diff --git a/src/serialize.h b/src/serialize.h
index 1b865bd875..b1c99983af 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -1,894 +1,919 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_SERIALIZE_H
 #define BITCOIN_SERIALIZE_H
 
 #include "compat/endian.h"
 
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
 #include <cstring>
 #include <ios>
 #include <limits>
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "prevector.h"
 
 static const uint64_t MAX_SIZE = 0x02000000;
 
 /**
  * Dummy data type to identify deserializing constructors.
  *
  * By convention, a constructor of a type T with signature
  *
  *   template <typename Stream> T::T(deserialize_type, Stream& s)
  *
  * is a deserializing constructor, which builds the type by deserializing it
  * from s. If T contains const fields, this is likely the only way to do so.
  */
 struct deserialize_type {};
 constexpr deserialize_type deserialize{};
 
 /**
  * Used to bypass the rule against non-const reference to temporary where it
  * makes sense with wrappers such as CFlatData or CTxDB
  */
 template <typename T> inline T &REF(const T &val) {
     return const_cast<T &>(val);
 }
 
 /**
  * Used to acquire a non-const pointer "this" to generate bodies of const
  * serialization operations from a template
  */
 template <typename T> inline T *NCONST_PTR(const T *val) {
     return const_cast<T *>(val);
 }
 
 /*
  * Lowest-level serialization and conversion.
  * @note Sizes of these types are verified in the tests
  */
 template <typename Stream> inline void ser_writedata8(Stream &s, uint8_t obj) {
     s.write((char *)&obj, 1);
 }
 template <typename Stream>
 inline void ser_writedata16(Stream &s, uint16_t obj) {
     obj = htole16(obj);
     s.write((char *)&obj, 2);
 }
 template <typename Stream>
 inline void ser_writedata32(Stream &s, uint32_t obj) {
     obj = htole32(obj);
     s.write((char *)&obj, 4);
 }
 template <typename Stream>
 inline void ser_writedata64(Stream &s, uint64_t obj) {
     obj = htole64(obj);
     s.write((char *)&obj, 8);
 }
 template <typename Stream> inline uint8_t ser_readdata8(Stream &s) {
     uint8_t obj;
     s.read((char *)&obj, 1);
     return obj;
 }
 template <typename Stream> inline uint16_t ser_readdata16(Stream &s) {
     uint16_t obj;
     s.read((char *)&obj, 2);
     return le16toh(obj);
 }
 template <typename Stream> inline uint32_t ser_readdata32(Stream &s) {
     uint32_t obj;
     s.read((char *)&obj, 4);
     return le32toh(obj);
 }
 template <typename Stream> inline uint64_t ser_readdata64(Stream &s) {
     uint64_t obj;
     s.read((char *)&obj, 8);
     return le64toh(obj);
 }
 inline uint64_t ser_double_to_uint64(double x) {
     union {
         double x;
         uint64_t y;
     } tmp;
     tmp.x = x;
     return tmp.y;
 }
 inline uint32_t ser_float_to_uint32(float x) {
     union {
         float x;
         uint32_t y;
     } tmp;
     tmp.x = x;
     return tmp.y;
 }
 inline double ser_uint64_to_double(uint64_t y) {
     union {
         double x;
         uint64_t y;
     } tmp;
     tmp.y = y;
     return tmp.x;
 }
 inline float ser_uint32_to_float(uint32_t y) {
     union {
         float x;
         uint32_t y;
     } tmp;
     tmp.y = y;
     return tmp.x;
 }
 
 /////////////////////////////////////////////////////////////////
 //
 // Templates for serializing to anything that looks like a stream,
 // i.e. anything that supports .read(char*, size_t) and .write(char*, size_t)
 //
 class CSizeComputer;
 
 enum {
     // primary actions
     SER_NETWORK = (1 << 0),
     SER_DISK = (1 << 1),
     SER_GETHASH = (1 << 2),
 };
 
 #define READWRITE(obj) (::SerReadWrite(s, (obj), ser_action))
 #define READWRITEMANY(...) (::SerReadWriteMany(s, ser_action, __VA_ARGS__))
 
