diff --git a/src/AuthConfigFactory.cc b/src/AuthConfigFactory.cc
index e8450269..a9922f54 100644
--- a/src/AuthConfigFactory.cc
+++ b/src/AuthConfigFactory.cc
@@ -253,8 +253,7 @@ AuthConfigFactory::findBasicCred
     std::lower_bound(basicCreds_.begin(), basicCreds_.end(), bc);
   for(; i != basicCreds_.end() && (*i).host_ == host && (*i).port_ == port;
       ++i) {
-    if(util::startsWith(bc.path_.begin(), bc.path_.end(),
-                        (*i).path_.begin(), (*i).path_.end())) {
+    if(util::startsWith(bc.path_, (*i).path_)) {
       return i;
     }
   }
diff --git a/src/ContentTypeRequestGroupCriteria.cc b/src/ContentTypeRequestGroupCriteria.cc
index b61c3bb7..078ef7df 100644
--- a/src/ContentTypeRequestGroupCriteria.cc
+++ b/src/ContentTypeRequestGroupCriteria.cc
@@ -49,8 +49,7 @@ bool tailMatch
 (InputIterator first, InputIterator last, const std::string& target)
 {
   for(; first != last; ++first) {
-    if(util::endsWith(target.begin(), target.end(),
-                      (*first).begin(), (*first).end())) {
+    if(util::endsWith(target, *first)) {
       return true;
     }
   }
diff --git a/src/DHTMessageTrackerEntry.cc b/src/DHTMessageTrackerEntry.cc
index bf3e34d0..59ad4322 100644
--- a/src/DHTMessageTrackerEntry.cc
+++ b/src/DHTMessageTrackerEntry.cc
@@ -71,13 +71,9 @@ bool DHTMessageTrackerEntry::match(const std::string& transactionID, const std::
   if(targetNode_->getIPAddress() == ipaddr) {
     return true;
   }
-  if(util::endsWith(targetNode_->getIPAddress().begin(),
-                    targetNode_->getIPAddress().end(),
-                    ipaddr.begin(), ipaddr.end())) {
+  if(util::endsWith(targetNode_->getIPAddress(), ipaddr)) {
     return targetNode_->getIPAddress() == "::ffff:"+ipaddr;
-  } else if(util::endsWith(ipaddr.begin(), ipaddr.end(),
-                           targetNode_->getIPAddress().begin(),
-                           targetNode_->getIPAddress().end())) {
+  } else if(util::endsWith(ipaddr, targetNode_->getIPAddress())) {
     return ipaddr == "::ffff:"+targetNode_->getIPAddress();
   }
   return false;
diff --git a/src/DownloadCommand.cc b/src/DownloadCommand.cc
index 4bdbe506..e405236f 100644
--- a/src/DownloadCommand.cc
+++ b/src/DownloadCommand.cc
@@ -383,10 +383,7 @@ void DownloadCommand::installStreamFilter
   streamFilter->installDelegate(streamFilter_);
   streamFilter_ = streamFilter;
   const std::string& name = streamFilter_->getName();
-  sinkFilterOnly_ =
-    util::endsWith(name.begin(), name.end(),
-                   SinkStreamFilter::NAME.begin(),
-                   SinkStreamFilter::NAME.end());
+  sinkFilterOnly_ = util::endsWith(name, SinkStreamFilter::NAME);
 }
 
