/*
This file was derived from the libwww code, version 2.15, from CERN.
A number of modifications have been made by Spyglass.
eric@spyglass.com
*/
/* Binary Tree for sorting things
** ==============================
** Author: Arthur Secret
**
** 4 March 94: Bug fixed in the balancing procedure
**
*/
#include "all.h"
#define MAXIMUM(a,b) ((a)>(b)?(a):(b))
PUBLIC HTBTree *HTBTree_new(HTComparer comp)
/*********************************************************
** This function returns an HTBTree with memory allocated
** for it when given a mean to compare things
*/
{
HTBTree *tree = (HTBTree *) GTR_MALLOC(sizeof(HTBTree));
if (tree != NULL)
{
tree->compare = comp;
tree->top = NULL;
}
return tree;
}
PRIVATE void HTBTElement_free(HTBTElement * element)
/**********************************************************
** This void will free the memory allocated for one element
*/
{
if (element)
{
if (element->left != NULL)
HTBTElement_free(element->left);
if (element->right != NULL)
HTBTElement_free(element->right);
GTR_FREE(element);
}
}
PUBLIC void HTBTree_free(HTBTree * tree)
/**************************************************************
** This void will free the memory allocated for the whole tree
*/
{
HTBTElement_free(tree->top);
GTR_FREE(tree);
}
PRIVATE void HTBTElementAndObject_free(HTBTElement * element)
/**********************************************************
** This void will free the memory allocated for one element
*/
{
if (element)
{ /* Just in case nothing was in the tree anyway */
if (element->left != NULL)
HTBTElementAndObject_free(element->left);
if (element->right != NULL)
HTBTElementAndObject_free(element->right);
GTR_FREE(element->object);
GTR_FREE(element);
}
}
PUBLIC void HTBTreeAndObject_free(HTBTree * tree)
/**************************************************************
** This void will free the memory allocated for the whole tree
*/
{
HTBTElementAndObject_free(tree->top);
GTR_FREE(tree);
}
/* TODO: The memory handling here might be a little unreliable in extreme
low-memory conditions. I recommend we just nuke this entire file and
replace the BTree with a flat list, since it's only used for reading
FTP directories anyway. - JLS */
PUBLIC void HTBTree_add(HTBTree * tree, void *object)
/**********************************************************************
** This void is the core of HTBTree.c . It will
** 1/ add a new element to the tree at the right place
** so that the tree remains sorted
** 2/ balance the tree to be as fast as possible when reading it
*/
{
HTBTElement *father_of_element;
HTBTElement *added_element;
HTBTElement *forefather_of_element;
HTBTElement *father_of_forefather;
BOOL father_found, top_found;
int depth, depth2, corrections;
