/*
 * tree234.c: reasonably generic counted 2-3-4 tree routines.
 * 
 * This file is copyright 1999-2001 Simon Tatham.
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT.  IN NO EVENT SHALL SIMON TATHAM BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#include "tree234.h"

#define smalloc malloc
#define sfree free

#define mknew(typ) ( (typ *) smalloc (sizeof (typ)) )

#ifdef TEST
#define LOG(x) (printf x)
#else
#define LOG(x)
#endif

typedef struct node234_Tag node234;

struct tree234_Tag {
  node234 *root;
  cmpfn234 cmp;
};

struct node234_Tag {
  node234 *parent;
  node234 *kids[4];
  int counts[4];
  void *elems[3];
};

/*
 * Create a 2-3-4 tree.
 */
tree234 *newtree234(cmpfn234 cmp)
{
  tree234 *ret = mknew(tree234);
  LOG(("created tree %p\n", ret));
  ret->root = NULL;
  ret->cmp = cmp;
  return ret;
}

/*
 * Free a 2-3-4 tree (not including freeing the elements).
 */
static void freenode234(node234 * n)
{
  if (!n)
    return;
  freenode234(n->kids[0]);
  freenode234(n->kids[1]);
  freenode234(n->kids[2]);
  freenode234(n->kids[3]);
  sfree(n);
}

void freetree234(tree234 * t)
{
  freenode234(t->root);
  sfree(t);
}

/*
 * Internal function to count a node.
 */
static int countnode234(node234 * n)
{
  int count = 0;
  int i;
  if (!n)
    return 0;
  for (i = 0; i < 4; i++)
    count += n->counts[i];
  for (i = 0; i < 3; i++)
    if (n->elems[i])
      count++;
  return count;
}

/*
 * Count the elements in a tree.
 */
int count234(tree234 * t)
{
  if (t->root)
    return countnode234(t->root);
  else
    return 0;
}

/*
 * Propagate a node overflow up a tree until it stops. Returns 0 or
 * 1, depending on whether the root had to be split or not.
 */
static int
add234_insert(node234 * left, void *e, node234 * right,
              node234 ** root, node234 * n, int ki)
{
  int lcount, rcount;
  /*
   * We need to insert the new left/element/right set in n at
   * child position ki.
   */
  lcount = countnode234(left);
  rcount = countnode234(right);
  while (n)
  {
    LOG(("  at %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
         n,
         n->kids[0], n->counts[0], n->elems[0],
         n->kids[1], n->counts[1], n->elems[1],
         n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3]));
    LOG(("  need to insert %p/%d \"%s\" %p/%d at position %d\n", left,
         lcount, e, right, rcount, ki));
    if (n->elems[1] == NULL)
    {
      /*
       * Insert in a 2-node; simple.
       */
      if (ki == 0)
      {
        LOG(("  inserting on left of 2-node\n"));
        n->kids[2] = n->kids[1];
        n->counts[2] = n->counts[1];
        n->elems[1] = n->elems[0];
        n->kids[1] = right;
        n->counts[1] = rcount;
        n->elems[0] = e;
        n->kids[0] = left;
        n->counts[0] = lcount;
      } else
      {                         /* ki == 1 */
        LOG(("  inserting on right of 2-node\n"));
        n->kids[2] = right;
        n->counts[2] = rcount;
        n->elems[1] = e;
        n->kids[1] = left;
        n->counts[1] = lcount;
      }
      if (n->kids[0])
        n->kids[0]->parent = n;
      if (n->kids[1])
        n->kids[1]->parent = n;
      if (n->kids[2])
        n->kids[2]->parent = n;
      LOG(("  done\n"));
      break;
    } else if (n->elems[2] == NULL)
    {
      /*
       * Insert in a 3-node; simple.
       */
      if (ki == 0)
      {
        LOG(("  inserting on left of 3-node\n"));
        n->kids[3] = n->kids[2];
        n->counts[3] = n->counts[2];
        n->elems[2] = n->elems[1];
        n->kids[2] = n->kids[1];
        n->counts[2] = n->counts[1];
        n->elems[1] = n->elems[0];
        n->kids[1] = right;
        n->counts[1] = rcount;
        n->elems[0] = e;
        n->kids[0] = left;
        n->counts[0] = lcount;
      } else if (ki == 1)
      {
        LOG(("  inserting in middle of 3-node\n"));
        n->kids[3] = n->kids[2];
        n->counts[3] = n->counts[2];
        n->elems[2] = n->elems[1];
        n->kids[2] = right;
        n->counts[2] = rcount;
        n->elems[1] = e;
        n->kids[1] = left;
        n->counts[1] = lcount;
      } else
      {                         /* ki == 2 */
        LOG(("  inserting on right of 3-node\n"));
        n->kids[3] = right;
        n->counts[3] = rcount;
        n->elems[2] = e;
        n->kids[2] = left;
        n->counts[2] = lcount;
      }
      if (n->kids[0])
        n->kids[0]->parent = n;
      if (n->kids[1])
        n->kids[1]->parent = n;
      if (n->kids[2])
        n->kids[2]->parent = n;
      if (n->kids[3])
        n->kids[3]->parent = n;
      LOG(("  done\n"));
      break;
    } else
    {
      node234 *m = mknew(node234);
      m->parent = n->parent;
      LOG(("  splitting a 4-node; created new node %p\n", m));
      /*
       * Insert in a 4-node; split into a 2-node and a
       * 3-node, and move focus up a level.
       * 
       * I don't think it matters which way round we put the
       * 2 and the 3. For simplicity, we'll put the 3 first
       * always.
       */
      if (ki == 0)
      {
        m->kids[0] = left;
        m->counts[0] = lcount;
        m->elems[0] = e;
        m->kids[1] = right;
        m->counts[1] = rcount;
        m->elems[1] = n->elems[0];
        m->kids[2] = n->kids[1];
        m->counts[2] = n->counts[1];
        e = n->elems[1];
        n->kids[0] = n->kids[2];
        n->counts[0] = n->counts[2];
        n->elems[0] = n->elems[2];
        n->kids[1] = n->kids[3];
        n->counts[1] = n->counts[3];
      } else if (ki == 1)
      {
        m->kids[0] = n->kids[0];
        m->counts[0] = n->counts[0];
        m->elems[0] = n->elems[0];
        m->kids[1] = left;
        m->counts[1] = lcount;
        m->elems[1] = e;
        m->kids[2] = right;
        m->counts[2] = rcount;
        e = n->elems[1];
        n->kids[0] = n->kids[2];
        n->counts[0] = n->counts[2];
        n->elems[0] = n->elems[2];
        n->kids[1] = n->kids[3];
        n->counts[1] = n->counts[3];
      } else if (ki == 2)
      {
        m->kids[0] = n->kids[0];
        m->counts[0] = n->counts[0];
        m->elems[0] = n->elems[0];
        m->kids[1] = n->kids[1];
        m->counts[1] = n->counts[1];
        m->elems[1] = n->elems[1];
        m->kids[2] = left;
        m->counts[2] = lcount;
        /* e = e; */
        n->kids[0] = right;
        n->counts[0] = rcount;
        n->elems[0] = n->elems[2];
        n->kids[1] = n->kids[3];
        n->counts[1] = n->counts[3];
      } else
      {                         /* ki == 3 */
        m->kids[0] = n->kids[0];
        m->counts[0] = n->counts[0];
        m->elems[0] = n->elems[0];
        m->kids[1] = n->kids[1];
        m->counts[1] = n->counts[1];
        m->elems[1] = n->elems[1];
        m->kids[2] = n->kids[2];
        m->counts[2] = n->counts[2];
        n->kids[0] = left;
        n->counts[0] = lcount;
        n->elems[0] = e;
        n->kids[1] = right;
        n->counts[1] = rcount;
        e = n->elems[2];
      }
      m->kids[3] = n->kids[3] = n->kids[2] = NULL;
      m->counts[3] = n->counts[3] = n->counts[2] = 0;
      m->elems[2] = n->elems[2] = n->elems[1] = NULL;
      if (m->kids[0])
        m->kids[0]->parent = m;
      if (m->kids[1])
        m->kids[1]->parent = m;
      if (m->kids[2])
        m->kids[2]->parent = m;
      if (n->kids[0])
        n->kids[0]->parent = n;
      if (n->kids[1])
        n->kids[1]->parent = n;
      LOG(("  left (%p): %p/%d \"%s\" %p/%d \"%s\" %p/%d\n", m,
           m->kids[0], m->counts[0], m->elems[0],
           m->kids[1], m->counts[1], m->elems[1],
           m->kids[2], m->counts[2]));
      LOG(("  right (%p): %p/%d \"%s\" %p/%d\n", n,
           n->kids[0], n->counts[0], n->elems[0],
           n->kids[1], n->counts[1]));
      left = m;
      lcount = countnode234(left);
      right = n;
      rcount = countnode234(right);
    }
    if (n->parent)
      ki = (n->parent->kids[0] == n ? 0 :
            n->parent->kids[1] == n ? 1 : n->parent->kids[2] == n ? 2 : 3);
    n = n->parent;
  }

