Abstract read and seek in unarchiving code, convert bunzip to file descriptors, support tar -j
diff --git a/archival/libunarchive/archive_copy_file.c b/archival/libunarchive/archive_copy_file.c
new file mode 100644
index 0000000..22355cc
--- /dev/null
+++ b/archival/libunarchive/archive_copy_file.c
@@ -0,0 +1,48 @@
+/*
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <unistd.h>
+
+#include "libbb.h"
+#include "unarchive.h"
+
+/* Copy CHUNKSIZE bytes (or untill EOF if chunksize == -1)
+ * from SRC_FILE to DST_FILE. */
+extern void archive_copy_file(const archive_handle_t *archive_handle, const int dst_fd)
+{
+ size_t size;
+ char buffer[BUFSIZ];
+ off_t chunksize = archive_handle->file_header->size;
+
+ while (chunksize != 0) {
+ if (chunksize > BUFSIZ) {
+ size = BUFSIZ;
+ } else {
+ size = chunksize;
+ }
+ archive_xread_all(archive_handle, buffer, size);
+
+ if (write(dst_fd, buffer, size) != size) {
+ error_msg_and_die ("Short write");
+ }
+
+ if (chunksize != -1) {
+ chunksize -= size;
+ }
+ }
+
+ return;
+}