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authorDan McGee <dan@archlinux.org>2011-02-02 20:46:28 -0600
committerAllan McRae <allan@archlinux.org>2011-02-04 09:55:46 +1000
commit14fd1e63a2ce420c555c6de34a815a8b62a9859b (patch)
treec7365b8f72e57f9c86ddb91aa8ee2e5660be6e8e
parent09e582b4117356f996f6d94ca5e490aebd0a0fd5 (diff)
Add new alpm_list_remove_item() function
This takes in the list and a list item, and does the pointer dance necessary to remove it from the list regardless of whether it is first, last, or somewhere in the middle. It is useful for callers that already know what item needs to be removed and have a pointer to it rather than doing a search by data that the plain alpm_list_remove() does. Refactor alpm_list_remove() to use this function as well. Signed-off-by: Dan McGee <dan@archlinux.org>
-rw-r--r--lib/libalpm/alpm_list.c86
-rw-r--r--lib/libalpm/alpm_list.h1
2 files changed, 54 insertions, 33 deletions
diff --git a/lib/libalpm/alpm_list.c b/lib/libalpm/alpm_list.c
index 3f9525e8..4cab665f 100644
--- a/lib/libalpm/alpm_list.c
+++ b/lib/libalpm/alpm_list.c
@@ -287,6 +287,53 @@ alpm_list_t SYMEXPORT *alpm_list_msort(alpm_list_t *list, size_t n, alpm_list_fn
/**
* @brief Remove an item from the list.
+ * item is not freed; this is the respnsiblity of the caller.
+ *
+ * @param haystack the list to remove the item from
+ * @param item the item to remove from the list
+ *
+ * @return the resultant list
+ */
+alpm_list_t SYMEXPORT *alpm_list_remove_item(alpm_list_t *haystack,
+ alpm_list_t *item)
+{
+ if(haystack == NULL || item == NULL) {
+ return(haystack);
+ }
+
+ if(item == haystack) {
+ /* Special case: removing the head node which has a back reference to
+ * the tail node */
+ haystack = item->next;
+ if(haystack) {
+ haystack->prev = item->prev;
+ }
+ item->prev = NULL;
+ } else if(item == haystack->prev) {
+ /* Special case: removing the tail node, so we need to fix the back
+ * reference on the head node. We also know tail != head. */
+ if(item->prev) {
+ /* i->next should always be null */
+ item->prev->next = item->next;
+ haystack->prev = item->prev;
+ item->prev = NULL;
+ }
+ } else {
+ /* Normal case, non-head and non-tail node */
+ if(item->next) {
+ item->next->prev = item->prev;
+ }
+ if(item->prev) {
+ item->prev->next = item->next;
+ }
+ }
+
+ return(haystack);
+}
+
+
+/**
+ * @brief Remove an item from the list.
*
* @param haystack the list to remove the item from
* @param needle the data member of the item we're removing
@@ -295,9 +342,10 @@ alpm_list_t SYMEXPORT *alpm_list_msort(alpm_list_t *list, size_t n, alpm_list_fn
*
* @return the resultant list
*/
-alpm_list_t SYMEXPORT *alpm_list_remove(alpm_list_t *haystack, const void *needle, alpm_list_fn_cmp fn, void **data)
+alpm_list_t SYMEXPORT *alpm_list_remove(alpm_list_t *haystack,
+ const void *needle, alpm_list_fn_cmp fn, void **data)
{
- alpm_list_t *i = haystack, *tmp = NULL;
+ alpm_list_t *i = haystack;
if(data) {
*data = NULL;
@@ -312,44 +360,16 @@ alpm_list_t SYMEXPORT *alpm_list_remove(alpm_list_t *haystack, const void *needl
i = i->next;
continue;
}
- tmp = i->next;
if(fn(i->data, needle) == 0) {
- /* we found a matching item */
- if(i == haystack) {
- /* Special case: removing the head node which has a back reference to
- * the tail node */
- haystack = i->next;
- if(haystack) {
- haystack->prev = i->prev;
- }
- i->prev = NULL;
- } else if(i == haystack->prev) {
- /* Special case: removing the tail node, so we need to fix the back
- * reference on the head node. We also know tail != head. */
- if(i->prev) {
- /* i->next should always be null */
- i->prev->next = i->next;
- haystack->prev = i->prev;
- i->prev = NULL;
- }
- } else {
- /* Normal case, non-head and non-tail node */
- if(i->next) {
- i->next->prev = i->prev;
- }
- if(i->prev) {
- i->prev->next = i->next;
- }
- }
+ haystack = alpm_list_remove_item(haystack, i);
if(data) {
*data = i->data;
}
- i->data = NULL;
free(i);
- i = NULL;
+ break;
} else {
- i = tmp;
+ i = i->next;
}
}
diff --git a/lib/libalpm/alpm_list.h b/lib/libalpm/alpm_list.h
index ee85a5dd..1f6393a6 100644
--- a/lib/libalpm/alpm_list.h
+++ b/lib/libalpm/alpm_list.h
@@ -57,6 +57,7 @@ alpm_list_t *alpm_list_add_sorted(alpm_list_t *list, void *data, alpm_list_fn_cm
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, size_t n, alpm_list_fn_cmp fn);
+alpm_list_t *alpm_list_remove_item(alpm_list_t *haystack, alpm_list_t *item);
alpm_list_t *alpm_list_remove(alpm_list_t *haystack, const void *needle, alpm_list_fn_cmp fn, void **data);
alpm_list_t *alpm_list_remove_str(alpm_list_t *haystack, const char *needle, char **data);
alpm_list_t *alpm_list_remove_dupes(const alpm_list_t *list);