up3

server/world/chunk/conversion.go

@@ -0,0 +1,45 @@
+package chunk
+
+import (
+	"bytes"
+	_ "embed"
+	"github.com/sandertv/gophertunnel/minecraft/nbt"
+)
+
+// legacyBlockEntry represents a block entry used in versions prior to 1.13.
+type legacyBlockEntry struct {
+	Name string `nbt:"name"`
+	Meta int16  `nbt:"meta"`
+}
+
+var (
+	//go:embed legacy_states.nbt
+	legacyMappingsData []byte
+	// legacyMappings allows simple conversion from a legacy block entry to a new one.
+	legacyMappings = make(map[legacyBlockEntry]blockEntry)
+)
+
+// upgradeLegacyEntry upgrades a legacy block entry to a new one.
+func upgradeLegacyEntry(name string, meta int16) (blockEntry, bool) {
+	entry, ok := legacyMappings[legacyBlockEntry{Name: name, Meta: meta}]
+	if !ok {
+		// Also try cases where the meta should be disregarded.
+		entry, ok = legacyMappings[legacyBlockEntry{Name: name}]
+	}
+	return entry, ok
+}
+
+// init creates conversions for each legacy and alias entry.
+func init() {
+	var entry struct {
+		Legacy  legacyBlockEntry `nbt:"legacy"`
+		Updated blockEntry       `nbt:"updated"`
+	}
+	dec := nbt.NewDecoder(bytes.NewBuffer(legacyMappingsData))
+	for {
+		if err := dec.Decode(&entry); err != nil {
+			break
+		}
+		legacyMappings[entry.Legacy] = entry.Updated
+	}
+}