diff --git a/tz.cpp b/tz.cpp
index e3c4da7..d465481 100644
--- a/tz.cpp
+++ b/tz.cpp
@@ -3,6 +3,7 @@
 // Copyright (c) 2015, 2016 Howard Hinnant
 // Copyright (c) 2015 Ville Voutilainen
 // Copyright (c) 2016 Alexander Kormanovsky
+// Copyright (c) 2016 Jiangang Zhuang
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
@@ -126,8 +127,17 @@
 #endif
 
 #ifdef _WIN32
+
 static CONSTDATA char folder_delimiter = '\\';
 
+#else
+
+static CONSTDATA char folder_delimiter = '/';
+
+#endif
+
+#ifdef _WIN32
+
 namespace
 {
     struct task_mem_deleter
@@ -176,7 +186,6 @@ get_download_folder()
 
 #else // !_WIN32
 
-static CONSTDATA char folder_delimiter = '/';
 
 static
 std::string
@@ -204,46 +213,39 @@ namespace date
 
 using namespace detail;
 
-static std::string get_install()
+static
+const std::string&
+get_install()
 {
-#ifdef _WIN32
-    std::string install = get_download_folder();
-    install += folder_delimiter;
-    install += "tzdata";
-#else
-    std::string install = expand_path("~/Downloads/tzdata");
-#endif
-    return install;
-}
-
+    static const std::string install 
 #ifndef INSTALL
 
-static const std::string install = get_install();
+#  ifdef _WIN32
+    = get_download_folder() + folder_delimiter + "tzdata";
+#  else
+    = expand_path("~/Downloads/tzdata");
+#  endif
 
 #else   // INSTALL
 
-#define STRINGIZEIMP(x) #x
-#define STRINGIZE(x) STRINGIZEIMP(x)
+#  define STRINGIZEIMP(x) #x
+#  define STRINGIZE(x) STRINGIZEIMP(x)
 
-static const std::string install = STRINGIZE(INSTALL) +
-                                   std::string(1, folder_delimiter) + "tzdata";
+    = STRINGIZE(INSTALL) + std::string(1, folder_delimiter) + "tzdata";
 
 #endif  // INSTALL
 
+    return install;
+}
+
 static
 std::string
 get_download_gz_file(const std::string& version)
 {
-    auto file = install + version + ".tar.gz";
+    auto file = get_install() + version + ".tar.gz";
     return file;
 }
 
-static const std::vector<std::string> files =
-{
-    "africa", "antarctica", "asia", "australasia", "backward", "etcetera", "europe",
-    "pacificnew", "northamerica", "southamerica", "systemv", "leapseconds"
-};
-
 // These can be used to reduce the range of the database to save memory
 CONSTDATA auto min_year = date::year::min();
 CONSTDATA auto max_year = date::year::max();
@@ -362,7 +364,7 @@ static
 std::string
 get_download_mapping_file(const std::string& version)
 {
-    auto file = install + version + "windowsZones.xml";
+    auto file = get_install() + version + "windowsZones.xml";
     return file;
 }
 
@@ -2549,7 +2551,7 @@ static
 std::string
 get_download_tar_file(const std::string& version)
 {
-    auto file = install;
+    auto file = get_install();
     file += folder_delimiter;
     file += "tzdata";
     file += version;
@@ -2601,7 +2603,7 @@ extract_gz_file(const std::string& version, const std::string& gz_file,
     cmd += "\" x \"";
     cmd += tar_file;
     cmd += "\" -o\"";
-    cmd += install;
+    cmd += get_install();
     cmd += '\"';
 #if USE_SHELL_API
     cmd = "\"" + cmd + "\"";
@@ -2671,12 +2673,12 @@ bool
 extract_gz_file(const std::string&, const std::string& gz_file, const std::string&)
 {
 #if USE_SHELL_API
-    bool unzipped = std::system(("tar -xzf " + gz_file + " -C " + install).c_str()) == EXIT_SUCCESS;
+    bool unzipped = std::system(("tar -xzf " + gz_file + " -C " + get_install()).c_str()) == EXIT_SUCCESS;
 #else  // !USE_SHELL_API
     const char prog[] = {"/usr/bin/tar"};
     const char*const args[] =
     {
-        prog, "-xzf", gz_file.c_str(), "-C", install.c_str(), nullptr
+        prog, "-xzf", gz_file.c_str(), "-C", get_install().c_str(), nullptr
     };
     bool unzipped = (run_program(prog, args) == EXIT_SUCCESS);
 #endif // !USE_SHELL_API
@@ -2696,6 +2698,7 @@ remote_install(const std::string& version)
     auto success = false;
     assert(!version.empty());
 
+    std::string install = get_install();
     auto gz_file = get_download_gz_file(version);
     if (file_exists(gz_file))
     {
@@ -2742,6 +2745,7 @@ TZ_DB
 init_tzdb()
 {
     using namespace date;
+    const std::string install = get_install();
     const std::string path = install + folder_delimiter;
     std::string line;
     bool continue_zone = false;
@@ -2796,6 +2800,12 @@ init_tzdb()
     db.version = get_version(path);
 #endif  // !AUTO_DOWNLOAD
 
+    CONSTDATA const char* files[] =
+    {
+        "africa", "antarctica", "asia", "australasia", "backward", "etcetera", "europe",
+        "pacificnew", "northamerica", "southamerica", "systemv", "leapseconds"
+    };
+
     for (const auto& filename : files)
     {
         std::ifstream infile(path + filename);