diff options
author | Nagy Gabor <ngaba@bibl.u-szeged.hu> | 2007-11-20 09:11:40 +0100 |
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committer | Dan McGee <dan@archlinux.org> | 2007-11-20 23:31:40 -0600 |
commit | 4696ad6cad9c659728e9e061689728fc0417ad73 (patch) | |
tree | d196162c7528243711886558e7c18a32009e697d /lib | |
parent | 967a78f5e476030c2d13104a7dadc5ce4daf5882 (diff) |
New alpm_list_join function
This O(1) function joins 2 lists.
Signed-off-by: Nagy Gabor <ngaba@bibl.u-szeged.hu>
Signed-off-by: Dan McGee <dan@archlinux.org>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/libalpm/alpm_list.c | 33 | ||||
-rw-r--r-- | lib/libalpm/alpm_list.h | 1 |
2 files changed, 34 insertions, 0 deletions
diff --git a/lib/libalpm/alpm_list.c b/lib/libalpm/alpm_list.c index e854cf63..69cd3479 100644 --- a/lib/libalpm/alpm_list.c +++ b/lib/libalpm/alpm_list.c @@ -185,6 +185,39 @@ alpm_list_t SYMEXPORT *alpm_list_add_sorted(alpm_list_t *list, void *data, alpm_ } /** + * @brief Join two lists. + * The two lists must be independent. Do not free the original lists after + * calling this function, as this is not a copy operation. The list pointers + * passed in should be considered invalid after calling this function. + * + * @param first the first list + * @param second the second list + * + * @return the resultant joined list + */ +alpm_list_t SYMEXPORT *alpm_list_join(alpm_list_t *first, alpm_list_t *second) +{ + alpm_list_t *tmp; + + if (first == NULL) { + return second; + } + if (second == NULL) { + return first; + } + /* tmp is the last element of the first list */ + tmp = first->prev; + /* link the first list to the second */ + tmp->next = second; + /* link the second list to the first */ + first->prev = second->prev; + /* set the back reference to the tail */ + second->prev = tmp; + + return(first); +} + +/** * @brief Merge the two sorted sublists into one sorted list. * * @param left the first list diff --git a/lib/libalpm/alpm_list.h b/lib/libalpm/alpm_list.h index a24aa8db..262d5e22 100644 --- a/lib/libalpm/alpm_list.h +++ b/lib/libalpm/alpm_list.h @@ -54,6 +54,7 @@ void alpm_list_free_inner(alpm_list_t *list, alpm_list_fn_free fn); /* item mutators */ alpm_list_t *alpm_list_add(alpm_list_t *list, void *data); alpm_list_t *alpm_list_add_sorted(alpm_list_t *list, void *data, alpm_list_fn_cmp fn); +alpm_list_t *alpm_list_join(alpm_list_t *first, alpm_list_t *second); alpm_list_t *alpm_list_mmerge(alpm_list_t *left, alpm_list_t *right, alpm_list_fn_cmp fn); alpm_list_t *alpm_list_msort(alpm_list_t *list, int n, alpm_list_fn_cmp fn); alpm_list_t *alpm_list_remove(alpm_list_t *haystack, const void *needle, alpm_list_fn_cmp fn, void **data); |