fix arena

1 files changed, 28 insertions, 14 deletions

diff --git a/src/mem.hff b/src/mem.hff
index 84064f3..a86bee3 100644
--- a/src/mem.hff
+++ b/src/mem.hff
@@ -9,30 +9,44 @@ extern fn xrealloc(p *void, n usize) *void;
 
 struct ArenaRegion {
    prev *ArenaRegion,
-   idx int,
-   mem [ARENA_SIZE]u8,
+   idx usize,
+   siz usize,
+   mem [0]u8,
 }
 
 struct Arena {
    r *ArenaRegion,
 
+   fn addregion(a *Arena, siz usize) void {
+      let r *ArenaRegion = xcalloc(sizeof ArenaRegion + siz, 1);
+      r.siz = siz;
+      r.prev = a.r;
+      a.r = r;
+   }
+
    fn allocf(a *void, n usize) *void {
       let a *Arena = a;
       n = ALIGNUP(n, 16);
-      if ARENA_SIZE < n {
-         return xmalloc(n);
+      if n > ARENA_SIZE {
+         a->addregion(n);
+         return a.r.mem;
       } else if a.r == #null {
-         a.r = xcalloc(1, sizeof ArenaRegion);
-         return allocf(a, n);
-      } else if ARENA_SIZE - a.r.idx >= n {
-         let ptr = &a.r.mem[a.r.idx];
-         a.r.idx += n;
-         return ptr;
+         a->addregion(ARENA_SIZE);
+         return allocf(a, n);         
+      } else if n > a.r.siz - a.r.idx {
+         a->addregion(ARENA_SIZE);
+         return allocf(a, n);         
       } else {
-         let rp *ArenaRegion = xmalloc(sizeof ArenaRegion);
-         *rp = *a.r;
-         let r = ArenaRegion { .prev: rp };
-         return allocf(a, n);
+         let p = &a.r.mem[a.r.idx];
+         a.r.idx += n;
+         return p;
+      }
+   }
+
+   fn destroy(a *Arena) void {
+      for let r = a.r, next *ArenaRegion = #null; r; r = next {
+         next = r.prev;
+         free(r);
       }
    }
 }