[PATCH v6 2/4] win32u: Use array indexes for d3dkmt handles.

[Rémi Bernon]

From: Rémi Bernon

---
 dlls/win32u/d3dkmt.c | 89 +++++++++++++++++++++++++-------------------
 1 file changed, 50 insertions(+), 39 deletions(-)

diff --git a/dlls/win32u/d3dkmt.c b/dlls/win32u/d3dkmt.c
index 13f05f2d069..c91ed0309ef 100644
--- a/dlls/win32u/d3dkmt.c
+++ b/dlls/win32u/d3dkmt.c
@@ -69,80 +69,91 @@ struct d3dkmt_vidpn_source
 static pthread_mutex_t d3dkmt_lock = PTHREAD_MUTEX_INITIALIZER;
 static struct list d3dkmt_vidpn_sources = LIST_INIT( d3dkmt_vidpn_sources );   /* VidPN source information list */

-static struct d3dkmt_object **objects;
-static unsigned int object_count, object_capacity, last_index;
+static struct d3dkmt_object **objects, **objects_end, **objects_next;

-/* return the position of the first object which handle is not less than
- * the given local handle, d3dkmt_lock must be held. */
-static unsigned int object_handle_lower_bound( D3DKMT_HANDLE local )
+#define D3DKMT_HANDLE_BIT  0x40000000
+
+static D3DKMT_HANDLE index_to_handle( int index )
 {
-    unsigned int begin = 0, end = object_count, mid;
+    return (index << 6) | D3DKMT_HANDLE_BIT;
+}

-    while (begin < end)
-    {
-        mid = begin + (end - begin) / 2;
-        if (objects[mid]->local < local) begin = mid + 1;
-        else end = mid;
-    }
+static int handle_to_index( D3DKMT_HANDLE handle )
+{
+    return (handle & ~0xc0000000) >> 6;
+}
+
+static NTSTATUS init_handle_table(void)
+{
+    if (!(objects = calloc( 1024, sizeof(*objects) ))) return STATUS_NO_MEMORY;
+    objects_end = objects + 1024;
+    objects_next = objects;
+    return STATUS_SUCCESS;
+}
+
+static struct d3dkmt_object **grow_handle_table(void)
+{
+    size_t old_capacity = objects_end - objects, max_capacity = handle_to_index( D3DKMT_HANDLE_BIT - 1 );
+    unsigned int new_capacity = old_capacity * 3 / 2;
+    struct d3dkmt_object **tmp;
+
+    if (new_capacity > max_capacity) new_capacity = max_capacity;
+    if (new_capacity <= old_capacity) return NULL; /* exhausted handle capacity */
+
+    if (!(tmp = realloc( objects, new_capacity * sizeof(*objects) ))) return NULL;
+    memset( tmp + old_capacity, 0, (new_capacity - old_capacity) * sizeof(*tmp) );
+
+    objects = tmp;
+    objects_end = tmp + new_capacity;
+    objects_next = tmp + old_capacity;

-    return begin;
+    return objects_next;
 }

/* allocate a d3dkmt object with a local handle */
 static NTSTATUS alloc_object_handle( struct d3dkmt_object *object )
 {
-    D3DKMT_HANDLE handle = 0;
-    unsigned int index;
+    struct d3dkmt_object **entry;

pthread_mutex_lock( &d3dkmt_lock );
+    if (!objects && init_handle_table()) goto done;

-    if (object_count >= object_capacity)
+    for (entry = objects_next; entry < objects_end; entry++) if (!*entry) break;
+    if (entry == objects_end)
     {
-        unsigned int capacity = max( 32, object_capacity * 3 / 2 );
-        struct d3dkmt_object **tmp;
-        assert( capacity > object_capacity );
-
-        if (capacity >= 0xffff) goto done;
-        if (!(tmp = realloc( objects, capacity * sizeof(*objects) ))) goto done;
-        object_capacity = capacity;
-        objects = tmp;
+        for (entry = objects; entry < objects_next; entry++) if (!*entry) break;
+        if (entry == objects_next && !(entry = grow_handle_table())) goto done;
     }

-    last_index += 0x40;
-    handle = object->local = (last_index & ~0xc0000000) | 0x40000000;
-    index = object_handle_lower_bound( object->local );
-    if (index < object_count) memmove( objects + index + 1, objects, (object_count - index) * sizeof(*objects) );
-    objects[index] = object;
-    object_count++;
+    object->local = index_to_handle( entry - objects );
+    objects_next = entry + 1;
+    *entry = object;

done:
     pthread_mutex_unlock( &d3dkmt_lock );
-    return handle ? STATUS_SUCCESS : STATUS_NO_MEMORY;
+    return object->local ? STATUS_SUCCESS : STATUS_NO_MEMORY;
 }

/* free a d3dkmt local object handle */
 static void free_object_handle( struct d3dkmt_object *object )
 {
-    unsigned int index;
+    unsigned int index = handle_to_index( object->local );

pthread_mutex_lock( &d3dkmt_lock );
-    index = object_handle_lower_bound( object->local );
-    assert( index < object_count && objects[index] == object );
-    object_count--;
+    assert( objects + index < objects_end && objects[index] == object );
+    objects[index] = NULL;
     object->local = 0;
-    memmove( objects + index, objects + index + 1, (object_count - index) * sizeof(*objects) );
     pthread_mutex_unlock( &d3dkmt_lock );
 }

/* return a pointer to a d3dkmt object from its local handle */
 static void *get_d3dkmt_object( D3DKMT_HANDLE local, enum d3dkmt_type type )
 {
+    unsigned int index = handle_to_index( local );
     struct d3dkmt_object *object;
-    unsigned int index;

pthread_mutex_lock( &d3dkmt_lock );
-    index = object_handle_lower_bound( local );
-    if (index >= object_count) object = NULL;
+    if (objects + index >= objects_end) object = NULL;
     else object = objects[index];
     pthread_mutex_unlock( &d3dkmt_lock );