summaryrefslogtreecommitdiffstats
path: root/Utilities/cmcurl/splay.c
diff options
context:
space:
mode:
Diffstat (limited to 'Utilities/cmcurl/splay.c')
-rw-r--r--Utilities/cmcurl/splay.c425
1 files changed, 425 insertions, 0 deletions
diff --git a/Utilities/cmcurl/splay.c b/Utilities/cmcurl/splay.c
new file mode 100644
index 0000000..9fb66c7
--- /dev/null
+++ b/Utilities/cmcurl/splay.c
@@ -0,0 +1,425 @@
+/***************************************************************************
+ * _ _ ____ _
+ * Project ___| | | | _ \| |
+ * / __| | | | |_) | |
+ * | (__| |_| | _ <| |___
+ * \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1997 - 2006, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * $Id$
+ ***************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "splay.h"
+
+#define compare(i,j) ((i)-(j))
+
+/* Set this to a key value that will *NEVER* appear otherwise */
+#define KEY_NOTUSED -1
+
+/*
+ * Splay using the key i (which may or may not be in the tree.) The starting
+ * root is t.
+ */
+struct Curl_tree *Curl_splay(int i, struct Curl_tree *t)
+{
+ struct Curl_tree N, *l, *r, *y;
+ int comp;
+
+ if (t == NULL)
+ return t;
+ N.smaller = N.larger = NULL;
+ l = r = &N;
+
+ for (;;) {
+ comp = compare(i, t->key);
+ if (comp < 0) {
+ if (t->smaller == NULL)
+ break;
+ if (compare(i, t->smaller->key) < 0) {
+ y = t->smaller; /* rotate smaller */
+ t->smaller = y->larger;
+ y->larger = t;
+ t = y;
+ if (t->smaller == NULL)
+ break;
+ }
+ r->smaller = t; /* link smaller */
+ r = t;
+ t = t->smaller;
+ }
+ else if (comp > 0) {
+ if (t->larger == NULL)
+ break;
+ if (compare(i, t->larger->key) > 0) {
+ y = t->larger; /* rotate larger */
+ t->larger = y->smaller;
+ y->smaller = t;
+ t = y;
+ if (t->larger == NULL)
+ break;
+ }
+ l->larger = t; /* link larger */
+ l = t;
+ t = t->larger;
+ }
+ else
+ break;
+ }
+
+ l->larger = t->smaller; /* assemble */
+ r->smaller = t->larger;
+ t->smaller = N.larger;
+ t->larger = N.smaller;
+
+ return t;
+}
+
+/* Insert key i into the tree t. Return a pointer to the resulting tree or
+ NULL if something went wrong. */
+struct Curl_tree *Curl_splayinsert(int i,
+ struct Curl_tree *t,
+ struct Curl_tree *node)
+{
+ if (node == NULL)
+ return t;
+
+ if (t != NULL) {
+ t = Curl_splay(i,t);
+ if (compare(i, t->key)==0) {
+ /* There already exists a node in the tree with the very same key. Build
+ a linked list of nodes. We make the new 'node' struct the new master
+ node and make the previous node the first one in the 'same' list. */
+
+ node->same = t;
+ node->key = i;
+ node->smaller = t->smaller;
+ node->larger = t->larger;
+
+ t->smaller = node; /* in the sub node for this same key, we use the
+ smaller pointer to point back to the master
+ node */
+
+ t->key = KEY_NOTUSED; /* and we set the key in the sub node to NOTUSED
+ to quickly identify this node as a subnode */
+
+ return node; /* new root node */
+ }
+ }
+
+ if (t == NULL) {
+ node->smaller = node->larger = NULL;
+ }
+ else if (compare(i, t->key) < 0) {
+ node->smaller = t->smaller;
+ node->larger = t;
+ t->smaller = NULL;
+
+ }
+ else {
+ node->larger = t->larger;
+ node->smaller = t;
+ t->larger = NULL;
+ }
+ node->key = i;
+
+ node->same = NULL; /* no identical node (yet) */
+ return node;
+}
+
+#if 0
+/* Deletes 'i' from the tree if it's there (with an exact match). Returns a
+ pointer to the resulting tree.
