Allow specifying a prefix for unpack and range
This pretty much removes any usefulness from `erlfdb_subspace` since
Erlang doesn't support operator overrides or other similar syntactic
sugar that makes subspaces useful in other languages.
diff --git a/src/erlfdb_tuple.erl b/src/erlfdb_tuple.erl
index b2dc893..46322d0 100644
--- a/src/erlfdb_tuple.erl
+++ b/src/erlfdb_tuple.erl
@@ -20,6 +20,7 @@
pack_vs/2,
unpack/1,
range/1,
+ range/2,
compare/2
]).
@@ -121,18 +122,33 @@
unpack(Binary) ->
- case decode(Binary, 0) of
- {Elems, <<>>} ->
- list_to_tuple(Elems);
- {_, Tail} ->
- erlang:error({invalid_trailing_data, Tail})
+ unpack(Binary, <<>>).
+
+
+unpack(Binary, Prefix) ->
+ PrefixLen = size(Prefix),
+ case Binary of
+ <<Prefix:PrefixLen/binary, Rest/binary>> ->
+ case decode(Binary, 0) of
+ {Elems, <<>>} ->
+ list_to_tuple(Elems);
+ {_, Tail} ->
+ erlang:error({invalid_trailing_data, Tail})
+ end;
+ _ ->
+ E = {erlfdb_tuple_error, invalid_unpack_prefix},
+ erlang:error(E)
end.
% Returns a {StartKey, EndKey} pair of binaries
% that includes all possible sub-tuples
range(Tuple) ->
- Base = pack(Tuple),
+ range(Tuple, <<>>).
+
+
+range(Tuple, Prefix) ->
+ Base = pack(Tuple, Prefix),
{<<Base/binary, 16#00>>, <<Base/binary, 16#FF>>}.
