From 3598fc24625f233cc0078f62da630d335604ef5b Mon Sep 17 00:00:00 2001
From: Adrian Cochrane <adrian@openwork.nz>
Date: Fri, 18 Nov 2022 15:57:18 +1300
Subject: [PATCH] Add more unboxing & null-checks to FcValue decoding.

---
 Graphics/Text/Font/Choose/Value.hs | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/Graphics/Text/Font/Choose/Value.hs b/Graphics/Text/Font/Choose/Value.hs
index 9e03e81..ce20729 100644
--- a/Graphics/Text/Font/Choose/Value.hs
+++ b/Graphics/Text/Font/Choose/Value.hs
@@ -102,16 +102,24 @@ thawValue ptr = do
         0 -> return $ Just ValueVoid
         1 -> Just <$> ValueInt <$> peek val'
         2 -> Just <$> ValueDouble <$> peek val'
-        3 -> Just <$> ValueString <$> peekCString val'
+        3 -> do
+            val <- throwNull <$> peek val'
+            Just <$> ValueString <$> peekCString val
         4 -> do
-            mat' <- peek val'
+            mat' <- throwNull <$> peek val'
             xx <- peekElemOff mat' 0
             xy <- peekElemOff mat' 1
             yx <- peekElemOff mat' 2
             yy <- peekElemOff mat' 3
             return $ Just $ ValueMatrix $ V2 (V2 xx yx) (V2 xy yy)
-        5 -> Just <$> ValueCharSet <$> thawCharSet val'
-        6 -> return $ Just $ ValueFTFace $ val'
-        7 -> Just <$> ValueLangSet <$> thawLangSet val'
-        8 -> Just <$> ValueRange <$> thawRange val'
+        5 -> do
+            val <- throwNull <$> peek val'
+            Just <$> ValueCharSet <$> thawCharSet val
+        6 -> Just <$> ValueFTFace <$> throwNull <$> peek val'
+        7 -> do
+            val <- throwNull <$> peek val'
+            Just <$> ValueLangSet <$> thawLangSet val
+        8 -> do
+            val <- throwNull <$> peek val'
+            Just <$> ValueRange <$> thawRange val
         _ -> return Nothing
-- 
2.30.2