Simplify coinstake checking logic

Author: ComputerCraftr

src/primitives/block.h

@@ -139,7 +139,7 @@ class CBlock : public CBlockHeader
     {
         READWRITEAS(CBlockHeader, obj);
         READWRITE(obj.vtx);
-        if (obj.vtx.size() > 1 && obj.vtx[1]->IsCoinStake())
+        if (obj.vtx.size() >= 2 && obj.vtx[1]->IsCoinStake())
             READWRITE(obj.vchBlockSig);
     }
 
@@ -166,7 +166,7 @@ class CBlock : public CBlockHeader
     // peercoin: two types of block: proof-of-work or proof-of-stake
     /*bool IsProofOfStake() const
     {
-        return (vtx.size() > 1 && vtx[1]->IsCoinStake());
+        return (vtx.size() >= 2 && vtx[1]->IsCoinStake());
     }
 
     bool IsProofOfWork() const

src/primitives/transaction.h

@@ -340,7 +340,7 @@ class CTransaction
     bool IsCoinStake() const
     {
         // peercoin: the coin stake transaction is marked with the first output empty
-        return (vin.size() > 0 && (!vin[0].prevout.IsNull()) && vout.size() >= 2 && vout[0].IsEmpty());
+        return (!vin.empty() && !vin[0].prevout.IsNull() && vout.size() >= 2 && vout[0].IsEmpty());
     }
 
     friend bool operator==(const CTransaction& a, const CTransaction& b)
@@ -406,7 +406,7 @@ struct CMutableTransaction
     bool IsCoinStake() const
     {
         // peercoin: the coin stake transaction is marked with the first output empty
-        return (vin.size() > 0 && (!vin[0].prevout.IsNull()) && vout.size() >= 2 && vout[0].IsEmpty());
+        return (!vin.empty() && !vin[0].prevout.IsNull() && vout.size() >= 2 && vout[0].IsEmpty());
     }
 
     friend bool operator==(const CMutableTransaction& a, const CMutableTransaction& b)