From a40b84252a7ec24bbd4bb993234e4b866be357d7 Mon Sep 17 00:00:00 2001
From: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Date: Sun, 17 Jan 2021 10:26:12 -0800
Subject: [PATCH] Fix base path handling for mixed slashes

On Windows, paths with mixed slashes weren't processed correctly as `\`
would be picked if it was anywhere in the path for the purpose of
determining base.

This also removes the #ifdef _WIN32 from the logic; this helps on
platforms like Emscripten where running the resulting binary that
wasn't compiled with WIN32 still needs backslash processing; paths with
backslashes on Linux should be exceedingly rare, plus we *already*
correct backslashes with forward slashes on Linux anyway...
---
 fast_obj.h | 39 ++++++++++-----------------------------
 1 file changed, 10 insertions(+), 29 deletions(-)

diff --git a/fast_obj.h b/fast_obj.h
index 69edefd..af79d4a 100644
--- a/fast_obj.h
+++ b/fast_obj.h
@@ -373,27 +373,6 @@ int string_equal(const char* a, const char* s, const char* e)
 }
 
 
-static
-int string_find_last(const char* s, char c, size_t* p)
-{
-    const char* e;
-
-    e = s + strlen(s);
-    while (e > s)
-    {
-        e--;
-
-        if (*e == c)
-        {
-            *p = (size_t)(e - s);
-            return 1;
-        }
-    }
-
-    return 0;
-}
-
-
 static
 void string_fix_separators(char* s)
 {
@@ -1289,7 +1268,6 @@ fastObjMesh* fast_obj_read(const char* path)
     char*        end;
     char*        last;
     fastObjUInt  read;
-    size_t       sep;
     fastObjUInt  bytes;
 
 
@@ -1336,13 +1314,16 @@ fastObjMesh* fast_obj_read(const char* path)
 
 
     /* Find base path for materials/textures */
-    if (string_find_last(path, FAST_OBJ_SEPARATOR, &sep))
-        data.base = string_substr(path, 0, sep + 1);
-#ifdef _WIN32
-    /* Check for the other direction slash on windows too, but not linux/mac where it's a valid char */
-    else if (string_find_last(path, FAST_OBJ_OTHER_SEP, &sep))
-        data.base = string_substr(path, 0, sep + 1);
-#endif
+    {
+        const char* sep1 = strrchr(path, FAST_OBJ_SEPARATOR);
+        const char* sep2 = strrchr(path, FAST_OBJ_OTHER_SEP);
+
+        /* Use the last separator in the path */
+        const char* sep = sep2 && (!sep1 || sep1 < sep2) ? sep2 : sep1;
+
+        if (sep)
+            data.base = string_substr(path, 0, sep - path + 1);
+    }
 
 
     /* Create buffer for reading file */