From 2e009f69c701c53123654785ff5cf0a0c67c22b2 Mon Sep 17 00:00:00 2001
From: Daniel Stone <daniel@fooishbar.org>
Date: Mon, 4 Jun 2012 16:15:10 +0100
Subject: [PATCH] Avoid duplicating keysyms for merge if possible

If we can merge cleanly (i.e. use the entirety of one entry rather than
having to go level by level), then just reuse the existing symbols array
and skip the entire merge process.

Signed-off-by: Daniel Stone <daniel@fooishbar.org>
---
 src/xkbcomp/symbols.c | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/src/xkbcomp/symbols.c b/src/xkbcomp/symbols.c
index 9a3e73f..5e243ec 100644
--- a/src/xkbcomp/symbols.c
+++ b/src/xkbcomp/symbols.c
@@ -366,11 +366,18 @@ ResizeKeyGroup(KeyInfo * key, unsigned int group, unsigned int numLevels,
     return true;
 }
 
+enum key_group_selector {
+    NONE = 0,
+    FROM = (1 << 0),
+    TO = (1 << 1),
+};
+
 static bool
 MergeKeyGroups(SymbolsInfo * info,
                KeyInfo * into, KeyInfo * from, unsigned group)
 {
     xkb_keysym_t *resultSyms = NULL;
+    enum key_group_selector using = NONE;
     union xkb_action *resultActs;
     unsigned int resultWidth;
     unsigned int resultSize = 0;
@@ -476,20 +483,34 @@ MergeKeyGroups(SymbolsInfo * info,
         if (fromSize == 0)
         {
             resultSize += toSize;
+            using |= TO;
         }
         else if (toSize == 0 || clobber)
         {
             resultSize += fromSize;
+            using |= FROM;
         }
         else
         {
             resultSize += toSize;
+            using |= TO;
         }
     }
 
     if (resultSize == 0)
         goto out;
 
+    if (using == FROM)
+    {
+        resultSyms = from->syms[group];
+        goto out;
+    }
+    else if (using == TO)
+    {
+        resultSyms = into->syms[group];
+        goto out;
+    }
+
     resultSyms = uTypedCalloc(resultSize, xkb_keysym_t);
     if (!resultSyms)
     {
@@ -500,7 +521,7 @@ MergeKeyGroups(SymbolsInfo * info,
 
     for (i = 0; i < resultWidth; i++)
     {
-        enum { NONE, FROM, TO } use;
+        enum key_group_selector use = NONE;
         unsigned int fromSize = 0;
         unsigned int toSize = 0;
 
@@ -557,9 +578,11 @@ out:
     if (resultActs != from->acts[group])
         free(from->acts[group]);
     into->numLevels[group] = resultWidth;
-    free(into->syms[group]);
+    if (resultSyms != into->syms[group])
+        free(into->syms[group]);
     into->syms[group] = resultSyms;
-    free(from->syms[group]);
+    if (resultSyms != from->syms[group])
+        free(from->syms[group]);
     from->syms[group] = NULL;
     from->sizeSyms[group] = 0;
     into->sizeSyms[group] = resultSize;
@@ -569,7 +592,8 @@ out:
     from->symsMapNumEntries[group] = NULL;
     into->acts[group] = resultActs;
     from->acts[group] = NULL;
-    into->symsDefined |= (1 << group);
+    if (into->syms[group])
+        into->symsDefined |= (1 << group);
     from->symsDefined &= ~(1 << group);
     into->actsDefined |= (1 << group);
     from->actsDefined &= ~(1 << group);