libsparse: add function to resparse a file and a utility to use it
Add sparse_file_repsarse, which splits chunks in an existing sparse
file such that the maximum size of a chunk, plus a header and footer,
is smaller than the given size. This will allow multiple smaller
sparse files to result in the same data as a large sparse file.
Change-Id: I177abdb958a23d5afd394ff265c5b0c6a3ff22fa
diff --git a/libsparse/sparse_defs.h b/libsparse/sparse_defs.h
index 9f32d59..b99cfd5 100644
--- a/libsparse/sparse_defs.h
+++ b/libsparse/sparse_defs.h
@@ -41,6 +41,7 @@
#define DIV_ROUND_UP(x, y) (((x) + (y) - 1)/(y))
#define ALIGN(x, y) ((y) * DIV_ROUND_UP((x), (y)))
+#define ALIGN_DOWN(x, y) ((y) * ((x) / (y)))
#define error(fmt, args...) do { fprintf(stderr, "error: %s: " fmt "\n", __func__, ## args); } while (0)
#define error_errno(s, args...) error(s ": %s", ##args, strerror(errno))