Abstract read and seek in unarchiving code, convert bunzip to file descriptors, support tar -j

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;
+}