summaryrefslogtreecommitdiffstats
path: root/alloc.c
diff options
context:
space:
mode:
Diffstat (limited to 'alloc.c')
-rw-r--r--alloc.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/alloc.c b/alloc.c
new file mode 100644
index 0000000..c661453
--- /dev/null
+++ b/alloc.c
@@ -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);
+}