 /**
  * Implement three methods for serializable objects. These are actually wrappers
  * over "SerializationOp" template, which implements the body of each class'
  * serialization code. Adding "ADD_SERIALIZE_METHODS" in the body of the class
  * causes these wrappers to be added as members.
  */
 #define ADD_SERIALIZE_METHODS                                                  \
     template <typename Stream> void Serialize(Stream &s) const {               \
         NCONST_PTR(this)->SerializationOp(s, CSerActionSerialize());           \
     }                                                                          \
     template <typename Stream> void Unserialize(Stream &s) {                   \
         SerializationOp(s, CSerActionUnserialize());                           \
     }
 
 template <typename Stream> inline void Serialize(Stream &s, char a) {
     ser_writedata8(s, a);
 } // TODO Get rid of bare char
 template <typename Stream> inline void Serialize(Stream &s, int8_t a) {
     ser_writedata8(s, a);
 }
 template <typename Stream> inline void Serialize(Stream &s, uint8_t a) {
     ser_writedata8(s, a);
 }
 template <typename Stream> inline void Serialize(Stream &s, int16_t a) {
     ser_writedata16(s, a);
 }
 template <typename Stream> inline void Serialize(Stream &s, uint16_t a) {
     ser_writedata16(s, a);
 }
 template <typename Stream> inline void Serialize(Stream &s, int32_t a) {
     ser_writedata32(s, a);
 }
 template <typename Stream> inline void Serialize(Stream &s, uint32_t a) {
     ser_writedata32(s, a);
 }
 template <typename Stream> inline void Serialize(Stream &s, int64_t a) {
     ser_writedata64(s, a);
 }
 template <typename Stream> inline void Serialize(Stream &s, uint64_t a) {
     ser_writedata64(s, a);
 }
 template <typename Stream> inline void Serialize(Stream &s, float a) {
     ser_writedata32(s, ser_float_to_uint32(a));
 }
 template <typename Stream> inline void Serialize(Stream &s, double a) {
     ser_writedata64(s, ser_double_to_uint64(a));
 }
 // TODO Get rid of bare char
 template <typename Stream> inline void Unserialize(Stream &s, char &a) {
     a = ser_readdata8(s);
 }
 template <typename Stream> inline void Unserialize(Stream &s, int8_t &a) {
     a = ser_readdata8(s);
 }
 template <typename Stream> inline void Unserialize(Stream &s, uint8_t &a) {
     a = ser_readdata8(s);
 }
 template <typename Stream> inline void Unserialize(Stream &s, int16_t &a) {
     a = ser_readdata16(s);
 }
 template <typename Stream> inline void Unserialize(Stream &s, uint16_t &a) {
     a = ser_readdata16(s);
 }
 template <typename Stream> inline void Unserialize(Stream &s, int32_t &a) {
     a = ser_readdata32(s);
 }
 template <typename Stream> inline void Unserialize(Stream &s, uint32_t &a) {
     a = ser_readdata32(s);
 }
 template <typename Stream> inline void Unserialize(Stream &s, int64_t &a) {
     a = ser_readdata64(s);
 }
 template <typename Stream> inline void Unserialize(Stream &s, uint64_t &a) {
     a = ser_readdata64(s);
 }
 template <typename Stream> inline void Unserialize(Stream &s, float &a) {
     a = ser_uint32_to_float(ser_readdata32(s));
 }
 template <typename Stream> inline void Unserialize(Stream &s, double &a) {
     a = ser_uint64_to_double(ser_readdata64(s));
 }
 
 template <typename Stream> inline void Serialize(Stream &s, bool a) {
     char f = a;
     ser_writedata8(s, f);
 }
 template <typename Stream> inline void Unserialize(Stream &s, bool &a) {
     char f = ser_readdata8(s);
     a = f;
 }
 
 /**
  * Compact Size
  * size <  253        -- 1 byte
  * size <= USHRT_MAX  -- 3 bytes  (253 + 2 bytes)
  * size <= UINT_MAX   -- 5 bytes  (254 + 4 bytes)
  * size >  UINT_MAX   -- 9 bytes  (255 + 8 bytes)
  */
-inline unsigned int GetSizeOfCompactSize(uint64_t nSize) {
-    if (nSize < 253)
+inline uint32_t GetSizeOfCompactSize(uint64_t nSize) {
+    if (nSize < 253) {
         return sizeof(uint8_t);
-    else if (nSize <= std::numeric_limits<unsigned short>::max())
-        return sizeof(uint8_t) + sizeof(unsigned short);
-    else if (nSize <= std::numeric_limits<unsigned int>::max())
-        return sizeof(uint8_t) + sizeof(unsigned int);
-    else
-        return sizeof(uint8_t) + sizeof(uint64_t);
+    }
+    if (nSize <= std::numeric_limits<uint16_t>::max()) {
+        return sizeof(uint8_t) + sizeof(uint16_t);
+    }
+    if (nSize <= std::numeric_limits<uint32_t>::max()) {
+        return sizeof(uint8_t) + sizeof(uint32_t);
+    }
+
+    return sizeof(uint8_t) + sizeof(uint64_t);
 }
 
