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 2021 Datadog, Inc.

#include <cstddef>
#include <memory>
#include <string>
#include <string_view>
#include <utility>

#include "configuration/common/parser_exception.hpp"
#include "dynamic_string.hpp"
#include "matcher/regex_match.hpp"
#include "re2.h"

namespace ddwaf::matcher {

regex_match::regex_match(const std::string &regex_str, std::size_t minLength, bool case_sensitive)
    : min_length(minLength)
{
    constexpr unsigned regex_max_mem = 512 * 1024;

    re2::RE2::Options options;
    options.set_max_mem(regex_max_mem);
    options.set_log_errors(false);
    options.set_case_sensitive(case_sensitive);

    regex = std::make_unique<re2::RE2>(regex_str, options);

    if (!regex->ok()) {
        throw parsing_error("invalid regular expression: " + regex->error_arg());
    }
}

std::pair<bool, dynamic_string> regex_match::match_impl(std::string_view pattern) const
{
    if (pattern.size() < min_length || pattern.empty()) {
        return {false, {}};
    }

    std::string_view match;
    if (!regex->Match(pattern, 0, pattern.size(), RE2::UNANCHORED, &match, 1)) {
        return {false, {}};
    }

    return {true, match};
}

} // namespace ddwaf::matcher