Replace direct use of 0 with SetNull and IsNull

Replace x=0 with .SetNull(),
x==0 with IsNull(), x!=0 with !IsNull().
Replace uses of uint256(0) with uint256().

1 files changed, 11 insertions, 11 deletions

diff --git a/src/main.cpp b/src/main.cpp
index 4fcb4f093a..c392138ff3 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -261,7 +261,7 @@ struct CNodeState {
         nMisbehavior = 0;
         fShouldBan = false;
         pindexBestKnownBlock = NULL;
-        hashLastUnknownBlock = uint256(0);
+        hashLastUnknownBlock.SetNull();
         pindexLastCommonBlock = NULL;
         fSyncStarted = false;
         nStallingSince = 0;
@@ -349,12 +349,12 @@ void ProcessBlockAvailability(NodeId nodeid) {
     CNodeState *state = State(nodeid);
     assert(state != NULL);
 
-    if (state->hashLastUnknownBlock != 0) {
+    if (!state->hashLastUnknownBlock.IsNull()) {
         BlockMap::iterator itOld = mapBlockIndex.find(state->hashLastUnknownBlock);
         if (itOld != mapBlockIndex.end() && itOld->second->nChainWork > 0) {
             if (state->pindexBestKnownBlock == NULL || itOld->second->nChainWork >= state->pindexBestKnownBlock->nChainWork)
                 state->pindexBestKnownBlock = itOld->second;
-            state->hashLastUnknownBlock = uint256(0);
+            state->hashLastUnknownBlock.SetNull();
         }
     }
 }
@@ -1712,7 +1712,7 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
         return false;
 
     // verify that the view's current state corresponds to the previous block
-    uint256 hashPrevBlock = pindex->pprev == NULL ? uint256(0) : pindex->pprev->GetBlockHash();
+    uint256 hashPrevBlock = pindex->pprev == NULL ? uint256() : pindex->pprev->GetBlockHash();
     assert(hashPrevBlock == view.GetBestBlock());
 
     // Special case for the genesis block, skipping connection of its transactions
@@ -2835,7 +2835,7 @@ boost::filesystem::path GetBlockPosFilename(const CDiskBlockPos &pos, const char
 
 CBlockIndex * InsertBlockIndex(uint256 hash)
 {
-    if (hash == 0)
+    if (hash.IsNull())
         return NULL;
 
     // Return existing
@@ -3369,7 +3369,7 @@ void static ProcessGetData(CNode* pfrom)
                         vector<CInv> vInv;
                         vInv.push_back(CInv(MSG_BLOCK, chainActive.Tip()->GetBlockHash()));
                         pfrom->PushMessage("inv", vInv);
-                        pfrom->hashContinue = 0;
+                        pfrom->hashContinue.SetNull();
                     }
                 }
             }
@@ -3604,7 +3604,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                     // Use deterministic randomness to send to the same nodes for 24 hours
                     // at a time so the setAddrKnowns of the chosen nodes prevent repeats
                     static uint256 hashSalt;
-                    if (hashSalt == 0)
+                    if (hashSalt.IsNull())
                         hashSalt = GetRandHash();
                     uint64_t hashAddr = addr.GetHash();
                     uint256 hashRand = hashSalt ^ (hashAddr<<32) ^ ((GetTime()+hashAddr)/(24*60*60));
@@ -3738,7 +3738,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         if (pindex)
             pindex = chainActive.Next(pindex);
         int nLimit = 500;
-        LogPrint("net", "getblocks %d to %s limit %d from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop==uint256(0) ? "end" : hashStop.ToString(), nLimit, pfrom->id);
+        LogPrint("net", "getblocks %d to %s limit %d from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop.IsNull() ? "end" : hashStop.ToString(), nLimit, pfrom->id);
         for (; pindex; pindex = chainActive.Next(pindex))
         {
             if (pindex->GetBlockHash() == hashStop)
@@ -3954,7 +3954,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             // TODO: optimize: if pindexLast is an ancestor of chainActive.Tip or pindexBestHeader, continue
             // from there instead.
             LogPrint("net", "more getheaders (%d) to end to peer=%d (startheight:%d)\n", pindexLast->nHeight, pfrom->id, pfrom->nStartingHeight);
-            pfrom->PushMessage("getheaders", chainActive.GetLocator(pindexLast), uint256(0));
+            pfrom->PushMessage("getheaders", chainActive.GetLocator(pindexLast), uint256());
         }
     }
 
@@ -4452,7 +4452,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
                 nSyncStarted++;
                 CBlockIndex *pindexStart = pindexBestHeader->pprev ? pindexBestHeader->pprev : pindexBestHeader;
                 LogPrint("net", "initial getheaders (%d) to peer=%d (startheight:%d)\n", pindexStart->nHeight, pto->id, pto->nStartingHeight);
-                pto->PushMessage("getheaders", chainActive.GetLocator(pindexStart), uint256(0));
+                pto->PushMessage("getheaders", chainActive.GetLocator(pindexStart), uint256());
             }
         }
 
@@ -4483,7 +4483,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
                 {
                     // 1/4 of tx invs blast to all immediately
                     static uint256 hashSalt;
-                    if (hashSalt == 0)
+                    if (hashSalt.IsNull())
                         hashSalt = GetRandHash();
                     uint256 hashRand = inv.hash ^ hashSalt;
                     hashRand = Hash(BEGIN(hashRand), END(hashRand));