dpkg: update supported compression methods

Based on a patch by Ron Yorston <rmy@tigress.co.uk>

function                                             old     new   delta
get_header_tar_xz                                      -      60     +60
filter_accept_list_reassign                          128     188     +60
unpack_package                                       585     621     +36
init_archive_deb_control                              52      76     +24
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 3/0 up/down: 180/0)             Total: 180 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/archival/libarchive/get_header_tar_xz.c b/archival/libarchive/get_header_tar_xz.c
new file mode 100644
index 000000000..7bf3b3b56
--- /dev/null
+++ b/archival/libarchive/get_header_tar_xz.c
@@ -0,0 +1,21 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+
+#include "libbb.h"
+#include "bb_archive.h"
+
+char FAST_FUNC get_header_tar_xz(archive_handle_t *archive_handle)
+{
+        /* Can't lseek over pipes */
+        archive_handle->seek = seek_by_read;
+
+        fork_transformer_with_sig(archive_handle->src_fd, unpack_xz_stream, "unxz");
+        archive_handle->offset = 0;
+        while (get_header_tar(archive_handle) == EXIT_SUCCESS)
+                continue;
+
+        /* Can only do one file at a time */
+        return EXIT_FAILURE;
+}