fossilize_hasher.hpp

/* Copyright (c) 2021 Hans-Kristian Arntzen
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#pragma once

#include "fossilize_types.hpp"
#include <stddef.h>
#include <string>

namespace Fossilize
{
class Hasher
{
public:
	explicit Hasher(Hash h_)
		: h(h_)
	{
	}

	Hasher() = default;

	template <typename T>
	inline void data(const T *data_, size_t size)
	{
		size /= sizeof(*data_);
		for (size_t i = 0; i < size; i++)
			h = (h * 0x100000001b3ull) ^ data_[i];
	}

	inline void u32(uint32_t value)
	{
		h = (h * 0x100000001b3ull) ^ value;
	}

	inline void s32(int32_t value)
	{
		u32(uint32_t(value));
	}

	inline void f32(float value)
	{
		union
		{
			float f32;
			uint32_t u32;
		} u;
		u.f32 = value;
		u32(u.u32);
	}

	inline void u64(uint64_t value)
	{
		u32(value & 0xffffffffu);
		u32(value >> 32);
	}

	template <typename T>
	inline void pointer(T *ptr)
	{
		u64(reinterpret_cast<uintptr_t>(ptr));
	}

	inline void string(const char *str)
	{
		char c;
		u32(0xff);
		while ((c = *str++) != '\0')
			u32(uint8_t(c));
	}

	inline void string(const std::string &str)
	{
		u32(0xff);
		for (auto &c : str)
			u32(uint8_t(c));
	}

	inline Hash get() const
	{
		return h;
	}

private:
	Hash h = 0xcbf29ce484222325ull;
};
}