 } // namespace aria2
diff --git a/src/HttpDownloadCommand.cc b/src/HttpDownloadCommand.cc
index c31b6089..f919dbfd 100644
--- a/src/HttpDownloadCommand.cc
+++ b/src/HttpDownloadCommand.cc
@@ -92,10 +92,7 @@ bool HttpDownloadCommand::prepareForNextSegment() {
        (getRequest()->isKeepAliveEnabled() &&
         (
          // Make sure that all filters are finished to pool socket
-         (!util::endsWith(streamFilterName.begin(),
-                          streamFilterName.end(),
-                          SinkStreamFilter::NAME.begin(),
-                          SinkStreamFilter::NAME.end()) &&
+         (!util::endsWith(streamFilterName, SinkStreamFilter::NAME) &&
           getStreamFilter()->finished()) ||
          getRequestEndOffset() ==
          getFileEntry()->gtoloff(getSegments().front()->getPositionToWrite())
diff --git a/src/HttpRequest.cc b/src/HttpRequest.cc
index 2b9ba982..d35acc96 100644
--- a/src/HttpRequest.cc
+++ b/src/HttpRequest.cc
@@ -248,8 +248,7 @@ std::string HttpRequest::createRequest()
     std::vector<std::string>::const_iterator j = headers_.begin();
     std::vector<std::string>::const_iterator jend = headers_.end();
     for(; j != jend; ++j) {
-      if(util::startsWith((*j).begin(), (*j).end(),
-                          (*i).first.begin(), (*i).first.end())) {
+      if(util::startsWith(*j, (*i).first)) {
         break;
       }
     }
diff --git a/src/HttpSkipResponseCommand.cc b/src/HttpSkipResponseCommand.cc
index 08499240..97ed1419 100644
--- a/src/HttpSkipResponseCommand.cc
+++ b/src/HttpSkipResponseCommand.cc
@@ -95,10 +95,7 @@ void HttpSkipResponseCommand::installStreamFilter
   streamFilter->installDelegate(streamFilter_);
   streamFilter_ = streamFilter;
   const std::string& name = streamFilter_->getName();
-  sinkFilterOnly_ =
-    util::endsWith(name.begin(), name.end(),
-                   SinkStreamFilter::NAME.begin(),
-                   SinkStreamFilter::NAME.end());
+  sinkFilterOnly_ = util::endsWith(name, SinkStreamFilter::NAME);
 }
 
 bool HttpSkipResponseCommand::executeInternal()
diff --git a/src/OptionHandlerImpl.cc b/src/OptionHandlerImpl.cc
index f43ea01c..8241e736 100644
--- a/src/OptionHandlerImpl.cc
+++ b/src/OptionHandlerImpl.cc
@@ -528,9 +528,9 @@ void HttpProxyOptionHandler::parseArg(Option& option, const std::string& optarg)
     option.put(pref_, optarg);
   } else {
     std::string uri;
-    if(util::startsWith(optarg.begin(), optarg.end(), "http://") ||
-       util::startsWith(optarg.begin(), optarg.end(), "https://") ||
-       util::startsWith(optarg.begin(), optarg.end(), "ftp://")) {
+    if(util::startsWith(optarg, "http://") ||
+       util::startsWith(optarg, "https://") ||
+       util::startsWith(optarg, "ftp://")) {
       uri = optarg;
     } else {
       uri = "http://";
diff --git a/src/cookie_helper.cc b/src/cookie_helper.cc
index 678728e3..d91108a8 100644
--- a/src/cookie_helper.cc
+++ b/src/cookie_helper.cc
@@ -373,8 +373,7 @@ std::string canonicalizeHost(const std::string& host)
 bool domainMatch(const std::string& requestHost, const std::string& domain)
 {
   return requestHost == domain ||
-    (util::endsWith(requestHost.begin(), requestHost.end(),
-                    domain.begin(), domain.end()) &&
+    (util::endsWith(requestHost, domain) &&
      requestHost[requestHost.size()-domain.size()-1] == '.' &&
      !util::isNumericHost(requestHost));
 }
@@ -382,8 +381,7 @@ bool domainMatch(const std::string& requestHost, const std::string& domain)
 bool pathMatch(const std::string& requestPath, const std::string& path)
 {
   return requestPath == path ||
-    (util::startsWith(requestPath.begin(), requestPath.end(),
-                      path.begin(), path.end()) &&
+    (util::startsWith(requestPath, path) &&
      (path[path.size()-1] == '/' || requestPath[path.size()] == '/'));
 }
 
diff --git a/src/util.cc b/src/util.cc
index 9c56a408..db5a32a2 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -1616,6 +1616,11 @@ bool startsWith(const std::string& a, const char* b)
   return startsWith(a.begin(), a.end(), b, b+strlen(b));
 }
 
+bool startsWith(const std::string& a, const std::string& b)
+{
+  return startsWith(a.begin(), a.end(), b.begin(), b.end());
+}
+
 bool istartsWith(const std::string& a, const char* b)
 {
   return istartsWith(a.begin(), a.end(), b, b+strlen(b));
diff --git a/src/util.h b/src/util.h
index 83fb1fc5..e655d4f9 100644
--- a/src/util.h
+++ b/src/util.h
@@ -624,6 +624,7 @@ bool startsWith(InputIterator first, InputIterator last, const char* b)
 }
 
 bool startsWith(const std::string& a, const char* b);
+bool startsWith(const std::string& a, const std::string& b);
 
 template<typename InputIterator1, typename InputIterator2>
 bool istartsWith