Use fixed-width array for storing hash and indices

src/crypto/equihash.tcc

@@ -0,0 +1,35 @@
+// Copyright (c) 2016 Jack Grigg
+// Copyright (c) 2016 The Zcash developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <algorithm>
+#include <cassert>
+
+// Checks if the intersection of a.indices and b.indices is empty
+template<size_t WIDTH>
+bool DistinctIndices(const FullStepRow<WIDTH>& a, const FullStepRow<WIDTH>& b, size_t len, size_t lenIndices)
+{
+    std::vector<eh_index> aSrt = a.GetIndices(len, lenIndices);
+    std::vector<eh_index> bSrt = b.GetIndices(len, lenIndices);
+
+    std::sort(aSrt.begin(), aSrt.end());
+    std::sort(bSrt.begin(), bSrt.end());
+
+    unsigned int i = 0;
+    for (unsigned int j = 0; j < bSrt.size(); j++) {
+        while (aSrt[i] < bSrt[j]) {
+            i++;
+            if (i == aSrt.size()) { return true; }
+        }
+        assert(aSrt[i] >= bSrt[j]);
+        if (aSrt[i] == bSrt[j]) { return false; }
+    }
+    return true;
+}
+
+template<size_t WIDTH>
+bool IsValidBranch(const FullStepRow<WIDTH>& a, const size_t len, const unsigned int ilen, const eh_trunc t)
+{
+    return TruncateIndex(ArrayToEhIndex(a.hash+len), ilen) == t;
+}