store members_offset as a varint

README.md

@@ -187,11 +187,9 @@ the beginning of the section.
 ```
 const PackedGroup = packed struct {
     gid: u32,
-    // index to a separate structure with a list of members.
-    members_offset: u32,
     groupname_len: u8, // max is 32, but have too much space here.
-    // a groupname_len-sized string
-    groupname []u8;
+    // varint members_offset + (groupname_len-1)-length string
+    groupdata []u8;
 }
 
 pub const PackedUser = packed struct {
@@ -206,11 +204,11 @@ pub const PackedUser = packed struct {
     gecos_len: u11,
     // pseudocode: variable-sized array that will be stored immediately after
     // this struct.
-    stringdata []u8;
+    userdata []u8;
 }
 ```
 
-`stringdata` contains a few string entries:
+`userdata` contains a few entries:
 - home.
 - name (optional).
 - gecos.
@@ -368,8 +366,8 @@ shellIndex            len(shells)*2    shell index array
 shellBlob             <= 4032          shell data blob (max 63*64 bytes)
 groups                ?                packed Group entries (8b padding)
 users                 ?                packed User entries (8b padding)
-groupMembers          ?                per-group varint memberlist (no padding)
-userGids              ?                per-user varint gidlist (no padding)
+groupMembers          ?                per-group delta varint memberlist (no padding)
+userGids              ?                per-user delta varint gidlist (no padding)
 ```
 
 Section creation order: