libdm: add dm_bitset_parse_list()

Add a function to parse a list of integer values and ranges into
a dm_bitset representation. Individual values signify that that bit
is set in the resulting mask and ranges are given as a pair of
start and end values, M-N, such that M and N are the first and
last members of the range (inclusive).

The implementation is based on the kernel's __bitmap_parselist()
that is used for cpumasks and other set configuration passed in
string form from user space.

1 files changed, 10 insertions, 0 deletions

diff --git a/libdm/libdevmapper.h b/libdm/libdevmapper.h
index 7fd765c8e..36681882d 100644
--- a/libdm/libdevmapper.h
+++ b/libdm/libdevmapper.h
@@ -1843,6 +1843,16 @@ int dm_bit_get_next(dm_bitset_t bs, int last_bit);
 #define dm_bit_copy(bs1, bs2) \
    memcpy((bs1) + 1, (bs2) + 1, ((*(bs1) / DM_BITS_PER_INT) + 1) * sizeof(int))
 
+/*
+ * Parse a string representation of a bitset into a dm_bitset_t. The
+ * notation used is identical to the kernel bitmap parser (cpuset etc.)
+ * and supports both lists ("1,2,3") and ranges ("1-2,5-8"). If the mem
+ * parameter is NULL memory for the bitset will be allocated using
+ * dm_malloc(). Otherwise the bitset will be allocated using the supplied
+ * dm_pool.
+ */
+dm_bitset_t dm_bitset_parse_list(const char *str, struct dm_pool *mem);
+
 /* Returns number of set bits */
 static inline unsigned hweight32(uint32_t i)
 {