  /*
   * If we've come out of here by `break', n will still be
   * non-NULL and all we need to do is go back up the tree
   * updating counts. If we've come here because n is NULL, we
   * need to create a new root for the tree because the old one
   * has just split into two. */
  if (n)
  {
    while (n->parent)
    {
      int count = countnode234(n);
      int childnum;
      childnum = (n->parent->kids[0] == n ? 0 :
                  n->parent->kids[1] == n ? 1 :
                  n->parent->kids[2] == n ? 2 : 3);
      n->parent->counts[childnum] = count;
      n = n->parent;
    }
    return 0;                   /* root unchanged */
  } else
  {
    LOG(("  root is overloaded, split into two\n"));
    (*root) = mknew(node234);
    (*root)->kids[0] = left;
    (*root)->counts[0] = lcount;
    (*root)->elems[0] = e;
    (*root)->kids[1] = right;
    (*root)->counts[1] = rcount;
    (*root)->elems[1] = NULL;
    (*root)->kids[2] = NULL;
    (*root)->counts[2] = 0;
    (*root)->elems[2] = NULL;
    (*root)->kids[3] = NULL;
    (*root)->counts[3] = 0;
    (*root)->parent = NULL;
    if ((*root)->kids[0])
      (*root)->kids[0]->parent = (*root);
    if ((*root)->kids[1])
      (*root)->kids[1]->parent = (*root);
    LOG(("  new root is %p/%d \"%s\" %p/%d\n",
         (*root)->kids[0], (*root)->counts[0],
         (*root)->elems[0], (*root)->kids[1], (*root)->counts[1]));
    return 1;                   /* root moved */
  }
}

/*
 * Add an element e to a 2-3-4 tree t. Returns e on success, or if
 * an existing element compares equal, returns that.
 */
static void *add234_internal(tree234 * t, void *e, int index)
{
  node234 *n;
  int ki;
  void *orig_e = e;
  int c;

  LOG(("adding element \"%s\" to tree %p\n", e, t));
  if (t->root == NULL)
  {
    t->root = mknew(node234);
    t->root->elems[1] = t->root->elems[2] = NULL;
    t->root->kids[0] = t->root->kids[1] = NULL;
    t->root->kids[2] = t->root->kids[3] = NULL;
    t->root->counts[0] = t->root->counts[1] = 0;
    t->root->counts[2] = t->root->counts[3] = 0;
    t->root->parent = NULL;
    t->root->elems[0] = e;
    LOG(("  created root %p\n", t->root));
    return orig_e;
  }

  n = t->root;
  while (n)
  {
    LOG(("  node %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
         n,
         n->kids[0], n->counts[0], n->elems[0],
         n->kids[1], n->counts[1], n->elems[1],
         n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3]));
    if (index >= 0)
    {
      if (!n->kids[0])
      {
        /*
         * Leaf node. We want to insert at kid position
         * equal to the index:
         * 
         *   0 A 1 B 2 C 3
         */
        ki = index;
      } else
      {
        /*
         * Internal node. We always descend through it (add
         * always starts at the bottom, never in the
         * middle).
         */
        if (index <= n->counts[0])
        {
          ki = 0;
        } else if (index -= n->counts[0] + 1, index <= n->counts[1])
        {
          ki = 1;
        } else if (index -= n->counts[1] + 1, index <= n->counts[2])
        {
          ki = 2;
        } else if (index -= n->counts[2] + 1, index <= n->counts[3])
        {
          ki = 3;
        } else
          return NULL;          /* error: index out of range */
      }
    } else
    {
      if ((c = t->cmp(e, n->elems[0])) < 0)
        ki = 0;
      else if (c == 0)
        return n->elems[0];     /* already exists */
      else if (n->elems[1] == NULL || (c = t->cmp(e, n->elems[1])) < 0)
        ki = 1;
      else if (c == 0)
        return n->elems[1];     /* already exists */
      else if (n->elems[2] == NULL || (c = t->cmp(e, n->elems[2])) < 0)
        ki = 2;
      else if (c == 0)
        return n->elems[2];     /* already exists */
      else
        ki = 3;
    }
    LOG(("  moving to child %d (%p)\n", ki, n->kids[ki]));
    if (!n->kids[ki])
      break;
    n = n->kids[ki];
  }

  add234_insert(NULL, e, NULL, &t->root, n, ki);

  return orig_e;
}

void *add234(tree234 * t, void *e)
{
  if (!t->cmp)                  /* tree is unsorted */
    return NULL;

  return add234_internal(t, e, -1);
}

void *addpos234(tree234 * t, void *e, int index)
{
  if (index < 0 ||              /* index out of range */
      t->cmp)                   /* tree is sorted */
    return NULL;                /* return failure */

  return add234_internal(t, e, index);  /* this checks the upper bound */
}

/*
 * Look up the element at a given numeric index in a 2-3-4 tree.
 * Returns NULL if the index is out of range.
 */
void *index234(tree234 * t, int index)
{
  node234 *n;

  if (!t->root)
    return NULL;                /* tree is empty */

  if (index < 0 || index >= countnode234(t->root))
    return NULL;                /* out of range */

  n = t->root;

  while (n)
  {
    if (index < n->counts[0])
      n = n->kids[0];
    else if (index -= n->counts[0] + 1, index < 0)
      return n->elems[0];
    else if (index < n->counts[1])
      n = n->kids[1];
    else if (index -= n->counts[1] + 1, index < 0)
      return n->elems[1];
    else if (index < n->counts[2])
      n = n->kids[2];
    else if (index -= n->counts[2] + 1, index < 0)
      return n->elems[2];
    else
      n = n->kids[3];
  }

