1 files changed, 115 insertions, 0 deletions
diff --git a/lib/btrfs/btrfsitem/item_dir.go b/lib/btrfs/btrfsitem/item_dir.go
new file mode 100644
index 0000000..57f6d6d
--- /dev/null
+++ b/lib/btrfs/btrfsitem/item_dir.go
@@ -0,0 +1,115 @@
+package btrfsitem
+
+import (
+	"fmt"
+	"hash/crc32"
+
+	"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/internal"
+)
+
+// key.objectid = inode of directory containing this entry
+// key.offset =
+//    for DIR_ITEM and XATTR_ITEM = NameHash(name)
+//    for DIR_INDEX               = index id in the directory (starting at 2, because "." and "..")
+type DirEntries []DirEntry // DIR_ITEM=84 DIR_INDEX=96 XATTR_ITEM=24
+
+func NameHash(dat []byte) uint64 {
+	return uint64(^crc32.Update(1, crc32.MakeTable(crc32.Castagnoli), dat))
+}
+
+func (o *DirEntries) UnmarshalBinary(dat []byte) (int, error) {
+	*o = nil
+	n := 0
+	for n < len(dat) {
+		var ref DirEntry
+		_n, err := binstruct.Unmarshal(dat, &ref)
+		n += _n
+		if err != nil {
+			return n, err
+		}
+		*o = append(*o, ref)
+	}
+	return n, nil
+}
+
+func (o DirEntries) MarshalBinary() ([]byte, error) {
+	var ret []byte
+	for _, ref := range o {
+		bs, err := binstruct.Marshal(ref)
+		ret = append(ret, bs...)
+		if err != nil {
+			return ret, err
+		}
+	}
+	return ret, nil
+}
+
+type DirEntry struct {
+	Location      internal.Key `bin:"off=0x0, siz=0x11"`
+	TransID       int64        `bin:"off=0x11, siz=8"`
+	DataLen       uint16       `bin:"off=0x19, siz=2"` // [ignored-when-writing]
+	NameLen       uint16       `bin:"off=0x1b, siz=2"` // [ignored-when-writing]
+	Type          FileType     `bin:"off=0x1d, siz=1"`
+	binstruct.End `bin:"off=0x1e"`
+	Data          []byte `bin:"-"`
+	Name          []byte `bin:"-"`
+}
+
+func (o *DirEntry) UnmarshalBinary(dat []byte) (int, error) {
+	n, err := binstruct.UnmarshalWithoutInterface(dat, o)
+	if err != nil {
+		return n, err
+	}
+	o.Data = dat[n : n+int(o.DataLen)]
+	n += int(o.DataLen)
+	o.Name = dat[n : n+int(o.NameLen)]
+	n += int(o.NameLen)
+	return n, nil
+}
+
+func (o DirEntry) MarshalBinary() ([]byte, error) {
+	o.DataLen = uint16(len(o.Data))
+	o.NameLen = uint16(len(o.Name))
+	dat, err := binstruct.MarshalWithoutInterface(o)
+	if err != nil {
+		return dat, err
+	}
+	dat = append(dat, o.Data...)
+	dat = append(dat, o.Name...)
+	return dat, nil
+}
+
+type FileType uint8
+
+const (
+	FT_UNKNOWN  = FileType(0)
+	FT_REG_FILE = FileType(1)
+	FT_DIR      = FileType(2)
+	FT_CHRDEV   = FileType(3)
+	FT_BLKDEV   = FileType(4)
+	FT_FIFO     = FileType(5)
+	FT_SOCK     = FileType(6)
+	FT_SYMLINK  = FileType(7)
+	FT_XATTR    = FileType(8)
+
+	FT_MAX = FileType(9)
+)
+
+func (ft FileType) String() string {
+	names := map[FileType]string{
+		FT_UNKNOWN:  "UNKNOWN",
+		FT_REG_FILE: "FILE", // XXX
+		FT_DIR:      "DIR",
+		FT_CHRDEV:   "CHRDEV",
+		FT_BLKDEV:   "BLKDEV",
+		FT_FIFO:     "FIFO",
+		FT_SOCK:     "SOCK",
+		FT_SYMLINK:  "SYMLINK",
+		FT_XATTR:    "XATTR",
+	}
+	if name, ok := names[ft]; ok {
+		return name
+	}
+	return fmt.Sprintf("DIR_ITEM.%d", uint8(ft))
+}