doc/html/hex__base_8h_source.html

 // Copyright (c) 2009-present 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_CRYPTO_HEX_BASE_H
 #define BITCOIN_CRYPTO_HEX_BASE_H

 #include <span.h>

 #include <cstddef>
 #include <cstdint>
 #include <string>

 std::string HexStr(const Span<const uint8_t> s);
 inline std::string HexStr(const Span<const char> s) { return HexStr(MakeUCharSpan(s)); }
 inline std::string HexStr(const Span<const std::byte> s) { return HexStr(MakeUCharSpan(s)); }

 signed char HexDigit(char c);

 #endif // BITCOIN_CRYPTO_HEX_BASE_H
span.h

HexDigit
signed char HexDigit(char c)
Definition: hex_base.cpp:63

MakeUCharSpan
constexpr auto MakeUCharSpan(V &&v) -> decltype(UCharSpanCast(Span
Like the Span constructor, but for (const) unsigned char member types only.
Definition: span.h:304

Span
A Span is an object that can refer to a contiguous sequence of objects.
Definition: solver.h:20

HexStr
std::string HexStr(const Span< const uint8_t > s)
Convert a span of bytes to a lower-case hexadecimal string.
Definition: hex_base.cpp:29