This is similar to using the hashmap in hashmap.c, but with an
easier-to-use API. In particular, custom entry comparisons no longer
need to be written, and lookups can be done without constructing a
temporary entry structure.
This is implemented as a thin wrapper over the hashmap API. In
particular, this means that there is an additional 4-byte overhead due
to the fact that the first 4 bytes of the hash is redundantly stored.
For now, I'm taking the simpler approach, but if need be, we can
reimplement oidmap without affecting the callers significantly.
oidset has been updated to use oidmap.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When using the hashmap a common need is to have access to caller provided
data in the compare function. A couple of times we abuse the keydata field
to pass in the data needed. This happens for example in patch-ids.c.
This patch changes the function signature of the compare function
to have one more void pointer available. The pointer given for each
invocation of the compare function must be defined in the init function
of the hashmap and is just passed through.
Documentation of this new feature is deferred to a later patch.
This is a rather mechanical conversion, just adding the new pass-through
parameter. However while at it improve the naming of the fields of all
compare functions used by hashmaps by ensuring unused parameters are
prefixed with 'unused_' and naming the parameters what they are (instead
of 'unused' make it 'unused_keydata').
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is similar to many of our uses of sha1-array, but it
overcomes one limitation of a sha1-array: when you are
de-duplicating a large input with relatively few unique
entries, sha1-array uses 20 bytes per non-unique entry.
Whereas this set will use memory linear in the number of
unique entries (albeit a few more than 20 bytes due to
hashmap overhead).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
