inspircd/include/stringutils.h

/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2013, 2018 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2013 Daniel Vassdal <shutter@canternet.org>
 *   Copyright (C) 2013 Attila Molnar <attilamolnar@hush.com>
 *   Copyright (C) 2012 Robby <robby@chatbelgie.be>
 *   Copyright (C) 2010 Daniel De Graaf <danieldg@inspircd.org>
 *   Copyright (C) 2008 Robin Burchell <robin+git@viroteck.net>
 *   Copyright (C) 2008 Pippijn van Steenhoven <pip88nl@gmail.com>
 *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
 *   Copyright (C) 2007 Craig Edwards <brain@inspircd.org>
 *
 * This file is part of InspIRCd.  InspIRCd is free software: you can
 * redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation, version 2.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#pragma once

/** @def INSP_FORMAT(FORMAT, ...)
 * Formats a string with format string checking.
 */
#if defined __cpp_if_constexpr && defined __cpp_return_type_deduction
# include <fmt/compile.h>
# define INSP_FORMAT(FORMAT, ...) fmt::format(FMT_COMPILE(FORMAT), __VA_ARGS__)
#else
# include <fmt/core.h>
# define INSP_FORMAT(FORMAT, ...) fmt::format(FMT_STRING(FORMAT), __VA_ARGS__)
#endif

namespace Base64
{
	/** The default table used when handling Base64-encoded strings. */
	inline constexpr const char* TABLE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

	/** Decodes a Base64-encoded byte array.
	 * @param data The byte array to decode from.
	 * @param length The length of the byte array.
	 * @param table The index table to use for decoding.
	 * @return The decoded form of the specified data.
	 */
	CoreExport std::string Decode(const void* data, size_t length, const char* table = nullptr);

	/** Decodes a Base64-encoded string.
	 * @param data The string to decode from.
	 * @param table The index table to use for decoding.
	 * @return The decoded form of the specified data.
	 */
	inline std::string Decode(const std::string& data, const char* table = nullptr)
	{
		return Decode(data.c_str(), data.length(), table);
	}

	/** Encodes a byte array using Base64.
	 * @param data The byte array to encode from.
	 * @param length The length of the byte array.
	 * @param table The index table to use for encoding.
	 * @param padding If non-zero then the character to pad encoded strings with.
	 * @return The encoded form of the specified data.
	 */
	CoreExport std::string Encode(const void* data, size_t length, const char* table = nullptr, char padding = 0);

	/** Encodes a string using Base64.
	 * @param data The string to encode from.
	 * @param table The index table to use for encoding.
	 * @param padding If non-zero then the character to pad encoded strings with.
	 * @return The encoded form of the specified data.
	 */
	inline std::string Encode(const std::string& data, const char* table = nullptr, char padding = 0)
	{
		return Encode(data.c_str(), data.length(), table, padding);
	}
}

namespace Hex
{
	/** The table used for encoding as a lower-case hexadecimal string. */
	inline constexpr const char* TABLE_LOWER = "0123456789abcdef";

	/** The table used for encoding as an upper-case hexadecimal string. */
	inline constexpr const char* TABLE_UPPER = "0123456789ABCDEF";

	/** Encodes a byte array using hexadecimal encoding.
	 * @param data The byte array to encode from.
	 * @param length The length of the byte array.
	 * @param table The index table to use for encoding.
	 * @param separator If non-zero then the character to separate hexadecimal digits with.
	 * @return The encoded form of the specified data.
	 */
	CoreExport std::string Encode(const void* data, size_t length, const char* table = nullptr, char separator = 0);

	/** Encodes a string using Base64.
	 * @param data The string to encode from.
	 * @param table The index table to use for encoding.
	 * @param separator If non-zero then the character to separate hexadecimal digits with.
	 * @return The encoded form of the specified data.
	 */
	inline std::string Encode(const std::string& data, const char* table = nullptr, char separator = 0)
	{
		return Encode(data.c_str(), data.length(), table);
	}
}

namespace Percent
{
	/** The table used to determine what characters are safe within a percent-encoded string. */
	inline constexpr const char* TABLE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_.~";

	/** Decodes a percent-encoded byte array.
	 * @param data The byte array to decode from.
	 * @param length The length of the byte array.
	 * @return The decoded form of the specified data.
	 */
	CoreExport std::string Decode(const void* data, size_t length);

	/** Decodes a percent-encoded string.
	 * @param data The string to decode from.
	 * @return The decoded form of the specified data.
	 */
	inline std::string Decode(const std::string& data)
	{
		return Decode(data.c_str(), data.length());
	}

	/** Encodes a byte array using percent encoding.
	 * @param data The byte array to encode from.
	 * @param length The length of the byte array.
	 * @param table The table of characters that do not require escaping.
	 * @param upper Whether to use upper or lower case.
	 * @return The encoded form of the specified data.
	 */
	CoreExport std::string Encode(const void* data, size_t length, const char* table = nullptr, bool upper = true);

	/** Encodes a string using percent encoding.
	 * @param data The string to encode from.
	 * @param table The table of characters that do not require escaping.
	 * @param upper Whether to use upper or lower case.
	 * @return The encoded form of the specified data.
	 */
	inline std::string Encode(const std::string& data, const char* table = nullptr, bool upper = true)
	{
		return Encode(data.c_str(), data.length(), table, upper);
	}
}

namespace Template
{
	/** Replaces template variables like %foo% within a string.
	 * @param str The string to template from.
	 * @param vars The variables to replace within the string.
	 * @return The specified string with all variables replaced within it.
	 */
	CoreExport std::string Replace(const std::string& str, const insp::flat_map<std::string, std::string>& vars);
}

/** Encapsulates a list of tokens in the format "* -FOO -BAR".*/
class CoreExport TokenList final
{
private:
	/** Whether this list includes all tokens by default. */
	bool permissive = false;

	/** Either the tokens to exclude if in permissive mode or the tokens to include if in strict mode. */
	insp::flat_set<std::string, irc::insensitive_swo> tokens;

public:
	/** Creates a new empty token list. */
	TokenList() = default;

	/** Creates a new token list from a list of tokens. */
	TokenList(const std::string& tokenlist);

	/** Adds a space-delimited list of tokens to the token list.
	 * @param tokenlist The list of space-delimited tokens to add.
	 */
	void AddList(const std::string& tokenlist);

	/** Adds a single token to the token list.
	 * @param token The token to add.
	 */
	void Add(const std::string& token);

	/** Removes all tokens from the token list. */
	void Clear();

	/** Determines whether the specified token exists in the token list.
	 * @param token The token to search for.
	 */
	bool Contains(const std::string& token) const;

	/** Removes the specified token from the token list.
	 * @param token The token to remove.
	 */
	void Remove(const std::string& token);

	/** Retrieves a string which represents the contents of this token list. */
	std::string ToString() const;

	/** Determines whether the specified token list contains the same tokens as this instance.
	 * @param other The tokenlist to compare against.
	 * @return True if the token lists are equal; otherwise, false.
	 */
	bool operator==(const TokenList& other) const;
};