diff --git a/inventory.go b/inventory.go
new file mode 100644
index 0000000..c0a6258
--- /dev/null
+++ b/inventory.go
@@ -0,0 +1,20 @@
+package types
+
+type Inventory struct {
+	Size  int     `json:"size"`
+	Items []*Item `json:"items"`
+}
+
+func (inv *Inventory) IsEmpty() bool {
+	if len(inv.Items) == 0 {
+		return true
+	}
+
+	for _, item := range inv.Items {
+		if item.Name != "" && item.Count > 0 {
+			return false
+		}
+	}
+
+	return true
+}
diff --git a/item.go b/item.go
new file mode 100644
index 0000000..2c92f59
--- /dev/null
+++ b/item.go
@@ -0,0 +1,12 @@
+package types
+
+type Item struct {
+	Name  string `json:"name"`
+	Count int    `json:"count"`
+	Wear  int    `json:"wear"`
+	//TODO: metadata
+}
+
+func (i *Item) IsEmpty() bool {
+	return i.Name == "" && i.Count == 0
+}
diff --git a/mapblock.go b/mapblock.go
new file mode 100644
index 0000000..cf06cb8
--- /dev/null
+++ b/mapblock.go
@@ -0,0 +1,36 @@
+package types
+
+type MapBlock struct {
+	Size         int            `json:"size"`
+	Version      byte           `json:"version"`
+	Underground  bool           `json:"underground"`
+	Timestamp    uint32         `json:"timestamp"`
+	Mapdata      *MapData       `json:"mapdata"`
+	Metadata     *Metadata      `json:"metadata"`
+	BlockMapping map[int]string `json:"blockmapping"`
+}
+
+func NewMapblock() *MapBlock {
+	mb := MapBlock{}
+	mb.Metadata = NewMetadata()
+	mb.BlockMapping = make(map[int]string)
+	return &mb
+}
+
+// returns true if the mapblock is empty (air-only)
+func (mb *MapBlock) IsEmpty() bool {
+	return len(mb.BlockMapping) == 0
+}
+
+func (mb *MapBlock) GetNodeId(p *Pos) int {
+	return mb.Mapdata.ContentId[p.Index()]
+}
+
+func (mb *MapBlock) GetParam2(p *Pos) int {
+	return mb.Mapdata.Param2[p.Index()]
+}
+
+func (mb *MapBlock) GetNodeName(p *Pos) string {
+	id := mb.GetNodeId(p)
+	return mb.BlockMapping[id]
+}
diff --git a/mapdata.go b/mapdata.go
new file mode 100644
index 0000000..c0e902a
--- /dev/null
+++ b/mapdata.go
@@ -0,0 +1,7 @@
+package types
+
+type MapData struct {
+	ContentId []int `json:"contentid"`
+	Param1    []int `json:"param1"`
+	Param2    []int `json:"param2"`
+}
diff --git a/metadata.go b/metadata.go
new file mode 100644
index 0000000..cc88120
--- /dev/null
+++ b/metadata.go
@@ -0,0 +1,52 @@
+package types
+
+type Metadata struct {
+	Inventories map[int]map[string]*Inventory `json:"inventories"`
+	Pairs       map[int]map[string]string     `json:"pairs"`
+}
+
+func NewMetadata() *Metadata {
+	md := Metadata{}
+	md.Inventories = make(map[int]map[string]*Inventory)
+	md.Pairs = make(map[int]map[string]string)
+	return &md
+}
+
+func (md *Metadata) GetMetadata(p *Pos) map[string]string {
+	return md.GetPairsMap(p.Index())
+}
+
+func (md *Metadata) GetPairsMap(pos int) map[string]string {
+	pairsMap := md.Pairs[pos]
+	if pairsMap == nil {
+		pairsMap = make(map[string]string)
+		md.Pairs[pos] = pairsMap
+	}
+
+	return pairsMap
+}
+
+func (md *Metadata) GetInventoryMap(index int) map[string]*Inventory {
+	invMap := md.Inventories[index]
+	if invMap == nil {
+		invMap = make(map[string]*Inventory)
+		md.Inventories[index] = invMap
+	}
+
+	return invMap
+}
+
+func (md *Metadata) GetInventoryMapAtPos(p *Pos) map[string]*Inventory {
+	return md.GetInventoryMap(p.Index())
+}
+
+func (md *Metadata) GetInventory(index int, name string) *Inventory {
+	m := md.GetInventoryMap(index)
+	inv := m[name]
+	if inv == nil {
+		inv = &Inventory{}
+		m[name] = inv
+	}
+
+	return inv
+}
diff --git a/pos.go b/pos.go
index 1ce291c..6498c50 100644
--- a/pos.go
+++ b/pos.go
@@ -11,6 +11,15 @@ func NewPos(x, y, z int) *Pos {
 	return &Pos{x, y, z}
 }
 
+func NewPosFromIndex(i int) *Pos {
+	x := i % 16
+	i /= 16
+	y := i % 16
+	i /= 16
+	z := i % 16
+	return NewPos(x, y, z)
+}
+
 func SortPos(p1, p2 *Pos) (*Pos, *Pos) {
 	return &Pos{
 			min(p1[0], p2[0]),
@@ -68,3 +77,7 @@ func (p *Pos) IsWithin(min, max *Pos) bool {
 		p[1] >= min[1] && p[1] <= max[1] &&
 		p[2] >= min[2] && p[2] <= max[2]
 }
+
+func (p *Pos) Index() int {
+	return p[0] + (p[1] * 16) + (p[2] * 256)
+}
diff --git a/pos_test.go b/pos_test.go
index 86d2b9b..b106806 100644
--- a/pos_test.go
+++ b/pos_test.go
@@ -18,6 +18,17 @@ func TestPos(t *testing.T) {
 	assert.Equal(t, 30, p2.Z())
 }
 
+func TestPosIndex(t *testing.T) {
+	pos := types.NewPos(5, 8, 12)
+
+	i := pos.Index()
+	pos = types.NewPosFromIndex(i)
+
+	assert.Equal(t, pos.X(), 5)
+	assert.Equal(t, pos.Y(), 8)
+	assert.Equal(t, pos.Z(), 12)
+}
+
 func TestSortPos(t *testing.T) {
 	p1 := &types.Pos{1, 2, 3}
 	p2 := &types.Pos{3, 2, 1}