  /* We shouldn't ever get here. I wonder how we did. */
  return NULL;
}

/*
 * Find an element e in a sorted 2-3-4 tree t. Returns NULL if not
 * found. e is always passed as the first argument to cmp, so cmp
 * can be an asymmetric function if desired. cmp can also be passed
 * as NULL, in which case the compare function from the tree proper
 * will be used.
 */
void *findrelpos234(tree234 * t, void *e, cmpfn234 cmp, int relation,
                    int *index)
{
  node234 *n;
  void *ret;
  int c;
  int idx, ecount, kcount, cmpret;

  if (t->root == NULL)
    return NULL;

  if (cmp == NULL)
    cmp = t->cmp;

  n = t->root;
  /*
   * Attempt to find the element itself.
   */
  idx = 0;
  ecount = -1;
  /*
   * Prepare a fake `cmp' result if e is NULL.
   */
  cmpret = 0;
  if (e == NULL)
  {
    assert(relation == REL234_LT || relation == REL234_GT);
    if (relation == REL234_LT)
      cmpret = +1;              /* e is a max: always greater */
    else if (relation == REL234_GT)
      cmpret = -1;              /* e is a min: always smaller */
  }
  while (1)
  {
    for (kcount = 0; kcount < 4; kcount++)
    {
      if (kcount >= 3 || n->elems[kcount] == NULL ||
          (c = cmpret ? cmpret : cmp(e, n->elems[kcount])) < 0)
      {
        break;
      }
      if (n->kids[kcount])
        idx += n->counts[kcount];
      if (c == 0)
      {
        ecount = kcount;
        break;
      }
      idx++;
    }
    if (ecount >= 0)
      break;
    if (n->kids[kcount])
      n = n->kids[kcount];
    else
      break;
  }

  if (ecount >= 0)
  {
    /*
     * We have found the element we're looking for. It's
     * n->elems[ecount], at tree index idx. If our search
     * relation is EQ, LE or GE we can now go home.
     */
    if (relation != REL234_LT && relation != REL234_GT)
    {
      if (index)
        *index = idx;
      return n->elems[ecount];
    }

    /*
     * Otherwise, we'll do an indexed lookup for the previous
     * or next element. (It would be perfectly possible to
     * implement these search types in a non-counted tree by
     * going back up from where we are, but far more fiddly.)
     */
    if (relation == REL234_LT)
      idx--;
    else
      idx++;
  } else
  {
    /*
     * We've found our way to the bottom of the tree and we
     * know where we would insert this node if we wanted to:
     * we'd put it in in place of the (empty) subtree
     * n->kids[kcount], and it would have index idx
     * 
     * But the actual element isn't there. So if our search
     * relation is EQ, we're doomed.
     */
    if (relation == REL234_EQ)
      return NULL;

    /*
     * Otherwise, we must do an index lookup for index idx-1
     * (if we're going left - LE or LT) or index idx (if we're
     * going right - GE or GT).
     */
    if (relation == REL234_LT || relation == REL234_LE)
    {
      idx--;
    }
  }

  /*
   * We know the index of the element we want; just call index234
   * to do the rest. This will return NULL if the index is out of
   * bounds, which is exactly what we want.
   */
  ret = index234(t, idx);
  if (ret && index)
    *index = idx;
  return ret;
}

void *find234(tree234 * t, void *e, cmpfn234 cmp)
{
  return findrelpos234(t, e, cmp, REL234_EQ, NULL);
}

void *findrel234(tree234 * t, void *e, cmpfn234 cmp, int relation)
{
  return findrelpos234(t, e, cmp, relation, NULL);
}

void *findpos234(tree234 * t, void *e, cmpfn234 cmp, int *index)
{
  return findrelpos234(t, e, cmp, REL234_EQ, index);
}

/*
 * Tree transformation used in delete and split: move a subtree
 * right, from child ki of a node to the next child. Update k and
 * index so that they still point to the same place in the
 * transformed tree. Assumes the destination child is not full, and
 * that the source child does have a subtree to spare. Can cope if
 * the destination child is undersized.
 * 
 *                . C .                     . B .
 *               /     \     ->            /     \
 * [more] a A b B c   d D e      [more] a A b   c C d D e
 * 
 *                 . C .                     . B .
 *                /     \    ->             /     \
 *  [more] a A b B c     d        [more] a A b   c C d
 */
static void trans234_subtree_right(node234 * n, int ki, int *k, int *index)
{
  node234 *src, *dest;
  int i, srclen, adjust;

  src = n->kids[ki];
  dest = n->kids[ki + 1];

  LOG(("  trans234_subtree_right(%p, %d):\n", n, ki));
  LOG(("    parent %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       n,
       n->kids[0], n->counts[0], n->elems[0],
       n->kids[1], n->counts[1], n->elems[1],
       n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3]));
  LOG(("    src %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       src,
       src->kids[0], src->counts[0], src->elems[0],
       src->kids[1], src->counts[1], src->elems[1],
       src->kids[2], src->counts[2], src->elems[2],
       src->kids[3], src->counts[3]));
  LOG(("    dest %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       dest,
       dest->kids[0], dest->counts[0], dest->elems[0],
       dest->kids[1], dest->counts[1], dest->elems[1],
       dest->kids[2], dest->counts[2], dest->elems[2],
       dest->kids[3], dest->counts[3]));
  /*
   * Move over the rest of the destination node to make space.
   */
  dest->kids[3] = dest->kids[2];
  dest->counts[3] = dest->counts[2];
  dest->elems[2] = dest->elems[1];
  dest->kids[2] = dest->kids[1];
  dest->counts[2] = dest->counts[1];
  dest->elems[1] = dest->elems[0];
  dest->kids[1] = dest->kids[0];
  dest->counts[1] = dest->counts[0];

  /* which element to move over */
  i = (src->elems[2] ? 2 : src->elems[1] ? 1 : 0);

  dest->elems[0] = n->elems[ki];
  n->elems[ki] = src->elems[i];
  src->elems[i] = NULL;

  dest->kids[0] = src->kids[i + 1];
  dest->counts[0] = src->counts[i + 1];
  src->kids[i + 1] = NULL;
  src->counts[i + 1] = 0;

  if (dest->kids[0])
    dest->kids[0]->parent = dest;

  adjust = dest->counts[0] + 1;

  n->counts[ki] -= adjust;
  n->counts[ki + 1] += adjust;

  srclen = n->counts[ki];

  if (k)
  {
    LOG(("    before: k,index = %d,%d\n", (*k), (*index)));
    if ((*k) == ki && (*index) > srclen)
    {
      (*index) -= srclen + 1;
      (*k)++;
    } else if ((*k) == ki + 1)
    {
      (*index) += adjust;
    }
    LOG(("    after: k,index = %d,%d\n", (*k), (*index)));
  }

  LOG(("    parent %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       n,
       n->kids[0], n->counts[0], n->elems[0],
       n->kids[1], n->counts[1], n->elems[1],
       n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3]));
  LOG(("    src %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       src,
       src->kids[0], src->counts[0], src->elems[0],
       src->kids[1], src->counts[1], src->elems[1],
       src->kids[2], src->counts[2], src->elems[2],
       src->kids[3], src->counts[3]));
  LOG(("    dest %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       dest,
       dest->kids[0], dest->counts[0], dest->elems[0],
       dest->kids[1], dest->counts[1], dest->elems[1],
       dest->kids[2], dest->counts[2], dest->elems[2],
       dest->kids[3], dest->counts[3]));
}

