Minor cleanup

include/ucore/slot_allocator.h

@@ -4,10 +4,11 @@
 #include <stdint.h>
 #include <assert.h>
 
-// Repurpose free memory to eep a linked list of free slots
-typedef struct UCSlot UCSlot;
-struct UCSlot {
-    UCSlot *next;
+//Free memory is reused to build a linked list of slots
+typedef union  UCSlot  UCSlot;
+union UCSlot {
+    UCSlot *next;       // next free block (when not allocated)
+    uint8_t data[0];   // data when allocated
 };
 
 typedef struct UCSlotArena UCSlotArena;
@@ -66,9 +67,12 @@ static inline void *uc_slot_alloc(UCSlotArena *arena)
     if (slot != NULL) {
         arena->free_list = slot->next;
         arena->used_slots++;
+#ifdef DEBUG
+        memset(slot, 0xCB, arena->slot_size);
+#endif
     }
 
-    return slot;
+    return &slot->data[0];
 }
 /**
  * Free a slot.
@@ -81,7 +85,7 @@ static inline void uc_slot_free(UCSlotArena *arena, void *memory)
 #ifdef DEBUG
         for (const UCSlot *slot = arena->free_list ; slot = slot->next) {
             if (slot == mem) {
-                assert("Double free detected");
+                assert(0 && "Double free detected");
             }
         }
 #endif

src/spool.c

@@ -41,7 +41,7 @@ void uc_pool_init(UCPool *pool, void *buffer, size_t buffer_size, size_t block_s
             p->next = next;
             p = next;
         }
-        ((UCPoolBlock *)p)->next = NULL; // last element
+        p->next = NULL; // last element
         pool->free_list = (UCPoolBlock *)first_addr;
     }
 
@@ -65,8 +65,6 @@ void *uc_pool_alloc(UCPool *pool)
 #endif
     return block->data;
 }
-#include <stdio.h>
-
 void uc_pool_free(UCPool *pool, void *p)
 {
     if (p == NULL) {
@@ -92,7 +90,6 @@ void uc_pool_free(UCPool *pool, void *p)
     pool->free_list = p;
 }
 
-
 void uc_pool_reset(UCPool *pool)
 {
    if (pool->capacity == 0)