--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/alloc.c	Wed Jan 29 10:50:34 2025 +0000
@@ -0,0 +1,32 @@
+#include "alloc.h"
+#include "error.h"
+extern char *malloc();
+extern void free();
+
+#define ALIGNMENT 16 /* XXX: assuming that this alignment is enough */
+#define SPACE 4096 /* must be multiple of ALIGNMENT */
+
+typedef union { char irrelevant[ALIGNMENT]; double d; } aligned;
+static aligned realspace[SPACE / ALIGNMENT];
+#define space ((char *) realspace)
+static unsigned int avail = SPACE; /* multiple of ALIGNMENT; 0<=avail<=SPACE */
+
+/*@null@*//*@out@*/char *alloc(n)
+unsigned int n;
+{
+  char *x;
+  n = ALIGNMENT + n - (n & (ALIGNMENT - 1)); /* XXX: could overflow */
+  if (n <= avail) { avail -= n; return space + avail; }
+  x = malloc(n);
+  if (!x) errno = error_nomem;
+  return x;
+}
+
+void alloc_free(x)
+char *x;
+{
+  if (x >= space)
+    if (x < space + SPACE)
+      return; /* XXX: assuming that pointers are flat */
+  free(x);
+}