gplib/include/gp_config.hpp

#pragma once

#include <new>
#include <type_traits>

#include <cstddef>
#include <cstdint>
#include <cstdlib>

#ifdef GP_TESTS
	class static_mapper;
#else
namespace gp {
	class c_allocator;
}
#endif

extern void log_failure(const char* failure);
extern void log_segment(const char* name, const char* text, int16_t prio = 0);

/**
 * @brief This namespace contains the configuration.
 * 
 * This namespace is expected to be fully defined in an include accessible from the root
 * of your header list:
 * \code{.cpp}
 * #include "gp_config.hpp"
 * \endcode
 * 
 * The code line above should always be the one including that config and that namespace.
 */
namespace gp_config{
	namespace rendering {
		/**
		 * @brief The default type used for rendering processes
		 */
		using default_type = float;

		/**
		 * @brief The small enough value used in signed distance function resolution
		 */
		constexpr default_type epsilon = 0.01;

		/**
		* @brief The default color type
		*/
		#define GP_CONFIG__RENDERING__COLOR_T vec4
	}

	/**
	 * @brief This namespace contains artificial limitations put on the runtime
	 */
	namespace limits {
		/**
		 * @brief the total number of processes the system is allowed to have
		 */
		constexpr size_t max_processes = 4096;

		/**
		 * @brief the maximum size a channel can address
		 */
		constexpr size_t channel_max_size = 1 << 20;

		/**
		 * @brief the default size a channel will take
		 */
		constexpr size_t channel_default_size = 1 << 16;

		/**
		 * @brief the number of open files each process is allowed to have
		 */
		constexpr size_t max_fd_per_process = 128;

		/**
		 * @brief the stack size for the new stacks generated by the concurrency system
		 */
		constexpr size_t process_stack = 1024;

		/**
		 * @brief expected stack alignment
		 */
		constexpr size_t process_stack_align_to = 16;

		/**
		 * @brief presents the direction of stack growth
		 */
		constexpr size_t stack_grow_upwards = false;

		#if __cpp_lib_hardware_interference_size >= 201603
			constexpr size_t hardware_constructive_interference_size = std::hardware_constructive_interference_size;
			constexpr size_t hardware_destructive_interference_size = std::hardware_destructive_interference_size;
		#else
			constexpr size_t hardware_constructive_interference_size = 128;
			constexpr size_t hardware_destructive_interference_size = 128;
		#endif

		constexpr size_t loggers_segment_size = 128;
	}

	namespace memory_module{
		constexpr bool is_ok = true;
		constexpr bool prefer_constant_memory = true;
	}

	typedef uint32_t file_descriptor_t;

	/**
	 * @brief  set to true to enable exceptions
	 */
	constexpr bool has_exceptions = true;

	/**
	 * @brief set to true to activate bounds checking
	 */
	constexpr bool has_buffer_bounds = true;

	/**
	 * @brief A value used to determine the strength used by random number generators
	 * 
	 * Value of  8 is considered not cryptographically secure
	 * Value of 12 offers a good compromise of performance and robustness
	 * Value of 20 offers maximum robustness
	 */
	constexpr size_t arc4random_strength = 20;

	/**
	 * @brief an exception that represents an assertion failure
	 */
	struct assert_failure : std::exception {
		assert_failure(const char* reason)
		: what_str{reason}
		{}
		const char* what_str;
		const char* what() {return what_str;}
	};

	/**
	 * @brief UNUSED
	 */
	constexpr size_t assert_buffer_size = 0;
	
	constexpr auto fail =  [] [[noreturn]] (auto reason) noexcept(not has_exceptions) {
		if constexpr (has_exceptions) {
			throw assert_failure(reason);
		} else {
			volatile uint8_t n = 0;
			{
				failure_point:
				n = n + 1;
				goto failure_point;
			}
		}
	};

	/**
	 * @brief an assertion function
	 */
	constexpr auto assertion = [](bool pred, const char* reason)
		noexcept(std::is_nothrow_invocable_v<decltype(fail), decltype(reason)>) -> void {
		if(!pred) {
			log_failure(reason);
			fail(reason);
		}
	};

	enum class cbor_tag {
		datetime = 0,
		unix_time = 1,
		ubignum = 2,
		nbignum = 3,
		decimal = 4,
		bigfloat = 5,
		cose_encrypt0 = 16,
		cose_mac0 = 17,
		cose_sign1 = 18,
		expected_base64url = 21,
		expected_base64 = 22,
		expected_base16 = 23,
		encoded_cbor = 24,
		url = 32,
		base64url = 33,
		base64 = 34,
		regexp = 35,
		mime = 36,
		cose_encrypt = 96,
		cose_mac = 97,
		cose_sign = 98,
		signature = 55799
	};
}

/**
 * @brief a list of error codes
 */
enum class gp_errorcodes : int {
	/**
	 * @brief this error code is activated upon reaching a skipstone limit that seems like infinity.
	 */
	infinite_skipstone = 3000
};