gpgscm: Use a compact vector representation.

* tests/gpgscm/scheme-private.h (struct cell): Add a compact vector
representation.
* tests/gpgscm/scheme.c (vector_length): Use new representation.
(vector_size): New macro.
(get_vector_object): Use the new representation.
(fill_vector): Likewise.
(vector_elem): Likewise.
(set_vector_elem): Likewise.
(mark): Likewise.
(gc): Likewise.  Be careful not to confuse immediate values for type
flags.
(finalize_cell): Vectors now require finalization.
--

Previously, vectors were represented using consecutive cons cells,
wasting one word per cell for the type information.  Fix that by using
a flat array.

Previously, a vector of size N required 1 + (n + 1) / 2 cells.  Now it
uses 1 + (n - 1 + 2) / 3 cells.

Signed-off-by: Justus Winter <[email protected]>

1 files changed, 4 insertions, 0 deletions

diff --git a/scheme-private.h b/scheme-private.h
index aba2319..ad8f571 100644
--- a/scheme-private.h
+++ b/scheme-private.h
@@ -56,6 +56,10 @@ struct cell {
       struct cell *_cdr;
     } _cons;
     struct {
+      size_t _length;
+      pointer _elements[0];
+    } _vector;
+    struct {
          char *_data;
          const foreign_object_vtable *_vtable;
     } _foreign_object;