Golang C.lua_next函數代碼示例

func packLuaTable(out io.Writer, state State, object int, depth int) (n int, err error) {
	depth++
	L := state.L

	if depth > MAX_PACK_DEPTH {
		return 0, fmt.Errorf("pack too depth, depth=%v", depth)
	}

	n = 0
	err = nil
	var mapSize int = 0
	C.lua_pushnil(L)
	for {
		if 0 == C.lua_next(L, C.int(object)) {
			break
		}
		mapSize++
		C.lua_settop(L, -2) // pop 1
	}

	var ni int
	ni, err = P.PackMapHead(out, uint32(mapSize))
	n += ni
	if err != nil {
		return
	}

	C.lua_pushnil(L)
	for {
		if 0 == C.lua_next(L, C.int(object)) {
			break
		}

		top := int(C.lua_gettop(L))
		// key
		ni, err = packLuaObject(out, state, top-1, depth)
		n += ni
		if err != nil {
			C.lua_settop(L, -3) // pop 2
			return
		}
		// value
		ni, err = packLuaObject(out, state, top, depth)
		n += ni
		if err != nil {
			C.lua_settop(L, -3) // pop 2
			return
		}
		C.lua_settop(L, -2) // removes value, keeps key for next iteration
	}

	return
}

func (tbl *Table) Foreach(fn func(key interface{}, value interface{}) bool) {
	if tbl.Ref == 0 {
		return
	}

	L := tbl.VM.globalL
	state := State{tbl.VM, L}
	bottom := C.lua_gettop(L)
	defer C.lua_settop(L, bottom)
	tbl.PushValue(state)

	ltable := C.lua_gettop(L)
	C.lua_pushnil(L)
	for {
		if 0 == C.lua_next(L, ltable) {
			return
		}

		vkey, err := state.luaToGoValue(-2, nil)
		if err != nil {
			return
		}
		vvalue, err := state.luaToGoValue(-1, nil)
		if err != nil {
			return
		}

		cont := fn(vkey.Interface(), vvalue.Interface())
		if !cont {
			return
		}

		C.lua_settop(L, -2)
	}
}

func sizeOfLuaTable(L *C.lua_State, ltable int) int {
	var size int = 0
	C.lua_pushnil(L)
	for {
		if 0 == C.lua_next(L, C.int(ltable)) {
			break
		}
		size++
		C.lua_settop(L, -2) // pop 1
	}
	return size
}

func (state *State) luaTableToKeyValues(ltable int) (value reflect.Value, err error) {
	var vvalue reflect.Value
	L := state.L

	size := sizeOfLuaTable(L, ltable)
	result := make([]base.KeyValue, 0, size)

	C.lua_pushnil(L)
	for {
		if 0 == C.lua_next(L, C.int(ltable)) {
			break
		}

		lvalue := int(C.lua_gettop(L))
		lkey := lvalue - 1

		vkey, err := state.luaToGoValue(lkey, nil)
		if err != nil {
			C.lua_settop(L, -3) // pop 2
			break
		}

		if C.LUA_TTABLE == C.lua_type(L, C.int(lvalue)) {
			vvalue, err = state.luaTableToKeyValues(lvalue)
		} else {
			vvalue, err = state.luaToGoValue(lvalue, nil)
		}
		if err != nil {
			C.lua_settop(L, -3) // pop 2
			break
		}

		key := vkey.Interface()
		var skey string
		if s, ok := key.(string); ok {
			skey = s
		} else {
			skey = fmt.Sprint(key)
		}
		value := vvalue.Interface()

		result = append(result, base.KeyValue{skey, value})

		C.lua_settop(L, -2) // pop 1
	}

	return reflect.ValueOf(result), err
}

// lua_next
func (L *State) Next(index int) int {
	return int(C.lua_next(L.s, C.int(index)))
}

