Unpack tar with D and libarchive

module main;

import std.stdio;
import std.string;
import std.conv;
import std.file;
import std.c.stdlib;

import libarchive.all;

void main(string[] args)
{
    if (args.length < 2)
    {
        writefln("Usage:\n%s filename.tar", args[0]);
        return;
    }

    string filename = args[1];

    archive* a = archive_read_new();
    archive_read_support_format_tar(a);
    int r = archive_read_open_filename(a, cast(char*)toStringz(filename), 10240);

    archive_entry* entry;
    while (archive_read_next_header(a, &entry) == ARCHIVE_OK)
    {
        char* n = archive_entry_pathname(entry);
        string path = to!string(n);

        if (archive_entry_filetype(entry) == AE_IFDIR)
        {
            if (!exists(path))
                mkdir(path);
        }
        else
        {
            size_t size = cast(size_t)archive_entry_size(entry);
            if (size > 0)
            {
                void* fileContents = malloc(size);
                archive_read_data_into_buffer(a, fileContents, size);
                std.file.write(path, fileContents[0..size]);
                free(fileContents);
            }
        }
    }
}