Addressed remaining comments

CMakeLists.txt

@@ -918,6 +918,7 @@ add_library( objUtil STATIC
     utils/sbufstream.h
     utils/scapp.h
     utils/stdafx.h
+    utils/platform_utils.h
     utils/unused.h
     )
 target_include_directories(

tools/imageio/imageinput.cc

@@ -14,6 +14,7 @@
 
 #include "imageio.h"
 #include "imageio_utility.h"
+#include "platform_utils.h"
 
 #include <iomanip>
 #include <map>
@@ -47,7 +48,7 @@ ImageInput::open(const _tstring& filename,
         // Check file exists, before looking for a suitable plugin.
         // MS's STL has `open` overloads that accept wchar_t to handle
         // Window's Unicode file names.
-        ifs.open(filename, std::ios::binary | std::ios::in);
+        ifs.open(DecodeUTF8Path(filename).c_str(), std::ios::binary | std::ios::in);
         if (ifs.fail()) {
             throw std::runtime_error(
                 fmt::format("Open of \"{}\" failed. {}",

tools/ktx/CMakeLists.txt

@@ -22,7 +22,6 @@ add_executable(ktxtools
         metrics_utils.h
         transcode_utils.cpp
         transcode_utils.h
-        platform_utils.h
         utility.h
         validate.cpp
         validate.h

tools/ktx/command_help.cpp

@@ -168,15 +168,15 @@ void CommandHelp::executeHelp() {
         fatal(rc::RUNTIME_ERROR, "Failed to open the html documentation: ERROR {}", r);
 
 #else
-#if defined(__APPLE__)
+#   if defined(__APPLE__)
     char buf[PATH_MAX];
     uint32_t bufsize = PATH_MAX;
     if (const auto ec = _NSGetExecutablePath(buf, &bufsize))
         fatal(rc::RUNTIME_ERROR, "Failed to determine executable path: ERROR {}", ec);
     const auto executablePath = std::filesystem::canonical(buf);
-#else // Linux
+#   else // Linux
     const auto executablePath = std::filesystem::canonical("/proc/self/exe");
-#endif
+#   endif
 
     const auto executableDir = std::filesystem::path(executablePath).remove_filename();
     const auto manFile = fmt::format("{}/../share/man/man1/ktx{}{}.1",

tools/ktx/ktx_main.cpp

@@ -4,27 +4,16 @@
 
 
 #include "command.h"
+#include "platform_utils.h"
 #include "stdafx.h"
 #include <iostream>
 #include <string>
-#include <memory>
 #include <unordered_map>
 
 #include <cxxopts.hpp>
 #include <fmt/ostream.h>
 #include <fmt/printf.h>
 
-#if defined(_WIN32)
-#ifndef WIN32_LEAN_AND_MEAN
-#define WIN32_LEAN_AND_MEAN
-#endif
-#ifndef NOMINMAX
-#define NOMINMAX
-#endif
-#include <windows.h>
-#include <shellapi.h>
-#endif
-
 // -------------------------------------------------------------------------------------------------
 
 namespace ktx {
@@ -197,23 +186,7 @@ int _tmain(int argc, _TCHAR* argv[]) {
     //      // pbxproj file, so it can't be disabled in a generated project.
     //      // Remove these from the arguments under consideration.
 
-#if defined(_WIN32)
-    // Windows does not support UTF-8 argv so we have to manually acquire it
-    LPWSTR commandLine = GetCommandLineW();
-    LPWSTR* wideArgv = CommandLineToArgvW(commandLine, &argc);
-    std::vector<std::unique_ptr<_TCHAR[]>> utf8Argv(argc);
-    for (int i = 0; i < argc; ++i) {
-        int byteSize = WideCharToMultiByte(CP_UTF8, 0, wideArgv[i], -1, nullptr, 0, nullptr, nullptr);
-        utf8Argv[i] = std::make_unique<_TCHAR[]>(byteSize);
-        WideCharToMultiByte(CP_UTF8, 0, wideArgv[i], -1, utf8Argv[i].get(), byteSize, nullptr, nullptr);
-        argv[i] = utf8Argv[i].get();
-    }
-
-    // Set UTF-8 codepage for the console
-    if (!SetConsoleOutputCP(CP_UTF8)) {
-        fmt::print(std::cerr, "{} warning: failed to set UTF-8 code page for console output.\n", argv[0]);
-    }
-#endif
+    InitUTF8CLI(argc, argv);
 
     if (argc >= 2) {
         // Has a subcommand, attempt to lookup

utils/platform_utils.h

@@ -0,0 +1,68 @@
+// Copyright 2022-2023 The Khronos Group Inc.
+// Copyright 2022-2023 RasterGrid Kft.
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "stdafx.h"
+#include <string>
+#include <iostream>
+#include <memory>
+#include <vector>
+#include <fmt/ostream.h>
+#include <fmt/printf.h>
+
+#if defined(_WIN32)
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+#include <windows.h>
+#include <shellapi.h>
+#endif
+
+#if defined(_WIN32)
+// For Windows, we convert the UTF-8 path to a UTF-16 path to force using the APIs
+// that correctly handle unicode characters
+inline std::wstring DecodeUTF8Path(std::string path) {
+    std::wstring result;
+    int len = MultiByteToWideChar(CP_UTF8, 0, path.c_str(), static_cast<int>(path.length()), NULL, 0);
+    if (len > 0)
+    {
+        result.resize(len);
+        MultiByteToWideChar(CP_UTF8, 0, path.c_str(), static_cast<int>(path.length()), &result[0], len);
+    }
+    return result;
+}
+#else
+// For other platforms there is no need for any conversion, they support UTF-8 natively
+inline std::string DecodeUTF8Path(std::string path) {
+    return path;
+}
+#endif
+
+inline void InitUTF8CLI(int argc, _TCHAR* argv[]) {
+#if defined(_WIN32)
+    // Windows does not support UTF-8 argv so we have to manually acquire it
+    static std::vector<std::unique_ptr<_TCHAR[]>> utf8Argv(argc);
+    LPWSTR commandLine = GetCommandLineW();
+    LPWSTR* wideArgv = CommandLineToArgvW(commandLine, &argc);
+    for (int i = 0; i < argc; ++i) {
+        int byteSize = WideCharToMultiByte(CP_UTF8, 0, wideArgv[i], -1, nullptr, 0, nullptr, nullptr);
+        utf8Argv[i] = std::make_unique<_TCHAR[]>(byteSize);
+        WideCharToMultiByte(CP_UTF8, 0, wideArgv[i], -1, utf8Argv[i].get(), byteSize, nullptr, nullptr);
+        argv[i] = utf8Argv[i].get();
+    }
+
+    // Set UTF-8 codepage for the console
+    if (!SetConsoleOutputCP(CP_UTF8)) {
+        fmt::print(std::cerr, "{} warning: failed to set UTF-8 code page for console output.\n", argv[0]);
+    }
+#else
+    // Nothing to do for other platforms
+    (void)argc;
+    (void)argv;
+#endif
+}