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/* A typesafe wrapper around libiberty's splay-tree.h.
Copyright (C) 2015-2021 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#ifndef GCC_TYPED_SPLAY_TREE_H
#define GCC_TYPED_SPLAY_TREE_H
/* Typesafe wrapper around libiberty's splay-tree.h. */
template <typename KEY_TYPE, typename VALUE_TYPE>
class typed_splay_tree
{
public:
typedef KEY_TYPE key_type;
typedef VALUE_TYPE value_type;
typedef int (*compare_fn) (key_type, key_type);
typedef void (*delete_key_fn) (key_type);
typedef void (*delete_value_fn) (value_type);
typedef int (*foreach_fn) (key_type, value_type, void *);
typed_splay_tree (compare_fn,
delete_key_fn,
delete_value_fn);
~typed_splay_tree ();
value_type lookup (key_type k);
value_type predecessor (key_type k);
value_type successor (key_type k);
void insert (key_type k, value_type v);
void remove (key_type k);
value_type max ();
value_type min ();
int foreach (foreach_fn, void *);
private:
/* Copy and assignment ops are not supported. */
typed_splay_tree (const typed_splay_tree &);
typed_splay_tree & operator = (const typed_splay_tree &);
typedef key_type splay_tree_key;
typedef value_type splay_tree_value;
/* The nodes in the splay tree. */
struct splay_tree_node_s {
/* The key. */
splay_tree_key key;
/* The value. */
splay_tree_value value;
/* The left and right children, respectively. */
splay_tree_node_s *left, *right;
/* Used as temporary value for tree traversals. */
splay_tree_node_s *back;
};
typedef splay_tree_node_s *splay_tree_node;
inline void KDEL (splay_tree_key);
inline void VDEL (splay_tree_value);
void splay_tree_delete_helper (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);
void splay_tree_splay (splay_tree_key);
static int splay_tree_foreach_helper (splay_tree_node,
foreach_fn, void*);
splay_tree_node splay_tree_insert (splay_tree_key, splay_tree_value);
void splay_tree_remove (splay_tree_key key);
splay_tree_node splay_tree_lookup (splay_tree_key key);
splay_tree_node splay_tree_predecessor (splay_tree_key);
splay_tree_node splay_tree_successor (splay_tree_key);
splay_tree_node splay_tree_max ();
splay_tree_node splay_tree_min ();
static value_type node_to_value (splay_tree_node node);
/* The root of the tree. */
splay_tree_node root;
/* The comparision function. */
compare_fn comp;
/* The deallocate-key function. NULL if no cleanup is necessary. */
delete_key_fn delete_key;
/* The deallocate-value function. NULL if no cleanup is necessary. */
delete_value_fn delete_value;
};
/* Constructor for typed_splay_tree <K, V>. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline typed_splay_tree<KEY_TYPE, VALUE_TYPE>::
typed_splay_tree (compare_fn compare_fn,
delete_key_fn delete_key_fn,
delete_value_fn delete_value_fn)
{
root = NULL;
comp = compare_fn;
delete_key = delete_key_fn;
delete_value = delete_value_fn;
}
/* Destructor for typed_splay_tree <K, V>. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline typed_splay_tree<KEY_TYPE, VALUE_TYPE>::
~typed_splay_tree ()
{
splay_tree_delete_helper (root);
}
/* Lookup KEY, returning a value if present, and NULL
otherwise. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline VALUE_TYPE
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::lookup (key_type key)
{
splay_tree_node node = splay_tree_lookup (key);
return node_to_value (node);
}
/* Return the immediate predecessor of KEY, or NULL if there is no
predecessor. KEY need not be present in the tree. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline VALUE_TYPE
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::predecessor (key_type key)
{
splay_tree_node node = splay_tree_predecessor (key);
return node_to_value (node);
}
/* Return the immediate successor of KEY, or NULL if there is no
successor. KEY need not be present in the tree. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline VALUE_TYPE
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::successor (key_type key)
{
splay_tree_node node = splay_tree_successor (key);
return node_to_value (node);
}
/* Insert a new node (associating KEY with VALUE). If a
previous node with the indicated KEY exists, its data is replaced
with the new value. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline void
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::insert (key_type key,
value_type value)
{
splay_tree_insert (key, value);
}
/* Remove a node (associating KEY with VALUE). */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline void
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::remove (key_type key)
{
splay_tree_remove (key);
}
/* Get the value with maximal key. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline VALUE_TYPE
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::max ()
{
return node_to_value (splay_tree_max ());
}
/* Get the value with minimal key. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline VALUE_TYPE
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::min ()
{
return node_to_value (splay_tree_min ());
}
/* Call OUTER_CB, passing it the OUTER_USER_DATA, for every node,
following an in-order traversal. If OUTER_CB ever returns a non-zero
value, the iteration ceases immediately, and the value is returned.