/*
 * Tree transformation used in delete and split: move a subtree
 * left, from child ki of a node to the previous child. Update k
 * and index so that they still point to the same place in the
 * transformed tree. Assumes the destination child is not full, and
 * that the source child does have a subtree to spare. Can cope if
 * the destination child is undersized. 
 *
 *      . B .                             . C .
 *     /     \                ->         /     \
 *  a A b   c C d D e [more]      a A b B c   d D e [more]
 *
 *     . A .                             . B .
 *    /     \                 ->        /     \
 *   a   b B c C d [more]            a A b   c C d [more]
 */
static void trans234_subtree_left(node234 * n, int ki, int *k, int *index)
{
  node234 *src, *dest;
  int i, adjust;

  src = n->kids[ki];
  dest = n->kids[ki - 1];

  LOG(("  trans234_subtree_left(%p, %d):\n", n, ki));
  LOG(("    parent %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       n,
       n->kids[0], n->counts[0], n->elems[0],
       n->kids[1], n->counts[1], n->elems[1],
       n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3]));
  LOG(("    dest %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       dest,
       dest->kids[0], dest->counts[0], dest->elems[0],
       dest->kids[1], dest->counts[1], dest->elems[1],
       dest->kids[2], dest->counts[2], dest->elems[2],
       dest->kids[3], dest->counts[3]));
  LOG(("    src %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       src,
       src->kids[0], src->counts[0], src->elems[0],
       src->kids[1], src->counts[1], src->elems[1],
       src->kids[2], src->counts[2], src->elems[2],
       src->kids[3], src->counts[3]));

  /* where in dest to put it */
  i = (dest->elems[1] ? 2 : dest->elems[0] ? 1 : 0);
  dest->elems[i] = n->elems[ki - 1];
  n->elems[ki - 1] = src->elems[0];

  dest->kids[i + 1] = src->kids[0];
  dest->counts[i + 1] = src->counts[0];

  if (dest->kids[i + 1])
    dest->kids[i + 1]->parent = dest;

  /*
   * Move over the rest of the source node.
   */
  src->kids[0] = src->kids[1];
  src->counts[0] = src->counts[1];
  src->elems[0] = src->elems[1];
  src->kids[1] = src->kids[2];
  src->counts[1] = src->counts[2];
  src->elems[1] = src->elems[2];
  src->kids[2] = src->kids[3];
  src->counts[2] = src->counts[3];
  src->elems[2] = NULL;
  src->kids[3] = NULL;
  src->counts[3] = 0;

  adjust = dest->counts[i + 1] + 1;

  n->counts[ki] -= adjust;
  n->counts[ki - 1] += adjust;

  if (k)
  {
    LOG(("    before: k,index = %d,%d\n", (*k), (*index)));
    if ((*k) == ki)
    {
      (*index) -= adjust;
      if ((*index) < 0)
      {
        (*index) += n->counts[ki - 1] + 1;
        (*k)--;
      }
    }
    LOG(("    after: k,index = %d,%d\n", (*k), (*index)));
  }

  LOG(("    parent %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       n,
       n->kids[0], n->counts[0], n->elems[0],
       n->kids[1], n->counts[1], n->elems[1],
       n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3]));
  LOG(("    dest %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       dest,
       dest->kids[0], dest->counts[0], dest->elems[0],
       dest->kids[1], dest->counts[1], dest->elems[1],
       dest->kids[2], dest->counts[2], dest->elems[2],
       dest->kids[3], dest->counts[3]));
  LOG(("    src %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       src,
       src->kids[0], src->counts[0], src->elems[0],
       src->kids[1], src->counts[1], src->elems[1],
       src->kids[2], src->counts[2], src->elems[2],
       src->kids[3], src->counts[3]));
}

/*
 * Tree transformation used in delete and split: merge child nodes
 * ki and ki+1 of a node. Update k and index so that they still
 * point to the same place in the transformed tree. Assumes both
 * children _are_ sufficiently small.
 *
 *      . B .                .
 *     /     \     ->        |
 *  a A b   c C d      a A b B c C d
 * 
 * This routine can also cope with either child being undersized:
 * 
 *     . A .                 .
 *    /     \      ->        |
 *   a     b B c         a A b B c
 *
 *    . A .                  .
 *   /     \       ->        |
 *  a   b B c C d      a A b B c C d
 */
static void trans234_subtree_merge(node234 * n, int ki, int *k, int *index)
{
  node234 *left, *right;
  int i, leftlen, rightlen, lsize, rsize;

  left = n->kids[ki];
  leftlen = n->counts[ki];
  right = n->kids[ki + 1];
  rightlen = n->counts[ki + 1];

  LOG(("  trans234_subtree_merge(%p, %d):\n", n, ki));
  LOG(("    parent %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       n,
       n->kids[0], n->counts[0], n->elems[0],
       n->kids[1], n->counts[1], n->elems[1],
       n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3]));
  LOG(("    left %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       left,
       left->kids[0], left->counts[0], left->elems[0],
       left->kids[1], left->counts[1], left->elems[1],
       left->kids[2], left->counts[2], left->elems[2],
       left->kids[3], left->counts[3]));
  LOG(("    right %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       right,
       right->kids[0], right->counts[0], right->elems[0],
       right->kids[1], right->counts[1], right->elems[1],
       right->kids[2], right->counts[2], right->elems[2],
       right->kids[3], right->counts[3]));

  assert(!left->elems[2] && !right->elems[2]);  /* neither is large! */
  lsize = (left->elems[1] ? 2 : left->elems[0] ? 1 : 0);
  rsize = (right->elems[1] ? 2 : right->elems[0] ? 1 : 0);

  left->elems[lsize] = n->elems[ki];

  for (i = 0; i < rsize + 1; i++)
  {
    left->kids[lsize + 1 + i] = right->kids[i];
    left->counts[lsize + 1 + i] = right->counts[i];
    if (left->kids[lsize + 1 + i])
      left->kids[lsize + 1 + i]->parent = left;
    if (i < rsize)
      left->elems[lsize + 1 + i] = right->elems[i];
  }

  n->counts[ki] += rightlen + 1;

  sfree(right);

  /*
   * Move the rest of n up by one.
   */
  for (i = ki + 1; i < 3; i++)
  {
    n->kids[i] = n->kids[i + 1];
    n->counts[i] = n->counts[i + 1];
  }
  for (i = ki; i < 2; i++)
  {
    n->elems[i] = n->elems[i + 1];
  }
  n->kids[3] = NULL;
  n->counts[3] = 0;
  n->elems[2] = NULL;

  if (k)
  {
    LOG(("    before: k,index = %d,%d\n", (*k), (*index)));
    if ((*k) == ki + 1)
    {
      (*k)--;
      (*index) += leftlen + 1;
    } else if ((*k) > ki + 1)
    {
      (*k)--;
    }
    LOG(("    after: k,index = %d,%d\n", (*k), (*index)));
  }

  LOG(("    parent %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       n,
       n->kids[0], n->counts[0], n->elems[0],
       n->kids[1], n->counts[1], n->elems[1],
       n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3]));
  LOG(("    merged %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
       left,
       left->kids[0], left->counts[0], left->elems[0],
       left->kids[1], left->counts[1], left->elems[1],
       left->kids[2], left->counts[2], left->elems[2],
       left->kids[3], left->counts[3]));

