shortener-bot/DPP/include/dpp/bignum.h

102 lines
3.4 KiB
C++

/************************************************************************************
*
* D++, A Lightweight C++ library for Discord
*
* SPDX-License-Identifier: Apache-2.0
* Copyright 2021 Craig Edwards and D++ contributors
* (https://github.com/brainboxdotcc/DPP/graphs/contributors)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
************************************************************************************/
#pragma once
#include <dpp/export.h>
#include <dpp/snowflake.h>
#include <memory>
namespace dpp {
/**
* @brief This contains the OpenSSL structs. It is not public,
* so that the public interface doesn't depend on OpenSSL directly.
*/
struct openssl_bignum;
/**
* @brief An arbitrary length integer number.
* Officially, the Discord documentation says that permission values can be any arbitrary
* number of digits. At time of writing there are only 50 bits of permissions, but this is
* set to grow larger and potentially past 64 bits. They will continue to send this data
* as a huge single integer at that point, because this is obviously sensible. /s
*
* @note dpp::bignumber uses OpenSSL BN_* under the hood, as we include openssl anyway
* for HTTPS.
*/
class DPP_EXPORT bignumber {
/**
* @brief Internal opaque struct to contain OpenSSL things
*/
std::shared_ptr<openssl_bignum> ssl_bn{nullptr};
public:
/**
* @brief Construct a new bignumber object
*/
bignumber() = default;
/**
* @brief Parse a std::string of an arbitrary length number into
* a bignumber.
* @param number_string string representation of a number. The
* number must be an integer, and can be positive or negative.
* @note Prefixing number_string with 0x will parse it as hexadecimal.
* This is not case sensitive.
*/
bignumber(const std::string& number_string);
/**
* @brief Build a bignumber from a vector of 64 bit values.
* The values are accepted in "reverse order", so the first vector
* entry at index 0 is the leftmost 64 bits of the bignum.
* The vector can be any arbitrary length.
* @param bits Vector of 64 bit values which represent the number
*/
bignumber(std::vector<uint64_t> bits);
/**
* @brief Default destructor
*/
~bignumber() = default;
/**
* @brief Get the string representation of the bignumber.
* @param hex If false (the default) the number is returned in
* decimal, else if this parameter is true, it will be returned
* as hex (without leading '0x')
* @return String representation of bignumber
*/
[[nodiscard]] std::string get_number(bool hex = false) const;
/**
* @brief Get the array of 64 bit values that represents the
* bignumber. This is what we should use to store bignumbers
* in memory, not this bignumber class itself, as the bignumber
* class instantiates OpenSSL structs and takes significantly
* more ram than just a vector.
* @return Vector of 64 bit values representing the bignumber
*/
[[nodiscard]] std::vector<uint64_t> get_binary() const;
};
}