summaryrefslogtreecommitdiff
path: root/libbcache/eytzinger.h
diff options
context:
space:
mode:
authorKent Overstreet <kent.overstreet@gmail.com>2017-03-19 15:56:34 -0800
committerKent Overstreet <kent.overstreet@gmail.com>2017-03-19 17:31:47 -0800
commit5ec39af8eaba49aee7bafa44c661da39e2f40dc3 (patch)
tree1fb1a981602cbf22c7d2b2dba1168c715d7cecb5 /libbcache/eytzinger.h
parentbb1941de5378a7b8122d3575dcbc7d0aeb6326f0 (diff)
Rename from bcache-tools to bcachefs-tools
Diffstat (limited to 'libbcache/eytzinger.h')
-rw-r--r--libbcache/eytzinger.h196
1 files changed, 0 insertions, 196 deletions
diff --git a/libbcache/eytzinger.h b/libbcache/eytzinger.h
deleted file mode 100644
index 13d54e5e..00000000
--- a/libbcache/eytzinger.h
+++ /dev/null
@@ -1,196 +0,0 @@
-#ifndef _EYTZINGER_H
-#define _EYTZINGER_H
-
-#include <linux/bitops.h>
-#include <linux/log2.h>
-
-#include "util.h"
-
-/*
- * Traversal for trees in eytzinger layout - a full binary tree layed out in an
- * array
- *
- * We used one based indexing, not zero based: with one based indexing, each
- * level of the tree starts at a power of two - leading to better alignment -
- * and it's what you want for implementing next/prev and to/from inorder.
- *
- * To/from inorder also uses 1 based indexing.
- *
- * Size parameter is treated as if we were using 0 based indexing, however:
- * valid nodes, and inorder indices, are in the range [1..size)
- */
-
-static inline unsigned eytzinger_child(unsigned j, unsigned child)
-{
- EBUG_ON(child > 1);
-
- return (j << 1) + child;
-}
-
-static inline unsigned eytzinger_left_child(unsigned j)
-{
- return eytzinger_child(j, 0);
-}
-
-static inline unsigned eytzinger_right_child(unsigned j)
-{
- return eytzinger_child(j, 1);
-}
-
-static inline unsigned eytzinger_first(unsigned size)
-{
- return rounddown_pow_of_two(size - 1);
-}
-
-static inline unsigned eytzinger_last(unsigned size)
-{
- return rounddown_pow_of_two(size) - 1;
-}
-
-/*
- * eytzinger_next() and eytzinger_prev() have the nice properties that
- *
- * eytzinger_next(0) == eytzinger_first())
- * eytzinger_prev(0) == eytzinger_last())
- *
- * eytzinger_prev(eytzinger_first()) == 0
- * eytzinger_next(eytzinger_last()) == 0
- */
-
-static inline unsigned eytzinger_next(unsigned j, unsigned size)
-{
- EBUG_ON(j >= size);
-
- if (eytzinger_right_child(j) < size) {
- j = eytzinger_right_child(j);
-
- j <<= __fls(size) - __fls(j);
- j >>= j >= size;
- } else {
- j >>= ffz(j) + 1;
- }
-
- return j;
-}
-
-static inline unsigned eytzinger_prev(unsigned j, unsigned size)
-{
- EBUG_ON(j >= size);
-
- if (eytzinger_left_child(j) < size) {
- j = eytzinger_left_child(j);
-
- j <<= __fls(size) - __fls(j);
- j -= 1;
- j >>= j >= size;
- } else {
- j >>= __ffs(j) + 1;
- }
-
- return j;
-}
-
-static inline unsigned eytzinger_extra(unsigned size)
-{
- return (size - rounddown_pow_of_two(size - 1)) << 1;
-}
-
-static inline unsigned __eytzinger_to_inorder(unsigned j, unsigned size,
- unsigned extra)
-{
- unsigned b = __fls(j);
- unsigned shift = __fls(size - 1) - b;
- int s;
-
- EBUG_ON(!j || j >= size);
-
- j ^= 1U << b;
- j <<= 1;
- j |= 1;
- j <<= shift;
-
- /*
- * sign bit trick:
- *
- * if (j > extra)
- * j -= (j - extra) >> 1;
- */
- s = extra - j;
- j += (s >> 1) & (s >> 31);
-
- return j;
-}
-
-static inline unsigned __inorder_to_eytzinger(unsigned j, unsigned size,
- unsigned extra)
-{
- unsigned shift;
- int s;
-
- EBUG_ON(!j || j >= size);
-
- /*
- * sign bit trick:
- *
- * if (j > extra)
- * j += j - extra;
- */
- s = extra - j;
- j -= s & (s >> 31);
-
- shift = __ffs(j);
-
- j >>= shift + 1;
- j |= 1U << (__fls(size - 1) - shift);
-
- return j;
-}
-
-static inline unsigned eytzinger_to_inorder(unsigned j, unsigned size)
-{
- return __eytzinger_to_inorder(j, size, eytzinger_extra(size));
-}
-
-static inline unsigned inorder_to_eytzinger(unsigned j, unsigned size)
-{
- return __inorder_to_eytzinger(j, size, eytzinger_extra(size));
-}
-
-#define eytzinger_for_each(_i, _size) \
- for ((_i) = eytzinger_first((_size)); \
- (_i) != 0; \
- (_i) = eytzinger_next((_i), (_size)))
-
-#if 0
-void eytzinger_test(void)
-{
- unsigned i, j, size;
-
- for (size = 2;
- size < 65536000;
- size++) {
- if (!(size % 4096))
- printk(KERN_INFO "tree size %u\n", size);
-
- assert(eytzinger_prev(0, size) == eytzinger_last(size));
- assert(eytzinger_next(0, size) == eytzinger_first(size));
-
- assert(eytzinger_prev(eytzinger_first(size), size) == 0);
- assert(eytzinger_next(eytzinger_last(size), size) == 0);
-
- eytzinger_for_each(j, size) {
- assert(from_inorder(i, size) == j);
- assert(to_inorder(j, size) == i);
-
- if (j != eytzinger_last(size)) {
- unsigned next = eytzinger_next(j, size);
-
- assert(eytzinger_prev(next, size) == j);
- }
- }
- }
-
-}
-#endif
-
-#endif /* _EYTZINGER_H */