[PATCH 3/5] resource: Remove a redundant field from client resource tracking

[Adam Jackson]

We only ever need log2(buckets) when rebuilding the table, which is
comparatively rare.  Compute it when we need it instead of tracking it
by hand.

Signed-off-by: Adam Jackson <ajax at redhat.com>
---
 dix/resource.c |   21 +++++++++++++++------
 1 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/dix/resource.c b/dix/resource.c
index fcda116..a5737f3 100644
--- a/dix/resource.c
+++ b/dix/resource.c
@@ -158,7 +158,6 @@ static void RebuildTable(
 #define SERVER_MINID 32
 
 #define INITBUCKETS 64
-#define INITHASHSIZE 6
 #define MAXHASHSIZE 11
 
 typedef struct _Resource {
@@ -172,7 +171,6 @@ typedef struct _ClientResource {
     ResourcePtr *resources;
     int		elements;
     int		buckets;
-    int		hashsize;	/* log(2)(buckets) */
     XID		fakeID;
     XID		endFakeID;
     XID		expectID;
@@ -233,6 +231,19 @@ static const struct ResourceType predefTypes[] = {
 
 CallbackListPtr ResourceStateCallback;
 
+static int
+ilog2(unsigned int x)
+{
+    int r = 0;
+
+    while (x > 1) {
+        r++;
+        x >>= 1;
+    }
+
+    return r;
+}
+
 static _X_INLINE void
 CallResourceStateCallback(ResourceState state, ResourceRec *res)
 {
@@ -313,7 +324,6 @@ InitClientResources(ClientPtr client)
 	return FALSE;
     clientTable[i].buckets = INITBUCKETS;
     clientTable[i].elements = 0;
-    clientTable[i].hashsize = INITHASHSIZE;
     /* Many IDs allocated from the server client are visible to clients,
      * so we don't use the SERVER_BIT for them, but we have to start
      * past the magic value constants used in the protocol.  For normal
@@ -335,7 +345,7 @@ static int
 Hash(int client, XID id)
 {
     id &= RESOURCE_ID_MASK;
-    switch (clientTable[client].hashsize)
+    switch (ilog2(clientTable[client].buckets))
     {
 	case 6:
 	    return ((int)(0x03F & (id ^ (id>>6) ^ (id>>12))));
@@ -495,7 +505,7 @@ AddResource(XID id, RESTYPE type, pointer value)
         FatalError("client not in use\n");
     }
     if ((rrec->elements >= 4*rrec->buckets) &&
-	(rrec->hashsize < MAXHASHSIZE))
+	(ilog2(rrec->buckets) < MAXHASHSIZE))
 	RebuildTable(client);
     head = &rrec->resources[Hash(client, id)];
     res = malloc(sizeof(ResourceRec));
@@ -544,7 +554,6 @@ RebuildTable(int client)
 	*rptr = NULL;
 	*tptr = rptr;
     }
-    clientTable[client].hashsize++;
     for (j = clientTable[client].buckets,
 	 rptr = clientTable[client].resources;
 	 --j >= 0;
-- 
1.7.3.1