libddwaf-src 2.1.0

Source distribution and build integration for DataDog/libddwaf
Documentation 
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// Unless explicitly stated otherwise all files in this repository are
// dual-licensed under the Apache-2.0 License or BSD-3-Clause License.
//
// This product includes software developed at Datadog (https://www.datadoghq.com/).
// Copyright 2025 Datadog, Inc.

#include <algorithm>
#include <charconv>
#include <cstddef>
#include <cstdint>
#include <span>
#include <sstream>
#include <string>
#include <string_view>
#include <system_error>
#include <utility>
#include <variant>
#include <vector>

#include <fmt/format.h>

#include "utils.hpp"

namespace ddwaf {
namespace {

template <typename T>
concept has_from_chars = requires(T v) { std::from_chars(nullptr, nullptr, v); };

static_assert(has_from_chars<int64_t>);

} // namespace

std::vector<std::string_view> split(std::string_view str, char sep)
{
    std::vector<std::string_view> components;

    std::size_t start = 0;
    while (start < str.size()) {
        const std::size_t end = str.find(sep, start);

        if (end == start) {
            // Ignore zero-sized strings
            start = end + 1;
            continue;
        }

        if (end == std::string_view::npos) {
            // Last element
            components.emplace_back(str.substr(start));
            start = str.size();
        } else {
            components.emplace_back(str.substr(start, end - start));
            start = end + 1;
        }
    }

    return components;
}

std::vector<std::variant<std::string_view, int64_t>> convert_key_path(
    std::span<const std::variant<std::string, int64_t>> key_path)
{
    std::vector<std::variant<std::string_view, int64_t>> result;
    result.reserve(key_path.size());

    for (const auto &key : key_path) {
        std::visit([&result](auto &&k) { result.emplace_back(k); }, key);
    }
    return result;
}

bool string_iequals(std::string_view left, std::string_view right)
{
    return left.size() == right.size() &&
           std::equal(left.begin(), left.end(), right.begin(),
               [](char l, char r) { return tolower(l) == tolower(r); });
}

template <typename T> std::string to_string(T value) { return ddwaf::fmt::format("{}", value); }

template <typename T> std::pair<bool, T> from_string(std::string_view str)
{
    T result;
    if constexpr (has_from_chars<T>) {
        const auto *end = str.data() + str.size();
        auto [endConv, err] = std::from_chars(str.data(), end, result);
        if (err == std::errc{} && endConv == end) {
            return {true, result};
        }
    } else {
        // NOLINTNEXTLINE(misc-const-correctness)
        std::istringstream iss(std::string{str});
        iss >> result;
        if (!iss.fail() && iss.eof()) {
            return {true, result};
        }
    }

    return {false, {}};
}

template std::string to_string<bool>(bool value);
template std::string to_string<int64_t>(int64_t value);
template std::string to_string<uint64_t>(uint64_t value);
template std::string to_string<unsigned>(unsigned value);
template std::string to_string<double>(double value);

template std::pair<bool, uint16_t> from_string<uint16_t>(std::string_view str);
template std::pair<bool, unsigned> from_string<unsigned>(std::string_view str);
template std::pair<bool, int64_t> from_string<int64_t>(std::string_view str);
template std::pair<bool, uint64_t> from_string<uint64_t>(std::string_view str);
template std::pair<bool, double> from_string<double>(std::string_view str);

} // namespace ddwaf