Switch blocks to a constant-space Merkle root/branch algorithm.

This switches the Merkle tree logic for blocks to one that runs in constant (small) space.
The old code is moved to tests, and a new test is added that for various combinations of
block sizes, transaction positions to compute a branch for, and mutations:
 * Verifies that the old code and new code agree for the Merkle root.
 * Verifies that the old code and new code agree for the Merkle branch.
 * Verifies that the computed Merkle branch is valid.
 * Verifies that mutations don't change the Merkle root.
 * Verifies that mutations are correctly detected.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/test/miner_tests.cpp b/src/test/miner_tests.cpp
index dc20e34634..1d7c9f65c0 100644
--- a/src/test/miner_tests.cpp
+++ b/src/test/miner_tests.cpp
@@ -5,6 +5,7 @@
 #include "chainparams.h"
 #include "coins.h"
 #include "consensus/consensus.h"
+#include "consensus/merkle.h"
 #include "consensus/validation.h"
 #include "main.h"
 #include "miner.h"
@@ -93,7 +94,7 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
         pblock->vtx[0] = CTransaction(txCoinbase);
         if (txFirst.size() < 2)
             txFirst.push_back(new CTransaction(pblock->vtx[0]));
-        pblock->hashMerkleRoot = pblock->ComputeMerkleRoot();
+        pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
         pblock->nNonce = blockinfo[i].nonce;
         CValidationState state;
         BOOST_CHECK(ProcessNewBlock(state, chainparams, NULL, pblock, true, NULL));