/* father_of_element is a pointer to the structure that is the father of the
** new object "object".
** added_element is a pointer to the structure that contains or will contain
** the new object "object".
** father_of_forefather and forefather_of_element are pointers that are used
** to modify the depths of upper elements, when needed.
**
** father_found indicates by a value NO when the future father of "object"
** is found.
** top_found indicates by a value NO when, in case of a difference of depths
** < 2, the top of the tree is encountered and forbids any further try to
** balance the tree.
** corrections is an integer used to avoid infinite loops in cases
** such as:
**
** 3 3
** 4 4
** 5 5
**
** 3 is used here to show that it need not be the top of the tree.
*/
/*
** 1/ Adding of the element to the binary tree
*/
if (tree->top == NULL)
{
tree->top = (HTBTElement *) GTR_MALLOC(sizeof(HTBTElement));
if (tree->top != NULL)
{
XX_DMsg(DBG_WWW, ("HTBTree_add: can't allocate tree->top\n"));
tree->top->up = NULL;
tree->top->object = object;
tree->top->left = NULL;
tree->top->left_depth = 0;
tree->top->right = NULL;
tree->top->right_depth = 0;
}
else
XX_DMsg(DBG_WWW, ("HTBTree_add: can't allocate tree->top\n"));
}
else
{
father_found = YES;
father_of_element = tree->top;
added_element = NULL;
father_of_forefather = NULL;
forefather_of_element = NULL;
while (father_found)
{
if (tree->compare(object, father_of_element->object) < 0)
{
if (father_of_element->left != NULL)
father_of_element = father_of_element->left;
else
{
father_found = NO;
father_of_element->left = (HTBTElement *) GTR_MALLOC(sizeof(HTBTElement));
if (father_of_element->left != NULL)
{
added_element = father_of_element->left;
added_element->up = father_of_element;
added_element->object = object;
added_element->left = NULL;
added_element->left_depth = 0;
added_element->right = NULL;
added_element->right_depth = 0;
}
else
XX_DMsg(DBG_WWW, ("HTBTree_add: can't allocate father_of_element->left\n"));
}
}
if (tree->compare(object, father_of_element->object) >= 0)
{
if (father_of_element->right != NULL)
father_of_element = father_of_element->right;
else
{
father_found = NO;
father_of_element->right =
(HTBTElement *) GTR_MALLOC(sizeof(HTBTElement));
if (father_of_element->right != NULL)
{
added_element = father_of_element->right;
added_element->up = father_of_element;
added_element->object = object;
added_element->left = NULL;
added_element->left_depth = 0;
added_element->right = NULL;
added_element->right_depth = 0;
}
else
XX_DMsg(DBG_WWW, ("HTBTree_add: can't allocate father_of_element->right\n"));
}
}
}
/*
** Changing of all depths that need to be changed
*/
father_of_forefather = father_of_element;
forefather_of_element = added_element;
do
{
if (father_of_forefather->left == forefather_of_element)
{
depth = father_of_forefather->left_depth;
father_of_forefather->left_depth = 1
+ MAXIMUM(forefather_of_element->right_depth,
forefather_of_element->left_depth);
depth2 = father_of_forefather->left_depth;
}
else
{
depth = father_of_forefather->right_depth;
father_of_forefather->right_depth = 1
+ MAXIMUM(forefather_of_element->right_depth,
forefather_of_element->left_depth);
depth2 = father_of_forefather->right_depth;
}
forefather_of_element = father_of_forefather;
father_of_forefather = father_of_forefather->up;
}
while ((depth != depth2) && (father_of_forefather != NULL));
/*
** 2/ Balancing the binary tree, if necessary
*/
top_found = YES;
corrections = 0;
while ((top_found) && (corrections < 7))
{
if ((abs(father_of_element->left_depth
- father_of_element->right_depth)) < 2)
{
if (father_of_element->up != NULL)
father_of_element = father_of_element->up;
else
top_found = NO;
}
else
{ /* We start the process of balancing */
corrections = corrections + 1;
/*
** corrections is an integer used to avoid infinite
** loops in cases such as:
**
** 3 3
** 4 4
** 5 5
**
** 3 is used to show that it need not be the top of the tree
** But let's avoid these two exceptions anyhow
** with the two following conditions (4 March 94 - AS)
*/
if ((father_of_element->left == NULL)
&& (father_of_element->right->right == NULL)
&& (father_of_element->right->left->left == NULL)
&& (father_of_element->right->left->right == NULL))
corrections = 7;
if ((father_of_element->right == NULL)
&& (father_of_element->left->left == NULL)
&& (father_of_element->left->right->right == NULL)
&& (father_of_element->left->right->left == NULL))
corrections = 7;
if (father_of_element->left_depth > father_of_element->right_depth)
{
added_element = father_of_element->left;
father_of_element->left_depth = added_element->right_depth;
added_element->right_depth = 1
+ MAXIMUM(father_of_element->right_depth,
father_of_element->left_depth);
if (father_of_element->up != NULL)
{
/* Bug fixed in March 94 - AS */
BOOL first_time;
father_of_forefather = father_of_element->up;
forefather_of_element = added_element;
first_time = YES;
do
{
if (father_of_forefather->left
== forefather_of_element->up)
{
depth = father_of_forefather->left_depth;
if (first_time)
{
father_of_forefather->left_depth = 1
+ MAXIMUM(forefather_of_element->left_depth,
forefather_of_element->right_depth);
first_time = NO;
}
else
father_of_forefather->left_depth = 1
+ MAXIMUM(forefather_of_element->up->left_depth,
forefather_of_element->up->right_depth);
depth2 = father_of_forefather->left_depth;
}
else
{
depth = father_of_forefather->right_depth;
if (first_time)
{
father_of_forefather->right_depth = 1
+ MAXIMUM(forefather_of_element->left_depth,
forefather_of_element->right_depth);
first_time = NO;
}
else
father_of_forefather->right_depth = 1
+ MAXIMUM(forefather_of_element->up->left_depth,
forefather_of_element->up->right_depth);
depth2 = father_of_forefather->right_depth;
}
forefather_of_element = forefather_of_element->up;
father_of_forefather = father_of_forefather->up;
}
while ((depth != depth2) &&
(father_of_forefather != NULL));
father_of_forefather = father_of_element->up;
if (father_of_forefather->left == father_of_element)
