More stuff

src/arena.c

@@ -15,12 +15,15 @@ static void memory_release(void *mem)
 
 Arena *arena_alloc_(const ArenaParams *params)
 {
+    Assert(params->size > ARENA_HEADER_SZ);
+    Assert(params->size < (U32_Max -  ARENA_HEADER_SZ - 1));
+
     // Note: only backend now is malloc
-    Assert(params.size > ARENA_HEADER_SZ);
     void *base = memory_allocate(params->size);
     Assert(base != NULL);
 
     Arena *arena = (Arena *)base;
+    arena->base     = base;
     arena->current  = arena;
     arena->size     = params->size;
     arena->pos      = ARENA_HEADER_SZ;
@@ -29,7 +32,6 @@ Arena *arena_alloc_(const ArenaParams *params)
     return arena;
 }
 
-
 void arena_free(Arena *arena)
 {
     Arena *it = arena->current;
@@ -42,35 +44,36 @@ void arena_free(Arena *arena)
     }
 }
 
-
-
 void *arena_push(Arena *arena, U32 size, U32 align)
 {
+    Assert(size < (U32_Max - align - ARENA_HEADER_SZ - 1));
+    Assert(IsPow2(align));
     Arena *current = arena->current;
     U32 start_pos = AlignUpPow2(arena->pos, align);
-    U32 available = current->size - start_pos;
+    U32 available = arena_available(current);
 
-    if (available > size) {
-
-        U8 *mem = &current->base[start_pos];
-        arena->pos = start_pos + size;
-        return mem;
-
-    } else {
-        // Note: We could hunt for a previous arena that still have room
+    if (available < size) {
         U32 new_size = current->size;
         if (new_size < size) {
-            new_size = size;
+            new_size = AlignUpPow2(size + ARENA_HEADER_SZ,align);
         }
 
         ArenaParams new_params  = {};
-        new_params.flags = current->flags;
-        new_params.size = size + ARENA_HEADER_SZ;
+        new_params.flags        = current->flags;
+        new_params.size         = new_size;
+
         Arena *new_arena = arena_alloc_(&new_params);
-
-        new_arena->prev = current;
+        new_arena->prev  = current;
         current->current = new_arena;
-        current = new_arena;
-
+        current          = new_arena;
+        start_pos        = AlignUpPow2(current->pos, align);
     }
+
+    U32 end_pos = start_pos + size;
+    Assert(end_pos <= current->size);
+
+    U8 *mem     = &current->base[start_pos];
+    arena->pos  = start_pos + size;
+
+    return mem;
 }