}

/*
 * Delete an element e in a 2-3-4 tree. Does not free the element,
 * merely removes all links to it from the tree nodes.
 */
static void *delpos234_internal(tree234 * t, int index)
{
  node234 *n;
  void *retval;
  int ki, i;

  retval = NULL;

  n = t->root;                  /* by assumption this is non-NULL */
  LOG(("deleting item %d from tree %p\n", index, t));
  while (1)
  {
    node234 *sub;

    LOG(("  node %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d index=%d\n", n, n->kids[0], n->counts[0], n->elems[0], n->kids[1], n->counts[1], n->elems[1], n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3], index));
    if (index <= n->counts[0])
    {
      ki = 0;
    } else if (index -= n->counts[0] + 1, index <= n->counts[1])
    {
      ki = 1;
    } else if (index -= n->counts[1] + 1, index <= n->counts[2])
    {
      ki = 2;
    } else if (index -= n->counts[2] + 1, index <= n->counts[3])
    {
      ki = 3;
    } else
    {
      assert(0);                /* can't happen */
    }

    if (!n->kids[0])
      break;                    /* n is a leaf node; we're here! */

    /*
     * Check to see if we've found our target element. If so,
     * we must choose a new target (we'll use the old target's
     * successor, which will be in a leaf), move it into the
     * place of the old one, continue down to the leaf and
     * delete the old copy of the new target.
     */
    if (index == n->counts[ki])
    {
      node234 *m;
      LOG(("  found element in internal node, index %d\n", ki));
      assert(n->elems[ki]);     /* must be a kid _before_ an element */
      ki++;
      index = 0;
      for (m = n->kids[ki]; m->kids[0]; m = m->kids[0])
        continue;
      LOG(("  replacing with element \"%s\" from leaf node %p\n",
           m->elems[0], m));
      retval = n->elems[ki - 1];
      n->elems[ki - 1] = m->elems[0];
    }

    /*
     * Recurse down to subtree ki. If it has only one element,
     * we have to do some transformation to start with.
     */
    LOG(("  moving to subtree %d\n", ki));
    sub = n->kids[ki];
    if (!sub->elems[1])
    {
      LOG(("  subtree has only one element!\n"));
      if (ki > 0 && n->kids[ki - 1]->elems[1])
      {
        /*
         * Child ki has only one element, but child
         * ki-1 has two or more. So we need to move a
         * subtree from ki-1 to ki.
         */
        trans234_subtree_right(n, ki - 1, &ki, &index);
      } else if (ki < 3 && n->kids[ki + 1] && n->kids[ki + 1]->elems[1])
      {
        /*
         * Child ki has only one element, but ki+1 has
         * two or more. Move a subtree from ki+1 to ki.
         */
        trans234_subtree_left(n, ki + 1, &ki, &index);
      } else
      {
        /*
         * ki is small with only small neighbours. Pick a
         * neighbour and merge with it.
         */
        trans234_subtree_merge(n, ki > 0 ? ki - 1 : ki, &ki, &index);
        sub = n->kids[ki];

        if (!n->elems[0])
        {
          /*
           * The root is empty and needs to be
           * removed.
           */
          LOG(("  shifting root!\n"));
          t->root = sub;
          sub->parent = NULL;
          sfree(n);
          n = NULL;
        }
      }
    }

    if (n)
      n->counts[ki]--;
    n = sub;
  }

  /*
   * Now n is a leaf node, and ki marks the element number we
   * want to delete. We've already arranged for the leaf to be
   * bigger than minimum size, so let's just go to it.
   */
  assert(!n->kids[0]);
  if (!retval)
    retval = n->elems[ki];

  for (i = ki; i < 2 && n->elems[i + 1]; i++)
    n->elems[i] = n->elems[i + 1];
  n->elems[i] = NULL;

  /*
   * It's just possible that we have reduced the leaf to zero
   * size. This can only happen if it was the root - so destroy
   * it and make the tree empty.
   */
  if (!n->elems[0])
  {
    LOG(("  removed last element in tree, destroying empty root\n"));
    assert(n == t->root);
    sfree(n);
    t->root = NULL;
  }

  return retval;                /* finished! */
}

void *delpos234(tree234 * t, int index)
{
  if (index < 0 || index >= countnode234(t->root))
    return NULL;
  return delpos234_internal(t, index);
}

void *del234(tree234 * t, void *e)
{
  int index;
  if (!findrelpos234(t, e, NULL, REL234_EQ, &index))
    return NULL;                /* it wasn't in there anyway */
  return delpos234_internal(t, index);  /* it's there; delete it. */
}

/*
 * Join two subtrees together with a separator element between
 * them, given their relative height.
 * 
 * (Height<0 means the left tree is shorter, >0 means the right
 * tree is shorter, =0 means (duh) they're equal.)
 * 
 * It is assumed that any checks needed on the ordering criterion
 * have _already_ been done.
 * 
 * The value returned in `height' is 0 or 1 depending on whether the
 * resulting tree is the same height as the original larger one, or
 * one higher.
 */
static node234 *join234_internal(node234 * left, void *sep,
                                 node234 * right, int *height)
{
  node234 *root, *node;
  int relht = *height;
  int ki;

  LOG(("  join: joining %p \"%s\" %p, relative height is %d\n",
       left, sep, right, relht));
  if (relht == 0)
  {
    /*
     * The trees are the same height. Create a new one-element
     * root containing the separator and pointers to the two
     * nodes.
     */
    node234 *newroot;
    newroot = mknew(node234);
    newroot->kids[0] = left;
    newroot->counts[0] = countnode234(left);
    newroot->elems[0] = sep;
    newroot->kids[1] = right;
    newroot->counts[1] = countnode234(right);
    newroot->elems[1] = NULL;
    newroot->kids[2] = NULL;
    newroot->counts[2] = 0;
    newroot->elems[2] = NULL;
    newroot->kids[3] = NULL;
    newroot->counts[3] = 0;
    newroot->parent = NULL;
    if (left)
      left->parent = newroot;
    if (right)
      right->parent = newroot;
    *height = 1;
    LOG(("  join: same height, brand new root\n"));
    return newroot;
  }

  /*
   * This now works like the addition algorithm on the larger
   * tree. We're replacing a single kid pointer with two kid
   * pointers separated by an element; if that causes the node to
   * overload, we split it in two, move a separator element up to
   * the next node, and repeat.
   */
  if (relht < 0)
  {
    /*
     * Left tree is shorter. Search down the right tree to find
     * the pointer we're inserting at.
     */
    node = root = right;
    while (++relht < 0)
    {
      node = node->kids[0];
    }
    ki = 0;
    right = node->kids[ki];
  } else
  {
    /*
     * Right tree is shorter; search down the left to find the
     * pointer we're inserting at.
     */
    node = root = left;
    while (--relht > 0)
    {
      if (node->elems[2])
        node = node->kids[3];
      else if (node->elems[1])
        node = node->kids[2];
      else
        node = node->kids[1];
    }
    if (node->elems[2])
      ki = 3;
    else if (node->elems[1])
      ki = 2;
    else
      ki = 1;
    left = node->kids[ki];
  }