{
/*
** 3 3
** 4 5
** When tree 5 6 becomes 7 4
** 7 8 8 6
**
** 3 is used to show that it may not be the top of the
** tree.
*/
father_of_forefather->left = added_element;
father_of_element->left = added_element->right;
added_element->right = father_of_element;
}
if (father_of_forefather->right == father_of_element)
{
/*
** 3 3
** 4 5
** When tree 5 6 becomes 7 4
** 7 8 8 6
**
** 3 is used to show that it may not be the top of the
** tree
*/
father_of_forefather->right = added_element;
father_of_element->left = added_element->right;
added_element->right = father_of_element;
}
added_element->up = father_of_forefather;
}
else
{
/*
**
** 1 2
** When tree 2 3 becomes 4 1
** 4 5 5 3
**
** 1 is used to show that it is the top of the tree
*/
added_element->up = NULL;
father_of_element->left = added_element->right;
added_element->right = father_of_element;
}
father_of_element->up = added_element;
if (father_of_element->left != NULL)
father_of_element->left->up = father_of_element;
}
else
{
added_element = father_of_element->right;
father_of_element->right_depth = added_element->left_depth;
added_element->left_depth = 1 +
MAXIMUM(father_of_element->right_depth,
father_of_element->left_depth);
if (father_of_element->up != NULL)
/* Bug fixed in March 94 - AS */
{
BOOL first_time;
father_of_forefather = father_of_element->up;
forefather_of_element = added_element;
first_time = YES;
do
{
if (father_of_forefather->left
== forefather_of_element->up)
{
depth = father_of_forefather->left_depth;
if (first_time)
{
father_of_forefather->left_depth = 1
+ MAXIMUM(forefather_of_element->left_depth,
forefather_of_element->right_depth);
first_time = NO;
}
else
father_of_forefather->left_depth = 1
+ MAXIMUM(forefather_of_element->up->left_depth,
forefather_of_element->up->right_depth);
depth2 = father_of_forefather->left_depth;
}
else
{
depth = father_of_forefather->right_depth;
if (first_time)
{
father_of_forefather->right_depth = 1
+ MAXIMUM(forefather_of_element->left_depth,
forefather_of_element->right_depth);
first_time = NO;
}
else
father_of_forefather->right_depth = 1
+ MAXIMUM(forefather_of_element->up->left_depth,
forefather_of_element->up->right_depth);
depth2 = father_of_forefather->right_depth;
}
father_of_forefather = father_of_forefather->up;
forefather_of_element = forefather_of_element->up;
}
while ((depth != depth2) &&
(father_of_forefather != NULL));
father_of_forefather = father_of_element->up;
if (father_of_forefather->left == father_of_element)
{
/*
** 3 3
** 4 6
** When tree 5 6 becomes 4 8
** 7 8 5 7
**
** 3 is used to show that it may not be the top of the
** tree.
*/
father_of_forefather->left = added_element;
father_of_element->right = added_element->left;
added_element->left = father_of_element;
}
if (father_of_forefather->right == father_of_element)
{
/*
** 3 3
** 4 6
** When tree 5 6 becomes 4 8
** 7 8 5 7
**
** 3 is used to show that it may not be the top of the
** tree
*/
father_of_forefather->right = added_element;
father_of_element->right = added_element->left;
added_element->left = father_of_element;
}
added_element->up = father_of_forefather;
}
else
{
/*
**
** 1 3
** When tree 2 3 becomes 1 5
** 4 5 2 4
**
** 1 is used to show that it is the top of the tree.
*/
added_element->up = NULL;
father_of_element->right = added_element->left;
added_element->left = father_of_element;
}
father_of_element->up = added_element;
if (father_of_element->right != NULL)
father_of_element->right->up = father_of_element;
}
}
}
while (father_of_element->up != NULL)
{
father_of_element = father_of_element->up;
}
tree->top = father_of_element;
}
}
PUBLIC HTBTElement *HTBTree_next(HTBTree * tree, HTBTElement * ele)
