overflows: helpers for integer assignment overflows.

Signed-off-by: Rusty Russell <[email protected]>
rsouvik · Jul 20, 2021 · 888774e · 888774e
1 parent dd00d4d
commit 888774e
Showing 1 changed file with 19 additions and 0 deletions.
diff --git a/common/overflows.h b/common/overflows.h
@@ -1,6 +1,7 @@
 #ifndef LIGHTNING_COMMON_OVERFLOWS_H
 #define LIGHTNING_COMMON_OVERFLOWS_H
 #include "config.h"
+#include <ccan/short_types/short_types.h>
 
 static inline bool add_overflows_size_t(uint64_t a, uint64_t b)
 {
@@ -21,4 +22,22 @@ static inline bool mul_overflows_u64(uint64_t a, uint64_t b)
 	ret = a * b;
 	return (ret / a != b);
 }
+
+static inline bool assign_overflow_u8(u8 *dst, uint64_t v)
+{
+	*dst = v;
+	return *dst == v;
+}
+
+static inline bool assign_overflow_u16(u16 *dst, uint64_t v)
+{
+	*dst = v;
+	return *dst == v;
+}
+
+static inline bool assign_overflow_u32(u32 *dst, uint64_t v)
+{
+	*dst = v;
+	return *dst == v;
+}
 #endif /* LIGHTNING_COMMON_OVERFLOWS_H */