 inline void WriteCompactSize(CSizeComputer &os, uint64_t nSize);
 
 template <typename Stream> void WriteCompactSize(Stream &os, uint64_t nSize) {
     if (nSize < 253) {
         ser_writedata8(os, nSize);
-    } else if (nSize <= std::numeric_limits<unsigned short>::max()) {
+    } else if (nSize <= std::numeric_limits<uint16_t>::max()) {
         ser_writedata8(os, 253);
         ser_writedata16(os, nSize);
-    } else if (nSize <= std::numeric_limits<unsigned int>::max()) {
+    } else if (nSize <= std::numeric_limits<uint32_t>::max()) {
         ser_writedata8(os, 254);
         ser_writedata32(os, nSize);
     } else {
         ser_writedata8(os, 255);
         ser_writedata64(os, nSize);
     }
     return;
 }
 
 template <typename Stream> uint64_t ReadCompactSize(Stream &is) {
     uint8_t chSize = ser_readdata8(is);
     uint64_t nSizeRet = 0;
     if (chSize < 253) {
         nSizeRet = chSize;
     } else if (chSize == 253) {
         nSizeRet = ser_readdata16(is);
-        if (nSizeRet < 253)
+        if (nSizeRet < 253) {
             throw std::ios_base::failure("non-canonical ReadCompactSize()");
+        }
     } else if (chSize == 254) {
         nSizeRet = ser_readdata32(is);
-        if (nSizeRet < 0x10000u)
+        if (nSizeRet < 0x10000u) {
             throw std::ios_base::failure("non-canonical ReadCompactSize()");
+        }
     } else {
         nSizeRet = ser_readdata64(is);
-        if (nSizeRet < 0x100000000ULL)
+        if (nSizeRet < 0x100000000ULL) {
             throw std::ios_base::failure("non-canonical ReadCompactSize()");
+        }
     }
     if (nSizeRet > MAX_SIZE) {
         throw std::ios_base::failure("ReadCompactSize(): size too large");
     }
     return nSizeRet;
 }
 
 /**
  * Variable-length integers: bytes are a MSB base-128 encoding of the number.
  * The high bit in each byte signifies whether another digit follows. To make
  * sure the encoding is one-to-one, one is subtracted from all but the last
  * digit. Thus, the byte sequence a[] with length len, where all but the last
  * byte has bit 128 set, encodes the number:
  *
  *  (a[len-1] & 0x7F) + sum(i=1..len-1, 128^i*((a[len-i-1] & 0x7F)+1))
  *
  * Properties:
  * * Very small (0-127: 1 byte, 128-16511: 2 bytes, 16512-2113663: 3 bytes)
  * * Every integer has exactly one encoding
  * * Encoding does not depend on size of original integer type
  * * No redundancy: every (infinite) byte sequence corresponds to a list
  *   of encoded integers.
  *
  * 0:         [0x00]  256:        [0x81 0x00]
  * 1:         [0x01]  16383:      [0xFE 0x7F]
  * 127:       [0x7F]  16384:      [0xFF 0x00]
  * 128:  [0x80 0x00]  16511:      [0xFF 0x7F]
  * 255:  [0x80 0x7F]  65535: [0x82 0xFE 0x7F]
  * 2^32:           [0x8E 0xFE 0xFE 0xFF 0x00]
  */
 template <typename I> inline unsigned int GetSizeOfVarInt(I n) {
     int nRet = 0;
     while (true) {
         nRet++;
-        if (n <= 0x7F) break;
+        if (n <= 0x7F) {
+            return nRet;
+        }
         n = (n >> 7) - 1;
     }
-    return nRet;
 }
 
 template <typename I> inline void WriteVarInt(CSizeComputer &os, I n);
 
