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author | Mathieu OTHACEHE <m.othacehe@gmail.com> | 2016-11-12 17:58:24 +0100 |
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committer | Jérémie Courrèges-Anglas <jca@wxcvbn.org> | 2016-11-17 11:26:11 +0100 |
commit | b0839d05a60e59dfa2722e13586a4857a295d4fd (patch) | |
tree | b73b797e5c2d49daf1dff7b9847826f56984abd7 /src/linkedlist.c | |
parent | 710ce5f7d25c96fed0390227d75f28f0c662a1fa (diff) | |
download | ratpoison-b0839d05a60e59dfa2722e13586a4857a295d4fd.zip |
Add xrandr support
Drop deprecated xinerama support and replace it with xrandr.
Signed-off-by: Mathieu OTHACEHE <m.othacehe@gmail.com>
Diffstat (limited to 'src/linkedlist.c')
-rw-r--r-- | src/linkedlist.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/src/linkedlist.c b/src/linkedlist.c index adedf8a..99cabc0 100644 --- a/src/linkedlist.c +++ b/src/linkedlist.c @@ -196,3 +196,142 @@ list_size (struct list_head *list) return i; } + +#define MAX_LIST_LENGTH_BITS 20 +#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x))) + +/* + * Returns a list organized in an intermediate format suited + * to chaining of merge() calls: null-terminated, no reserved or + * sentinel head node, "prev" links not maintained. + */ +static struct list_head * +merge(void *priv, + int (*cmp)(void *priv, struct list_head *a, + struct list_head *b), + struct list_head *a, struct list_head *b) +{ + struct list_head head, *tail = &head; + + while (a && b) { + /* if equal, take 'a' -- important for sort stability */ + if ((*cmp) (priv, a, b) <= 0) { + tail->next = a; + a = a->next; + } else { + tail->next = b; + b = b->next; + } + tail = tail->next; + } + tail->next = a?:b; + return head.next; +} + +/* + * Combine final list merge with restoration of standard doubly-linked + * list structure. This approach duplicates code from merge(), but + * runs faster than the tidier alternatives of either a separate final + * prev-link restoration pass, or maintaining the prev links + * throughout. + */ +static void +merge_and_restore_back_links(void *priv, + int (*cmp)(void *priv, struct list_head *a, + struct list_head *b), + struct list_head *head, + struct list_head *a, struct list_head *b) +{ + struct list_head *tail = head; + unsigned int count = 0; + + while (a && b) { + /* if equal, take 'a' -- important for sort stability */ + if ((*cmp) (priv, a, b) <= 0) { + tail->next = a; + a->prev = tail; + a = a->next; + } else { + tail->next = b; + b->prev = tail; + b = b->next; + } + tail = tail->next; + } + tail->next = a ? : b; + + do { + /* + * In worst cases this loop may run many iterations. + * Continue callbacks to the client even though no + * element comparison is needed, so the client's cmp() + * routine can invoke cond_resched() periodically. + */ + if (!(++count)) + (*cmp) (priv, tail->next, tail->next); + + tail->next->prev = tail; + tail = tail->next; + } while (tail->next); + + tail->next = head; + head->prev = tail; +} + +/** + * list_sort - sort a list + * @priv: private data, opaque to list_sort(), passed to @cmp + * @head: the list to sort + * @cmp: the elements comparison function + * + * This function implements "merge sort", which has O(nlog(n)) + * complexity. + * + * The comparison function @cmp must return a negative value if @a + * should sort before @b, and a positive value if @a should sort after + * @b. If @a and @b are equivalent, and their original relative + * ordering is to be preserved, @cmp must return 0. + */ +void +list_sort(void *priv, struct list_head *head, + int (*cmp)(void *priv, struct list_head *a, + struct list_head *b)) +{ + struct list_head *part[MAX_LIST_LENGTH_BITS+1]; /* sorted partial lists + -- last slot is a sentinel */ + int lev; /* index into part[] */ + int max_lev = 0; + struct list_head *list; + + if (list_empty (head)) + return; + + memset(part, 0, sizeof(part)); + + head->prev->next = NULL; + list = head->next; + + while (list) { + struct list_head *cur = list; + list = list->next; + cur->next = NULL; + + for (lev = 0; part[lev]; lev++) { + cur = merge (priv, cmp, part[lev], cur); + part[lev] = NULL; + } + if (lev > max_lev) { + if (lev >= ARRAY_SIZE(part)-1) { + lev--; + } + max_lev = lev; + } + part[lev] = cur; + } + + for (lev = 0; lev < max_lev; lev++) + if (part[lev]) + list = merge (priv, cmp, part[lev], list); + + merge_and_restore_back_links (priv, cmp, head, part[max_lev], list); +} |