Add support for repacking condensed sparse files

This commit broadly does the following things:
 - Rename and move the sparse mapping structure to libutil
 - Add a function to the data writer for writing condensed versions
   of sparse files, given the mapping.
 - This shares code with the already existing function for regular
   files. The shared code is moved to a common helper function.
 - Add support to tar2sqfs for repacking sparse files.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/util.h b/include/util.h
index d5b20dd..997cbf5 100644
--- a/include/util.h
+++ b/include/util.h
@@ -5,6 +5,13 @@
 #include <sys/types.h>
 #include <stdint.h>
 
+/* layout structure for sparse files, indicating where the actual data is */
+typedef struct sparse_map_t {
+	struct sparse_map_t *next;
+	uint64_t offset;
+	uint64_t count;
+} sparse_map_t;
+
 /*
   Convert back to forward slashed, remove all preceeding and trailing slashes,
   collapse all sequences of slashes, remove all path components that are '.'