 template <typename Stream, typename I> void WriteVarInt(Stream &os, I n) {
     uint8_t tmp[(sizeof(n) * 8 + 6) / 7];
     int len = 0;
     while (true) {
         tmp[len] = (n & 0x7F) | (len ? 0x80 : 0x00);
-        if (n <= 0x7F) break;
+        if (n <= 0x7F) {
+            break;
+        }
         n = (n >> 7) - 1;
         len++;
     }
     do {
         ser_writedata8(os, tmp[len]);
     } while (len--);
 }
 
 template <typename Stream, typename I> I ReadVarInt(Stream &is) {
     I n = 0;
     while (true) {
         uint8_t chData = ser_readdata8(is);
         n = (n << 7) | (chData & 0x7F);
-        if (chData & 0x80)
-            n++;
-        else
+        if ((chData & 0x80) == 0) {
             return n;
+        }
+        n++;
     }
 }
 
 #define FLATDATA(obj)                                                          \
     REF(CFlatData((char *)&(obj), (char *)&(obj) + sizeof(obj)))
 #define VARINT(obj) REF(WrapVarInt(REF(obj)))
 #define COMPACTSIZE(obj) REF(CCompactSize(REF(obj)))
 #define LIMITED_STRING(obj, n) REF(LimitedString<n>(REF(obj)))
 
 /**
  * Wrapper for serializing arrays and POD.
  */
 class CFlatData {
 protected:
     char *pbegin;
     char *pend;
 
 public:
     CFlatData(void *pbeginIn, void *pendIn)
         : pbegin((char *)pbeginIn), pend((char *)pendIn) {}
     template <class T, class TAl> explicit CFlatData(std::vector<T, TAl> &v) {
         pbegin = (char *)v.data();
         pend = (char *)(v.data() + v.size());
     }
     template <unsigned int N, typename T, typename S, typename D>
     explicit CFlatData(prevector<N, T, S, D> &v) {
         pbegin = (char *)v.data();
         pend = (char *)(v.data() + v.size());
     }
     char *begin() { return pbegin; }
     const char *begin() const { return pbegin; }
     char *end() { return pend; }
     const char *end() const { return pend; }
 
     template <typename Stream> void Serialize(Stream &s) const {
         s.write(pbegin, pend - pbegin);
     }
 
     template <typename Stream> void Unserialize(Stream &s) {
         s.read(pbegin, pend - pbegin);
     }
 };
 
 template <typename I> class CVarInt {
 protected:
     I &n;
 
 public:
     CVarInt(I &nIn) : n(nIn) {}
 
     template <typename Stream> void Serialize(Stream &s) const {
         WriteVarInt<Stream, I>(s, n);
     }
 
     template <typename Stream> void Unserialize(Stream &s) {
         n = ReadVarInt<Stream, I>(s);
     }
 };
 
 class CCompactSize {
 protected:
     uint64_t &n;
 
 public:
     CCompactSize(uint64_t &nIn) : n(nIn) {}
 
     template <typename Stream> void Serialize(Stream &s) const {
         WriteCompactSize<Stream>(s, n);
     }
 
     template <typename Stream> void Unserialize(Stream &s) {
         n = ReadCompactSize<Stream>(s);
     }
 };
 
 template <size_t Limit> class LimitedString {
 protected:
     std::string &string;
 
 public:
     LimitedString(std::string &_string) : string(_string) {}
 
     template <typename Stream> void Unserialize(Stream &s) {
         size_t size = ReadCompactSize(s);
         if (size > Limit) {
             throw std::ios_base::failure("String length limit exceeded");
         }
         string.resize(size);
-        if (size != 0) s.read((char *)&string[0], size);
+        if (size != 0) {
+            s.read((char *)&string[0], size);
+        }
     }
 
     template <typename Stream> void Serialize(Stream &s) const {
         WriteCompactSize(s, string.size());
-        if (!string.empty()) s.write((char *)&string[0], string.size());
+        if (!string.empty()) {
+            s.write((char *)&string[0], string.size());
+        }
     }
 };
 
 template <typename I> CVarInt<I> WrapVarInt(I &n) {
     return CVarInt<I>(n);
 }
 
 /**
  * Forward declarations
  */
 
 /**
  *  string
  */
 template <typename Stream, typename C>
 void Serialize(Stream &os, const std::basic_string<C> &str);
 template <typename Stream, typename C>
 void Unserialize(Stream &is, std::basic_string<C> &str);
 
