diff --git a/jmode.c b/jmode.c
index 6094d3d..afe084f 100644
--- a/jmode.c
+++ b/jmode.c
@@ -168,6 +168,20 @@ int rsd32(u8 data[N]) {
   return count;
 }
 
+// ============================================================================
+//  ZRLE.
+// ============================================================================
+static bool zrle_consider(u8 * restrict in, sz n) {
+  i32 savings = 0;
+  Fi(n, if (!in[i]) {
+    sz j = i + 1;
+    while (j < n && in[j] == 0) j++;
+    savings += j - i - 2;
+    i = j - 1;
+  })
+  return savings > 0;
+}
+
 // ============================================================================
 //  Processing. We apply a few strategies that depend on some specifics of the
 //  process at hand: