Add merge to URL (can merge absolute paths with relative paths)

src/URL.cpp

@@ -2,21 +2,55 @@
 
 #include "StringUtils.h"
 
+URL::URL() {
+    protocol = "";
+    host = "";
+    document = "";
+}
+
 URL::URL(std::string const& url) {
     construct(url);
 }
 
-std::string URL::toString() {
+std::string URL::toString() const {
     if (isRelative()) {
         return document;
     }
     return protocol + "://" + host + document;
 }
 
-bool URL::isRelative() {
+bool URL::isRelative() const {
     return protocol.size() == 0;
 }
 
+URL URL::merge(URL const& url) const {
+    if (!url.isRelative()) {
+        return url.copy();
+    }
+    
+    URL returnURL = copy();
+
+    if (url.document[0] == '/' && url.document[1] == '/') {
+        auto slashPos = url.document.find('/', 2);
+        returnURL.host = url.document.substr(2, slashPos - 2);
+        if (slashPos == std::string::npos) {
+            returnURL.document = "/";
+        } else {
+            returnURL.document = url.document.substr(slashPos);
+        }
+    } else if (url.document[0] == '/') {
+        returnURL.document = url.document;
+    } else {
+        if (returnURL.document.back() != '/') {
+            auto finalSlashPos = returnURL.document.find_last_of('/');
+            returnURL.document.erase(finalSlashPos + 1);
+        }
+        returnURL.document += url.document;
+    }
+    
+    return returnURL;
+}
+
 void URL::construct(std::string const& url) {
     protocol = getProtocolFromURL(url);
     if (protocol.size() != 0) {
@@ -33,7 +67,15 @@ void URL::construct(std::string const& url) {
 
 }
 
-std::ostream& operator<<(std::ostream& out, URL& url) {
+URL URL::copy() const {
+    URL url;
+    url.protocol = protocol;
+    url.host = host;
+    url.document = document;
+    return url;
+}
+
+std::ostream& operator<<(std::ostream& out, URL const& url) {
     out << url.toString();
     return out;
 }

src/URL.h

@@ -5,10 +5,12 @@
 #include <iostream>
 
 struct URL {
+    URL();
     URL(std::string const& url);
 
-    std::string toString();
-    bool isRelative();
+    std::string toString() const;
+    bool isRelative() const;
+    URL merge(URL const& url) const;
     
     std::string protocol;
     std::string host;
@@ -16,8 +18,9 @@ struct URL {
 
 private:
     void construct(std::string const& url);
+    URL copy() const;
 };
 
-std::ostream& operator<<(std::ostream& out, URL& url);
+std::ostream& operator<<(std::ostream& out, URL const& url);
 
 #endif