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curl
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Ifdef'ed out unused function, added lots of comments and renamed a few 

variables, simplified the splayprint function, modified
Curl_splayremovebyaddr() to return error code. All in an effort to track down
the reported splay problem, but I've failed to do that so far...
This commit is contained in:
Daniel Stenberg 2006-05-27 22:25:55 +00:00
parent edb5444fa3
commit f81724969d
1 changed files with 107 additions and 99 deletions
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206
lib/splay.c
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@ -77,9 +77,8 @@ struct Curl_tree *Curl_splay(int i, struct Curl_tree *t)
l = t;
t = t->larger;
}
else {
else
break;
}
}
l->larger = r->smaller = NULL;
@ -93,51 +92,61 @@ struct Curl_tree *Curl_splay(int i, struct Curl_tree *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)
struct Curl_tree *Curl_splayinsert(int i,
struct Curl_tree *t,
struct Curl_tree *node)
{
if (area == NULL)
if (node == NULL)
return t;
if (t != NULL) {
t = Curl_splay(i,t);
if (compare(i, t->key)==0) {
/* it already exists one of this size */
/* 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. */
area->same = t;
area->key = i;
area->smaller = t->smaller;
area->larger = t->larger;
node->same = t;
node->key = i;
node->smaller = t->smaller;
node->larger = t->larger;
t->smaller = area;
t->key = KEY_NOTUSED;
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 area; /* new root node */
return node; /* new root node */
}
}
if (t == NULL) {
area->smaller = area->larger = NULL;
node->smaller = node->larger = NULL;
}
else if (compare(i, t->key) < 0) {
area->smaller = t->smaller;
area->larger = t;
node->smaller = t->smaller;
node->larger = t;
t->smaller = NULL;
}
else {
area->larger = t->larger;
area->smaller = t;
node->larger = t->larger;
node->smaller = t;
t->larger = NULL;
}
area->key = i;
node->key = i;
area->same = NULL; /* no identical node (yet) */
return area;
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. */
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)
{
@ -179,6 +188,7 @@ struct Curl_tree *Curl_splayremove(int i, struct Curl_tree *t,
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 */
@ -238,61 +248,81 @@ struct Curl_tree *Curl_splaygetbest(int i, struct Curl_tree *t,
}
/* 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)
/* 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 NULL;
return 1;
if(KEY_NOTUSED == remove->key) {
/* just unlink ourselves nice and quickly: */
/* 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. */
remove->smaller->same = remove->same;
if(remove->same)
remove->same->smaller = remove->smaller;
/* voila, we're done! */
return t;
*newroot = t; /* return the same root */
return 0;
}
t = Curl_splay(remove->key, t);
/* Check if there is a list with identical sizes */
/* First make sure that we got a root node witht he same key as the one we
want to remove, as otherwise we might be trying to remove a node that
isn't actually in the tree. */
if(t->key != remove->key)
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 */
/* '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;
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;
/* Remove the root node */
if (t->smaller == NULL)
x = t->larger;
else {
x = Curl_splay(remove->key, t->smaller);
x->larger = t->larger;
}
}
return x;
*newroot = x; /* store new root pointer */
return 0;
}
#ifdef CURLDEBUG
int Curl_splayprint(struct Curl_tree * t, int d, char output)
void Curl_splayprint(struct Curl_tree * t, int d, char output)
{
int distance=0;
struct Curl_tree *node;
int i;
int count;
if (t == NULL)
return 0;
distance += Curl_splayprint(t->larger, d+1, output);
return;
Curl_splayprint(t->larger, d+1, output);
for (i=0; i<d; i++)
if(output)
printf(" ");
@ -301,20 +331,17 @@ int Curl_splayprint(struct Curl_tree * t, int d, char output)
printf("%d[%d]", t->key, i);
}
for(node = t->same; node; node = node->same) {
distance += i; /* this has the same "virtual" distance */
for(count=0, node = t->same; node; node = node->same, count++)
;
if(output)
printf(" [+]");
if(output) {
if(count)
printf(" [%d more]\n", count);
else
printf("\n");
}
if(output)
puts("");
distance += i;
distance += Curl_splayprint(t->smaller, d+1, output);
return distance;
Curl_splayprint(t->smaller, d+1, output);
}
#endif
@ -322,7 +349,7 @@ int Curl_splayprint(struct Curl_tree * t, int d, char output)
/*#define TEST2 */
#define MAX 50
#define OUTPUT 0 /* 1 enables, 0 disables */
#define TEST2
/* A sample use of these functions. Start with the empty tree, insert some
stuff into it, and then delete it */
@ -330,6 +357,8 @@ 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,
@ -340,66 +369,45 @@ int main(int argc, char **argv)
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;
}
#ifdef TEST2
root = Curl_splayinsert(sizes[i], root, t);
#else
root = Curl_splayinsert((541*i)&1023, root, t);
#endif
root = Curl_splayinsert(key, root, t);
}
#if 0
puts("Result:");
printtree(root, 0, 1);
Curl_splayprint(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]);
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
#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;
}