4 files changed, 17 insertions, 2 deletions
diff --git a/lib/btrfs/Makefile b/lib/btrfs/Makefile
index b98a1b7..2c70363 100644
--- a/lib/btrfs/Makefile
+++ b/lib/btrfs/Makefile
@@ -74,10 +74,15 @@ btrfsprim/itemtype.go: btrfsitem/items.txt $(MAKEFILE_LIST)
 	  echo '// Code generated by Make.  DO NOT EDIT.'; \
 	  echo; \
 	  echo 'package $(@D)'; \
-	  echo 'import "fmt"'; \
+	  echo 'import ('; \
+	  echo '  "fmt"'; \
+	  echo '  "math"'; \
+	  echo ')'; \
 	  echo 'type ItemType uint8'; \
 	  echo 'const ('; \
 	  sed -E 's,(.*)=([^:]*)(:.*)? (trivial|complex) (.*),\1_KEY ItemType=\2,' $< | uniq; \
+	  echo; \
+	  echo 'MAX_KEY ItemType = math.MaxUint8'; \
 	  echo ')'; \
 	  echo 'func (t ItemType) String() string {'; \
 	  echo '  switch t {'; \
diff --git a/lib/btrfs/btrfsprim/itemtype.go b/lib/btrfs/btrfsprim/itemtype.go
index f33179a..682fecd 100644
--- a/lib/btrfs/btrfsprim/itemtype.go
+++ b/lib/btrfs/btrfsprim/itemtype.go
@@ -2,7 +2,10 @@
 
 package btrfsprim
 
-import "fmt"
+import (
+	"fmt"
+	"math"
+)
 
 type ItemType uint8
 
@@ -39,6 +42,8 @@ const (
 	UUID_RECEIVED_SUBVOL_KEY ItemType = 252
 	UUID_SUBVOL_KEY          ItemType = 251
 	XATTR_ITEM_KEY           ItemType = 24
+
+	MAX_KEY ItemType = math.MaxUint8
 )
 
 func (t ItemType) String() string {
diff --git a/lib/btrfs/btrfsprim/key.go b/lib/btrfs/btrfsprim/key.go
index 55f7c05..7a3cc5c 100644
--- a/lib/btrfs/btrfsprim/key.go
+++ b/lib/btrfs/btrfsprim/key.go
@@ -19,6 +19,8 @@ type Key struct {
 	binstruct.End `bin:"off=0x11"`
 }
 
+const MaxOffset uint64 = math.MaxUint64
+
 // mimics print-tree.c:btrfs_print_key()
 func (key Key) Format(tree ObjID) string {
 	switch tree {
diff --git a/lib/btrfs/btrfsprim/objid.go b/lib/btrfs/btrfsprim/objid.go
index 1aea030..f364957 100644
--- a/lib/btrfs/btrfsprim/objid.go
+++ b/lib/btrfs/btrfsprim/objid.go
@@ -6,6 +6,7 @@ package btrfsprim
 
 import (
 	"fmt"
+	"math"
 )
 
 type ObjID uint64
@@ -52,6 +53,8 @@ const (
 
 	// ???
 	EMPTY_SUBVOL_DIR_OBJECTID ObjID = 2
+
+	MAX_OBJECTID ObjID = math.MaxUint64
 )
 
 var (