8 files changed, 90 insertions, 10 deletions
diff --git a/object/blob_serialize.go b/object/blob_serialize.go
index e9c0ac5e..55240f44 100644
--- a/object/blob_serialize.go
+++ b/object/blob_serialize.go
@@ -3,7 +3,7 @@ package object
 import (
 	"errors"
 
-	"codeberg.org/lindenii/furgit/objectheader"
+	"codeberg.org/lindenii/furgit/object/header"
 	"codeberg.org/lindenii/furgit/objecttype"
 )
 
@@ -19,7 +19,7 @@ func (blob *Blob) SerializeWithHeader() ([]byte, error) {
 		return nil, err
 	}
 
-	header, ok := objectheader.Encode(objecttype.TypeBlob, int64(len(body)))
+	header, ok := header.Encode(objecttype.TypeBlob, int64(len(body)))
 	if !ok {
 		return nil, errors.New("object: blob: failed to encode object header")
 	}
diff --git a/object/commit_serialize.go b/object/commit_serialize.go
index eef45ef4..7ff022c4 100644
--- a/object/commit_serialize.go
+++ b/object/commit_serialize.go
@@ -5,7 +5,7 @@ import (
 	"errors"
 	"fmt"
 
-	"codeberg.org/lindenii/furgit/objectheader"
+	"codeberg.org/lindenii/furgit/object/header"
 	"codeberg.org/lindenii/furgit/objecttype"
 )
 
@@ -71,7 +71,7 @@ func (commit *Commit) SerializeWithHeader() ([]byte, error) {
 		return nil, err
 	}
 
-	header, ok := objectheader.Encode(objecttype.TypeCommit, int64(len(body)))
+	header, ok := header.Encode(objecttype.TypeCommit, int64(len(body)))
 	if !ok {
 		return nil, errors.New("object: commit: failed to encode object header")
 	}
diff --git a/object/header/append.go b/object/header/append.go
new file mode 100644
index 00000000..92dbe686
--- /dev/null
+++ b/object/header/append.go
@@ -0,0 +1,29 @@
+package header
+
+import (
+	"strconv"
+
+	"codeberg.org/lindenii/furgit/objecttype"
+)
+
+// Append appends a canonical loose-object header ("type size\\x00") to dst.
+func Append(dst []byte, ty objecttype.Type, size int64) ([]byte, bool) {
+	if size < 0 {
+		return nil, false
+	}
+
+	tyName, ok := objecttype.Name(ty)
+	if !ok {
+		return nil, false
+	}
+
+	sizeStr := strconv.FormatInt(size, 10)
+	out := make([]byte, 0, len(dst)+len(tyName)+len(sizeStr)+2)
+	out = append(out, dst...)
+	out = append(out, tyName...)
+	out = append(out, ' ')
+	out = append(out, sizeStr...)
+	out = append(out, 0)
+
+	return out, true
+}
diff --git a/object/header/encode.go b/object/header/encode.go
new file mode 100644
index 00000000..e0393af6
--- /dev/null
+++ b/object/header/encode.go
@@ -0,0 +1,8 @@
+package header
+
+import "codeberg.org/lindenii/furgit/objecttype"
+
+// Encode returns a canonical loose-object header ("type size\\x00").
+func Encode(ty objecttype.Type, size int64) ([]byte, bool) {
+	return Append(nil, ty, size)
+}
diff --git a/object/header/parse.go b/object/header/parse.go
new file mode 100644
index 00000000..d0a0ada8
--- /dev/null
+++ b/object/header/parse.go
@@ -0,0 +1,43 @@
+// Package header parses and serializes object headers ("type size\0").
+package header
+
+import (
+	"bytes"
+	"strconv"
+
+	"codeberg.org/lindenii/furgit/objecttype"
+)
+
+// Parse parses a canonical loose-object header ("type size\\x00").
+// It returns the parsed type, size, bytes consumed (including trailing NUL),
+// and whether parsing succeeded.
+func Parse(data []byte) (objecttype.Type, int64, int, bool) {
+	space := bytes.IndexByte(data, ' ')
+	if space <= 0 {
+		return objecttype.TypeInvalid, 0, 0, false
+	}
+
+	nulRel := bytes.IndexByte(data[space+1:], 0)
+	if nulRel < 0 {
+		return objecttype.TypeInvalid, 0, 0, false
+	}
+
+	nul := space + 1 + nulRel
+
+	ty, ok := objecttype.ParseName(string(data[:space]))
+	if !ok {
+		return objecttype.TypeInvalid, 0, 0, false
+	}
+
+	sizeBytes := data[space+1 : nul]
+	if len(sizeBytes) == 0 {
+		return objecttype.TypeInvalid, 0, 0, false
+	}
+
+	size, err := strconv.ParseInt(string(sizeBytes), 10, 64)
+	if err != nil || size < 0 {
+		return objecttype.TypeInvalid, 0, 0, false
+	}
+
+	return ty, size, nul + 1, true
+}
diff --git a/object/parse.go b/object/parse.go
index 9afe5cb8..54752a5d 100644
--- a/object/parse.go
+++ b/object/parse.go
@@ -3,7 +3,7 @@ package object
 import (
 	"fmt"
 
-	"codeberg.org/lindenii/furgit/objectheader"
+	"codeberg.org/lindenii/furgit/object/header"
 	"codeberg.org/lindenii/furgit/objectid"
 	"codeberg.org/lindenii/furgit/objecttype"
 )
@@ -12,7 +12,7 @@ import (
 //
 //nolint:ireturn
 func ParseObjectWithHeader(raw []byte, algo objectid.Algorithm) (Object, error) {
-	ty, size, headerLen, ok := objectheader.Parse(raw)
+	ty, size, headerLen, ok := header.Parse(raw)
 	if !ok {
 		return nil, fmt.Errorf("object: malformed object header")
 	}
diff --git a/object/tag_serialize.go b/object/tag_serialize.go
index 1e016cdb..fb212485 100644
--- a/object/tag_serialize.go
+++ b/object/tag_serialize.go
@@ -5,7 +5,7 @@ import (
 	"errors"
 	"fmt"
 
-	"codeberg.org/lindenii/furgit/objectheader"
+	"codeberg.org/lindenii/furgit/object/header"
 	"codeberg.org/lindenii/furgit/objecttype"
 )
 
@@ -55,7 +55,7 @@ func (tag *Tag) SerializeWithHeader() ([]byte, error) {
 		return nil, err
 	}
 
-	header, ok := objectheader.Encode(objecttype.TypeTag, int64(len(body)))
+	header, ok := header.Encode(objecttype.TypeTag, int64(len(body)))
 	if !ok {
 		return nil, errors.New("object: tag: failed to encode object header")
 	}
diff --git a/object/tree_serialize.go b/object/tree_serialize.go
index 42f60f72..64542a37 100644
--- a/object/tree_serialize.go
+++ b/object/tree_serialize.go
@@ -4,7 +4,7 @@ import (
 	"errors"
 	"strconv"
 
-	"codeberg.org/lindenii/furgit/objectheader"
+	"codeberg.org/lindenii/furgit/object/header"
 	"codeberg.org/lindenii/furgit/objecttype"
 )
 
@@ -42,7 +42,7 @@ func (tree *Tree) SerializeWithHeader() ([]byte, error) {
 		return nil, err
 	}
 
-	header, ok := objectheader.Encode(objecttype.TypeTree, int64(len(body)))
+	header, ok := header.Encode(objecttype.TypeTree, int64(len(body)))
 	if !ok {
 		return nil, errors.New("object: tree: failed to encode object header")
 	}