+
+ Function not used in libcurl.
+*/
+struct Curl_tree *Curl_splayremove(int i, struct Curl_tree *t,
+ struct Curl_tree **removed)
+{
+ struct Curl_tree *x;
+
+ *removed = NULL; /* default to no removed */
+
+ if (t==NULL)
+ return NULL;
+
+ t = Curl_splay(i,t);
+ if (compare(i, t->key) == 0) { /* found it */
+
+ /* FIRST! Check if there is a list with identical sizes */
+ if((x = t->same)) {
+ /* there is, pick one from the list */
+
+ /* 'x' is the new root node */
+
+ x->key = t->key;
+ x->larger = t->larger;
+ x->smaller = t->smaller;
+
+ *removed = t;
+ return x; /* new root */
+ }
+
+ if (t->smaller == NULL) {
+ x = t->larger;
+ }
+ else {
+ x = Curl_splay(i, t->smaller);
+ x->larger = t->larger;
+ }
+ *removed = t;
+
+ return x;
+ }
+ else
+ return t; /* It wasn't there */
+}
+#endif
+
+/* Finds and deletes the best-fit node from the tree. Return a pointer to the
+ resulting tree. best-fit means the node with the given or lower number */
+struct Curl_tree *Curl_splaygetbest(int i, struct Curl_tree *t,
+ struct Curl_tree **removed)
+{
+ struct Curl_tree *x;
+
+ if (!t) {
+ *removed = NULL; /* none removed since there was no root */
+ return NULL;
+ }
+
+ t = Curl_splay(i,t);
+ if(compare(i, t->key) < 0) {
+ /* too big node, try the smaller chain */
+ if(t->smaller)
+ t=Curl_splay(t->smaller->key, t);
+ else {
+ /* fail */
+ *removed = NULL;
+ return t;
+ }
+ }
+
+ if (compare(i, t->key) >= 0) { /* found it */
+ /* FIRST! Check if there is a list with identical sizes */
+ x = t->same;
+ if(x) {
+ /* there is, pick one from the list */
+
+ /* 'x' is the new root node */
+
+ x->key = t->key;
+ x->larger = t->larger;
+ x->smaller = t->smaller;
+
+ *removed = t;
+ return x; /* new root */
+ }
+
+ if (t->smaller == NULL) {
+ x = t->larger;
+ }
+ else {
+ x = Curl_splay(i, t->smaller);
+ x->larger = t->larger;
+ }
+ *removed = t;
+
+ return x;
+ }
+ else {
+ *removed = NULL; /* no match */
+ return t; /* It wasn't there */
+ }
+}
+
+
+/* Deletes the very node we point out from the tree if it's there. Stores a
+ pointer to the new resulting tree in 'newroot'.
+
+ Returns zero on success and non-zero on errors! TODO: document error codes.
+ When returning error, it does not touch the 'newroot' pointer.
+
+ NOTE: when the last node of the tree is removed, there's no tree left so
+ 'newroot' will be made to point to NULL.
+*/
+int Curl_splayremovebyaddr(struct Curl_tree *t,
+ struct Curl_tree *remove,
+ struct Curl_tree **newroot)
+{
+ struct Curl_tree *x;
+
+ if (!t || !remove)
+ return 1;
+
+ if(KEY_NOTUSED == remove->key) {
+ /* Key set to NOTUSED means it is a subnode within a 'same' linked list
+ and thus we can unlink it easily. The 'smaller' link of a subnode
+ links to the parent node. */
+ if (remove->smaller == NULL)
+ return 3;
+
+ remove->smaller->same = remove->same;
+ if(remove->same)
+ remove->same->smaller = remove->smaller;
+
+ /* Ensures that double-remove gets caught. */
+ remove->smaller = NULL;
+
+ /* voila, we're done! */
+ *newroot = t; /* return the same root */
+ return 0;
+ }
+
+ t = Curl_splay(remove->key, t);
+
+ /* First make sure that we got the same root node as the one we want
+ to remove, as otherwise we might be trying to remove a node that
+ isn't actually in the tree.
