From 1ca796b3a323527584f671ded7e67d44c7e926ce Mon Sep 17 00:00:00 2001
From: piepie62 <christopherfeger@yahoo.com>
Date: Thu, 23 Apr 2020 22:12:31 -0400
Subject: [PATCH] Add invalid glyph index protection

---
 libctru/source/font.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/libctru/source/font.c b/libctru/source/font.c
index 1272cdd..81c61c8 100644
--- a/libctru/source/font.c
+++ b/libctru/source/font.c
@@ -48,7 +48,7 @@ int fontGlyphIndexFromCodePoint(CFNT_s* font, u32 codePoint)
 		font = g_sharedFont;
 	if (!font)
 		return -1;
-	int ret = font->finf.alterCharIndex;
+	int ret = 0xFFFF;
 	if (codePoint < 0x10000)
 	{
 		for (CMAP_s* cmap = font->finf.cmap; cmap; cmap = cmap->next)
@@ -79,6 +79,13 @@ int fontGlyphIndexFromCodePoint(CFNT_s* font, u32 codePoint)
 			}
 		}
 	}
+	if (ret == 0xFFFF) // Bogus CMAP entry. Probably exist to save space by using TABLE mappings?
+	{
+		if (font->finf.alterCharIndex == 0xFFFF)
+			return -1;
+		else
+			return font->finf.alterCharIndex;
+	}
 	return ret;
 }