]> git.ozlabs.org Git - ccan/blobdiff - ccan/crypto/shachain/shachain.c
crypto/shachain/tools: update to new rbuf API.
[ccan] / ccan / crypto / shachain / shachain.c
index 2c9cb3d5464c42855d7e9d3dc0c18455ed6907ea..9cb54a37bdd9da6c18b1567e400ca132010af9a2 100644 (file)
@@ -10,7 +10,7 @@ static void change_bit(unsigned char *arr, size_t index)
        arr[index / CHAR_BIT] ^= (1 << (index % CHAR_BIT));
 }
 
-static unsigned int count_trailing_zeroes(shachain_index_t index)
+static unsigned int count_trailing_zeroes(uint64_t index)
 {
 #if HAVE_BUILTIN_CTZLL
        return index ? (unsigned int)__builtin_ctzll(index) : SHACHAIN_BITS;
@@ -25,24 +25,24 @@ static unsigned int count_trailing_zeroes(shachain_index_t index)
 #endif
 }
 
-static bool can_derive(shachain_index_t from, shachain_index_t to)
+static bool can_derive(uint64_t from, uint64_t to)
 {
-       shachain_index_t mask;
+       uint64_t mask;
 
        /* Corner case: can always derive from seed. */
        if (from == 0)
                return true;
 
        /* Leading bits must be the same */
-       mask = ~((1ULL << count_trailing_zeroes(from))-1);
+       mask = ~(((uint64_t)1 << count_trailing_zeroes(from))-1);
        return ((from ^ to) & mask) == 0;
 }
 
-static void derive(shachain_index_t from, shachain_index_t to,
+static void derive(uint64_t from, uint64_t to,
                   const struct sha256 *from_hash,
                   struct sha256 *hash)
 {
-       shachain_index_t branches;
+       uint64_t branches;
        int i;
 
        assert(can_derive(from, to));
@@ -60,27 +60,31 @@ static void derive(shachain_index_t from, shachain_index_t to,
        }
 }
 
-void shachain_from_seed(const struct sha256 *seed, shachain_index_t index,
+void shachain_from_seed(const struct sha256 *seed, uint64_t index,
                        struct sha256 *hash)
 {
        derive(0, index, seed, hash);
 }
 
+uint64_t shachain_next_index(const struct shachain *chain)
+{
+       return chain->min_index - 1;
+}
+
 void shachain_init(struct shachain *chain)
 {
        chain->num_valid = 0;
-       chain->min_index = 0;
+       /* This is 0 in the case where SHACHAIN_BITS is 64. */
+       chain->min_index = (UINT64_MAX >> (64 - SHACHAIN_BITS)) + 1;
 }
 
 bool shachain_add_hash(struct shachain *chain,
-                      shachain_index_t index, const struct sha256 *hash)
+                      uint64_t index, const struct sha256 *hash)
 {
        unsigned int i, pos;
 
        /* You have to insert them in order! */
-       assert(index == chain->min_index - 1 ||
-              (index == (shachain_index_t)(UINT64_MAX >> (64 - SHACHAIN_BITS))
-               && chain->num_valid == 0));
+       assert(index == shachain_next_index(chain));
 
        pos = count_trailing_zeroes(index);
 
@@ -104,7 +108,7 @@ bool shachain_add_hash(struct shachain *chain,
 }
 
 bool shachain_get_hash(const struct shachain *chain,
-                      shachain_index_t index, struct sha256 *hash)
+                      uint64_t index, struct sha256 *hash)
 {
        unsigned int i;