diff --git a/liberty/LibertyParser.cc b/liberty/LibertyParser.cc
index 446ce30d..f8249300 100644
--- a/liberty/LibertyParser.cc
+++ b/liberty/LibertyParser.cc
@@ -26,6 +26,7 @@
 
 #include <cstdio>
 #include <cstring>
+#include <istream>
 #include <regex>
 #include <string>
 
@@ -46,15 +47,25 @@ parseLibertyFile(std::string_view filename,
   std::string fn(filename);
   gzstream::igzstream stream(fn.c_str());
   if (stream.is_open()) {
-    LibertyParser reader(filename, library_visitor, report);
-    LibertyScanner scanner(&stream, filename, &reader, report);
-    LibertyParse parser(&scanner, &reader);
-    parser.parse();
+    parseLibertyFile(stream, filename, library_visitor, report);
   }
   else
     throw FileNotReadable(filename);
 }
 
+void
+parseLibertyFile(std::istream& file_contents,
+                 std::string_view filename,
+                 LibertyGroupVisitor *library_visitor,
+                 Report *report)
+{
+ 
+  LibertyParser reader(filename, library_visitor, report);
+  LibertyScanner scanner(&file_contents, filename, &reader, report);
+  LibertyParse parser(&scanner, &reader);
+  parser.parse();
+}
+
 LibertyParser::LibertyParser(std::string_view filename,
                              LibertyGroupVisitor *library_visitor,
                              Report *report) :
diff --git a/liberty/LibertyParser.hh b/liberty/LibertyParser.hh
index de9ec60c..9f0ce4a4 100644
--- a/liberty/LibertyParser.hh
+++ b/liberty/LibertyParser.hh
@@ -25,6 +25,7 @@
 #pragma once
 
 #include <functional>
+#include <istream>
 #include <string_view>
 #include <vector>
 #include <map>
@@ -280,6 +281,11 @@ public:
   virtual void visitVariable(LibertyVariable *variable) = 0;
 };
 
+void
+parseLibertyFile(std::istream& file_contents,
+                 std::string_view filename,
+                 LibertyGroupVisitor *library_visitor,
+                 Report *report);
 void
 parseLibertyFile(std::string_view filename,
                  LibertyGroupVisitor *library_visitor,