3 files changed, 98 insertions, 0 deletions
diff --git a/ccan/ccan/check_type/LICENSE b/ccan/ccan/check_type/LICENSE
new file mode 120000
index 0000000..b7951da
--- /dev/null
+++ b/ccan/ccan/check_type/LICENSE
@@ -0,0 +1 @@
+../../licenses/CC0
+\ No newline at end of file
diff --git a/ccan/ccan/check_type/_info b/ccan/ccan/check_type/_info
new file mode 100644
index 0000000..cc42673
--- /dev/null
+++ b/ccan/ccan/check_type/_info
@@ -0,0 +1,33 @@
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+
+/**
+ * check_type - routines for compile time type checking
+ *
+ * C has fairly weak typing: ints get automatically converted to longs, signed
+ * to unsigned, etc.  There are some cases where this is best avoided, and
+ * these macros provide methods for evoking warnings (or build errors) when
+ * a precise type isn't used.
+ *
+ * On compilers which don't support typeof() these routines are less effective,
+ * since they have to use sizeof() which can only distiguish between types of
+ * different size.
+ *
+ * License: CC0 (Public domain)
+ * Author: Rusty Russell <rusty@rustcorp.com.au>
+ */
+int main(int argc, char *argv[])
+{
+	if (argc != 2)
+		return 1;
+
+	if (strcmp(argv[1], "depends") == 0) {
+#if !HAVE_TYPEOF
+		printf("ccan/build_assert\n");
+#endif
+		return 0;
+	}
+
+	return 1;
+}
diff --git a/ccan/ccan/check_type/check_type.h b/ccan/ccan/check_type/check_type.h
new file mode 100644
index 0000000..837aef7
--- /dev/null
+++ b/ccan/ccan/check_type/check_type.h
@@ -0,0 +1,64 @@
+/* CC0 (Public domain) - see LICENSE file for details */
+#ifndef CCAN_CHECK_TYPE_H
+#define CCAN_CHECK_TYPE_H
+#include "config.h"
+
+/**
+ * check_type - issue a warning or build failure if type is not correct.
+ * @expr: the expression whose type we should check (not evaluated).
+ * @type: the exact type we expect the expression to be.
+ *
+ * This macro is usually used within other macros to try to ensure that a macro
+ * argument is of the expected type.  No type promotion of the expression is
+ * done: an unsigned int is not the same as an int!
+ *
+ * check_type() always evaluates to 0.
+ *
+ * If your compiler does not support typeof, then the best we can do is fail
+ * to compile if the sizes of the types are unequal (a less complete check).
+ *
+ * Example:
+ *	// They should always pass a 64-bit value to _set_some_value!
+ *	#define set_some_value(expr)			\
+ *		_set_some_value((check_type((expr), uint64_t), (expr)))
+ */
+
+/**
+ * check_types_match - issue a warning or build failure if types are not same.
+ * @expr1: the first expression (not evaluated).
+ * @expr2: the second expression (not evaluated).
+ *
+ * This macro is usually used within other macros to try to ensure that
+ * arguments are of identical types.  No type promotion of the expressions is
+ * done: an unsigned int is not the same as an int!
+ *
+ * check_types_match() always evaluates to 0.
+ *
+ * If your compiler does not support typeof, then the best we can do is fail
+ * to compile if the sizes of the types are unequal (a less complete check).
+ *
+ * Example:
+ *	// Do subtraction to get to enclosing type, but make sure that
+ *	// pointer is of correct type for that member.
+ *	#define container_of(mbr_ptr, encl_type, mbr)			\
+ *		(check_types_match((mbr_ptr), &((encl_type *)0)->mbr),	\
+ *		 ((encl_type *)						\
+ *		  ((char *)(mbr_ptr) - offsetof(encl_type, mbr))))
+ */
+#if HAVE_TYPEOF
+#define check_type(expr, type)			\
+	((typeof(expr) *)0 != (type *)0)
+
+#define check_types_match(expr1, expr2)		\
+	((typeof(expr1) *)0 != (typeof(expr2) *)0)
+#else
+#include <ccan/build_assert/build_assert.h>
+/* Without typeof, we can only test the sizes. */
+#define check_type(expr, type)					\
+	BUILD_ASSERT_OR_ZERO(sizeof(expr) == sizeof(type))
+
+#define check_types_match(expr1, expr2)				\
+	BUILD_ASSERT_OR_ZERO(sizeof(expr1) == sizeof(expr2))
+#endif /* HAVE_TYPEOF */
+
+#endif /* CCAN_CHECK_TYPE_H */