evas/cserve2: Optimize shared strings

Shared string indexes are not repacked, since they live in a
memory pool (where the indexes can be reused).
So, the index in the table is equal to their ID. Add initial
test to check if the item at index n has the ID n.

src/bin/evas/evas_cserve2_index.c

@@ -544,6 +544,14 @@ _shared_index_entry_get_by_id(Shared_Index *si, unsigned int id)
    base = si->sa->ds->data + sizeof(Shared_Array_Header);
    elemsize = si->sa->header->elemsize;
 
+   // Direct access, works for non-repacked arrays
+   if ((int) id < high)
+     {
+        obj = (Index_Entry *) (base + (elemsize * id));
+        if (obj->id == id)
+          return obj;
+     }
+
    // Binary search
    start_high = high;
    while(high != low)

src/bin/evas/evas_cserve2_shm_debug.c

@@ -286,6 +286,14 @@ _shared_index_item_get_by_id(Shm_File *si, int elemsize, unsigned int id)
 
    base = si->data  + sizeof(Shared_Array_Header);
 
+   // Direct access, works for non-repacked arrays
+   if ((int) id < high)
+     {
+        obj = (Shm_Object *) (base + (elemsize * id));
+        if (obj->id == id)
+          return obj;
+     }
+
    // Binary search
    start_high = high;
    while(high != low)

src/lib/evas/cserve2/evas_cs2_client.c

@@ -1929,6 +1929,14 @@ _shared_index_item_get_by_id(Shared_Index *si, int elemsize, unsigned int id)
 
    base = si->data  + sizeof(Shared_Array_Header);
 
+   // Direct access, works for non-repacked arrays
+   if ((int) id < high)
+     {
+        obj = (Shm_Object *) (base + (elemsize * id));
+        if (obj->id == id)
+          return obj;
+     }
+
    // Binary search
    start_high = high;
    while(high != low)