// Pops a key from the stack, and pushes a key-value pair from the table
// at the given index (the "next" pair after the given key). If there are
// no more elements in the table, then Next returns 0 (and pushes nothing).
//
// A typical traversal looks like this:
// 	// table is in the stack at index 't'
// 	s.Pushnil()	// first key
// 	for s.Next(t) != 0 {
// 		// use key (at index -2) and value (index -1)
// 		fmt.Printf("%s - %s\n",
// 			s.Typename(s.Type(-2)),
// 			s.Typename(s.Type(-1)))
// 		// remove value, keep key for next iteration
// 		s.Pop(1)
// 	}
//
func (s *State) Next(index int) int {
	return int(C.lua_next(s.l, C.int(index)))
}

func (lua *Lua) toGoValue(i C.int, paramType reflect.Type) (ret reflect.Value) {
	luaType := C.lua_type(lua.State, i)
	paramKind := paramType.Kind()
	switch paramKind {
	case reflect.Bool:
		if luaType != C.LUA_TBOOLEAN {
			lua.Panic("not a boolean")
		}
		ret = reflect.ValueOf(C.lua_toboolean(lua.State, i) == C.int(1))
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		if luaType != C.LUA_TNUMBER {
			lua.Panic("not an integer")
		}
		ret = reflect.New(paramType).Elem()
		ret.SetInt(int64(C.lua_tointegerx(lua.State, i, nil)))
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		if luaType != C.LUA_TNUMBER {
			lua.Panic("not an unsigned")
		}
		ret = reflect.New(paramType).Elem()
		ret.SetUint(uint64(C.lua_tointegerx(lua.State, i, nil)))
	case reflect.Float32, reflect.Float64:
		if luaType != C.LUA_TNUMBER {
			lua.Panic("not a float")
		}
		ret = reflect.New(paramType).Elem()
		ret.SetFloat(float64(C.lua_tonumberx(lua.State, i, nil)))
	case reflect.Interface:
		switch luaType {
		case C.LUA_TNUMBER:
			ret = reflect.New(floatType).Elem()
			ret.SetFloat(float64(C.lua_tonumberx(lua.State, i, nil)))
		case C.LUA_TSTRING:
			ret = reflect.New(stringType).Elem()
			ret.SetString(C.GoString(C.lua_tolstring(lua.State, i, nil)))
		case C.LUA_TLIGHTUSERDATA:
			ret = reflect.ValueOf(C.lua_topointer(lua.State, i))
		case C.LUA_TBOOLEAN:
			ret = reflect.New(boolType).Elem()
			ret.SetBool(C.lua_toboolean(lua.State, i) == C.int(1))
		//TODO nil
		//TODO table
		default:
			lua.Panic("wrong interface argument: %v", paramKind)
		}
	case reflect.String:
		if luaType != C.LUA_TSTRING {
			lua.Panic("not a string")
		}
		ret = reflect.New(paramType).Elem()
		ret.SetString(C.GoString(C.lua_tolstring(lua.State, i, nil)))
	case reflect.Slice:
		switch luaType {
		case C.LUA_TSTRING:
			ret = reflect.New(paramType).Elem()
			cstr := C.lua_tolstring(lua.State, i, nil)
			ret.SetBytes(C.GoBytes(unsafe.Pointer(cstr), C.int(C.strlen(cstr))))
		case C.LUA_TTABLE:
			ret = reflect.MakeSlice(paramType, 0, 0)
			C.lua_pushnil(lua.State)
			elemType := paramType.Elem()
			for C.lua_next(lua.State, i) != 0 {
				ret = reflect.Append(ret, lua.toGoValue(-1, elemType))
				C.lua_settop(lua.State, -2)
			}
		default:
			lua.Panic("wrong slice argument")
		}
	case reflect.Ptr:
		if luaType != C.LUA_TLIGHTUSERDATA {
			lua.Panic("not a pointer")
		}
		pointer := C.lua_topointer(lua.State, i)
		ret = reflect.NewAt(paramType, unsafe.Pointer(&pointer)).Elem()
	case reflect.Map:
		if luaType != C.LUA_TTABLE {
			lua.Panic("not a map")
		}
		ret = reflect.MakeMap(paramType)
		C.lua_pushnil(lua.State)
		keyType := paramType.Key()
		elemType := paramType.Elem()
		for C.lua_next(lua.State, i) != 0 {
			ret.SetMapIndex(
				lua.toGoValue(-2, keyType),
				lua.toGoValue(-1, elemType))
			C.lua_settop(lua.State, -2)
		}
	case reflect.UnsafePointer:
		ret = reflect.ValueOf(C.lua_topointer(lua.State, i))
	//TODO complex64/128
	//TODO array
	//TODO chan
	//TODO func
	//TODO struct
	default:
		lua.Panic("unknown argument type %v", paramType)
	}
	return
}