  /*
   * Now proceed as for addition.
   */
  *height = add234_insert(left, sep, right, &root, node, ki);

  return root;
}
static int height234(tree234 * t)
{
  int level = 0;
  node234 *n = t->root;
  while (n)
  {
    level++;
    n = n->kids[0];
  }
  return level;
}

tree234 *join234(tree234 * t1, tree234 * t2)
{
  int size2 = countnode234(t2->root);
  if (size2 > 0)
  {
    void *element;
    int relht;

    if (t1->cmp)
    {
      element = index234(t2, 0);
      element = findrelpos234(t1, element, NULL, REL234_GE, NULL);
      if (element)
        return NULL;
    }

    element = delpos234(t2, 0);
    relht = height234(t1) - height234(t2);
    t1->root = join234_internal(t1->root, element, t2->root, &relht);
    t2->root = NULL;
  }
  return t1;
}

tree234 *join234r(tree234 * t1, tree234 * t2)
{
  int size1 = countnode234(t1->root);
  if (size1 > 0)
  {
    void *element;
    int relht;

    if (t2->cmp)
    {
      element = index234(t1, size1 - 1);
      element = findrelpos234(t2, element, NULL, REL234_LE, NULL);
      if (element)
        return NULL;
    }

    element = delpos234(t1, size1 - 1);
    relht = height234(t1) - height234(t2);
    t2->root = join234_internal(t1->root, element, t2->root, &relht);
    t1->root = NULL;
  }
  return t2;
}

/*
 * Split out the first <index> elements in a tree and return a
 * pointer to the root node. Leave the root node of the remainder
 * in t.
 */
static node234 *split234_internal(tree234 * t, int index)
{
  node234 *halves[2], *n, *sib, *sub;
  node234 *lparent, *rparent;
  int ki, pki=0, i, half, lcount, rcount;

  n = t->root;
  LOG(("splitting tree %p at point %d\n", t, index));

  /*
   * Easy special cases. After this we have also dealt completely
   * with the empty-tree case and we can assume the root exists.
   */
  if (index == 0)               /* return nothing */
    return NULL;
  if (index == countnode234(t->root))
  {                             /* return the whole tree */
    node234 *ret = t->root;
    t->root = NULL;
    return ret;
  }

  /*
   * Search down the tree to find the split point.
   */
  lparent = rparent = NULL;
  while (n)
  {
    LOG(("  node %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d index=%d\n", n, n->kids[0], n->counts[0], n->elems[0], n->kids[1], n->counts[1], n->elems[1], n->kids[2], n->counts[2], n->elems[2], n->kids[3], n->counts[3], index));
    lcount = index;
    rcount = countnode234(n) - lcount;
    if (index <= n->counts[0])
    {
      ki = 0;
    } else if (index -= n->counts[0] + 1, index <= n->counts[1])
    {
      ki = 1;
    } else if (index -= n->counts[1] + 1, index <= n->counts[2])
    {
      ki = 2;
    } else
    {
      index -= n->counts[2] + 1;
      ki = 3;
    }

    LOG(("  splitting at subtree %d\n", ki));
    sub = n->kids[ki];

    LOG(("  splitting at child index %d\n", ki));

    /*
     * Split the node, put halves[0] on the right of the left
     * one and halves[1] on the left of the right one, put the
     * new node pointers in halves[0] and halves[1], and go up
     * a level.
     */
    sib = mknew(node234);
    for (i = 0; i < 3; i++)
    {
      if (i + ki < 3 && n->elems[i + ki])
      {
        sib->elems[i] = n->elems[i + ki];
        sib->kids[i + 1] = n->kids[i + ki + 1];
        if (sib->kids[i + 1])
          sib->kids[i + 1]->parent = sib;
        sib->counts[i + 1] = n->counts[i + ki + 1];
        n->elems[i + ki] = NULL;
        n->kids[i + ki + 1] = NULL;
        n->counts[i + ki + 1] = 0;
      } else
      {
        sib->elems[i] = NULL;
        sib->kids[i + 1] = NULL;
        sib->counts[i + 1] = 0;
      }
    }
    if (lparent)
    {
      lparent->kids[pki] = n;
      lparent->counts[pki] = lcount;
      n->parent = lparent;
      rparent->kids[0] = sib;
      rparent->counts[0] = rcount;
      sib->parent = rparent;
    } else
    {
      halves[0] = n;
      n->parent = NULL;
      halves[1] = sib;
      sib->parent = NULL;
    }
    lparent = n;
    rparent = sib;
    pki = ki;
    LOG(("  left node %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
         n, n->kids[0], n->counts[0], n->elems[0], n->kids[1],
         n->counts[1], n->elems[1], n->kids[2], n->counts[2], n->elems[2],
         n->kids[3], n->counts[3]));
    LOG(("  right node %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
         sib, sib->kids[0], sib->counts[0], sib->elems[0], sib->kids[1],
         sib->counts[1], sib->elems[1], sib->kids[2], sib->counts[2],
         sib->elems[2], sib->kids[3], sib->counts[3]));

    n = sub;
  }

  /*
   * We've come off the bottom here, so we've successfully split
   * the tree into two equally high subtrees. The only problem is
   * that some of the nodes down the fault line will be smaller
   * than the minimum permitted size. (Since this is a 2-3-4
   * tree, that means they'll be zero-element one-child nodes.)
   */
  LOG(("  fell off bottom, lroot is %p, rroot is %p\n",
       halves[0], halves[1]));
  lparent->counts[pki] = rparent->counts[0] = 0;
  lparent->kids[pki] = rparent->kids[0] = NULL;

  /*
   * So now we go back down the tree from each of the two roots,
   * fixing up undersize nodes.
   */
  for (half = 0; half < 2; half++)
  {
    /*
     * Remove the root if it's undersize (it will contain only
     * one child pointer, so just throw it away and replace it
     * with its child). This might happen several times.
     */
    while (halves[half] && !halves[half]->elems[0])
    {
      LOG(("  root %p is undersize, throwing away\n", halves[half]));
      halves[half] = halves[half]->kids[0];
      sfree(halves[half]->parent);
      halves[half]->parent = NULL;
      LOG(("  new root is %p\n", halves[half]));
    }

    n = halves[half];
    while (n)
    {
      void (*toward) (node234 * n, int ki, int *k, int *index);
      int ni, merge;

      /*
       * Now we have a potentially undersize node on the
       * right (if half==0) or left (if half==1). Sort it
       * out, by merging with a neighbour or by transferring
       * subtrees over. At this time we must also ensure that
       * nodes are bigger than minimum, in case we need an
       * element to merge two nodes below.
       */
      LOG(("  node %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n", n,
           n->kids[0], n->counts[0], n->elems[0], n->kids[1], n->counts[1],
           n->elems[1], n->kids[2], n->counts[2], n->elems[2], n->kids[3],
           n->counts[3]));
      if (half == 1)
      {
        ki = 0;                 /* the kid we're interested in */
        ni = 1;                 /* the neighbour */
        merge = 0;              /* for merge: leftmost of the two */
        toward = trans234_subtree_left;
      } else
      {
        ki = (n->kids[3] ? 3 : n->kids[2] ? 2 : 1);
        ni = ki - 1;
        merge = ni;
        toward = trans234_subtree_right;
      }

