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splay-tree.c (splay_tree_delete_helper): Redesign the logic so that recursion (and thus large stack space) is not needed. 

* splay-tree.c (splay_tree_delete_helper): Redesign the logic so
that recursion (and thus large stack space) is not needed.

From-SVN: r91815
This commit is contained in:
DJ Delorie 2004-12-07 15:01:17 -05:00 committed by DJ Delorie
parent 354e49c1d9
commit b180d5fb7b
2 changed files with 53 additions and 7 deletions
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5
libiberty/ChangeLog
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@ -1,3 +1,8 @@
2004-12-07 DJ Delorie <dj@redhat.com>
* splay-tree.c (splay_tree_delete_helper): Redesign the logic so
that recursion (and thus large stack space) is not needed.
2004-11-29 Matt Kraai <kraai@alumni.cmu.edu> 2004-11-29 Matt Kraai <kraai@alumni.cmu.edu>
* pex-unix.c: Fix the spelling of longjmp. * pex-unix.c: Fix the spelling of longjmp.

55
libiberty/splay-tree.c
View File

@ -59,18 +59,59 @@ splay_tree_delete_helper (sp, node)
splay_tree sp; splay_tree sp;
splay_tree_node node; splay_tree_node node;
{ {
splay_tree_node pending = 0;
splay_tree_node active = 0;
if (!node) if (!node)
return; return;
splay_tree_delete_helper (sp, node->left); #define KDEL(x) if (sp->delete_key) (*sp->delete_key)(x);
splay_tree_delete_helper (sp, node->right); #define VDEL(x) if (sp->delete_value) (*sp->delete_value)(x);
if (sp->delete_key) KDEL (node->key);
(*sp->delete_key)(node->key); VDEL (node->value);
if (sp->delete_value)
(*sp->delete_value)(node->value);
(*sp->deallocate) ((char*) node, sp->allocate_data); /* We use the "key" field to hold the "next" pointer. */
node->key = (splay_tree_key)pending;
pending = (splay_tree_node)node;
/* Now, keep processing the pending list until there aren't any
more. This is a little more complicated than just recursing, but
it doesn't toast the stack for large trees. */
while (pending)
{
active = pending;
pending = 0;
while (active)
{
splay_tree_node temp;
/* active points to a node which has its key and value
deallocated, we just need to process left and right. */
if (active->left)
{
KDEL (active->left->key);
VDEL (active->left->value);
active->left->key = (splay_tree_key)pending;
pending = (splay_tree_node)(active->left);
}
if (active->right)
{
KDEL (active->right->key);
VDEL (active->right->value);
active->right->key = (splay_tree_key)pending;
pending = (splay_tree_node)(active->right);
}
temp = active;
active = (splay_tree_node)(temp->key);
(*sp->deallocate) ((char*) temp, sp->allocate_data);
}
}
#undef KDEL
#undef VDEL
} }
/* Help splay SP around KEY. PARENT and GRANDPARENT are the parent /* Help splay SP around KEY. PARENT and GRANDPARENT are the parent