Otherwise, this function returns 0. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline int
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::foreach (foreach_fn foreach_fn,
void *user_data)
{
return splay_tree_foreach_helper (root, foreach_fn, user_data);
}
/* Internal function for converting from splay_tree_node to
VALUE_TYPE. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline VALUE_TYPE
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::node_to_value (splay_tree_node node)
{
if (node)
return node->value;
else
return 0;
}
template <typename KEY_TYPE, typename VALUE_TYPE>
inline void
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::KDEL(splay_tree_key x)
{
if (delete_key)
(*delete_key)(x);
}
template <typename KEY_TYPE, typename VALUE_TYPE>
inline void
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::VDEL(splay_tree_value x)
{
if (delete_value)
(*delete_value)(x);
}
/* Deallocate NODE (a member of SP), and all its sub-trees. */
template <typename KEY_TYPE, typename VALUE_TYPE>
void
typed_splay_tree<KEY_TYPE,
VALUE_TYPE>::splay_tree_delete_helper (splay_tree_node node)
{
splay_tree_node pending = NULL;
splay_tree_node active = NULL;
if (!node)
return;
KDEL (node->key);
VDEL (node->value);
/* We use the "back" field to hold the "next" pointer. */
node->back = pending;
pending = 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 = NULL;
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->back = pending;
pending = active->left;
}
if (active->right)
{
KDEL (active->right->key);
VDEL (active->right->value);
active->right->back = pending;
pending = active->right;
}
temp = active;
active = temp->back;
delete temp;
}
}
}
/* Rotate the edge joining the left child N with its parent P. PP is the
grandparents' pointer to P. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline void
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::rotate_left (splay_tree_node *pp,
splay_tree_node p,
splay_tree_node n)
{
splay_tree_node tmp;
tmp = n->right;
n->right = p;
p->left = tmp;
*pp = n;
}
/* Rotate the edge joining the right child N with its parent P. PP is the
grandparents' pointer to P. */
template <typename KEY_TYPE, typename VALUE_TYPE>
inline void
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::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. */
template <typename KEY_TYPE, typename VALUE_TYPE>
void
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_splay (splay_tree_key key)
{
if (root == NULL)
return;
do {
int cmp1, cmp2;
splay_tree_node n, c;
n = root;
cmp1 = (*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 = (*comp) (key, c->key);
if (cmp2 == 0
|| (cmp2 < 0 && !c->left)
|| (cmp2 > 0 && !c->right))
{
if (cmp1 < 0)
rotate_left (&root, n, c);
else
rotate_right (&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 (&root, n, n->left);
}
else if (cmp1 > 0 && cmp2 > 0)
{
rotate_right (&n->right, c, c->right);
rotate_right (&root, n, n->right);
}
else if (cmp1 < 0 && cmp2 > 0)
{
rotate_right (&n->left, c, c->right);
rotate_left (&root, n, n->left);
}
else if (cmp1 > 0 && cmp2 < 0)
{
rotate_left (&n->right, c, c->left);
rotate_right (&root, n, n->right);
}
} while (1);
}
/* Call FN, passing it the DATA, for every node below NODE, all of
which are from SP, following an in-order traversal. If FN every
returns a non-zero value, the iteration ceases immediately, and the
value is returned. Otherwise, this function returns 0. */
template <typename KEY_TYPE, typename VALUE_TYPE>
int
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_foreach_helper (
splay_tree_node node,
foreach_fn fn, void *data)
{
int val;
splay_tree_node stack;
/* A non-recursive implementation is used to avoid filling the stack
for large trees. Splay trees are worst case O(n) in the depth of
the tree. */
stack = NULL;
val = 0;
for (;;)
{
while (node != NULL)
{
node->back = stack;
stack = node;
node = node->left;
}
if (stack == NULL)
break;
node = stack;
stack = stack->back;
val = (*fn) (node->key, node->value, data);
if (val)
break;
node = node->right;
}
return val;
}
/* Insert a new node (associating KEY with DATA) into SP. If a
previous node with the indicated KEY exists, its data is replaced
with the new value. Returns the new node. */
template <typename KEY_TYPE, typename VALUE_TYPE>
typename typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_node
