X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fcrypto%2Fshachain%2Fshachain.h;h=90f2380ed39b89d8277db3542e669fcc22f7176e;hp=ba4ba11cd64c02d1d66a362d35bac98e39a2f0bc;hb=4bb69fe6d568f84bd682cf6f86bae168313deb91;hpb=d07f742c5925b97ed558eb07aae285616f5df823

diff --git a/ccan/crypto/shachain/shachain.h b/ccan/crypto/shachain/shachain.h
index ba4ba11c..90f2380e 100644
--- a/ccan/crypto/shachain/shachain.h
+++ b/ccan/crypto/shachain/shachain.h
@@ -11,6 +11,10 @@
 #define shachain_index_t uint64_t
 #endif
 
+#ifndef SHACHAIN_BITS
+#define SHACHAIN_BITS (sizeof(shachain_index_t) * 8)
+#endif
+
 /**
  * shachain_from_seed - Generate an unpredictable SHA from a seed value.
  * @seed: (secret) seed value to use
@@ -56,7 +60,7 @@ struct shachain {
 	struct {
 		shachain_index_t index;
 		struct sha256 hash;
-	} known[sizeof(shachain_index_t) * 8 + 1];
+	} known[SHACHAIN_BITS + 1];
 };
 
 /**