/**************************************************************************
** this function returns a pointer to the leftmost element if ele is NULL,
** and to the next object to the right otherways.
** If no elements left, returns a pointer to NULL.
*/
{
HTBTElement *father_of_element;
HTBTElement *father_of_forefather;
if (ele == NULL)
{
father_of_element = tree->top;
if (father_of_element != NULL)
while (father_of_element->left != NULL)
father_of_element = father_of_element->left;
}
else
{
father_of_element = ele;
if (father_of_element->right != NULL)
{
father_of_element = father_of_element->right;
while (father_of_element->left != NULL)
father_of_element = father_of_element->left;
}
else
{
father_of_forefather = father_of_element->up;
while (father_of_forefather &&
(father_of_forefather->right == father_of_element))
{
father_of_element = father_of_forefather;
father_of_forefather = father_of_element->up;
}
father_of_element = father_of_forefather;
}
}
#ifdef BTREE_TRACE
/* The option -DBTREE_TRACE will give much more information
** about the way the process is running, for debugging matters
*/
if (father_of_element != NULL)
{
printf("\nObject = %s\t", (char *) father_of_element->object);
if (father_of_element->up != NULL)
printf("Objet du pere = %s\n",
(char *) father_of_element->up->object);
else
printf("Pas de Pere\n");
if (father_of_element->left != NULL)
printf("Objet du fils gauche = %s\t",
(char *) father_of_element->left->object);
else
printf("Pas de fils gauche\t");
if (father_of_element->right != NULL)
printf("Objet du fils droit = %s\n",
(char *) father_of_element->right->object);
else
printf("Pas de fils droit\n");
printf("Profondeur gauche = %i\t", father_of_element->left_depth);
printf("Profondeur droite = %i\n", father_of_element->right_depth);
printf(" **************\n");
}
#endif
return father_of_element;
}
#ifdef TEST
main()
/******************************************************
** This is just a test to show how to handle HTBTree.c
*/
{
HTBTree *tree;
HTBTElement *next_element;
tree = HTBTree_new((HTComparer) strcasecmp);
HTBTree_add(tree, "hypertext");
HTBTree_add(tree, "Addressing");
HTBTree_add(tree, "X11");
HTBTree_add(tree, "Tools");
HTBTree_add(tree, "Proposal.wn");
HTBTree_add(tree, "Protocols");
HTBTree_add(tree, "NeXT");
HTBTree_add(tree, "Daemon");
HTBTree_add(tree, "Test");
HTBTree_add(tree, "Administration");
HTBTree_add(tree, "LineMode");
HTBTree_add(tree, "DesignIssues");
HTBTree_add(tree, "MarkUp");
HTBTree_add(tree, "Macintosh");
HTBTree_add(tree, "Proposal.rtf.wn");
HTBTree_add(tree, "FIND");
HTBTree_add(tree, "Paper");
HTBTree_add(tree, "Tcl");
HTBTree_add(tree, "Talks");
HTBTree_add(tree, "Architecture");
HTBTree_add(tree, "VMSHelp");
HTBTree_add(tree, "Provider");
HTBTree_add(tree, "Archive");
HTBTree_add(tree, "SLAC");
HTBTree_add(tree, "Project");
HTBTree_add(tree, "News");
HTBTree_add(tree, "Viola");
HTBTree_add(tree, "Users");
HTBTree_add(tree, "FAQ");
HTBTree_add(tree, "WorkingNotes");
HTBTree_add(tree, "Windows");
HTBTree_add(tree, "FineWWW");
HTBTree_add(tree, "Frame");
HTBTree_add(tree, "XMosaic");
HTBTree_add(tree, "People");
HTBTree_add(tree, "All");
HTBTree_add(tree, "Curses");
HTBTree_add(tree, "Erwise");
HTBTree_add(tree, "Carl");
HTBTree_add(tree, "MidasWWW");
HTBTree_add(tree, "XPM");
HTBTree_add(tree, "MailRobot");
HTBTree_add(tree, "Illustrations");
