Reduce memory footprint of struct bidi_it by a factor of 5.

 src/dispextern.h (enum bidi_dir_t): Force NEUTRAL_DIR to be zero.
 (struct bidi_stack): Reduce size by using bit fields and by
 packing sos, override, and isolate_status into a single 8-bit
 byte called 'flags'.
 src/bidi.c (ISOLATE_STATUS, OVERRIDE): New macros.
 (bidi_push_embedding_level): Construct flags from individual
 bits.  Adapt to changes in prev_for_neutral and next_for_neutral
 members.
 (bidi_pop_embedding_level): Use ISOLATE_STATUS.  Extract 'sos'
 from flags.  Adapt to changes in prev_for_neutral,
 next_for_neutral, and last_strong members.
 (bidi_line_init): Initialize flags to zero.
 (bidi_resolve_explicit, bidi_resolve_weak, bidi_resolve_brackets)
 (bidi_resolve_neutral): Use ISOLATE_STATUS and OVERRIDE.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 2f64a9758bc..82aabb389a3 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,21 @@
+2014-12-05  Eli Zaretskii  <eliz@gnu.org>
+
+        * dispextern.h (enum bidi_dir_t): Force NEUTRAL_DIR to be zero.
+        (struct bidi_stack): Reduce size by using bit fields and by
+        packing sos, override, and isolate_status into a single 8-bit
+        byte called 'flags'.
+
+        * bidi.c (ISOLATE_STATUS, OVERRIDE): New macros.
+        (bidi_push_embedding_level): Construct flags from individual
+        bits.  Adapt to changes in prev_for_neutral and next_for_neutral
+        members.
+        (bidi_pop_embedding_level): Use ISOLATE_STATUS.  Extract 'sos'
+        from flags.  Adapt to changes in prev_for_neutral,
+        next_for_neutral, and last_strong members.
+        (bidi_line_init): Initialize flags to zero.
+        (bidi_resolve_explicit, bidi_resolve_weak, bidi_resolve_brackets)
+        (bidi_resolve_neutral): Use ISOLATE_STATUS and OVERRIDE.
+
 2014-12-04  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * eval.c (backtrace_eval_unrewind): Rewind also the excursions.