From 7bb894eb0d862eedaf0c0eab0bb204512060487d Mon Sep 17 00:00:00 2001
From: shermp <14854761+shermp@users.noreply.github.com>
Date: Wed, 10 Apr 2019 22:25:29 +1200
Subject: [PATCH] Create cross platform fopen() wrapper

---
 minivhd.c | 13 +------------
 vhdutil.c | 32 +++++++++++++++++++++++++++++++-
 vhdutil.h |  4 +++-
 3 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/minivhd.c b/minivhd.c
index 48e03d0..65b277e 100644
--- a/minivhd.c
+++ b/minivhd.c
@@ -197,21 +197,10 @@ static VHDError vhd_load_parent(VHDMeta* vhdm, FILE* f, const char* child_filepa
         /* (Hopefully) get the absolute path of the parent VHD */
         cwk_path_get_absolute(child_dir, u8_rel_path, abs_path, sizeof abs_path);
         free(u8_rel_path);
-#ifdef _WIN32
-        uint16_t w_filemode[3] = {0x0072, 0x0062, 0x0000}; /* "rb" */
-        char *w_abs_path = NULL;
-        vhd_utf_convert(VHD_UTF_16_LE, abs_path, &w_abs_path);
-        FILE* par_f = _wfopen((uint16_t*)w_abs_path, w_filemode);
+        FILE* par_f = vhd_fopen(abs_path, "rb");
         if (par_f) {
                 vhdm->parent.f = par_f;
         }
-        free(w_abs_path);
-#else
-        FILE* par_f = fopen(abs_path, "rb");
-        if (par_f) {
-                vhdm->parent.f = par_f;
-        }
-#endif
         vhdm->parent.meta = calloc(1, sizeof(VHDMeta));
         return VHD_RET_OK;
 }
diff --git a/vhdutil.c b/vhdutil.c
index 241a1fb..71f73a8 100644
--- a/vhdutil.c
+++ b/vhdutil.c
@@ -1,12 +1,14 @@
 #include <stdlib.h>
+#include <stdio.h>
 #include <string.h>
-#include "vhdutil.h"
+#include <error.h>
 #ifdef _WIN32
 #include <windows.h>
 #else
 #include <iconv.h>
 #include <error.h>
 #endif
+#include "vhdutil.h"
 
 int vhd_utf_convert(VHDUtfType toUTF, void* in_str, char** out_str) 
 {
@@ -56,4 +58,32 @@ size_t vhd_u16_strlen(uint16_t* u16_str) {
                 u16_str += 1;
         }
         return count;
+}
+
+FILE* vhd_fopen(char* utf8_path, char* mode) 
+{
+#ifdef _WIN32
+        errno_t err = 0;
+        char* u16_path = NULL;
+        WCHAR u16_mode[5] = {0};
+        /* Convert mode to UTF-16LE. Thankfully it's ASCII, which make the conversion simple...
+           Note, we're on Windows, so guaranteed to be little endian, therefore, no byte swapping needed. */
+        int mode_len = strlen(mode);
+        if (mode_len > 0 && mode_len < 5) {
+                for (int i = 0; i < mode_len; i++) {
+                        u16_mode[i] = (WCHAR)mode[i];
+                }
+        }
+        /* Convert utf8_path to UTF-16LE */
+        vhd_utf_convert(VHD_UTF_16_LE, utf8_path, &u16_path);
+        FILE* f = _wfopen((LPCWCH)u16_path, u16_mode);
+        if (f == NULL) {_get_errno(&err);}
+        free(u16_path);
+        /* We want to mimic (_w)fopen() behavior */
+        if (err) {_set_errno(err);}
+        return f;
+#else
+        /* Non-Windows OS's speak UTF-8 for fopen() */
+        return fopen(utf8_path, mode);
+#endif
 }
\ No newline at end of file
diff --git a/vhdutil.h b/vhdutil.h
index 59a2ce0..492cb9f 100644
--- a/vhdutil.h
+++ b/vhdutil.h
@@ -15,4 +15,6 @@ int vhd_utf_convert(VHDUtfType toUTF, void* in_str, char** out_str);
 /* Count the number of "characters" in a null terminated UTF-16 string. Not a true character count, as surrogate
    pairs are counted as two "characters". Appears to be the Windows definition of a character for filepath 
    purposes. */
-size_t vhd_u16_strlen(uint16_t* u16_str);
\ No newline at end of file
+size_t vhd_u16_strlen(uint16_t* u16_str);
+/* Cross platform function to open a (potentially) non-ascii filepath */
+FILE* vhd_fopen(char* utf8_path, char* mode);
\ No newline at end of file