/**

 * ShaderShark

 * Copyright © 2023 František Kučera (Frantovo.cz, GlobalCode.info)

 *

 * This program 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 3 of the License.

 *

 * 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

#include <sys/mman.h>

#include <unistd.h>

#include <sys/stat.h>

#include <fcntl.h>

#include "Buffer.h"

class MappedFile : public Buffer {

private:

	int fd = -1;

public:

	MappedFile(const std::string& fileName) {

		struct stat stat;

		fd = open(fileName.c_str(), O_RDONLY);

		if (fd < 0) throw std::invalid_argument("unable to open file");

		int result = fstat(fd, &stat);

		if (result) throw std::invalid_argument("unable to stat file");

		size = stat.st_size;

		data = static_cast<char*> (

				mmap(nullptr, size, PROT_READ, MAP_SHARED, fd, 0));

		if (data == MAP_FAILED) throw std::invalid_argument("unable to mmap");

		// std::cerr << "MappedFile() / mmap()" << std::endl;

	}

	virtual ~MappedFile() {

		int result = munmap(data, size);

		// std::cerr << "~MappedFile() / munmap() = " << result << std::endl;

		result = close(fd);

		// std::cerr << "~MappedFile() / close() = " << result << std::endl;

	}

	MappedFile(const MappedFile&) = delete;

	MappedFile& operator=(const MappedFile&) = delete;

};