 /**
  * prevector
  * prevectors of uint8_t are a special case and are intended to be serialized as
  * a single opaque blob.
  */
 template <typename Stream, unsigned int N, typename T>
 void Serialize_impl(Stream &os, const prevector<N, T> &v, const uint8_t &);
 template <typename Stream, unsigned int N, typename T, typename V>
 void Serialize_impl(Stream &os, const prevector<N, T> &v, const V &);
 template <typename Stream, unsigned int N, typename T>
 inline void Serialize(Stream &os, const prevector<N, T> &v);
 template <typename Stream, unsigned int N, typename T>
 void Unserialize_impl(Stream &is, prevector<N, T> &v, const uint8_t &);
 template <typename Stream, unsigned int N, typename T, typename V>
 void Unserialize_impl(Stream &is, prevector<N, T> &v, const V &);
 template <typename Stream, unsigned int N, typename T>
 inline void Unserialize(Stream &is, prevector<N, T> &v);
 
 /**
  * vector
  * vectors of uint8_t are a special case and are intended to be serialized as a
  * single opaque blob.
  */
 template <typename Stream, typename T, typename A>
 void Serialize_impl(Stream &os, const std::vector<T, A> &v, const uint8_t &);
 template <typename Stream, typename T, typename A, typename V>
 void Serialize_impl(Stream &os, const std::vector<T, A> &v, const V &);
 template <typename Stream, typename T, typename A>
 inline void Serialize(Stream &os, const std::vector<T, A> &v);
 template <typename Stream, typename T, typename A>
 void Unserialize_impl(Stream &is, std::vector<T, A> &v, const uint8_t &);
 template <typename Stream, typename T, typename A, typename V>
 void Unserialize_impl(Stream &is, std::vector<T, A> &v, const V &);
 template <typename Stream, typename T, typename A>
 inline void Unserialize(Stream &is, std::vector<T, A> &v);
 
 /**
  * pair
  */
 template <typename Stream, typename K, typename T>
 void Serialize(Stream &os, const std::pair<K, T> &item);
 template <typename Stream, typename K, typename T>
 void Unserialize(Stream &is, std::pair<K, T> &item);
 
 /**
  * map
  */
 template <typename Stream, typename K, typename T, typename Pred, typename A>
 void Serialize(Stream &os, const std::map<K, T, Pred, A> &m);
 template <typename Stream, typename K, typename T, typename Pred, typename A>
 void Unserialize(Stream &is, std::map<K, T, Pred, A> &m);
 
 /**
  * set
  */
 template <typename Stream, typename K, typename Pred, typename A>
 void Serialize(Stream &os, const std::set<K, Pred, A> &m);
 template <typename Stream, typename K, typename Pred, typename A>
 void Unserialize(Stream &is, std::set<K, Pred, A> &m);
 
 /**
  * shared_ptr
  */
 template <typename Stream, typename T>
 void Serialize(Stream &os, const std::shared_ptr<const T> &p);
 template <typename Stream, typename T>
 void Unserialize(Stream &os, std::shared_ptr<const T> &p);
 
 /**
  * unique_ptr
  */
 template <typename Stream, typename T>
 void Serialize(Stream &os, const std::unique_ptr<const T> &p);
 template <typename Stream, typename T>
 void Unserialize(Stream &os, std::unique_ptr<const T> &p);
 
 /**
  * If none of the specialized versions above matched, default to calling member
  * function.
  */
 template <typename Stream, typename T>
 inline void Serialize(Stream &os, const T &a) {
     a.Serialize(os);
 }
 
 template <typename Stream, typename T>
 inline void Unserialize(Stream &is, T &a) {
     a.Unserialize(is);
 }
 
 /**
  * string
  */
 template <typename Stream, typename C>
 void Serialize(Stream &os, const std::basic_string<C> &str) {
     WriteCompactSize(os, str.size());
-    if (!str.empty()) os.write((char *)&str[0], str.size() * sizeof(str[0]));
+    if (!str.empty()) {
+        os.write((char *)&str[0], str.size() * sizeof(str[0]));
+    }
 }
 
 template <typename Stream, typename C>
 void Unserialize(Stream &is, std::basic_string<C> &str) {
-    unsigned int nSize = ReadCompactSize(is);
+    size_t nSize = ReadCompactSize(is);
     str.resize(nSize);
-    if (nSize != 0) is.read((char *)&str[0], nSize * sizeof(str[0]));
+    if (nSize != 0) {
+        is.read((char *)&str[0], nSize * sizeof(str[0]));
+    }
 }
 
