refactor: Use reinterpret_cast where appropriate

Also, wrap reinterpret_cast into a CharCast to ensure it is only called
on byte pointers.

Author: MarcoFalke

Diff for: src/dbwrapper.h

@@ -54,6 +54,8 @@ struct DBParams {
     DBOptions options{};
 };
 
+inline auto CharCast(const std::byte* data) { return reinterpret_cast<const char*>(data); }
+
 class dbwrapper_error : public std::runtime_error
 {
 public:
@@ -113,12 +115,12 @@ class CDBBatch
     {
         ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
         ssKey << key;
-        leveldb::Slice slKey((const char*)ssKey.data(), ssKey.size());
+        leveldb::Slice slKey(CharCast(ssKey.data()), ssKey.size());
 
         ssValue.reserve(DBWRAPPER_PREALLOC_VALUE_SIZE);
         ssValue << value;
         ssValue.Xor(dbwrapper_private::GetObfuscateKey(parent));
-        leveldb::Slice slValue((const char*)ssValue.data(), ssValue.size());
+        leveldb::Slice slValue(CharCast(ssValue.data()), ssValue.size());
 
         batch.Put(slKey, slValue);
         // LevelDB serializes writes as:
@@ -138,7 +140,7 @@ class CDBBatch
     {
         ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
         ssKey << key;
-        leveldb::Slice slKey((const char*)ssKey.data(), ssKey.size());
+        leveldb::Slice slKey(CharCast(ssKey.data()), ssKey.size());
 
         batch.Delete(slKey);
         // LevelDB serializes erases as:
@@ -177,7 +179,7 @@ class CDBIterator
         DataStream ssKey{};
         ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
         ssKey << key;
-        leveldb::Slice slKey((const char*)ssKey.data(), ssKey.size());
+        leveldb::Slice slKey(CharCast(ssKey.data()), ssKey.size());
         piter->Seek(slKey);
     }
 
@@ -265,7 +267,7 @@ class CDBWrapper
         DataStream ssKey{};
         ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
         ssKey << key;
-        leveldb::Slice slKey((const char*)ssKey.data(), ssKey.size());
+        leveldb::Slice slKey(CharCast(ssKey.data()), ssKey.size());
 
         std::string strValue;
         leveldb::Status status = pdb->Get(readoptions, slKey, &strValue);
@@ -307,7 +309,7 @@ class CDBWrapper
         DataStream ssKey{};
         ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
         ssKey << key;
-        leveldb::Slice slKey((const char*)ssKey.data(), ssKey.size());
+        leveldb::Slice slKey(CharCast(ssKey.data()), ssKey.size());
 
         std::string strValue;
         leveldb::Status status = pdb->Get(readoptions, slKey, &strValue);
@@ -351,8 +353,8 @@ class CDBWrapper
         ssKey2.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
         ssKey1 << key_begin;
         ssKey2 << key_end;
-        leveldb::Slice slKey1((const char*)ssKey1.data(), ssKey1.size());
-        leveldb::Slice slKey2((const char*)ssKey2.data(), ssKey2.size());
+        leveldb::Slice slKey1(CharCast(ssKey1.data()), ssKey1.size());
+        leveldb::Slice slKey2(CharCast(ssKey2.data()), ssKey2.size());
         uint64_t size = 0;
         leveldb::Range range(slKey1, slKey2);
         pdb->GetApproximateSizes(&range, 1, &size);

Diff for: src/span.h

@@ -5,10 +5,10 @@
 #ifndef BITCOIN_SPAN_H
 #define BITCOIN_SPAN_H
 
-#include <type_traits>
-#include <cstddef>
 #include <algorithm>
-#include <assert.h>
+#include <cassert>
+#include <cstddef>
+#include <type_traits>
 
 #ifdef DEBUG
 #define CONSTEXPR_IF_NOT_DEBUG
@@ -267,9 +267,9 @@ Span<std::byte> MakeWritableByteSpan(V&& v) noexcept
 }
 
 // Helper functions to safely cast to unsigned char pointers.
-inline unsigned char* UCharCast(char* c) { return (unsigned char*)c; }
+inline unsigned char* UCharCast(char* c) { return reinterpret_cast<unsigned char*>(c); }
 inline unsigned char* UCharCast(unsigned char* c) { return c; }
-inline unsigned char* UCharCast(std::byte* c) { return (unsigned char*)c; }
+inline unsigned char* UCharCast(std::byte* c) { return reinterpret_cast<unsigned char*>(c); }
 inline const unsigned char* UCharCast(const char* c) { return reinterpret_cast<const unsigned char*>(c); }
 inline const unsigned char* UCharCast(const unsigned char* c) { return c; }
 inline const unsigned char* UCharCast(const std::byte* c) { return reinterpret_cast<const unsigned char*>(c); }