#include <fxos/util.h>

#include <sys/stat.h>
#include <sys/mman.h>

#include <unistd.h>
#include <fcntl.h>

/* A file abstraction that supports both direct load and memory mapping */
File::File(std::string file_path, bool use_mmap):
	m_path(file_path), m_mmap(use_mmap)
{
	char const *path = file_path.c_str();

	int fd = open(path, O_RDONLY);
	if(!fd) throw std::runtime_error(format("cannot open '%s'", path));

	struct stat statbuf;
	ssize_t x = fstat(fd, &statbuf);

	if(x < 0)
	{
		close(fd);
		throw std::runtime_error(format("cannot stat '%s'", path));
	}

	m_size = statbuf.st_size;

	if(use_mmap)
	{
		m_addr = (char *)mmap(nullptr, m_size, PROT_READ, MAP_SHARED,
			fd, 0);
		close(fd);

		if(m_addr == (char *)MAP_FAILED)
		{
			throw std::runtime_error(format(
				"cannot map '%s'", path));
		}
	}
	else
	{
		m_addr = new char [m_size];

		x = read(fd, m_addr, m_size);
		close(fd);

		if(x != statbuf.st_size)
		{
			throw std::runtime_error(format(
				"error while reading '%s'", path));
		}
	}
}

std::string File::path() const noexcept
{
	return m_path;
}

size_t File::size() const noexcept
{
	return m_size;
}

char *File::data() const noexcept
{
	return m_addr;
}


File::~File()
{
	if(m_mmap) munmap(m_addr, m_size);
	else delete[] m_addr;
}