 /**
  * prevector
  */
 template <typename Stream, unsigned int N, typename T>
 void Serialize_impl(Stream &os, const prevector<N, T> &v, const uint8_t &) {
     WriteCompactSize(os, v.size());
-    if (!v.empty()) os.write((char *)&v[0], v.size() * sizeof(T));
+    if (!v.empty()) {
+        os.write((char *)&v[0], v.size() * sizeof(T));
+    }
 }
 
 template <typename Stream, unsigned int N, typename T, typename V>
 void Serialize_impl(Stream &os, const prevector<N, T> &v, const V &) {
     WriteCompactSize(os, v.size());
-    for (typename prevector<N, T>::const_iterator vi = v.begin(); vi != v.end();
-         ++vi)
-        ::Serialize(os, (*vi));
+    for (const T &i : v) {
+        ::Serialize(os, i);
+    }
 }
 
 template <typename Stream, unsigned int N, typename T>
 inline void Serialize(Stream &os, const prevector<N, T> &v) {
     Serialize_impl(os, v, T());
 }
 
 template <typename Stream, unsigned int N, typename T>
 void Unserialize_impl(Stream &is, prevector<N, T> &v, const uint8_t &) {
     // Limit size per read so bogus size value won't cause out of memory
     v.clear();
-    unsigned int nSize = ReadCompactSize(is);
-    unsigned int i = 0;
+    size_t nSize = ReadCompactSize(is);
+    size_t i = 0;
     while (i < nSize) {
-        unsigned int blk =
-            std::min(nSize - i, (unsigned int)(1 + 4999999 / sizeof(T)));
+        size_t blk = std::min(nSize - i, size_t(1 + 4999999 / sizeof(T)));
         v.resize(i + blk);
         is.read((char *)&v[i], blk * sizeof(T));
         i += blk;
     }
 }
 
 template <typename Stream, unsigned int N, typename T, typename V>
 void Unserialize_impl(Stream &is, prevector<N, T> &v, const V &) {
     v.clear();
-    unsigned int nSize = ReadCompactSize(is);
-    unsigned int i = 0;
-    unsigned int nMid = 0;
+    size_t nSize = ReadCompactSize(is);
+    size_t i = 0;
+    size_t nMid = 0;
     while (nMid < nSize) {
         nMid += 5000000 / sizeof(T);
-        if (nMid > nSize) nMid = nSize;
+        if (nMid > nSize) {
+            nMid = nSize;
+        }
         v.resize(nMid);
-        for (; i < nMid; i++)
+        for (; i < nMid; i++) {
             Unserialize(is, v[i]);
+        }
     }
 }
 
 template <typename Stream, unsigned int N, typename T>
 inline void Unserialize(Stream &is, prevector<N, T> &v) {
     Unserialize_impl(is, v, T());
 }
 
 /**
  * vector
  */
 template <typename Stream, typename T, typename A>
 void Serialize_impl(Stream &os, const std::vector<T, A> &v, const uint8_t &) {
     WriteCompactSize(os, v.size());
-    if (!v.empty()) os.write((char *)&v[0], v.size() * sizeof(T));
+    if (!v.empty()) {
+        os.write((char *)&v[0], v.size() * sizeof(T));
+    }
 }
 
 template <typename Stream, typename T, typename A, typename V>
 void Serialize_impl(Stream &os, const std::vector<T, A> &v, const V &) {
     WriteCompactSize(os, v.size());
-    for (typename std::vector<T, A>::const_iterator vi = v.begin();
-         vi != v.end(); ++vi)
-        ::Serialize(os, (*vi));
+    for (const T &i : v) {
+        ::Serialize(os, i);
+    }
 }
 
 template <typename Stream, typename T, typename A>
 inline void Serialize(Stream &os, const std::vector<T, A> &v) {
     Serialize_impl(os, v, T());
 }
 
