add header mgr struct

binding/golang/xdb/index.go

@@ -105,3 +105,29 @@ func (v VectorIndexBlock) Encode() []byte {
 func (v VectorIndexBlock) String() string {
 	return fmt.Sprintf("{FristPtr: %d, LastPtr: %d}", v.FirstPtr, v.LastPtr)
 }
+
+// ------------
+
+type Header struct {
+	data []byte
+}
+
+func (h *Header) Version() int {
+	return int(binary.LittleEndian.Uint16(h.data))
+}
+
+func (h *Header) IndexPolicy() IndexPolicy {
+	return IndexPolicy(binary.LittleEndian.Uint16(h.data[2:]))
+}
+
+func (h *Header) CreatedAt() uint32 {
+	return binary.LittleEndian.Uint32(h.data[4:])
+}
+
+func (h *Header) StartIndexPtr() uint32 {
+	return binary.LittleEndian.Uint32(h.data[8:])
+}
+
+func (h *Header) EndIndexPtr() uint32 {
+	return binary.LittleEndian.Uint32(h.data[12:])
+}

binding/golang/xdb/util.go

@@ -116,7 +116,7 @@ func LoadVectorIndexFromBuff(cBuff []byte) ([][]*VectorIndexBlock, error) {
 }
 
 // LoadHeader load the header info from the specified handle
-func LoadHeader(handle *os.File) ([]byte, error) {
+func LoadHeader(handle *os.File) (*Header, error) {
 	_, err := handle.Seek(0, 0)
 	if err != nil {
 		return nil, fmt.Errorf("seek to the header: %w", err)
@@ -132,11 +132,13 @@ func LoadHeader(handle *os.File) ([]byte, error) {
 		return nil, fmt.Errorf("incomplete read: readed bytes should be %d", len(buff))
 	}
 
-	return buff, nil
+	return &Header{
+		data: buff,
+	}, nil
 }
 
 // LoadHeaderFromFile load header info from the specified db file path
-func LoadHeaderFromFile(dbFile string) ([]byte, error) {
+func LoadHeaderFromFile(dbFile string) (*Header, error) {
 	handle, err := os.OpenFile(dbFile, os.O_RDONLY, 0600)
 	if err != nil {
 		return nil, fmt.Errorf("open xdb file `%s`: %w", dbFile, err)
@@ -145,6 +147,13 @@ func LoadHeaderFromFile(dbFile string) ([]byte, error) {
 	return LoadHeader(handle)
 }
 
+// LoadHeaderFromBuff wrap the header info from the content buffer
+func LoadHeaderFromBuff(cBuff []byte) (*Header, error) {
+	return &Header{
+		data: cBuff[0:256],
+	}, nil
+}
+
 // LoadContent load the whole xdb content from the specified file handle
 func LoadContent(handle *os.File) ([]byte, error) {
 	// get file size

binding/golang/xdb/util_test.go

@@ -11,6 +11,7 @@ package xdb
 import (
 	"fmt"
 	"testing"
+	"time"
 )
 
 func TestLoadVectorIndex(t *testing.T) {
@@ -50,11 +51,15 @@ func TestLoadVectorIndexFromBuff(t *testing.T) {
 }
 
 func TestLoadHeader(t *testing.T) {
-	buff, err := LoadHeaderFromFile("../../../data/ip2region.xdb")
+	header, err := LoadHeaderFromFile("../../../data/ip2region.xdb")
 	if err != nil {
 		fmt.Printf("failed to load xdb header info: %s\n", err)
 		return
 	}
 
-	fmt.Printf("buff length: %d\n", len(buff))
+	fmt.Printf("Version        : %d\n", header.Version())
+	fmt.Printf("IndexPolicy    : %s\n", header.IndexPolicy().String())
+	fmt.Printf("CreatedAt      : %d(%s)\n", header.CreatedAt(), time.Unix(int64(header.CreatedAt()), 0).Format(time.RFC3339))
+	fmt.Printf("StartIndexPtr  : %d\n", header.StartIndexPtr())
+	fmt.Printf("EndIndexPtr    : %d\n", header.EndIndexPtr())
 }