return parsedict(content);
-        } catch (...) {
-            return defaultValue;
-        }
+        auto result = concore_base::parsedict(buf.str());
+        if (result.empty()) return defaultValue;
+        return std::unordered_map<std::string, std::string>(result.begin(), result.end());
     }
 
     void load_params() {
-        std::ifstream file(inpath + "/1/concore.params");
-        if (!file) return;
-        std::stringstream buffer;
-        buffer << file.rdbuf();
-        std::string sparams = buffer.str();
-
-        if (!sparams.empty() && sparams[0] == '"') {
-            sparams = sparams.substr(1, sparams.find('"') - 1);
-        }
-
-        if (!sparams.empty() && sparams[0] != '{') {
-            sparams = "{\"" + std::regex_replace(std::regex_replace(std::regex_replace(sparams, std::regex(","), ",\""), std::regex("="), "\":"), std::regex(" "), "") + "}";
-        }
-        try {
-            params = parsedict(sparams);
-        } catch (...) {}
+        auto ordered = concore_base::load_params(inpath + "/1/concore.params");
+        params = std::unordered_map<std::string, std::string>(ordered.begin(), ordered.end());
     }
 
     std::string tryparam(const std::string& n, const std::string& i) {
@@ -120,11 +73,8 @@ class Concore {
     }
 
     void default_maxtime(double defaultValue) {
-        maxtime = defaultValue;
-        std::ifstream file(inpath + "/1/concore.maxtime");
-        if (file) {
-            file >> maxtime;
-        }
+        maxtime = concore_base::load_maxtime(
+            inpath + "/1/concore.maxtime", defaultValue);
     }
 
     bool unchanged() {
@@ -188,7 +138,7 @@ class Concore {
                 outfile << val[i] << (i + 1 < val.size() ? ", " : "");
             }
             outfile << "]";
-            simtime += delta;
+            // simtime must not be mutated here (issue #385).
         }
     }
 
@@ -204,4 +154,4 @@ class Concore {
     }
 };
 
-#endif
+#endif // CONCOREDOCKER_HPP
diff --git a/concoredocker.java b/concoredocker.java
index 2ac7cbd..58b68e7 100644
--- a/concoredocker.java
+++ b/concoredocker.java
@@ -39,7 +39,7 @@ public class concoredocker {
         } catch (IOException e) {
         }
         try {
-            String sparams = new String(Files.readAllBytes(Paths.get(inpath + "1/concore.params")), java.nio.charset.StandardCharsets.UTF_8);
+            String sparams = new String(Files.readAllBytes(Paths.get(inpath + "/1/concore.params")), java.nio.charset.StandardCharsets.UTF_8);
             if (sparams.length() > 0 && sparams.charAt(0) == '"') { // windows keeps "" need to remove
                 sparams = sparams.substring(1);
                 sparams = sparams.substring(0, sparams.indexOf('"'));
@@ -114,7 +114,7 @@ private static Map<String, Object> parseFile(String filename) throws IOException
      */
     private static void defaultMaxTime(double defaultValue) {
         try {
-            String content = new String(Files.readAllBytes(Paths.get(inpath + "1/concore.maxtime")));
+            String content = new String(Files.readAllBytes(Paths.get(inpath + "/1/concore.maxtime")));
             Object parsed = literalEval(content.trim());
             if (parsed instanceof Number) {
                 maxtime = ((Number) parsed).doubleValue();
@@ -161,7 +161,7 @@ private static List<Object> read(int port, String name, String initstr) {
             // initstr not parseable as list; defaultVal stays empty
         }
 
-        String filePath = inpath + port + "/" + name;
+        String filePath = inpath + "/" + port + "/" + name;
         try {
             Thread.sleep(delay);
         } catch (InterruptedException e) {
@@ -277,7 +277,7 @@ private static String toPythonLiteral(Object obj) {
      */
     private static void write(int port, String name, Object val, int delta) {
         try {
-            String path = outpath + port + "/" + name;
+            String path = outpath + "/" + port + "/" + name;
             StringBuilder content = new StringBuilder();
             if (val instanceof String) {
                 Thread.sleep(2 * delay);
@@ -291,7 +291,8 @@ private static void write(int port, String name, Object val, int delta) {
                     content.append(toPythonLiteral(listVal.get(i)));
                 }
                 content.append("]");
-                simtime += delta;
+                // simtime must not be mutated here.
+                // Mutation breaks cross-language determinism (see issue #385).
             } else if (val instanceof Object[]) {
                 // Legacy support for Object[] arguments
                 Object[] arrayVal = (Object[]) val;
@@ -302,7 +303,8 @@ private static void write(int port, String name, Object val, int delta) {
                     content.append(toPythonLiteral(o));
                 }
                 content.append("]");
-                simtime += delta;
+                // simtime must not be mutated here.
+                // Mutation breaks cross-language determinism (see issue #385).
             } else {
                 System.out.println("write must have list or str");
                 return;
@@ -310,9 +312,9 @@ private static void write(int port, String name, Object val, int delta) {
             Files.write(Paths.get(path), content.toString().getBytes());
         } catch (InterruptedException e) {
             Thread.currentThread().interrupt();
-            System.out.println("skipping " + outpath + port + "/" + name);
+            System.out.println("skipping " + outpath + "/" + port + "/" + name);
         } catch (IOException e) {
-            System.out.println("skipping " + outpath + port + "/" + name);
+            System.out.println("skipping " + outpath + "/" + port + "/" + name);
         }
     }