6 files changed, 49 insertions, 46 deletions
diff --git a/lib/btrfs/btrfsitem/item_dir.go b/lib/btrfs/btrfsitem/item_dir.go
index 0049072..c1b3c09 100644
--- a/lib/btrfs/btrfsitem/item_dir.go
+++ b/lib/btrfs/btrfsitem/item_dir.go
@@ -84,33 +84,34 @@ func (o DirEntry) MarshalBinary() ([]byte, error) {
 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_UNKNOWN FileType = iota
+	FT_REG_FILE
+	FT_DIR
+	FT_CHRDEV
+	FT_BLKDEV
+	FT_FIFO
+	FT_SOCK
+	FT_SYMLINK
+	FT_XATTR
 
-	FT_MAX = FileType(9)
+	FT_MAX
 )
 
+var fileTypeNames = []string{
+	"UNKNOWN",
+	"FILE", // NB: Just "FILE", despite corresponding to "REG_FILE"
+	"DIR",
+	"CHRDEV",
+	"BLKDEV",
+	"FIFO",
+	"SOCK",
+	"SYMLINK",
+	"XATTR",
+}
+
 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
+	if ft < FT_MAX {
+		return fileTypeNames[ft]
 	}
 	return fmt.Sprintf("DIR_ITEM.%d", uint8(ft))
 }
diff --git a/lib/btrfs/btrfsitem/item_extent.go b/lib/btrfs/btrfsitem/item_extent.go
index 3789cfe..871ed90 100644
--- a/lib/btrfs/btrfsitem/item_extent.go
+++ b/lib/btrfs/btrfsitem/item_extent.go
@@ -111,7 +111,7 @@ type TreeBlockInfo struct {
 type ExtentFlags uint64
 
 const (
-	EXTENT_FLAG_DATA = ExtentFlags(1 << iota)
+	EXTENT_FLAG_DATA ExtentFlags = 1 << iota
 	EXTENT_FLAG_TREE_BLOCK
 )
 
diff --git a/lib/btrfs/btrfsitem/item_fileextent.go b/lib/btrfs/btrfsitem/item_fileextent.go
index 30a14ef..6b08897 100644
--- a/lib/btrfs/btrfsitem/item_fileextent.go
+++ b/lib/btrfs/btrfsitem/item_fileextent.go
@@ -101,11 +101,17 @@ func (o FileExtent) MarshalBinary() ([]byte, error) {
 type FileExtentType uint8
 
 const (
-	FILE_EXTENT_INLINE = FileExtentType(iota)
+	FILE_EXTENT_INLINE FileExtentType = iota
 	FILE_EXTENT_REG
 	FILE_EXTENT_PREALLOC
 )
 
+var fileExtentTypeNames = []string{
+	"inline",
+	"regular",
+	"prealloc",
+}
+
 func (o FileExtent) Size() (int64, error) {
 	switch o.Type {
 	case FILE_EXTENT_INLINE:
@@ -118,14 +124,9 @@ func (o FileExtent) Size() (int64, error) {
 }
 
 func (fet FileExtentType) String() string {
-	names := map[FileExtentType]string{
-		FILE_EXTENT_INLINE:   "inline",
-		FILE_EXTENT_REG:      "regular",
-		FILE_EXTENT_PREALLOC: "prealloc",
-	}
-	name, ok := names[fet]
-	if !ok {
-		name = "unknown"
+	name := "unknown"
+	if int(fet) < len(fileExtentTypeNames) {
+		name = fileExtentTypeNames[fet]
 	}
 	return fmt.Sprintf("%d (%s)", fet, name)
 }
@@ -133,22 +134,23 @@ func (fet FileExtentType) String() string {
 type CompressionType uint8
 
 const (
-	COMPRESS_NONE = CompressionType(iota)
+	COMPRESS_NONE CompressionType = iota
 	COMPRESS_ZLIB
 	COMPRESS_LZO
 	COMPRESS_ZSTD
 )
 
+var compressionTypeNames = []string{
+	"none",
+	"zlib",
+	"lzo",
+	"zstd",
+}
+
 func (ct CompressionType) String() string {
-	names := map[CompressionType]string{
-		COMPRESS_NONE: "none",
-		COMPRESS_ZLIB: "zlib",
-		COMPRESS_LZO:  "lzo",
-		COMPRESS_ZSTD: "zstd",
-	}
-	name, ok := names[ct]
-	if !ok {
-		name = "unknown"
+	name := "unknown"
+	if int(ct) < len(compressionTypeNames) {
+		name = compressionTypeNames[ct]
 	}
 	return fmt.Sprintf("%d (%s)", ct, name)
 }
diff --git a/lib/btrfs/btrfsitem/item_freespaceinfo.go b/lib/btrfs/btrfsitem/item_freespaceinfo.go
index 0699367..9b886af 100644
--- a/lib/btrfs/btrfsitem/item_freespaceinfo.go
+++ b/lib/btrfs/btrfsitem/item_freespaceinfo.go
@@ -20,7 +20,7 @@ type FreeSpaceInfo struct { // trivial FREE_SPACE_INFO=198
 type FreeSpaceFlags uint32
 
 const (
-	FREE_SPACE_USING_BITMAPS = FreeSpaceFlags(1 << iota)
+	FREE_SPACE_USING_BITMAPS FreeSpaceFlags = 1 << iota
 )
 
 var freeSpaceFlagNames = []string{
diff --git a/lib/btrfs/btrfsitem/item_inode.go b/lib/btrfs/btrfsitem/item_inode.go
index 69f8445..6951c76 100644
--- a/lib/btrfs/btrfsitem/item_inode.go
+++ b/lib/btrfs/btrfsitem/item_inode.go
@@ -36,7 +36,7 @@ type Inode struct { // trivial INODE_ITEM=1
 type InodeFlags uint64
 
 const (
-	INODE_NODATASUM = InodeFlags(1 << iota)
+	INODE_NODATASUM InodeFlags = 1 << iota
 	INODE_NODATACOW
 	INODE_READONLY
 	INODE_NOCOMPRESS
diff --git a/lib/btrfs/btrfsitem/item_root.go b/lib/btrfs/btrfsitem/item_root.go
index c0db900..d39bd70 100644
--- a/lib/btrfs/btrfsitem/item_root.go
+++ b/lib/btrfs/btrfsitem/item_root.go
@@ -48,7 +48,7 @@ type Root struct { // trivial ROOT_ITEM=132
 type RootFlags uint64
 
 const (
-	ROOT_SUBVOL_RDONLY = RootFlags(1 << iota)
+	ROOT_SUBVOL_RDONLY RootFlags = 1 << iota
 )
 
 var rootFlagNames = []string{