c/ffi: add _demo

c/ffi/_demo/closure/main.go

@@ -0,0 +1,78 @@
+package main
+
+import (
+	"unsafe"
+
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/ffi"
+)
+
+const (
+	LLGoPackage = "link"
+	LLGoFiles   = "../_wrap/wrap.c"
+)
+
+//llgo:type C
+type Callback func(array) c.Int
+
+//go:linkname demo1 C.demo1
+func demo1(array) c.Int
+
+//go:linkname demo2 C.demo2
+func demo2(fn Callback) c.Int
+
+//llgo:type C
+type array struct {
+	x c.Int
+	y c.Int
+	z c.Int
+	k c.Int
+}
+
+func demo(a array) c.Int {
+	c.Printf(c.Str("go.demo %d %d %d %d\n"), a.x, a.y, a.z, a.k)
+	return a.x + a.y + a.z + a.k
+}
+
+func main() {
+	gofn()
+	c.Printf(c.Str("\n"))
+	goclosure()
+}
+
+func gofn() {
+	sig, err := ffi.NewSignature(ffi.TypeInt32, ffi.TypePointer)
+	if err != nil {
+		panic(err)
+	}
+	closure := ffi.NewClosure()
+	defer closure.Free()
+	err = closure.Bind(sig, func(cif *ffi.Signature, ret unsafe.Pointer, args *unsafe.Pointer, userdata unsafe.Pointer) {
+		ar := *(*array)(ffi.Index(args, 0))
+		*(*c.Int)(ret) = demo(ar)
+	}, nil)
+	var ret int32
+	ffi.Call(sig, c.Func(demo2), unsafe.Pointer(&ret), unsafe.Pointer(&closure.Fn))
+	c.Printf(c.Str("ret: %d\n"), ret)
+}
+
+func goclosure() {
+	sig, err := ffi.NewSignature(ffi.TypeInt32, ffi.TypePointer)
+	if err != nil {
+		panic(err)
+	}
+	fn := func(ar array) c.Int {
+		c.Printf(c.Str("call closure %d\n"), sig.NArgs)
+		return demo(ar)
+	}
+	closure := ffi.NewClosure()
+	defer closure.Free()
+	err = closure.Bind(sig, func(cif *ffi.Signature, ret unsafe.Pointer, args *unsafe.Pointer, userdata unsafe.Pointer) {
+		ar := *(*array)(ffi.Index(args, 0))
+		fn := *(*func(array) c.Int)(userdata)
+		*(*c.Int)(ret) = fn(ar)
+	}, unsafe.Pointer(&fn))
+	var ret int32
+	ffi.Call(sig, c.Func(demo2), unsafe.Pointer(&ret), unsafe.Pointer(&closure.Fn))
+	c.Printf(c.Str("ret: %d\n"), ret)
+}