From 72aa534b813f957053849be7668f6da35faad9f2 Mon Sep 17 00:00:00 2001
From: shiagarw <shiagarw@adobe.com>
Date: Sun, 20 Dec 2020 23:49:18 +0530
Subject: [PATCH] Adding support of UTF8 file name processing in mio on windows

Contributing back changes from app.
---
 include/mio/detail/mmap.ipp | 12 +++++++++++-
 single_include/mio/mio.hpp  | 12 +++++++++++-
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/include/mio/detail/mmap.ipp b/include/mio/detail/mmap.ipp
index aaf6494..2dbfe1f 100644
--- a/include/mio/detail/mmap.ipp
+++ b/include/mio/detail/mmap.ipp
@@ -68,13 +68,23 @@ template<
             0);
 }
 
+std::wstring s_2_ws(const std::string& s)
+{
+    if (s.empty())
+        return{};
+    const auto s_length = static_cast<int>(s.length());
+    auto buf = std::vector<wchar_t>(s_length);
+    const auto wide_char_count = MultiByteToWideChar(CP_UTF8, 0, s.c_str(), sLength, buf.data(), s_length);
+    return std::wstring(buf.data(), wide_char_count);
+}
+
 template<typename String>
 typename std::enable_if<
     std::is_same<typename char_type<String>::type, wchar_t>::value,
     file_handle_type
 >::type open_file_helper(const String& path, const access_mode mode)
 {
-    return ::CreateFileW(c_str(path),
+    return ::CreateFileW(s_2_ws(path).c_str(),
             mode == access_mode::read ? GENERIC_READ : GENERIC_READ | GENERIC_WRITE,
             FILE_SHARE_READ | FILE_SHARE_WRITE,
             0,
diff --git a/single_include/mio/mio.hpp b/single_include/mio/mio.hpp
index 95c696c..f1b53c7 100644
--- a/single_include/mio/mio.hpp
+++ b/single_include/mio/mio.hpp
@@ -810,13 +810,23 @@ template<
             0);
 }
 
+std::wstring s_2_ws(const std::string& s)
+{
+    if (s.empty())
+        return{};
+    const auto s_length = static_cast<int>(s.length());
+    auto buf = std::vector<wchar_t>(s_length);
+    const auto wide_char_count = MultiByteToWideChar(CP_UTF8, 0, s.c_str(), sLength, buf.data(), s_length);
+    return std::wstring(buf.data(), wide_char_count);
+}
+
 template<typename String>
 typename std::enable_if<
     std::is_same<typename char_type<String>::type, wchar_t>::value,
     file_handle_type
 >::type open_file_helper(const String& path, const access_mode mode)
 {
-    return ::CreateFileW(c_str(path),
+    return ::CreateFileW(s_2_ws(path).c_str(),
             mode == access_mode::read ? GENERIC_READ : GENERIC_READ | GENERIC_WRITE,
             FILE_SHARE_READ | FILE_SHARE_WRITE,
             0,