      sub = n->kids[ki];
      if (sub && !sub->elems[1])
      {
        /*
         * This node is undersized or minimum-size. If we
         * can merge it with its neighbour, we do so;
         * otherwise we must be able to transfer subtrees
         * over to it until it is greater than minimum
         * size.
         */
        int undersized = (!sub->elems[0]);
        LOG(("  child %d is %ssize\n", ki,
             undersized ? "under" : "minimum-"));
        LOG(("  neighbour is %s\n",
             n->kids[ni]->elems[2] ? "large" :
             n->kids[ni]->elems[1] ? "medium" : "small"));
        if (!n->kids[ni]->elems[1] ||
            (undersized && !n->kids[ni]->elems[2]))
        {
          /*
           * Neighbour is small, or possibly neighbour is
           * medium and we are undersize.
           */
          trans234_subtree_merge(n, merge, NULL, NULL);
          sub = n->kids[merge];
          if (!n->elems[0])
          {
            /*
             * n is empty, and hence must have been the
             * root and needs to be removed.
             */
            assert(!n->parent);
            LOG(("  shifting root!\n"));
            halves[half] = sub;
            halves[half]->parent = NULL;
            sfree(n);
          }
        } else
        {
          /* Neighbour is big enough to move trees over. */
          toward(n, ni, NULL, NULL);
          if (undersized)
            toward(n, ni, NULL, NULL);
        }
      }
      n = sub;
    }
  }

  t->root = halves[1];
  return halves[0];
}

tree234 *splitpos234(tree234 * t, int index, int before)
{
  tree234 *ret;
  node234 *n;
  int count;

  count = countnode234(t->root);
  if (index < 0 || index > count)
    return NULL;                /* error */
  ret = newtree234(t->cmp);
  n = split234_internal(t, index);
  if (before)
  {
    /* We want to return the ones before the index. */
    ret->root = n;
  } else
  {
    /*
     * We want to keep the ones before the index and return the
     * ones after.
     */
    ret->root = t->root;
    t->root = n;
  }
  return ret;
}

tree234 *split234(tree234 * t, void *e, cmpfn234 cmp, int rel)
{
  int before;
  int index;

  assert(rel != REL234_EQ);

  if (rel == REL234_GT || rel == REL234_GE)
  {
    before = 1;
    rel = (rel == REL234_GT ? REL234_LE : REL234_LT);
  } else
  {
    before = 0;
  }
  if (!findrelpos234(t, e, cmp, rel, &index))
    index = 0;

  return splitpos234(t, index + 1, before);
}

static node234 *copynode234(node234 * n, copyfn234 copyfn,
                            void *copyfnstate)
{
  int i;
  node234 *n2 = mknew(node234);

  for (i = 0; i < 3; i++)
  {
    if (n->elems[i] && copyfn)
      n2->elems[i] = copyfn(copyfnstate, n->elems[i]);
    else
      n2->elems[i] = n->elems[i];
  }

  for (i = 0; i < 4; i++)
  {
    if (n->kids[i])
    {
      n2->kids[i] = copynode234(n->kids[i], copyfn, copyfnstate);
      n2->kids[i]->parent = n2;
    } else
    {
      n2->kids[i] = NULL;
    }
    n2->counts[i] = n->counts[i];
  }

  return n2;
}

tree234 *copytree234(tree234 * t, copyfn234 copyfn, void *copyfnstate)
{
  tree234 *t2;

  t2 = newtree234(t->cmp);
  t2->root = copynode234(t->root, copyfn, copyfnstate);
  t2->root->parent = NULL;

  return t2;
}

#ifdef TEST

/*
 * Test code for the 2-3-4 tree. This code maintains an alternative
 * representation of the data in the tree, in an array (using the
 * obvious and slow insert and delete functions). After each tree
 * operation, the verify() function is called, which ensures all
 * the tree properties are preserved:
 *  - node->child->parent always equals node
 *  - tree->root->parent always equals NULL
 *  - number of kids == 0 or number of elements + 1;
 *  - tree has the same depth everywhere
 *  - every node has at least one element
 *  - subtree element counts are accurate
 *  - any NULL kid pointer is accompanied by a zero count
 *  - in a sorted tree: ordering property between elements of a
 *    node and elements of its children is preserved
 * and also ensures the list represented by the tree is the same
 * list it should be. (This last check also doubly verifies the
 * ordering properties, because the `same list it should be' is by
 * definition correctly ordered. It also ensures all nodes are
 * distinct, because the enum functions would get caught in a loop
 * if not.)
 */

#include <stdarg.h>

#define srealloc realloc

/*
 * Error reporting function.
 */
void error(char *fmt, ...)
{
  va_list ap;
  printf("ERROR: ");
  va_start(ap, fmt);
  vfprintf(stdout, fmt, ap);
  va_end(ap);
  printf("\n");
}

/* The array representation of the data. */
void **array;
int arraylen, arraysize;
cmpfn234 cmp;

/* The tree representation of the same data. */
tree234 *tree;

/*
 * Routines to provide a diagnostic printout of a tree. Currently
 * relies on every element in the tree being a one-character string
 * :-)
 */
typedef struct {
  char **levels;
} dispctx;

int dispnode(node234 * n, int level, dispctx * ctx)
{
  if (level == 0)
  {
    int xpos = strlen(ctx->levels[0]);
    int len;

    if (n->elems[2])
      len = sprintf(ctx->levels[0] + xpos, " %s%s%s",
                    n->elems[0], n->elems[1], n->elems[2]);
    else if (n->elems[1])
      len = sprintf(ctx->levels[0] + xpos, " %s%s",
                    n->elems[0], n->elems[1]);
    else
      len = sprintf(ctx->levels[0] + xpos, " %s", n->elems[0]);
    return xpos + 1 + (len - 1) / 2;
  } else
  {
    int xpos[4], nkids;
    int nodelen, mypos, myleft, x, i;

    xpos[0] = dispnode(n->kids[0], level - 3, ctx);
    xpos[1] = dispnode(n->kids[1], level - 3, ctx);
    nkids = 2;
    if (n->kids[2])
    {
      xpos[2] = dispnode(n->kids[2], level - 3, ctx);
      nkids = 3;
    }
    if (n->kids[3])
    {
      xpos[3] = dispnode(n->kids[3], level - 3, ctx);
      nkids = 4;
    }

    if (nkids == 4)
      mypos = (xpos[1] + xpos[2]) / 2;
    else if (nkids == 3)
      mypos = xpos[1];
    else
      mypos = (xpos[0] + xpos[1]) / 2;
    nodelen = nkids * 2 - 1;
    myleft = mypos - ((nodelen - 1) / 2);
    assert(myleft >= xpos[0]);
    assert(myleft + nodelen - 1 <= xpos[nkids - 1]);

    x = strlen(ctx->levels[level]);
    while (x <= xpos[0] && x < myleft)
      ctx->levels[level][x++] = ' ';
    while (x < myleft)
      ctx->levels[level][x++] = '_';
    if (nkids == 4)
      x += sprintf(ctx->levels[level] + x, ".%s.%s.%s.",
                   n->elems[0], n->elems[1], n->elems[2]);
    else if (nkids == 3)
      x += sprintf(ctx->levels[level] + x, ".%s.%s.",
                   n->elems[0], n->elems[1]);
    else
      x += sprintf(ctx->levels[level] + x, ".%s.", n->elems[0]);
    while (x < xpos[nkids - 1])
      ctx->levels[level][x++] = '_';
    ctx->levels[level][x] = '\0';

