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splay-tree.c (rotate_left): New function.

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2005-11-07  Richard Guenther  <rguenther@suse.de>

	* splay-tree.c (rotate_left): New function.
	(rotate_right): Likewise.
	(splay_tree_splay_helper): Remove.
	(splay_tree_splay): Re-implement.

From-SVN: r106584
This commit is contained in:
Richard Guenther 2005-11-07 07:45:35 +00:00 • committed by Richard Biener
parent fd159af7b3
commit 73a08f8717
2 changed files with 89 additions and 113 deletions
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7
libiberty/ChangeLog
View file

@ -1,3 +1,10 @@
2005-11-06 Richard Guenther <rguenther@suse.de>
* splay-tree.c (rotate_left): New function.
(rotate_right): Likewise.
(splay_tree_splay_helper): Remove.
(splay_tree_splay): Re-implement.
2005-10-31 Mark Kettenis <kettenis@gnu.org>
* floatformat.c (floatformat_vax_aingle, floatformat_vax_double):

195
libiberty/splay-tree.c
View file

@ -38,12 +38,11 @@ Boston, MA 02110-1301, USA. */
#include "splay-tree.h"
static void splay_tree_delete_helper (splay_tree, splay_tree_node);
static inline void rotate_left (splay_tree_node *,
splay_tree_node, splay_tree_node);
static inline void rotate_right (splay_tree_node *,
splay_tree_node, splay_tree_node);
static void splay_tree_splay (splay_tree, splay_tree_key);
static splay_tree_node splay_tree_splay_helper (splay_tree,
splay_tree_key,
splay_tree_node*,
splay_tree_node*,
splay_tree_node*);
static int splay_tree_foreach_helper (splay_tree, splay_tree_node,
splay_tree_foreach_fn, void*);
@ -107,116 +106,33 @@ splay_tree_delete_helper (splay_tree sp, splay_tree_node node)
#undef VDEL
}
/* Help splay SP around KEY. PARENT and GRANDPARENT are the parent
and grandparent, respectively, of NODE. */
/* Rotate the edge joining the left child N with its parent P. PP is the
grandparents pointer to P. */
static splay_tree_node
splay_tree_splay_helper (splay_tree sp, splay_tree_key key,
splay_tree_node *node, splay_tree_node *parent,
splay_tree_node *grandparent)
static inline void
rotate_left (splay_tree_node *pp, splay_tree_node p, splay_tree_node n)
{
splay_tree_node *next;
splay_tree_node n;
int comparison;
n = *node;
if (!n)
return *parent;
comparison = (*sp->comp) (key, n->key);
if (comparison == 0)
/* We've found the target. */
next = 0;
else if (comparison < 0)
/* The target is to the left. */
next = &n->left;
else
/* The target is to the right. */
next = &n->right;
if (next)
{
/* Continue down the tree. */
n = splay_tree_splay_helper (sp, key, next, node, parent);
/* The recursive call will change the place to which NODE
points. */
if (*node != n)
return n;
}
if (!parent)
/* NODE is the root. We are done. */
return n;
/* First, handle the case where there is no grandparent (i.e.,
*PARENT is the root of the tree.) */
if (!grandparent)
{
if (n == (*parent)->left)
{
*node = n->right;
n->right = *parent;
}
else
{
*node = n->left;
n->left = *parent;
}
*parent = n;
return n;
}
/* Next handle the cases where both N and *PARENT are left children,
or where both are right children. */
if (n == (*parent)->left && *parent == (*grandparent)->left)
{
splay_tree_node p = *parent;
(*grandparent)->left = p->right;
p->right = *grandparent;
p->left = n->right;
n->right = p;
*grandparent = n;
return n;
}
else if (n == (*parent)->right && *parent == (*grandparent)->right)
{
splay_tree_node p = *parent;
(*grandparent)->right = p->left;
p->left = *grandparent;
p->right = n->left;
n->left = p;
*grandparent = n;
return n;
}
/* Finally, deal with the case where N is a left child, but *PARENT
is a right child, or vice versa. */
if (n == (*parent)->left)
{
(*parent)->left = n->right;
n->right = *parent;
(*grandparent)->right = n->left;
n->left = *grandparent;
*grandparent = n;
return n;
}
else
{
(*parent)->right = n->left;
n->left = *parent;
(*grandparent)->left = n->right;
n->right = *grandparent;
*grandparent = n;
return n;
}
splay_tree_node tmp;
tmp = n->right;
n->right = p;
p->left = tmp;
*pp = n;
}
/* Splay SP around KEY. */
/* Rotate the edge joining the right child N with its parent P. PP is the
grandparents pointer to P. */
static inline void
rotate_right (splay_tree_node *pp, splay_tree_node p, splay_tree_node n)
{
splay_tree_node tmp;
tmp = n->left;
n->left = p;
p->right = tmp;
*pp = n;
}
/* Bottom up splay of key. */
static void
splay_tree_splay (splay_tree sp, splay_tree_key key)
@ -224,8 +140,61 @@ splay_tree_splay (splay_tree sp, splay_tree_key key)
if (sp->root == 0)
return;
splay_tree_splay_helper (sp, key, &sp->root,
/*grandparent=*/0, /*parent=*/0);
do {
int cmp1, cmp2;
splay_tree_node n, c;
n = sp->root;
cmp1 = (*sp->comp) (key, n->key);
/* Found. */
if (cmp1 == 0)
return;
/* Left or right? If no child, then we're done. */
if (cmp1 < 0)
c = n->left;
else
c = n->right;
if (!c)
return;
/* Next one left or right? If found or no child, we're done
after one rotation. */
cmp2 = (*sp->comp) (key, c->key);
if (cmp2 == 0
|| (cmp2 < 0 && !c->left)
|| (cmp2 > 0 && !c->right))
{
if (cmp1 < 0)
rotate_left (&sp->root, n, c);
else
rotate_right (&sp->root, n, c);
return;
}
/* Now we have the four cases of double-rotation. */
if (cmp1 < 0 && cmp2 < 0)
{
rotate_left (&n->left, c, c->left);
rotate_left (&sp->root, n, n->left);
}
else if (cmp1 > 0 && cmp2 > 0)
{
rotate_right (&n->right, c, c->right);
rotate_right (&sp->root, n, n->right);
}
else if (cmp1 < 0 && cmp2 > 0)
{
rotate_right (&n->left, c, c->right);
rotate_left (&sp->root, n, n->left);
}
else if (cmp1 > 0 && cmp2 < 0)
{
rotate_left (&n->right, c, c->left);
rotate_right (&sp->root, n, n->right);
}
} while (1);
}
/* Call FN, passing it the DATA, for every node below NODE, all of