Read a file into a vector using C++11

readfile.cc

#include <cstring> // For strerror
#include <list>
#include <memory>
#include <vector>
#include <stdexcept>
#include <unistd.h> // For read

std::vector<unsigned char> readfile(int fd)
{
	struct Chunk
	{
		size_t        used;
		unsigned char data[16*1024];

		Chunk() : used(0) {}

		void fill(int fd)
		{
			while (used < sizeof(data))
			{
				ssize_t n = read(fd, data + used, sizeof(data) - used);

				if (n < 0)
					throw std::runtime_error(std::strerror(errno));

				used += n;

				if (n == 0)
					break;
			}
		}
	};

	std::list<std::unique_ptr<Chunk>> chunks;
	size_t count = 0;

	for (;;)
	{
		std::unique_ptr<Chunk> c(new Chunk);

		c->fill(fd);

		if (!c->used)
			break;

		count += c->used;
		chunks.push_back(std::move(c));
	}

	std::vector<unsigned char> v(count);
	unsigned char* next = v.data();

	for (const auto& c : chunks)
	{
		std::copy(c->data, c->data + c->used, next);
		next += c->used;
	}

	return v;
}