Complete v1.2.0 release

arena.h

@@ -78,6 +78,13 @@
 // Warning: this functions may cause fragmentation, consider setting an
 // appropriate region capacity.
 //
+//     void arena_trim(Arena *a)
+//
+// This functions frees all of the regions where no buffers are allocated.
+// This is useful after an arena_rewind() was performed to preserve memory.
+// Note: this function always keeps the first region allocated to preserve an
+// ideal behaviour.
+//
 //     void *arena_alloc(Arena *a, size_t size)
 //
 // This function allocates a buffer of <size> bytes into the specified arena
@@ -197,6 +204,7 @@ typedef struct Arena {
 Arena arena_create(size_t region_capacity);
 void arena_free(Arena *a);
 void arena_reset(Arena *a);
+void arena_trim(Arena *a);
 
 // Allocation and other utilities
 void *arena_alloc(Arena *a, size_t size);
@@ -246,7 +254,6 @@ void arena_free(Arena *a)
 
     a->head = NULL;
     a->tail = NULL;
-    // a->region_capacity = 0;
 }
 
 void arena_reset(Arena *a)
@@ -262,6 +269,21 @@ void arena_reset(Arena *a)
     a->tail = a->head;
 }
 
+void arena_trim(Arena *a)
+{
+    if (a == NULL) {
+        return;
+    }
+
+    Arena_Region *to_free = a->tail->next;
+    a->tail->next = NULL;
+    while (to_free != NULL) {
+        Arena_Region *next = to_free->next;
+        ARENA_FREE(to_free);
+        to_free = next;
+    }
+}
+
 void *arena_alloc(Arena *a, size_t size)
 {
     if (a == NULL || size == 0) {
@@ -469,8 +491,8 @@ size_t arena__align(size_t n)
 /*
  * Revision history:
  *
- *     1.2.0 (2026-04-08) New helper functions: arena_sprintf(),
- *                        arena_snapshot() and arena_rewind()
+ *     1.2.0 (2026-04-08) New functions: arena_sprintf(), arena_snapshot(),
+ *                        arena_rewind() and arena_trim()
  *     1.1.3 (2026-01-14) Align Arena_Region data flexible array member
  *     1.1.2 (2026-01-10) Minor changes; check result of alloc in arena_copy()
  *     1.1.1 (2025-11-18) Implement memory alignment; improve docs