libmisc: obj.h: Use LM_DEFAPPEND() to implement magic LO_BOX()

2 files changed, 100 insertions, 0 deletions

diff --git a/libmisc/tests/test_obj_autobox.c b/libmisc/tests/test_obj_autobox.c
new file mode 100644
index 0000000..1bf442d
--- /dev/null
+++ b/libmisc/tests/test_obj_autobox.c
@@ -0,0 +1,83 @@
+/* libmisc/tests/test_obj_autobox.c - Generated by `libmisc/tests/test_obj_nest.c libmisc/tests/test_obj_autobox.c`.  DO NOT EDIT!  */
+/* libmisc/tests/test_obj_nest.c - Tests for <libmisc/obj.h> nesting
+ *
+ * Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#include <string.h> /* for memcpy() */
+
+#include <libmisc/obj.h>
+
+#include "test.h"
+
+/* interfaces *****************************************************************/
+
+#define reader_LO_IFACE \
+	LO_FUNC(ssize_t, read, void *, size_t)
+LO_INTERFACE(reader);
+
+#define writer_LO_IFACE \
+	LO_FUNC(ssize_t, write, void *, size_t)
+LO_INTERFACE(writer);
+
+#define read_writer_LO_IFACE \
+	LO_NEST(reader) \
+	LO_NEST(writer)
+LO_INTERFACE(read_writer);
+
+/* implementation header ******************************************************/
+
+struct myclass {
+	size_t len;
+	char   buf[512];
+};
+LO_IMPLEMENTATION_H(reader, struct myclass, myclass);
+LO_IMPLEMENTATION_H(writer, struct myclass, myclass);
+LO_IMPLEMENTATION_H(read_writer, struct myclass, myclass);
+
+/* implementation main ********************************************************/
+
+LO_IMPLEMENTATION_C(reader, struct myclass, myclass, static);
+LO_IMPLEMENTATION_C(writer, struct myclass, myclass, static);
+LO_IMPLEMENTATION_C(read_writer, struct myclass, myclass, static);
+
+static ssize_t myclass_read(struct myclass *self, void *buf, size_t count) {
+	test_assert(self);
+	if (count > self->len)
+		count = self->len;
+	memcpy(buf, self->buf, count);
+	return count;
+}
+
+static ssize_t myclass_write(struct myclass *self, void *buf, size_t count) {
+	test_assert(self);
+	if (self->len)
+		return -1;
+	if (count > sizeof(self->buf))
+		count = sizeof(self->buf);
+	memcpy(self->buf, buf, count);
+	self->len = count;
+	return count;
+}
+
+/* main test body *************************************************************/
+
+int main() {
+	struct myclass _obj = {};
+	lo_interface read_writer obj = LO_BOX(read_writer, &_obj);
+	test_assert(LO_CALL(obj, write, "Hello", 6) == 6);
+	char buf[6] = {};
+	test_assert(LO_CALL(obj, read, buf, 3) == 3);
+	test_assert(memcmp(buf, "Hel\0\0\0", 6) == 0);
+
+	lo_interface reader rd = LO_BOX(reader, &_obj);
+	rd = LO_BOX(reader, obj);
+	(void) rd;
+
+	lo_interface writer wr = LO_BOX(writer, &_obj);
+	wr = LO_BOX(writer, obj);
+	(void) wr;
+
+	return 0;
+}
diff --git a/libmisc/tests/test_obj_autobox.c.gen b/libmisc/tests/test_obj_autobox.c.gen
new file mode 100755
index 0000000..3cfa3d4
--- /dev/null
+++ b/libmisc/tests/test_obj_autobox.c.gen
@@ -0,0 +1,17 @@
+#!/bin/sh
+# libmisc/tests/test_obj_autobox.c.gen - Generate tests for LO_BOX()
+#
+# Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+infile=$1
+outfile=$2
+
+grep --quiet lo_box_ -- "$infile"
+
+{
+	echo "/* ${outfile} - Generated by \`$*\`.  DO NOT EDIT!  */"
+	sed -E 's/lo_box_([a-z0-9_]+)_as_([a-z0-9_]+)\(/LO_BOX(\2, /g' <"$infile"
+} >"$outfile"
+
+! grep -H lo_box_ -- "$outfile"