+
+ We cannot just compare the keys here as a double remove in quick
+ succession of a node with key != KEY_NOTUSED && same != NULL
+ could return the same key but a different node. */
+ if(t != remove)
+ return 2;
+
+ /* Check if there is a list with identical sizes, as then we're trying to
+ remove the root node of a list of nodes with identical keys. */
+ x = t->same;
+ if(x) {
+ /* 'x' is the new root node, we just make it use the root node's
+ smaller/larger links */
+
+ x->key = t->key;
+ x->larger = t->larger;
+ x->smaller = t->smaller;
+ }
+ else {
+ /* Remove the root node */
+ if (t->smaller == NULL)
+ x = t->larger;
+ else {
+ x = Curl_splay(remove->key, t->smaller);
+ x->larger = t->larger;
+ }
+ }
+
+ *newroot = x; /* store new root pointer */
+
+ return 0;
+}
+
+#ifdef CURLDEBUG
+
+void Curl_splayprint(struct Curl_tree * t, int d, char output)
+{
+ struct Curl_tree *node;
+ int i;
+ int count;
+ if (t == NULL)
+ return;
+
+ Curl_splayprint(t->larger, d+1, output);
+ for (i=0; i<d; i++)
+ if(output)
+ printf(" ");
+
+ if(output) {
+ printf("%d[%d]", t->key, i);
+ }
+
+ for(count=0, node = t->same; node; node = node->same, count++)
+ ;
+
+ if(output) {
+ if(count)
+ printf(" [%d more]\n", count);
+ else
+ printf("\n");
+ }
+
+ Curl_splayprint(t->smaller, d+1, output);
+}
+#endif
+
+#ifdef TEST_SPLAY
+
+/*#define TEST2 */
+#define MAX 50
+#define TEST2
+
+/* A sample use of these functions. Start with the empty tree, insert some
+ stuff into it, and then delete it */
+int main(int argc, char **argv)
+{
+ struct Curl_tree *root, *t;
+ void *ptrs[MAX];
+ int adds=0;
+ int rc;
+
+ long sizes[]={
+ 50, 60, 50, 100, 60, 200, 120, 300, 400, 200, 256, 122, 60, 120, 200, 300,
+ 220, 80, 90, 50, 100, 60, 200, 120, 300, 400, 200, 256, 122, 60, 120, 200,
+ 300, 220, 80, 90, 50, 100, 60, 200, 120, 300, 400, 200, 256, 122, 60, 120,
+ 200, 300, 220, 80, 90};
+ int i;
+ root = NULL; /* the empty tree */
+
+ for (i = 0; i < MAX; i++) {
+ int key;
+ ptrs[i] = t = (struct Curl_tree *)malloc(sizeof(struct Curl_tree));
+
+#ifdef TEST2
+ key = sizes[i];
+#elif defined(TEST1)
+ key = (541*i)%1023;
+#elif defined(TEST3)
+ key = 100;
+#endif
+
+ t->payload = (void *)key; /* for simplicity */
+ if(!t) {
+ puts("out of memory!");
+ return 0;
+ }
+ root = Curl_splayinsert(key, root, t);
+ }
+
+#if 0
+ puts("Result:");
+ Curl_splayprint(root, 0, 1);
+#endif
+
+#if 1
+ for (i = 0; i < MAX; i++) {
+ int rem = (i+7)%MAX;
+ struct Curl_tree *r;
+ printf("Tree look:\n");
+ Curl_splayprint(root, 0, 1);
+ printf("remove pointer %d, payload %d\n", rem,
+ (int)((struct Curl_tree *)ptrs[rem])->payload);
+ rc = Curl_splayremovebyaddr(root, (struct Curl_tree *)ptrs[rem], &root);
+ if(rc)
+ /* failed! */
+ printf("remove %d failed!\n", rem);
+ }
+#endif
+
+ return 0;
+}
+
+#endif /* TEST_SPLAY */
generated by cgit v0.12 at 2024-11-14 07:22:08 (GMT)