Merge pull request #4796

e8b5f0d Move CBlockIndex, CChain and related code out of main (jtimon)
6db83db Decouple CChain from mapBlockIndex (jtimon)

src/Makefile.am

@@ -67,6 +67,7 @@ BITCOIN_CORE_H = \
   allocators.h \
   base58.h \
   bloom.h \
+  chain.h \
   chainparams.h \
   chainparamsbase.h \
   chainparamsseeds.h \
@@ -145,6 +146,7 @@ libbitcoin_server_a_SOURCES = \
   addrman.cpp \
   alert.cpp \
   bloom.cpp \
+  chain.cpp \
   checkpoints.cpp \
   init.cpp \
   leveldbwrapper.cpp \

src/chain.cpp

@@ -0,0 +1,59 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "chain.h"
+
+using namespace std;
+
+// CChain implementation
+
+CBlockIndex *CChain::SetTip(CBlockIndex *pindex) {
+    if (pindex == NULL) {
+        vChain.clear();
+        return NULL;
+    }
+    vChain.resize(pindex->nHeight + 1);
+    while (pindex && vChain[pindex->nHeight] != pindex) {
+        vChain[pindex->nHeight] = pindex;
+        pindex = pindex->pprev;
+    }
+    return pindex;
+}
+
+CBlockLocator CChain::GetLocator(const CBlockIndex *pindex) const {
+    int nStep = 1;
+    std::vector<uint256> vHave;
+    vHave.reserve(32);
+
+    if (!pindex)
+        pindex = Tip();
+    while (pindex) {
+        vHave.push_back(pindex->GetBlockHash());
+        // Stop when we have added the genesis block.
+        if (pindex->nHeight == 0)
+            break;
+        // Exponentially larger steps back, plus the genesis block.
+        int nHeight = std::max(pindex->nHeight - nStep, 0);
+        if (Contains(pindex)) {
+            // Use O(1) CChain index if possible.
+            pindex = (*this)[nHeight];
+        } else {
+            // Otherwise, use O(log n) skiplist.
+            pindex = pindex->GetAncestor(nHeight);
+        }
+        if (vHave.size() > 10)
+            nStep *= 2;
+    }
+
+    return CBlockLocator(vHave);
+}
+
+const CBlockIndex *CChain::FindFork(const CBlockIndex *pindex) const {
+    if (pindex->nHeight > Height())
+        pindex = pindex->GetAncestor(Height());
+    while (pindex && !Contains(pindex))
+        pindex = pindex->pprev;
+    return pindex;
+}