初步实现bfs原型（仅用于实验）

internal/utils/bfs/meta_block.go

@@ -0,0 +1,48 @@
+// Copyright 2024 GoEdge CDN goedge.cdn@gmail.com. All rights reserved. Official site: https://goedge.cn .
+
+package bfs
+
+import (
+	"encoding/binary"
+	"errors"
+)
+
+type MetaAction = byte
+
+const (
+	MetaActionNew    MetaAction = '+'
+	MetaActionRemove MetaAction = '-'
+)
+
+func EncodeMetaBlock(action MetaAction, hash string, data []byte) ([]byte, error) {
+	var hl = len(hash)
+	if hl != HashLen {
+		return nil, errors.New("invalid hash length")
+	}
+
+	var l = 1 /** Action **/ + hl /** Hash **/ + len(data)
+
+	var b = make([]byte, 4 /** Len **/ +l)
+	binary.BigEndian.PutUint32(b, uint32(l))
+	b[4] = action
+	copy(b[5:], hash)
+	copy(b[5+hl:], data)
+	return b, nil
+}
+
+func DecodeMetaBlock(blockBytes []byte) (action MetaAction, hash string, data []byte, err error) {
+	var dataOffset = 4 /** Len **/ + HashLen + 1 /** Action **/
+	if len(blockBytes) < dataOffset {
+		err = errors.New("decode failed: invalid block data")
+		return
+	}
+
+	action = blockBytes[4]
+	hash = string(blockBytes[5 : 5+HashLen])
+
+	if action == MetaActionNew {
+		data = blockBytes[dataOffset:]
+	}
+
+	return
+}