things

1 files changed, 62 insertions, 0 deletions

diff --git a/src/mem.hff b/src/mem.hff
new file mode 100644
index 0000000..9fee910
--- /dev/null
+++ b/src/mem.hff
@@ -0,0 +1,62 @@
+import "all.hff";
+
+def ARENA_SIZE = 16 * 1024;
+
+struct ArenaRegion {
+   prev *ArenaRegion,
+   idx int,
+   mem [ARENA_SIZE]u8,
+}
+
+struct Arena {
+   r *ArenaRegion,
+
+   fn allocf(a *void, n usize) *void {
+      let a *Arena = a;
+      n = ALIGNUP(n, 16);
+      if ARENA_SIZE < n {
+         return xmalloc(n);
+      } 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;
+      } else {
+         let rp = xmalloc(sizeof ArenaRegion);
+         *rp = a.r;
+         let r = ArenaRegion { .prev: rp };
+         return allocf(a, n);
+      }
+   }
+}
+
+struct Mallocator {
+   fn allocf(*void, n usize) *void {
+      return xmalloc(n);
+   }
+
+   fn freef(*void, ptr *void) void {
+      free(ptr);
+   }
+}
+
+struct Allocator {
+   a *void,
+   allocf *fn(a *void, n usize) *void,
+   freef *fn(a *void, ptr *void) void,
+
+   fn alloc(self *Allocator, n usize) *void {
+      if self.allocf {
+         return self.allocf(self.a, n);
+      }
+      return #null;
+   }
+
+   fn free(self *Allocator, ptr *void) void {
+      if self.freef {
+         self.freef(self.a, ptr);
+      }
+   }
+}