Add CMerkleBlock constructor for tx set + block and an empty one

Author: TheBlueMatt

src/merkleblock.cpp

@@ -37,6 +37,29 @@ CMerkleBlock::CMerkleBlock(const CBlock& block, CBloomFilter& filter)
     txn = CPartialMerkleTree(vHashes, vMatch);
 }
 
+CMerkleBlock::CMerkleBlock(const CBlock& block, const std::set<uint256>& txids)
+{
+    header = block.GetBlockHeader();
+
+    vector<bool> vMatch;
+    vector<uint256> vHashes;
+
+    vMatch.reserve(block.vtx.size());
+    vHashes.reserve(block.vtx.size());
+
+    for (unsigned int i = 0; i < block.vtx.size(); i++)
+    {
+        const uint256& hash = block.vtx[i].GetHash();
+        if (txids.count(hash))
+            vMatch.push_back(true);
+        else
+            vMatch.push_back(false);
+        vHashes.push_back(hash);
+    }
+
+    txn = CPartialMerkleTree(vHashes, vMatch);
+}
+
 uint256 CPartialMerkleTree::CalcHash(int height, unsigned int pos, const std::vector<uint256> &vTxid) {
     if (height == 0) {
         // hash at height 0 is the txids themself

src/merkleblock.h

@@ -139,6 +139,11 @@ class CMerkleBlock
      */
     CMerkleBlock(const CBlock& block, CBloomFilter& filter);
 
+    // Create from a CBlock, matching the txids in the set
+    CMerkleBlock(const CBlock& block, const std::set<uint256>& txids);
+
+    CMerkleBlock() {}
+
     ADD_SERIALIZE_METHODS;
 
     template <typename Stream, typename Operation>