From e9a5b640ac2498a8d45fe9ba8d21a188422d1c6d Mon Sep 17 00:00:00 2001
From: Joshua Suskalo <joshua@suskalo.org>
Date: Thu, 7 Jul 2022 16:08:41 -0500
Subject: [PATCH] Add support for flagset composite types

---
 README.md             |  1 -
 src/clj/coffi/mem.clj | 22 ++++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 71ae4ea..461233e 100644
--- a/README.md
+++ b/README.md
@@ -1104,7 +1104,6 @@ These features are planned for future releases.
 - Support for va_args type
 - Header parsing tool for generating a data model?
 - Generic type aliases
-- Helpers for generating bitflags
 - Unsigned integer types
 - Record-based struct types
 - Helper macro for out arguments
diff --git a/src/clj/coffi/mem.clj b/src/clj/coffi/mem.clj
index e95a518..792c04f 100644
--- a/src/clj/coffi/mem.clj
+++ b/src/clj/coffi/mem.clj
@@ -1279,6 +1279,28 @@
   [obj [_enum variants & {:keys [_repr]}]]
   ((set/map-invert (enum-variants-map variants)) obj))
 
+;;; Flagsets
+
+(defmethod primitive-type ::flagset
+  [[_flagset _bits & {:keys [repr]}]]
+  (if repr
+    (primitive-type repr)
+    ::int))
+
+(defmethod serialize* ::flagset
+  [obj [_flagset bits & {:keys [repr]}] scope]
+  (let [bits-map (enum-variants-map bits)]
+    (reduce #(bit-set %1 (get bits-map %2)) (serialize* 0 (or repr ::int) scope) obj)))
+
+(defmethod deserialize* ::flagset
+  [obj [_flagset bits & {:keys [repr]}]]
+  (let [bits-map (set/map-invert (enum-variants-map bits))]
+    (reduce #(if-not (zero? (bit-and 1 (bit-shift-right obj %2)))
+               (conj %1 (bits-map %2))
+               %1)
+            #{}
+            (range (* 8 (size-of (or repr ::int)))))))
+
 (s/def ::type
   (s/spec
    (s/nonconforming