HTBTree_add(tree, "VMClient");
HTBTree_add(tree, "XPA");
HTBTree_add(tree, "Clients.html");
HTBTree_add(tree, "Library");
HTBTree_add(tree, "CERNLIB_Distribution");
HTBTree_add(tree, "libHTML");
HTBTree_add(tree, "WindowsPC");
HTBTree_add(tree, "tkWWW");
HTBTree_add(tree, "tk2.3");
HTBTree_add(tree, "CVS-RCS");
HTBTree_add(tree, "DecnetSockets");
HTBTree_add(tree, "SGMLStream");
HTBTree_add(tree, "NextStep");
HTBTree_add(tree, "CVSRepository_old");
HTBTree_add(tree, "ArthurSecret");
HTBTree_add(tree, "CVSROOT");
HTBTree_add(tree, "HytelnetGate");
HTBTree_add(tree, "cern.www.new.src");
HTBTree_add(tree, "Conditions");
HTBTree_add(tree, "HTMLGate");
HTBTree_add(tree, "Makefile");
HTBTree_add(tree, "Newsgroups.html");
HTBTree_add(tree, "People.html");
HTBTree_add(tree, "Bugs.html");
HTBTree_add(tree, "Summary.html");
HTBTree_add(tree, "zDesignIssues.wn");
HTBTree_add(tree, "HT.draw");
HTBTree_add(tree, "HTandCERN.wn");
HTBTree_add(tree, "Ideas.wn");
HTBTree_add(tree, "MarkUp.wn");
HTBTree_add(tree, "Proposal.html");
HTBTree_add(tree, "SearchPanel.draw");
HTBTree_add(tree, "Comments.wn");
HTBTree_add(tree, "Xanadu.html");
HTBTree_add(tree, "Storinglinks.html");
HTBTree_add(tree, "TheW3Book.html");
HTBTree_add(tree, "Talk_Feb-91.html");
HTBTree_add(tree, "JFosterEntry.txt");
HTBTree_add(tree, "Summary.txt");
HTBTree_add(tree, "Bibliography.html");
HTBTree_add(tree, "HTandCern.txt");
HTBTree_add(tree, "Talk.draw");
HTBTree_add(tree, "zDesignNotes.html");
HTBTree_add(tree, "Link.html");
HTBTree_add(tree, "Status.html");
HTBTree_add(tree, "http.txt");
HTBTree_add(tree, "People.html~");
HTBTree_add(tree, "TAGS");
HTBTree_add(tree, "summary.txt");
HTBTree_add(tree, "Technical.html");
HTBTree_add(tree, "Terms.html");
HTBTree_add(tree, "JANETAccess.html");
HTBTree_add(tree, "People.txt");
HTBTree_add(tree, "README.txt");
HTBTree_add(tree, "CodingStandards.html");
HTBTree_add(tree, "Copyright.txt");
HTBTree_add(tree, "Status_old.html");
HTBTree_add(tree, "patches~");
HTBTree_add(tree, "RelatedProducts.html");
HTBTree_add(tree, "Implementation");
HTBTree_add(tree, "History.html");
HTBTree_add(tree, "Makefile.bak");
HTBTree_add(tree, "Makefile.old");
HTBTree_add(tree, "Policy.html");
HTBTree_add(tree, "WhatIs.html");
HTBTree_add(tree, "TheProject.html");
HTBTree_add(tree, "Notation.html");
HTBTree_add(tree, "Helping.html");
HTBTree_add(tree, "Cyber-WWW.sit.Hqx");
HTBTree_add(tree, "Glossary.html");
HTBTree_add(tree, "maketags.html");
HTBTree_add(tree, "IntroCS.html");
HTBTree_add(tree, "Contrib");
HTBTree_add(tree, "Help.html");
HTBTree_add(tree, "CodeManagExec");
HTBTree_add(tree, "HT-0.1draz");
HTBTree_add(tree, "Cello");
HTBTree_add(tree, "TOPUB");
HTBTree_add(tree, "BUILD");
HTBTree_add(tree, "BUILDALL");
HTBTree_add(tree, "Lynx");
HTBTree_add(tree, "ArthurLibrary");
HTBTree_add(tree, "RashtyClient");
HTBTree_add(tree, "#History.html#");
HTBTree_add(tree, "PerlServers");
HTBTree_add(tree, "modules");
HTBTree_add(tree, "NCSA_httpd");
HTBTree_add(tree, "MAIL2HTML");
HTBTree_add(tree, "core");
HTBTree_add(tree, "EmacsWWW");
#ifdef BTREE_TRACE
printf("\nTreeTopObject=%s\n\n", tree->top->object);
#endif
next_element = HTBTree_next(tree, NULL);
while (next_element != NULL)
{
#ifndef BTREE_TRACE
printf("The next element is %s\n", next_element->object);
#endif
next_element = HTBTree_next(tree, next_element);
}
HTBTree_free(tree);
}
#endif