Snapshot format change: extend the slice syntax with a length-only form.

[cumulus.git] / ref.h

diff --git a/ref.h b/ref.h
index e7d41e1..9a565ee 100644 (file)
--- a/ref.h
+++ b/ref.h
@@ -39,7 +39,8 @@
  * range specifier is given, then by default the entire object is used.
  *    <range> ::= <start> "+" <length>
  * Both <start> and <length> are decimal values.  If included, the range is
- * enclosed in brackets.
+ * enclosed in brackets.  As an abbreviation, if <start> is 0 then the range
+ * can be given as just <length> (no "+" needed).
  *
  * When both a checksum and a range are included, note that the checksum is
  * taken over the entire original object, before the range is taken into
@@ -64,11 +65,15 @@ std::string generate_uuid();
  * and converted to and from the text representation. */
 class ObjectReference {
 public:
+    enum RefType { REF_NULL, REF_ZERO, REF_NORMAL };
+
     ObjectReference();
+    ObjectReference(RefType t);
     ObjectReference(const std::string& segment, int sequence);
     ObjectReference(const std::string& segment, const std::string& sequence);
 
-    bool is_null() const { return segment.size() == 0; }
+    bool is_null() const { return type == REF_NULL; }
+    bool is_normal() const { return type == REF_NORMAL; }
     std::string to_string() const;
     static ObjectReference parse(const std::string& s);
 
@@ -92,6 +97,7 @@ public:
     bool merge(ObjectReference ref);
 
 private:
+    RefType type;
     std::string segment, object, checksum;
     size_t range_start, range_length;
     bool checksum_valid, range_valid;