refactor: modernize the implementation of uint256.*

- Constructors of uint256 to utilize Span instead of requiring a std::vector
- converts m_data into a std::array
- Prefers using `WIDTH` instead of `sizeof(m_data)`
- make all the things constexpr
- replace C style functions with c++ equivalents
    - memset -> std::fill
    - memcpy -> std::copy
        Note: In practice, implementations of std::copy avoid multiple assignments and use bulk copy functions such as std::memmove if the value type is TriviallyCopyable and the iterator types satisfy LegacyContiguousIterator. (https://en.cppreference.com/w/cpp/algorithm/copy)
    - memcmp -> std::memcmp

1 files changed, 2 insertions, 13 deletions

diff --git a/src/uint256.cpp b/src/uint256.cpp
index cd9cbb566a..7f81c3c448 100644
--- a/src/uint256.cpp
+++ b/src/uint256.cpp
@@ -7,15 +7,6 @@
 
 #include <util/strencodings.h>
 
-#include <string.h>
-
-template <unsigned int BITS>
-base_blob<BITS>::base_blob(const std::vector<unsigned char>& vch)
-{
-    assert(vch.size() == sizeof(m_data));
-    memcpy(m_data, vch.data(), sizeof(m_data));
-}
-
 template <unsigned int BITS>
 std::string base_blob<BITS>::GetHex() const
 {
@@ -29,7 +20,7 @@ std::string base_blob<BITS>::GetHex() const
 template <unsigned int BITS>
 void base_blob<BITS>::SetHex(const char* psz)
 {
-    memset(m_data, 0, sizeof(m_data));
+    std::fill(m_data.begin(), m_data.end(), 0);
 
     // skip leading spaces
     while (IsSpace(*psz))
@@ -43,7 +34,7 @@ void base_blob<BITS>::SetHex(const char* psz)
     size_t digits = 0;
     while (::HexDigit(psz[digits]) != -1)
         digits++;
-    unsigned char* p1 = (unsigned char*)m_data;
+    unsigned char* p1 = m_data.data();
     unsigned char* pend = p1 + WIDTH;
     while (digits > 0 && p1 < pend) {
         *p1 = ::HexDigit(psz[--digits]);
@@ -67,14 +58,12 @@ std::string base_blob<BITS>::ToString() const
 }
 
 // Explicit instantiations for base_blob<160>
-template base_blob<160>::base_blob(const std::vector<unsigned char>&);
 template std::string base_blob<160>::GetHex() const;
 template std::string base_blob<160>::ToString() const;
 template void base_blob<160>::SetHex(const char*);
 template void base_blob<160>::SetHex(const std::string&);
 
 // Explicit instantiations for base_blob<256>
-template base_blob<256>::base_blob(const std::vector<unsigned char>&);
 template std::string base_blob<256>::GetHex() const;
 template std::string base_blob<256>::ToString() const;
 template void base_blob<256>::SetHex(const char*);