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_insert (
splay_tree_key key,
splay_tree_value value)
{
int comparison = 0;
splay_tree_splay (key);
if (root)
comparison = (*comp)(root->key, key);
if (root && comparison == 0)
{
/* If the root of the tree already has the indicated KEY, just
replace the value with VALUE. */
VDEL(root->value);
root->value = value;
}
else
{
/* Create a new node, and insert it at the root. */
splay_tree_node node;
node = new splay_tree_node_s;
node->key = key;
node->value = value;
if (!root)
node->left = node->right = 0;
else if (comparison < 0)
{
node->left = root;
node->right = node->left->right;
node->left->right = 0;
}
else
{
node->right = root;
node->left = node->right->left;
node->right->left = 0;
}
root = node;
}
return root;
}
/* Remove KEY from SP. It is not an error if it did not exist. */
template <typename KEY_TYPE, typename VALUE_TYPE>
void
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_remove (splay_tree_key key)
{
splay_tree_splay (key);
if (root && (*comp) (root->key, key) == 0)
{
splay_tree_node left, right;
left = root->left;
right = root->right;
/* Delete the root node itself. */
VDEL (root->value);
delete root;
/* One of the children is now the root. Doesn't matter much
which, so long as we preserve the properties of the tree. */
if (left)
{
root = left;
/* If there was a right child as well, hang it off the
right-most leaf of the left child. */
if (right)
{
while (left->right)
left = left->right;
left->right = right;
}
}
else
root = right;
}
}
/* Lookup KEY in SP, returning VALUE if present, and NULL
otherwise. */
template <typename KEY_TYPE, typename VALUE_TYPE>
typename typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_node
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_lookup (splay_tree_key key)
{
splay_tree_splay (key);
if (root && (*comp)(root->key, key) == 0)
return root;
else
return 0;
}
/* Return the node in SP with the greatest key. */
template <typename KEY_TYPE, typename VALUE_TYPE>
typename typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_node
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_max ()
{
splay_tree_node n = root;
if (!n)
return NULL;
while (n->right)
n = n->right;
return n;
}
/* Return the node in SP with the smallest key. */
template <typename KEY_TYPE, typename VALUE_TYPE>
typename typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_node
typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_min ()
{
splay_tree_node n = root;
if (!n)
return NULL;
while (n->left)
n = n->left;
return n;
}
/* Return the immediate predecessor KEY, or NULL if there is no
predecessor. KEY need not be present in the tree. */
template <typename KEY_TYPE, typename VALUE_TYPE>
typename typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_node
typed_splay_tree<KEY_TYPE,
VALUE_TYPE>::splay_tree_predecessor (splay_tree_key key)
{
int comparison;
splay_tree_node node;
/* If the tree is empty, there is certainly no predecessor. */
if (!root)
return NULL;
/* Splay the tree around KEY. That will leave either the KEY
itself, its predecessor, or its successor at the root. */
splay_tree_splay (key);
comparison = (*comp)(root->key, key);
/* If the predecessor is at the root, just return it. */
if (comparison < 0)
return root;
/* Otherwise, find the rightmost element of the left subtree. */
node = root->left;
if (node)
while (node->right)
node = node->right;
return node;
}
/* Return the immediate successor KEY, or NULL if there is no
successor. KEY need not be present in the tree. */
template <typename KEY_TYPE, typename VALUE_TYPE>
typename typed_splay_tree<KEY_TYPE, VALUE_TYPE>::splay_tree_node
typed_splay_tree<KEY_TYPE,
VALUE_TYPE>::splay_tree_successor (splay_tree_key key)
{
int comparison;
splay_tree_node node;
/* If the tree is empty, there is certainly no successor. */
if (!root)
return NULL;
/* Splay the tree around KEY. That will leave either the KEY
itself, its predecessor, or its successor at the root. */
splay_tree_splay (key);
comparison = (*comp)(root->key, key);
/* If the successor is at the root, just return it. */
if (comparison > 0)
return root;
/* Otherwise, find the leftmost element of the right subtree. */
node = root->right;
if (node)
while (node->left)
node = node->left;
return node;
}
#endif /* GCC_TYPED_SPLAY_TREE_H */