refactor: Avoid &foo[0] on C-Style arrays

This is confusing at best when parts of a class use the
redundant operators and other parts do not.

Author: MarcoFalke

src/key.cpp

@@ -293,7 +293,7 @@ bool CKey::Derive(CKey& keyChild, ChainCode &ccChild, unsigned int nChild, const
 bool CExtKey::Derive(CExtKey &out, unsigned int _nChild) const {
     out.nDepth = nDepth + 1;
     CKeyID id = key.GetPubKey().GetID();
-    memcpy(&out.vchFingerprint[0], &id, 4);
+    memcpy(out.vchFingerprint, &id, 4);
     out.nChild = _nChild;
     return key.Derive(out.key, out.chaincode, _nChild, chaincode);
 }
@@ -312,7 +312,7 @@ void CExtKey::SetSeed(const unsigned char *seed, unsigned int nSeedLen) {
 CExtPubKey CExtKey::Neuter() const {
     CExtPubKey ret;
     ret.nDepth = nDepth;
-    memcpy(&ret.vchFingerprint[0], &vchFingerprint[0], 4);
+    memcpy(ret.vchFingerprint, vchFingerprint, 4);
     ret.nChild = nChild;
     ret.pubkey = key.GetPubKey();
     ret.chaincode = chaincode;

src/key.h

@@ -151,7 +151,7 @@ struct CExtKey {
     friend bool operator==(const CExtKey& a, const CExtKey& b)
     {
         return a.nDepth == b.nDepth &&
-            memcmp(&a.vchFingerprint[0], &b.vchFingerprint[0], sizeof(vchFingerprint)) == 0 &&
+            memcmp(a.vchFingerprint, b.vchFingerprint, sizeof(vchFingerprint)) == 0 &&
             a.nChild == b.nChild &&
             a.chaincode == b.chaincode &&
             a.key == b.key;

src/pubkey.cpp

@@ -293,7 +293,7 @@ void CExtPubKey::Decode(const unsigned char code[BIP32_EXTKEY_SIZE]) {
 bool CExtPubKey::Derive(CExtPubKey &out, unsigned int _nChild) const {
     out.nDepth = nDepth + 1;
     CKeyID id = pubkey.GetID();
-    memcpy(&out.vchFingerprint[0], &id, 4);
+    memcpy(out.vchFingerprint, &id, 4);
     out.nChild = _nChild;
     return pubkey.Derive(out.pubkey, out.chaincode, _nChild, chaincode);
 }

src/pubkey.h

@@ -247,7 +247,7 @@ struct CExtPubKey {
     friend bool operator==(const CExtPubKey &a, const CExtPubKey &b)
     {
         return a.nDepth == b.nDepth &&
-            memcmp(&a.vchFingerprint[0], &b.vchFingerprint[0], sizeof(vchFingerprint)) == 0 &&
+            memcmp(a.vchFingerprint, b.vchFingerprint, sizeof(vchFingerprint)) == 0 &&
             a.nChild == b.nChild &&
             a.chaincode == b.chaincode &&
             a.pubkey == b.pubkey;

src/zmq/zmqpublishnotifier.cpp

@@ -168,7 +168,7 @@ bool CZMQAbstractPublishNotifier::SendZmqMessage(const char *command, const void
 
     /* send three parts, command & data & a LE 4byte sequence number */
     unsigned char msgseq[sizeof(uint32_t)];
-    WriteLE32(&msgseq[0], nSequence);
+    WriteLE32(msgseq, nSequence);
     int rc = zmq_send_multipart(psocket, command, strlen(command), data, size, msgseq, (size_t)sizeof(uint32_t), nullptr);
     if (rc == -1)
         return false;