/* A splay-tree datatype.
- Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+ Copyright (C) 1998, 1999, 2000, 2001, 2009,
+ 2010, 2011 Free Software Foundation, Inc.
Contributed by Mark Mitchell (mark@markmitchell.com).
This file is part of GNU CC.
You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+the Free Software Foundation, 51 Franklin Street - Fifth Floor,
+Boston, MA 02110-1301, USA. */
/* For an easily readable description of splay-trees, see:
#include "libiberty.h"
#include "splay-tree.h"
-static void splay_tree_delete_helper PARAMS((splay_tree,
- splay_tree_node));
-static void splay_tree_splay PARAMS((splay_tree,
- splay_tree_key));
-static splay_tree_node splay_tree_splay_helper
- PARAMS((splay_tree,
- splay_tree_key,
- splay_tree_node*,
- splay_tree_node*,
- splay_tree_node*));
-static int splay_tree_foreach_helper PARAMS((splay_tree,
- splay_tree_node,
- splay_tree_foreach_fn,
- void*));
+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 int splay_tree_foreach_helper (splay_tree_node,
+ splay_tree_foreach_fn, void*);
/* Deallocate NODE (a member of SP), and all its sub-trees. */
static void
-splay_tree_delete_helper (sp, node)
- splay_tree sp;
- splay_tree_node node;
+splay_tree_delete_helper (splay_tree sp, splay_tree_node node)
{
+ splay_tree_node pending = 0;
+ splay_tree_node active = 0;
+
if (!node)
return;
- splay_tree_delete_helper (sp, node->left);
- splay_tree_delete_helper (sp, node->right);
-
- if (sp->delete_key)
- (*sp->delete_key)(node->key);
- if (sp->delete_value)
- (*sp->delete_value)(node->value);
-
- free ((char*) node);
-}
-
-/* Help splay SP around KEY. PARENT and GRANDPARENT are the parent
- and grandparent, respectively, of NODE. */
+#define KDEL(x) if (sp->delete_key) (*sp->delete_key)(x);
+#define VDEL(x) if (sp->delete_value) (*sp->delete_value)(x);
-static splay_tree_node
-splay_tree_splay_helper (sp, key, node, parent, grandparent)
- splay_tree sp;
- splay_tree_key key;
- splay_tree_node *node;
- splay_tree_node *parent;
- splay_tree_node *grandparent;
-{
- splay_tree_node *next;
- splay_tree_node n;
- int comparison;
-
- n = *node;
+ KDEL (node->key);
+ VDEL (node->value);
- if (!n)
- return *parent;
+ /* We use the "key" field to hold the "next" pointer. */
+ node->key = (splay_tree_key)pending;
+ pending = (splay_tree_node)node;
- 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;
+ /* 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. */
- if (next)
+ while (pending)
{
- /* Continue down the tree. */
- n = splay_tree_splay_helper (sp, key, next, node, parent);
+ active = pending;
+ pending = 0;
+ while (active)
+ {
+ splay_tree_node temp;
- /* The recursive call will change the place to which NODE
- points. */
- if (*node != n)
- return n;
- }
+ /* active points to a node which has its key and value
+ deallocated, we just need to process left and right. */
- if (!parent)
- /* NODE is the root. We are done. */
- return n;
+ 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);
+ }
- /* 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;
+ temp = active;
+ active = (splay_tree_node)(temp->key);
+ (*sp->deallocate) ((char*) temp, sp->allocate_data);
}
- else
- {
- *node = n->left;
- n->left = *parent;
- }
- *parent = n;
- return n;
}
+#undef KDEL
+#undef VDEL
+}
- /* 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;
- }
+/* Rotate the edge joining the left child N with its parent P. PP is the
+ grandparents' pointer to P. */
- /* 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;
- }
+static inline void
+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;
}
-/* 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 (sp, key)
- splay_tree sp;