 template <typename Stream, typename T, typename A>
 void Unserialize_impl(Stream &is, std::vector<T, A> &v, const uint8_t &) {
     // Limit size per read so bogus size value won't cause out of memory
     v.clear();
-    unsigned int nSize = ReadCompactSize(is);
-    unsigned int i = 0;
+    size_t nSize = ReadCompactSize(is);
+    size_t i = 0;
     while (i < nSize) {
-        unsigned int blk =
-            std::min(nSize - i, (unsigned int)(1 + 4999999 / sizeof(T)));
+        size_t blk = std::min(nSize - i, size_t(1 + 4999999 / sizeof(T)));
         v.resize(i + blk);
         is.read((char *)&v[i], blk * sizeof(T));
         i += blk;
     }
 }
 
 template <typename Stream, typename T, typename A, typename V>
 void Unserialize_impl(Stream &is, std::vector<T, A> &v, const V &) {
     v.clear();
-    unsigned int nSize = ReadCompactSize(is);
-    unsigned int i = 0;
-    unsigned int nMid = 0;
+    size_t nSize = ReadCompactSize(is);
+    size_t i = 0;
+    size_t nMid = 0;
     while (nMid < nSize) {
         nMid += 5000000 / sizeof(T);
-        if (nMid > nSize) nMid = nSize;
+        if (nMid > nSize) {
+            nMid = nSize;
+        }
         v.resize(nMid);
-        for (; i < nMid; i++)
+        for (; i < nMid; i++) {
             Unserialize(is, v[i]);
+        }
     }
 }
 
 template <typename Stream, typename T, typename A>
 inline void Unserialize(Stream &is, std::vector<T, A> &v) {
     Unserialize_impl(is, v, T());
 }
 
 /**
  * pair
  */
 template <typename Stream, typename K, typename T>
 void Serialize(Stream &os, const std::pair<K, T> &item) {
     Serialize(os, item.first);
     Serialize(os, item.second);
 }
 
 template <typename Stream, typename K, typename T>
 void Unserialize(Stream &is, std::pair<K, T> &item) {
     Unserialize(is, item.first);
     Unserialize(is, item.second);
 }
 
 /**
  * map
  */
 template <typename Stream, typename K, typename T, typename Pred, typename A>
 void Serialize(Stream &os, const std::map<K, T, Pred, A> &m) {
     WriteCompactSize(os, m.size());
-    for (typename std::map<K, T, Pred, A>::const_iterator mi = m.begin();
-         mi != m.end(); ++mi)
-        Serialize(os, (*mi));
+    for (const std::pair<K, T> &p : m) {
+        Serialize(os, p);
+    }
 }
 
 template <typename Stream, typename K, typename T, typename Pred, typename A>
 void Unserialize(Stream &is, std::map<K, T, Pred, A> &m) {
     m.clear();
-    unsigned int nSize = ReadCompactSize(is);
+    size_t nSize = ReadCompactSize(is);
     typename std::map<K, T, Pred, A>::iterator mi = m.begin();
-    for (unsigned int i = 0; i < nSize; i++) {
+    for (size_t i = 0; i < nSize; i++) {
         std::pair<K, T> item;
         Unserialize(is, item);
         mi = m.insert(mi, item);
     }
 }
 
 /**
  * set
  */
 template <typename Stream, typename K, typename Pred, typename A>
 void Serialize(Stream &os, const std::set<K, Pred, A> &m) {
     WriteCompactSize(os, m.size());
-    for (typename std::set<K, Pred, A>::const_iterator it = m.begin();
-         it != m.end(); ++it)
-        Serialize(os, (*it));
+    for (const K &i : m) {
+        Serialize(os, i);
+    }
 }
 
 template <typename Stream, typename K, typename Pred, typename A>
 void Unserialize(Stream &is, std::set<K, Pred, A> &m) {
     m.clear();
-    unsigned int nSize = ReadCompactSize(is);
+    size_t nSize = ReadCompactSize(is);
     typename std::set<K, Pred, A>::iterator it = m.begin();
-    for (unsigned int i = 0; i < nSize; i++) {
+    for (size_t i = 0; i < nSize; i++) {
         K key;
         Unserialize(is, key);
         it = m.insert(it, key);
     }
 }
 
 /**
  * unique_ptr
  */
 template <typename Stream, typename T>
 void Serialize(Stream &os, const std::unique_ptr<const T> &p) {
     Serialize(os, *p);
 }
 
 template <typename Stream, typename T>
 void Unserialize(Stream &is, std::unique_ptr<const T> &p) {
     p.reset(new T(deserialize, is));
 }
 
