Merge #14838: Use const in COutPoint class

cf4b032 Use std::numeric_limits<UNSIGNED>::max()) instead of (UNSIGNED)-1 (practicalswift)
6b82fc5 Use const in COutPoint class (Hennadii Stepanov)

Pull request description:

  Refactoring:
  - all cases of using `(uint32_t) -1` in `COutPoint` class are replaced with const;
  - also all remaining instances of `(UNSIGNED)-1` transformed to `std::numeric_limits<UNSIGNED>::max()` (by @practicalswift).

Tree-SHA512: fc7fe9838b6e5136d8b97ea3d6f64c4aaa1215f4369832df432cab017396620bb6e30520a64180ceab6de222562ac11eab243a78dfa5a658ba018835a34caa19

Author: laanwj

src/arith_uint256.h

@@ -8,6 +8,7 @@
 
 #include <assert.h>
 #include <cstring>
+#include <limits>
 #include <stdexcept>
 #include <stdint.h>
 #include <string>
@@ -189,7 +190,7 @@ class base_uint
     {
         // prefix operator
         int i = 0;
-        while (i < WIDTH && --pn[i] == (uint32_t)-1)
+        while (i < WIDTH && --pn[i] == std::numeric_limits<uint32_t>::max())
             i++;
         return *this;
     }

src/primitives/transaction.h

@@ -21,7 +21,9 @@ class COutPoint
     uint256 hash;
     uint32_t n;
 
-    COutPoint(): n((uint32_t) -1) { }
+    static constexpr uint32_t NULL_INDEX = std::numeric_limits<uint32_t>::max();
+
+    COutPoint(): n(NULL_INDEX) { }
     COutPoint(const uint256& hashIn, uint32_t nIn): hash(hashIn), n(nIn) { }
 
     ADD_SERIALIZE_METHODS;
@@ -32,8 +34,8 @@ class COutPoint
         READWRITE(n);
     }
 
-    void SetNull() { hash.SetNull(); n = (uint32_t) -1; }
-    bool IsNull() const { return (hash.IsNull() && n == (uint32_t) -1); }
+    void SetNull() { hash.SetNull(); n = NULL_INDEX; }
+    bool IsNull() const { return (hash.IsNull() && n == NULL_INDEX); }
 
     friend bool operator<(const COutPoint& a, const COutPoint& b)
     {

src/streams.h

@@ -761,7 +761,7 @@ class CBufferedFile
 
 public:
     CBufferedFile(FILE *fileIn, uint64_t nBufSize, uint64_t nRewindIn, int nTypeIn, int nVersionIn) :
-        nType(nTypeIn), nVersion(nVersionIn), nSrcPos(0), nReadPos(0), nReadLimit((uint64_t)(-1)), nRewind(nRewindIn), vchBuf(nBufSize, 0)
+        nType(nTypeIn), nVersion(nVersionIn), nSrcPos(0), nReadPos(0), nReadLimit(std::numeric_limits<uint64_t>::max()), nRewind(nRewindIn), vchBuf(nBufSize, 0)
     {
         src = fileIn;
     }
@@ -846,7 +846,7 @@ class CBufferedFile
 
     // prevent reading beyond a certain position
     // no argument removes the limit
-    bool SetLimit(uint64_t nPos = (uint64_t)(-1)) {
+    bool SetLimit(uint64_t nPos = std::numeric_limits<uint64_t>::max()) {
         if (nPos < nReadPos)
             return false;
         nReadLimit = nPos;

src/test/serialize_tests.cpp

@@ -200,7 +200,7 @@ BOOST_AUTO_TEST_CASE(varints)
     }
 
     for (uint64_t i = 0;  i < 100000000000ULL; i += 999999937) {
-        uint64_t j = -1;
+        uint64_t j = std::numeric_limits<uint64_t>::max();
         ss >> VARINT(j);
         BOOST_CHECK_MESSAGE(i == j, "decoded:" << j << " expected:" << i);
     }

src/test/sighash_tests.cpp

@@ -105,7 +105,7 @@ void static RandomTransaction(CMutableTransaction &tx, bool fSingle) {
         txin.prevout.hash = InsecureRand256();
         txin.prevout.n = InsecureRandBits(2);
         RandomScript(txin.scriptSig);
-        txin.nSequence = (InsecureRandBool()) ? InsecureRand32() : (unsigned int)-1;
+        txin.nSequence = (InsecureRandBool()) ? InsecureRand32() : std::numeric_limits<uint32_t>::max();
     }
     for (int out = 0; out < outs; out++) {
         tx.vout.push_back(CTxOut());