Function DecodeBase58

src/scripts/bitcoin_base58.cpp:21–70

    static const char* pszBase58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";

    bool DecodeBase58(const char* psz, std::vector<unsigned char>& vch)
    {
        // Skip leading spaces.
        while (*psz && isspace(*psz))
            psz++;
        // Skip and count leading '1's.
        size_t zeroes = 0;
        size_t length = 0;
        while (*psz == '1') {
            zeroes++;
            psz++;
        }
        // Allocate enough space in big-endian base256 representation.
        size_t size = strlen(psz) * 733 /1000 + 1; // log(58) / log(256), rounded up.
        std::vector<unsigned char> b256(size);
        // Process the characters.
        while (*psz && !isspace(*psz)) {
            // Decode base58 character
            const char* ch = strchr(pszBase58, *psz);
            if (ch == nullptr)
                return false;
            // Apply "b256 = b256 * 58 + ch".
            auto carry = ch - pszBase58;
            size_t i = 0;
            for (std::vector<unsigned char>::reverse_iterator it = b256.rbegin(); (carry != 0 || i < length) && (it != b256.rend()); ++it, ++i) {
                carry += 58 * (*it);
                *it = static_cast<unsigned char>(carry % 256);
                carry /= 256;
            }
            assert(carry == 0);
            length = i;
            psz++;
        }
        // Skip trailing spaces.
        while (isspace(*psz))
            psz++;
        if (*psz != 0)
            return false;
        // Skip leading zeroes in b256.
        auto it = b256.begin();
        std::advance(it, static_cast<int64_t>(size - length));
        while (it != b256.end() && *it == 0)
            ++it;
        // Copy result into output vector.
        vch.reserve(zeroes + static_cast<size_t>(std::distance(it, b256.end())));
        vch.assign(zeroes, 0x00);
        while (it != b256.end())
            vch.push_back(*(it++));
        return true;
    }

    std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend)
    {