initial commit

internal/item/upgrader.go

@@ -0,0 +1,109 @@
+package item
+
+import (
+	"github.com/df-mc/worldupgrader/blockupgrader"
+)
+
+// Item ...
+type Item struct {
+	Name     string
+	Metadata uint32
+	Version  uint16
+}
+
+// Upgrade upgrades the given item using the registered item upgrade schemas.
+func Upgrade(item Item, ver uint16) Item {
+	version := item.Version
+	for id, s := range schemas {
+		if version > id || id > ver {
+			continue
+		}
+
+		name := item.Name
+		metadata := item.Metadata
+		nameRenamed := false
+		metadataRemapped := false
+
+		if metadataCombinations, ok := s.RemappedMetas[name]; ok {
+			name, metadataRemapped = metadataCombinations[item.Metadata]
+			metadata = 0
+		} else if name, nameRenamed = s.RenamedIDs[item.Name]; !nameRenamed {
+			name = item.Name
+		}
+
+		if nameRenamed || metadataRemapped {
+			item = Item{
+				Name:     name,
+				Metadata: metadata,
+				Version:  id,
+			}
+		}
+	}
+	return item
+}
+
+// Downgrade downgrades the given item using the registered item upgrade schemas.
+func Downgrade(item Item, ver uint16) Item {
+	for i, id := range schemaIDs {
+		s := schemas[uint16(id)]
+		if uint16(id) > item.Version {
+			continue
+		}
+
+		name := item.Name
+		metadata := item.Metadata
+		nameRenamed := false
+		metadataRemapped := false
+
+		for oldName, newName := range s.RenamedIDs {
+			if newName == name {
+				name = oldName
+				nameRenamed = true
+			}
+		}
+
+		if !nameRenamed {
+			for oldName, m := range s.RemappedMetas {
+				for meta, newName := range m {
+					if newName == name {
+						name = oldName
+						metadata = meta
+						nameRenamed = true
+						metadataRemapped = true
+					}
+				}
+				if metadataRemapped {
+					break
+				}
+			}
+		}
+
+		if ver > item.Version || i == len(schemaIDs)-1 {
+			break
+		}
+
+		return Downgrade(Item{
+			Name:     name,
+			Metadata: metadata,
+			Version:  uint16(schemaIDs[i+1]),
+		}, ver)
+	}
+	return item
+}
+
+func BlockStateFromItemName(itemName string, metadata uint32) (blockupgrader.BlockState, bool) {
+	blockId, ok := itemToBlockIdMap[itemName]
+	if !ok {
+		return blockupgrader.BlockState{}, false
+	}
+
+	blockState, ok := blockStateMap[stateHash{
+		Name:     blockId,
+		Metadata: metadata,
+	}]
+	return blockState, ok
+}
+
+func BlockStateFromItem(item Item) (blockupgrader.BlockState, bool) {
+	return BlockStateFromItemName(item.Name, item.Metadata)
+}