- splay_tree_key key;
+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
value is returned. Otherwise, this function returns 0. */
static int
-splay_tree_foreach_helper (sp, node, fn, data)
- splay_tree sp;
- splay_tree_node node;
- splay_tree_foreach_fn fn;
- void* data;
+splay_tree_foreach_helper (splay_tree_node node,
+ splay_tree_foreach_fn fn, void *data)
{
int val;
+ splay_tree_node *stack;
+ int stack_ptr, stack_size;
- if (!node)
- return 0;
+ /* 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. */
- val = splay_tree_foreach_helper (sp, node->left, fn, data);
- if (val)
- return val;
+#define INITIAL_STACK_SIZE 100
+ stack_size = INITIAL_STACK_SIZE;
+ stack_ptr = 0;
+ stack = XNEWVEC (splay_tree_node, stack_size);
+ val = 0;
- val = (*fn)(node, data);
- if (val)
- return val;
+ for (;;)
+ {
+ while (node != NULL)
+ {
+ if (stack_ptr == stack_size)
+ {
+ stack_size *= 2;
+ stack = XRESIZEVEC (splay_tree_node, stack, stack_size);
+ }
+ stack[stack_ptr++] = node;
+ node = node->left;
+ }
+
+ if (stack_ptr == 0)
+ break;
+
+ node = stack[--stack_ptr];
+
+ val = (*fn) (node, data);
+ if (val)
+ break;
+
+ node = node->right;
+ }
+
+ XDELETEVEC (stack);
+ return val;
+}
+
+/* An allocator and deallocator based on xmalloc. */
+static void *
+splay_tree_xmalloc_allocate (int size, void *data ATTRIBUTE_UNUSED)
+{
+ return (void *) xmalloc (size);
+}
+
+static void
+splay_tree_xmalloc_deallocate (void *object, void *data ATTRIBUTE_UNUSED)
+{
+ free (object);
+}
- return splay_tree_foreach_helper (sp, node->right, fn, data);
+
+/* Allocate a new splay tree, using COMPARE_FN to compare nodes,
+ DELETE_KEY_FN to deallocate keys, and DELETE_VALUE_FN to deallocate
+ values. Use xmalloc to allocate the splay tree structure, and any
+ nodes added. */
+
+splay_tree
+splay_tree_new (splay_tree_compare_fn compare_fn,
+ splay_tree_delete_key_fn delete_key_fn,
+ splay_tree_delete_value_fn delete_value_fn)
+{
+ return (splay_tree_new_with_allocator
+ (compare_fn, delete_key_fn, delete_value_fn,
+ splay_tree_xmalloc_allocate, splay_tree_xmalloc_deallocate, 0));
}
+
/* Allocate a new splay tree, using COMPARE_FN to compare nodes,
DELETE_KEY_FN to deallocate keys, and DELETE_VALUE_FN to deallocate
values. */
splay_tree
-splay_tree_new (compare_fn, delete_key_fn, delete_value_fn)
- splay_tree_compare_fn compare_fn;
- splay_tree_delete_key_fn delete_key_fn;
- splay_tree_delete_value_fn delete_value_fn;
+splay_tree_new_with_allocator (splay_tree_compare_fn compare_fn,
+ splay_tree_delete_key_fn delete_key_fn,
+ splay_tree_delete_value_fn delete_value_fn,
+ splay_tree_allocate_fn allocate_fn,
+ splay_tree_deallocate_fn deallocate_fn,
+ void *allocate_data)
+{
+ return
+ splay_tree_new_typed_alloc (compare_fn, delete_key_fn, delete_value_fn,
+ allocate_fn, allocate_fn, deallocate_fn,
+ allocate_data);
+}
+
+/*
+
+@deftypefn Supplemental splay_tree splay_tree_new_with_typed_alloc @
+(splay_tree_compare_fn @var{compare_fn}, @
+splay_tree_delete_key_fn @var{delete_key_fn}, @
+splay_tree_delete_value_fn @var{delete_value_fn}, @
+splay_tree_allocate_fn @var{tree_allocate_fn}, @
+splay_tree_allocate_fn @var{node_allocate_fn}, @
+splay_tree_deallocate_fn @var{deallocate_fn}, @
+void * @var{allocate_data})
+
+This function creates a splay tree that uses two different allocators
+@var{tree_allocate_fn} and @var{node_allocate_fn} to use for allocating the
+tree itself and its nodes respectively. This is useful when variables of
+different types need to be allocated with different allocators.
+
+The splay tree will use @var{compare_fn} to compare nodes,
+@var{delete_key_fn} to deallocate keys, and @var{delete_value_fn} to
+deallocate values.
