add zn_save, zn_load

1 files changed, 24 insertions, 0 deletions

diff --git a/zone.h b/zone.h
index 8199bda..c2e033e 100644
--- a/zone.h
+++ b/zone.h
@@ -16,8 +16,15 @@ typedef struct {
 	ZoneFrame *tail, *here;
 } Zone;
 
+typedef struct {
+	ZoneFrame *zf;
+	size_t length;
+} ZoneState;
+
 void zn_free(Zone *z);
 void zn_clear(Zone *z);
+void zn_save(Zone *z, ZoneState *m);
+void zn_load(Zone *z, ZoneState *m);
 
 void *zn_alloc(Zone *z, size_t n);
 void *zn_zf_alloc(Zone *z, ZoneFrame **zf, size_t n);
@@ -115,5 +122,22 @@ char *zn_strdup(Zone *z, const char *s) {
 	return d;
 }
 
+void zn_save(Zone *z, ZoneState *m) {
+	m->zf = z->here;
+	m->length = z->here ? z->tail->length : 0;
+}
+
+void zn_load(Zone *z, ZoneState *m) {
+	if (m->zf) {
+		while (z->here != m->zf) {
+			z->here->length = 0;
+			z->here = z->here->prev;
+		}
+		m->zf->length = m->length;
+	} else {
+		zn_clear(z);
+	}
+}
+
 #endif
 #endif