 /**
  * shared_ptr
  */
 template <typename Stream, typename T>
 void Serialize(Stream &os, const std::shared_ptr<const T> &p) {
     Serialize(os, *p);
 }
 
 template <typename Stream, typename T>
 void Unserialize(Stream &is, std::shared_ptr<const T> &p) {
     p = std::make_shared<const T>(deserialize, is);
 }
 
 /**
  * Support for ADD_SERIALIZE_METHODS and READWRITE macro
  */
 struct CSerActionSerialize {
     constexpr bool ForRead() const { return false; }
 };
 struct CSerActionUnserialize {
     constexpr bool ForRead() const { return true; }
 };
 
 template <typename Stream, typename T>
 inline void SerReadWrite(Stream &s, const T &obj,
                          CSerActionSerialize ser_action) {
     ::Serialize(s, obj);
 }
 
 template <typename Stream, typename T>
 inline void SerReadWrite(Stream &s, T &obj, CSerActionUnserialize ser_action) {
     ::Unserialize(s, obj);
 }
 
 /**
  * ::GetSerializeSize implementations
  *
  * Computing the serialized size of objects is done through a special stream
  * object of type CSizeComputer, which only records the number of bytes written
  * to it.
  *
  * If your Serialize or SerializationOp method has non-trivial overhead for
  * serialization, it may be worthwhile to implement a specialized version for
  * CSizeComputer, which uses the s.seek() method to record bytes that would
  * be written instead.
  */
 class CSizeComputer {
 protected:
     size_t nSize;
 
     const int nType;
     const int nVersion;
 
 public:
     CSizeComputer(int nTypeIn, int nVersionIn)
         : nSize(0), nType(nTypeIn), nVersion(nVersionIn) {}
 
     void write(const char *psz, size_t _nSize) { this->nSize += _nSize; }
 
     /** Pretend _nSize bytes are written, without specifying them. */
     void seek(size_t _nSize) { this->nSize += _nSize; }
 
     template <typename T> CSizeComputer &operator<<(const T &obj) {
         ::Serialize(*this, obj);
         return (*this);
     }
 
     size_t size() const { return nSize; }
 
     int GetVersion() const { return nVersion; }
     int GetType() const { return nType; }
 };
 
 template <typename Stream> void SerializeMany(Stream &s) {}
 
 template <typename Stream, typename Arg>
 void SerializeMany(Stream &s, Arg &&arg) {
     ::Serialize(s, std::forward<Arg>(arg));
 }
 
 template <typename Stream, typename Arg, typename... Args>
 void SerializeMany(Stream &s, Arg &&arg, Args &&... args) {
     ::Serialize(s, std::forward<Arg>(arg));
     ::SerializeMany(s, std::forward<Args>(args)...);
 }
 
 template <typename Stream> inline void UnserializeMany(Stream &s) {}
 
 template <typename Stream, typename Arg>
 inline void UnserializeMany(Stream &s, Arg &arg) {
     ::Unserialize(s, arg);
 }
 
 template <typename Stream, typename Arg, typename... Args>
 inline void UnserializeMany(Stream &s, Arg &arg, Args &... args) {
     ::Unserialize(s, arg);
     ::UnserializeMany(s, args...);
 }
 
 template <typename Stream, typename... Args>
 inline void SerReadWriteMany(Stream &s, CSerActionSerialize ser_action,
                              Args &&... args) {
     ::SerializeMany(s, std::forward<Args>(args)...);
 }
 
 template <typename Stream, typename... Args>
 inline void SerReadWriteMany(Stream &s, CSerActionUnserialize ser_action,
                              Args &... args) {
     ::UnserializeMany(s, args...);
 }
 
 template <typename I> inline void WriteVarInt(CSizeComputer &s, I n) {
     s.seek(GetSizeOfVarInt<I>(n));
 }
 
 inline void WriteCompactSize(CSizeComputer &s, uint64_t nSize) {
     s.seek(GetSizeOfCompactSize(nSize));
 }
 
 template <typename T>
 size_t GetSerializeSize(const T &t, int nType, int nVersion = 0) {
     return (CSizeComputer(nType, nVersion) << t).size();
 }
 
 template <typename S, typename T>
 size_t GetSerializeSize(const S &s, const T &t) {
     return (CSizeComputer(s.GetType(), s.GetVersion()) << t).size();
 }
 
 #endif // BITCOIN_SERIALIZE_H