+
+@end deftypefn
+
+*/
+
+splay_tree
+splay_tree_new_typed_alloc (splay_tree_compare_fn compare_fn,
+ splay_tree_delete_key_fn delete_key_fn,
+ splay_tree_delete_value_fn delete_value_fn,
+ splay_tree_allocate_fn tree_allocate_fn,
+ splay_tree_allocate_fn node_allocate_fn,
+ splay_tree_deallocate_fn deallocate_fn,
+ void * allocate_data)
{
- splay_tree sp = (splay_tree) xmalloc (sizeof (struct splay_tree_s));
+ splay_tree sp = (splay_tree) (*tree_allocate_fn)
+ (sizeof (struct splay_tree_s), allocate_data);
+
sp->root = 0;
sp->comp = compare_fn;
sp->delete_key = delete_key_fn;
sp->delete_value = delete_value_fn;
+ sp->allocate = node_allocate_fn;
+ sp->deallocate = deallocate_fn;
+ sp->allocate_data = allocate_data;
return sp;
}
/* Deallocate SP. */
void
-splay_tree_delete (sp)
- splay_tree sp;
+splay_tree_delete (splay_tree sp)
{
splay_tree_delete_helper (sp, sp->root);
- free ((char*) sp);
+ (*sp->deallocate) ((char*) sp, sp->allocate_data);
}
/* Insert a new node (associating KEY with DATA) into SP. If a
with the new value. Returns the new node. */
splay_tree_node
-splay_tree_insert (sp, key, value)
- splay_tree sp;
- splay_tree_key key;
- splay_tree_value value;
+splay_tree_insert (splay_tree sp, splay_tree_key key, splay_tree_value value)
{
int comparison = 0;
{
/* Create a new node, and insert it at the root. */
splay_tree_node node;
-
- node = (splay_tree_node) xmalloc (sizeof (struct splay_tree_node_s));
+
+ node = ((splay_tree_node)
+ (*sp->allocate) (sizeof (struct splay_tree_node_s),
+ sp->allocate_data));
node->key = key;
node->value = value;
/* Remove KEY from SP. It is not an error if it did not exist. */
void
-splay_tree_remove (sp, key)
- splay_tree sp;
- splay_tree_key key;
+splay_tree_remove (splay_tree sp, splay_tree_key key)
{
splay_tree_splay (sp, key);
/* Delete the root node itself. */
if (sp->delete_value)
(*sp->delete_value) (sp->root->value);
- free (sp->root);
+ (*sp->deallocate) (sp->root, sp->allocate_data);
/* One of the children is now the root. Doesn't matter much
which, so long as we preserve the properties of the tree. */
otherwise. */
splay_tree_node
-splay_tree_lookup (sp, key)
- splay_tree sp;
- splay_tree_key key;
+splay_tree_lookup (splay_tree sp, splay_tree_key key)
{
splay_tree_splay (sp, key);
/* Return the node in SP with the greatest key. */
splay_tree_node
-splay_tree_max (sp)
- splay_tree sp;
+splay_tree_max (splay_tree sp)
{
splay_tree_node n = sp->root;
/* Return the node in SP with the smallest key. */
splay_tree_node
-splay_tree_min (sp)
- splay_tree sp;
+splay_tree_min (splay_tree sp)
{
splay_tree_node n = sp->root;
predecessor. KEY need not be present in the tree. */
splay_tree_node
-splay_tree_predecessor (sp, key)
- splay_tree sp;
- splay_tree_key key;
+splay_tree_predecessor (splay_tree sp, splay_tree_key key)
{
int comparison;
splay_tree_node node;
if (comparison < 0)
return sp->root;
- /* Otherwise, find the leftmost element of the right subtree. */
+ /* Otherwise, find the rightmost element of the left subtree. */
node = sp->root->left;
if (node)
while (node->right)
}
/* Return the immediate successor KEY, or NULL if there is no
- predecessor. KEY need not be present in the tree. */
+ successor. KEY need not be present in the tree. */
splay_tree_node
-splay_tree_successor (sp, key)
- splay_tree sp;
- splay_tree_key key;
+splay_tree_successor (splay_tree sp, splay_tree_key key)
{
int comparison;
splay_tree_node node;
- /* If the tree is empty, there is certainly no predecessor. */
+ /* If the tree is empty, there is certainly no successor. */
if (!sp->root)
return NULL;
if (comparison > 0)
return sp->root;
- /* Otherwise, find the rightmost element of the left subtree. */
+ /* Otherwise, find the leftmost element of the right subtree. */
node = sp->root->right;
if (node)
while (node->left)
Otherwise, this function returns 0. */
int
-splay_tree_foreach (sp, fn, data)
- splay_tree sp;
- splay_tree_foreach_fn fn;
- void *data;
+splay_tree_foreach (splay_tree sp, splay_tree_foreach_fn fn, void *data)
{
- return splay_tree_foreach_helper (sp, sp->root, fn, data);
+ return splay_tree_foreach_helper (sp->root, fn, data);
}
/* Splay-tree comparison function, treating the keys as ints. */
int
-splay_tree_compare_ints (k1, k2)
- splay_tree_key k1;
- splay_tree_key k2;
+splay_tree_compare_ints (splay_tree_key k1, splay_tree_key k2)
{
if ((int) k1 < (int) k2)
return -1;
/* Splay-tree comparison function, treating the keys as pointers. */
int
-splay_tree_compare_pointers (k1, k2)
- splay_tree_key k1;
- splay_tree_key k2;
+splay_tree_compare_pointers (splay_tree_key k1, splay_tree_key k2)
{
if ((char*) k1 < (char*) k2)
return -1;
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