fuzz coverage

// Copyright (c) 2019-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.

#include <util/string.h>

#include <regex>

#include <string>

namespace util {

void ReplaceAll(std::string& in_out, const std::string& search, const std::string& substitute)

{

    if (search.empty()) return;

    in_out = std::regex_replace(in_out, std::regex(search), substitute);

}

LineReader::LineReader(std::span<const std::byte> buffer, size_t max_line_length)

    : start(buffer.begin()), end(buffer.end()), max_line_length(max_line_length), it(buffer.begin()) {}

std::optional<std::string> LineReader::ReadLine()

{

    if (it == end) {

        return std::nullopt;

    }

    auto line_start = it;

    size_t count = 0;

    while (it != end) {

        // Read a character from the incoming buffer and increment the iterator

        auto c = static_cast<char>(*it);

        ++it;

        ++count;

        // If the character we just consumed was \n, the line is terminated.

        // The \n itself does not count against max_line_length.

        if (c == '\n') {

            const std::string_view untrimmed_line(reinterpret_cast<const char*>(std::to_address(line_start)), count);

            const std::string_view line = TrimStringView(untrimmed_line); // delete leading and trailing whitespace including \r and \n

            return std::string(line);

        }

        // If the character we just consumed gives us a line length greater

        // than max_line_length, and we are not at the end of the line (or buffer) yet,

        // that means the line we are currently reading is too long, and we throw.

        if (count > max_line_length) {

            // Reset iterator

            it = line_start;

            throw std::runtime_error("max_line_length exceeded by LineReader");

        }

    }

    // End of buffer reached without finding a \n or exceeding max_line_length.

    // Reset the iterator so the rest of the buffer can be read granularly

    // with ReadLength() and return null to indicate a line was not found.

    it = line_start;

    return std::nullopt;

}

// Ignores max_line_length but won't overflow

std::string LineReader::ReadLength(size_t len)

{

    if (len == 0) return "";

    if (Remaining() < len) throw std::runtime_error("Not enough data in buffer");

    std::string out(reinterpret_cast<const char*>(std::to_address(it)), len);

    it += len;

    return out;

}

size_t LineReader::Remaining() const

{

    return std::distance(it, end);

}

} // namespace util