func (l *Lua) toGoValue(i C.int, paramType reflect.Type) (ret *reflect.Value, err error) {
	luaType := C.lua_type(l.State, i)
	paramKind := paramType.Kind()
	switch paramKind {
	case reflect.Bool:
		if luaType != C.LUA_TBOOLEAN {
			err = fmt.Errorf("not a boolean")
			return
		}
		v := reflect.ValueOf(C.lua_toboolean(l.State, i) == C.int(1))
		ret = &v
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		if luaType != C.LUA_TNUMBER {
			err = fmt.Errorf("not an integer")
			return
		}
		v := reflect.New(paramType).Elem()
		v.SetInt(int64(C.lua_tointeger(l.State, i)))
		ret = &v
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		if luaType != C.LUA_TNUMBER {
			err = fmt.Errorf("not a unsigned")
			return
		}
		v := reflect.New(paramType).Elem()
		v.SetUint(uint64(C.lua_tointeger(l.State, i)))
		ret = &v
	case reflect.Float32, reflect.Float64:
		if luaType != C.LUA_TNUMBER {
			err = fmt.Errorf("not a float")
			return
		}
		v := reflect.New(paramType).Elem()
		v.SetFloat(float64(C.lua_tonumber(l.State, i)))
		ret = &v
	case reflect.Interface:
		switch paramType {
		case interfaceType:
			switch luaType {
			case C.LUA_TNUMBER:
				v := reflect.New(floatType).Elem() // always return float64 for interface{}
				v.SetFloat(float64(C.lua_tonumber(l.State, i)))
				ret = &v
			case C.LUA_TSTRING:
				v := reflect.New(stringType).Elem()
				v.SetString(C.GoString(C.lua_tolstring(l.State, i, nil)))
				ret = &v
			case C.LUA_TLIGHTUSERDATA, C.LUA_TUSERDATA:
				v := reflect.ValueOf(C.lua_touserdata(l.State, i))
				ret = &v
			case C.LUA_TBOOLEAN:
				v := reflect.New(boolType).Elem()
				v.SetBool(C.lua_toboolean(l.State, i) == C.int(1))
				ret = &v
			case C.LUA_TNIL:
				ret = nil
			default:
				err = fmt.Errorf("unsupported type %s for interface{}", luaTypeName(luaType))
				return
			}
		default:
			err = fmt.Errorf("only interface{} is supported, no %v", paramType)
			return
		}
	case reflect.String:
		if luaType != C.LUA_TSTRING {
			err = fmt.Errorf("not a string")
			return
		}
		v := reflect.New(paramType).Elem()
		v.SetString(C.GoString(C.lua_tolstring(l.State, i, nil)))
		ret = &v
	case reflect.Slice:
		switch luaType {
		case C.LUA_TSTRING:
			v := reflect.New(paramType).Elem()
			cstr := C.lua_tolstring(l.State, i, nil)
			v.SetBytes(C.GoBytes(unsafe.Pointer(cstr), C.int(C.strlen(cstr))))
			ret = &v
		case C.LUA_TTABLE:
			v := reflect.MakeSlice(paramType, 0, 0)
			C.lua_pushnil(l.State)
			elemType := paramType.Elem()
			for C.lua_next(l.State, i) != 0 {
				elemValue, e := l.toGoValue(-1, elemType)
				if e != nil {
					err = e
					return
				}
				// there is no nil value in lua table so elemValue will never be nil
				v = reflect.Append(v, *elemValue)
				C.lua_settop(l.State, -2)
				ret = &v
			}
		default:
			err = fmt.Errorf("wrong slice argument")
			return
		}
	case reflect.Ptr:
		if luaType != C.LUA_TLIGHTUSERDATA {
//.........這裏部分代碼省略.........