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authorDaniel Stenberg <daniel@haxx.se>2006-04-10 15:00:53 +0000
committerDaniel Stenberg <daniel@haxx.se>2006-04-10 15:00:53 +0000
commit686d90745be4417127050ad4b36d0a5403def200 (patch)
tree786a63b7554065aa0514440adf35fd7b639ae94c /lib/splay.c
parent5dc02d53c3edebab7597cd4ada446273e3a6daa8 (diff)
downloadcurl-686d90745be4417127050ad4b36d0a5403def200.tar.gz
First curl_multi_socket() commit. Should primarily be considered as an internal
code rearrange to fit the future better.
Diffstat (limited to 'lib/splay.c')
-rw-r--r--lib/splay.c406
1 files changed, 406 insertions, 0 deletions
diff --git a/lib/splay.c b/lib/splay.c
new file mode 100644
index 000000000..0ea078b6c
--- /dev/null
+++ b/lib/splay.c
@@ -0,0 +1,406 @@
+/***************************************************************************
+ * _ _ ____ _
+ * 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 = r->smaller = NULL;
+
+ 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 *area)
+{
+ if (area == NULL)
+ return t;
+
+ if (t != NULL) {
+ t = Curl_splay(i,t);
+ if (compare(i, t->key)==0) {
+ /* it already exists one of this size */
+
+ area->same = t;
+ area->key = i;
+ area->smaller = t->smaller;
+ area->larger = t->larger;
+
+ t->smaller = area;
+ t->key = KEY_NOTUSED;
+
+ return area; /* new root node */
+ }
+ }
+
+ if (t == NULL) {
+ area->smaller = area->larger = NULL;
+ }
+ else if (compare(i, t->key) < 0) {
+ area->smaller = t->smaller;
+ area->larger = t;
+ t->smaller = NULL;
+
+ }
+ else {
+ area->larger = t->larger;
+ area->smaller = t;
+ t->larger = NULL;
+ }
+ area->key = i;
+
+ area->same = NULL; /* no identical node (yet) */
+ return area;
+}
+
+/* Deletes 'i' from the tree if it's there (with an exact match). Returns a
+ pointer to the resulting tree. */
+struct Curl_tree *Curl_splayremove(int i, struct Curl_tree *t,
+ struct Curl_tree **removed)
+{
+ struct Curl_tree *x;
+
+ 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 {
+ *removed = NULL; /* no match */
+ return t; /* It wasn't there */
+ }
+}
+
+/* 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 node we point out from the tree if it's there. Return a pointer
+ to the resulting tree. */
+struct Curl_tree *Curl_splayremovebyaddr(struct Curl_tree *t,
+ struct Curl_tree *remove)
+{
+ struct Curl_tree *x;
+
+ if (!t || !remove)
+ return NULL;
+
+ if(KEY_NOTUSED == remove->key) {
+ /* just unlink ourselves nice and quickly: */
+ remove->smaller->same = remove->same;
+ if(remove->same)
+ remove->same->smaller = remove->smaller;
+ /* voila, we're done! */
+ return t;
+ }
+
+ t = Curl_splay(remove->key, t);
+
+ /* Check if there is a list with identical sizes */
+
+ x = t->same;
+ if(x) {
+ /* 'x' is the new root node */
+
+ x->key = t->key;
+ x->larger = t->larger;
+ x->smaller = t->smaller;
+
+ return x; /* new root */
+ }
+
+ /* Remove the actualy root node: */
+ if (t->smaller == NULL)
+ x = t->larger;
+ else {
+ x = Curl_splay(remove->key, t->smaller);
+ x->larger = t->larger;
+ }
+
+ return x;
+}
+
+#ifdef CURLDEBUG
+
+int Curl_splayprint(struct Curl_tree * t, int d, char output)
+{
+ int distance=0;
+ struct Curl_tree *node;
+ int i;
+ if (t == NULL)
+ return 0;
+ distance += 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(node = t->same; node; node = node->same) {
+ distance += i; /* this has the same "virtual" distance */
+
+ if(output)
+ printf(" [+]");
+ }
+ if(output)
+ puts("");
+
+ distance += i;
+
+ distance += Curl_splayprint(t->smaller, d+1, output);
+
+ return distance;
+}
+#endif
+
+#ifdef TEST_SPLAY
+
+/*#define TEST2 */
+#define MAX 50
+#define OUTPUT 0 /* 1 enables, 0 disables */
+
+/* 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];
+
+ 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++) {
+ ptrs[i] = t = (struct Curl_tree *)malloc(sizeof(struct Curl_tree));
+ if(!t) {
+ puts("out of memory!");
+ return 0;
+ }
+#ifdef TEST2
+ root = Curl_splayinsert(sizes[i], root, t);
+#else
+ root = Curl_splayinsert((541*i)&1023, root, t);
+#endif
+ }
+
+#if 0
+ puts("Result:");
+ printtree(root, 0, 1);
+#endif
+
+#if 1
+ for (i=0; root; i+=30) {
+ Curl_splayprint(root, 0, 1);
+ do {
+ root = Curl_splaygetbest(i, root, &t);
+ if(t)
+ printf("bestfit %d became %d\n", i, t->key);
+ else
+ printf("bestfit %d failed!\n", i);
+ } while(t && root);
+ }
+#endif
+#if 0
+ for (i = 0; i < MAX; i++) {
+ printf("remove pointer %d size %d\n", i, sizes[i]);
+ root = removebyaddr(root, (struct Curl_tree *)ptrs[i]);
+ Curl_splayprint(root, 0, 1);
+ }
+#endif
+
+#if 0
+#ifdef WEIGHT
+ for (i = -1; i<=root->weight; i++) {
+ t = find_rank(i, root);
+ if (t == NULL) {
+ printf("could not find a node of rank %d.\n", i);
+ } else {
+ printf("%d is of rank %d\n", t->key, i);
+ }
+ }
+#endif
+#endif
+
+#if 0
+#ifdef TEST2
+ for (i = 0; i < MAX; i++) {
+ printf("remove size %d\n", sizes[i]);
+ root = Curl_splayremove(sizes[i], root, &t);
+ free(t);
+ Curl_splayprint(root, 0, 1);
+ }
+#endif
+#endif
+ return 0;
+}
+
+#endif /* TEST_SPLAY */