Support IDA/x64Dbg style signatures in FindSignature

[Nukoooo]

Currently the FindSignature only supports the old-fashion \x2A as a wildcard. However, if a signature is outdated after an update, finding it in an old binary will need to remove all \ and replace 2A with ? and that will be tedious if there are a lot of outdated signature IMO.

Since most signature-maker plugins like A200K/IDA-Pro-SigMaker and senator715/IDA-Fusion generate either IDA style (48 89 1D ? ? ? ?) or code stlye (\x48\x89\x1D\x00\x00\x00\x00) with bitmask provided, to make compatible with current signature style will require to generate code style signature and replace \x00 with \x2A or modify the plugin so it will generate signatures with \x2A as wildcard, and both are a no-go IMO.

I can make a pr if needed, please let me know :)

[Nukoooo]

The solution I have is this (requires C++20 due to the usage of std::ranges::split), it can potentially get rid of std::optional and use -1 for wildcard with type int16_t instead

std::optional<uint8_t> HexCharToByte(char c) noexcept
{
    if (c >= '0' && c <= '9')
        return c - '0';
    if (c >= 'A' && c <= 'F')
        return c - 'A' + 10;
    if (c >= 'a' && c <= 'f')
        return c - 'a' + 10;

    return std::nullopt;
}

std::vector<std::optional<uint8_t>> ConvertToByteArray(std::string_view byteStr) {
    if (byteStr.empty()) {
        return {};
    }

    std::vector<std::optional<uint8_t>> result{};

    const bool isCodeStyle = byteStr[0] == '\\';

    const std::string_view pattern = isCodeStyle ? R"(\x)" : " ";
    const std::string_view wildcard = isCodeStyle ? "2A" : "?";

    auto split = std::views::split(byteStr, pattern);

    for (auto&& str : split) {
        
        if (str.empty()) {
            continue;
        }

        // std::string_view(std::subrange) constructor only exists in C++23 or above
        const std::string_view byte(str.begin(), str.end());
        
        if (byte == wildcard) {
            result.emplace_back(std::nullopt);
            continue;
        }
        
        auto high = HexCharToByte(byte[0]);
        auto low = HexCharToByte(byte[1]);

        // if then is malformed, return nothing
        // maybe print error message here?
        if (!high.has_value() || !low.has_value()) [[unlikely]] {
            return {};
        }

        result.emplace_back((high.value() << 4) | low.value());
    }

    return result;
}

[roflmuffin]

Closed by #407, thanks for the contribution 🧡