diff --git a/Makefile b/Makefile
index 52097446..470f817e 100644
--- a/Makefile
+++ b/Makefile
@@ -113,6 +113,7 @@ LIB_SOURCES =	src/libhttp.c					\
 		src/httplib_sslize.c				\
 		src/httplib_start.c				\
 		src/httplib_stop.c				\
+		src/httplib_substitute_index_file.c		\
 		src/httplib_timer.c				\
 		src/httplib_tls_dtor.c				\
 		src/httplib_uninitialize_ssl.c			\
diff --git a/src/httplib_substitute_index_file.c b/src/httplib_substitute_index_file.c
new file mode 100644
index 00000000..b6b58c7b
--- /dev/null
+++ b/src/httplib_substitute_index_file.c
@@ -0,0 +1,82 @@
+/* 
+ * Copyright (c) 2016 Lammert Bies
+ * Copyright (c) 2013-2016 the Civetweb developers
+ * Copyright (c) 2004-2013 Sergey Lyubka
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+
+
+#include "libhttp-private.h"
+
+
+
+/*
+ * int XX_httplib_substitute_index_file( struct mg_connection *conn, char *path, size_t path_len, struct file *filep );
+ *
+ * The function XX_httplib_substiture_index_file() tries to find an index file
+ * matching a given directory path. The function returns 1 of an index file has
+ * been found and 0 if the file could not be found. If a file could be located,
+ * it's stats are returnd in stp.
+ */
+
+#if !defined(NO_FILES)
+
+int XX_httplib_substitute_index_file( struct mg_connection *conn, char *path, size_t path_len, struct file *filep ) {
+
+	if ( conn == NULL  ||  conn->ctx == NULL ) return 0;
+
+	const char *list = conn->ctx->config[INDEX_FILES];
+	struct file file = STRUCT_FILE_INITIALIZER;
+	struct vec filename_vec;
+	size_t n = strlen(path);
+	int found = 0;
+
+	/* The 'path' given to us points to the directory. Remove all trailing
+	 * directory separator characters from the end of the path, and
+	 * then append single directory separator character. */
+	while (n > 0 && path[n - 1] == '/') n--;
+	path[n] = '/';
+
+	/* Traverse index files list. For each entry, append it to the given
+	 * path and see if the file exists. If it exists, break the loop */
+	while ((list = XX_httplib_next_option(list, &filename_vec, NULL)) != NULL) {
+		/* Ignore too long entries that may overflow path buffer */
+		if (filename_vec.len > path_len - (n + 2)) continue;
+
+		/* Prepare full path to the index file */
+		XX_httplib_strlcpy(path + n + 1, filename_vec.ptr, filename_vec.len + 1);
+
+		/* Does it exist? */
+		if (XX_httplib_stat(conn, path, &file)) {
+			/* Yes it does, break the loop */
+			*filep = file;
+			found = 1;
+			break;
+		}
+	}
+
+	/* If no index file exists, restore directory path */
+	if (!found) path[n] = '\0';
+
+	return found;
+
+}  /* XX_httplib_substitute_index_file */
+#endif
diff --git a/src/libhttp.c b/src/libhttp.c
index 86840cba..800e701b 100644
--- a/src/libhttp.c
+++ b/src/libhttp.c
@@ -5379,49 +5379,3 @@ int XX_httplib_read_request( FILE *fp, struct mg_connection *conn, char *buf, in
 	return ((request_len <= 0) && (n <= 0)) ? -1 : request_len;
 
 }  /* XX_httplib_read_request */
-
-#if !defined(NO_FILES)
-/* For given directory path, substitute it to valid index file.
- * Return 1 if index file has been found, 0 if not found.
- * If the file is found, it's stats is returned in stp. */
-int XX_httplib_substitute_index_file( struct mg_connection *conn, char *path, size_t path_len, struct file *filep ) {
-
-	if ( conn == NULL  ||  conn->ctx == NULL ) return 0;
-
-	const char *list = conn->ctx->config[INDEX_FILES];
-	struct file file = STRUCT_FILE_INITIALIZER;
-	struct vec filename_vec;
-	size_t n = strlen(path);
-	int found = 0;
-
-	/* The 'path' given to us points to the directory. Remove all trailing
-	 * directory separator characters from the end of the path, and
-	 * then append single directory separator character. */
-	while (n > 0 && path[n - 1] == '/') n--;
-	path[n] = '/';
-
-	/* Traverse index files list. For each entry, append it to the given
-	 * path and see if the file exists. If it exists, break the loop */
-	while ((list = XX_httplib_next_option(list, &filename_vec, NULL)) != NULL) {
-		/* Ignore too long entries that may overflow path buffer */
-		if (filename_vec.len > path_len - (n + 2)) continue;
-
-		/* Prepare full path to the index file */
-		XX_httplib_strlcpy(path + n + 1, filename_vec.ptr, filename_vec.len + 1);
-
-		/* Does it exist? */
-		if (XX_httplib_stat(conn, path, &file)) {
-			/* Yes it does, break the loop */
-			*filep = file;
-			found = 1;
-			break;
-		}
-	}
-
-	/* If no index file exists, restore directory path */
-	if (!found) path[n] = '\0';
-
-	return found;
-
-}  /* XX_httplib_substitute_index_file */
-#endif