    x = strlen(ctx->levels[level - 1]);
    for (i = 0; i < nkids; i++)
    {
      int rpos, pos;
      rpos = xpos[i];
      if (i > 0 && i < nkids - 1)
        pos = myleft + 2 * i;
      else
        pos = rpos;
      if (rpos < pos)
        rpos++;
      while (x < pos && x < rpos)
        ctx->levels[level - 1][x++] = ' ';
      if (x == pos)
        ctx->levels[level - 1][x++] = '|';
      while (x < pos || x < rpos)
        ctx->levels[level - 1][x++] = '_';
      if (x == pos)
        ctx->levels[level - 1][x++] = '|';
    }
    ctx->levels[level - 1][x] = '\0';

    x = strlen(ctx->levels[level - 2]);
    for (i = 0; i < nkids; i++)
    {
      int rpos = xpos[i];

      while (x < rpos)
        ctx->levels[level - 2][x++] = ' ';
      ctx->levels[level - 2][x++] = '|';
    }
    ctx->levels[level - 2][x] = '\0';

    return mypos;
  }
}

void disptree(tree234 * t)
{
  dispctx ctx;
  char *leveldata;
  int width = count234(t);
  int ht = height234(t) * 3 - 2;
  int i;

  if (!t->root)
  {
    printf("[empty tree]\n");
  }

  leveldata = smalloc(ht * (width + 2));
  ctx.levels = smalloc(ht * sizeof(char *));
  for (i = 0; i < ht; i++)
  {
    ctx.levels[i] = leveldata + i * (width + 2);
    ctx.levels[i][0] = '\0';
  }

  (void) dispnode(t->root, ht - 1, &ctx);

  for (i = ht; i--;)
    printf("%s\n", ctx.levels[i]);

  sfree(ctx.levels);
  sfree(leveldata);
}

typedef struct {
  int treedepth;
  int elemcount;
} chkctx;

int
chknode(chkctx * ctx, int level, node234 * node,
        void *lowbound, void *highbound)
{
  int nkids, nelems;
  int i;
  int count;

  /* Count the non-NULL kids. */
  for (nkids = 0; nkids < 4 && node->kids[nkids]; nkids++);
  /* Ensure no kids beyond the first NULL are non-NULL. */
  for (i = nkids; i < 4; i++)
    if (node->kids[i])
    {
      error("node %p: nkids=%d but kids[%d] non-NULL", node, nkids, i);
    } else if (node->counts[i])
    {
      error("node %p: kids[%d] NULL but count[%d]=%d nonzero",
            node, i, i, node->counts[i]);
    }

  /* Count the non-NULL elements. */
  for (nelems = 0; nelems < 3 && node->elems[nelems]; nelems++);
  /* Ensure no elements beyond the first NULL are non-NULL. */
  for (i = nelems; i < 3; i++)
    if (node->elems[i])
    {
      error("node %p: nelems=%d but elems[%d] non-NULL", node, nelems, i);
    }

  if (nkids == 0)
  {
    /*
     * If nkids==0, this is a leaf node; verify that the tree
     * depth is the same everywhere.
     */
    if (ctx->treedepth < 0)
      ctx->treedepth = level;   /* we didn't know the depth yet */
    else if (ctx->treedepth != level)
      error("node %p: leaf at depth %d, previously seen depth %d",
            node, level, ctx->treedepth);
  } else
  {
    /*
     * If nkids != 0, then it should be nelems+1, unless nelems
     * is 0 in which case nkids should also be 0 (and so we
     * shouldn't be in this condition at all).
     */
    int shouldkids = (nelems ? nelems + 1 : 0);
    if (nkids != shouldkids)
    {
      error("node %p: %d elems should mean %d kids but has %d",
            node, nelems, shouldkids, nkids);
    }
  }

  /*
   * nelems should be at least 1.
   */
  if (nelems == 0)
  {
    error("node %p: no elems", node, nkids);
  }

  /*
   * Add nelems to the running element count of the whole tree.
   */
  ctx->elemcount += nelems;

  /*
   * Check ordering property: all elements should be strictly >
   * lowbound, strictly < highbound, and strictly < each other in
   * sequence. (lowbound and highbound are NULL at edges of tree
   * - both NULL at root node - and NULL is considered to be <
   * everything and > everything. IYSWIM.)
   */
  if (cmp)
  {
    for (i = -1; i < nelems; i++)
    {
      void *lower = (i == -1 ? lowbound : node->elems[i]);
      void *higher = (i + 1 == nelems ? highbound : node->elems[i + 1]);
      if (lower && higher && cmp(lower, higher) >= 0)
      {
        error("node %p: kid comparison [%d=%s,%d=%s] failed",
              node, i, lower, i + 1, higher);
      }
    }
  }

  /*
   * Check parent pointers: all non-NULL kids should have a
   * parent pointer coming back to this node.
   */
  for (i = 0; i < nkids; i++)
    if (node->kids[i]->parent != node)
    {
      error("node %p kid %d: parent ptr is %p not %p",
            node, i, node->kids[i]->parent, node);
    }


  /*
   * Now (finally!) recurse into subtrees.
   */
  count = nelems;

  for (i = 0; i < nkids; i++)
  {
    void *lower = (i == 0 ? lowbound : node->elems[i - 1]);
    void *higher = (i >= nelems ? highbound : node->elems[i]);
    int subcount = chknode(ctx, level + 1, node->kids[i], lower, higher);
    if (node->counts[i] != subcount)
    {
      error("node %p kid %d: count says %d, subtree really has %d",
            node, i, node->counts[i], subcount);
    }
    count += subcount;
  }

  return count;
}

void verifytree(tree234 * tree, void **array, int arraylen)
{
  chkctx ctx;
  int i;
  void *p;

  ctx.treedepth = -1;           /* depth unknown yet */
  ctx.elemcount = 0;            /* no elements seen yet */
  /*
   * Verify validity of tree properties.
   */
  if (tree->root)
  {
    if (tree->root->parent != NULL)
      error("root->parent is %p should be null", tree->root->parent);
    chknode(&ctx, 0, tree->root, NULL, NULL);
  }
  printf("tree depth: %d\n", ctx.treedepth);
  /*
   * Enumerate the tree and ensure it matches up to the array.
   */
  for (i = 0; NULL != (p = index234(tree, i)); i++)
  {
    if (i >= arraylen)
      error("tree contains more than %d elements", arraylen);
    if (array[i] != p)
      error("enum at position %d: array says %s, tree says %s",
            i, array[i], p);
  }
  if (ctx.elemcount != i)
  {
    error("tree really contains %d elements, enum gave %d",
          ctx.elemcount, i);
  }
  if (i < arraylen)
  {
    error("enum gave only %d elements, array has %d", i, arraylen);
  }
  i = count234(tree);
  if (ctx.elemcount != i)
  {
    error("tree really contains %d elements, count234 gave %d",
          ctx.elemcount, i);
  }
}
void verify(void)
{
  verifytree(tree, array, arraylen);
}

void internal_addtest(void *elem, int index, void *realret)
{
  int i, j;
  void *retval;

  if (arraysize < arraylen + 1)
  {
    arraysize = arraylen + 1 + 256;
    array = (array == NULL ? smalloc(arraysize * sizeof(*array)) :
             srealloc(array, arraysize * sizeof(*array)));
  }

  i = index;
  /* now i points to the first element >= elem */
  retval = elem;                /* expect elem returned (success) */
  for (j = arraylen; j > i; j--)
    array[j] = array[j - 1];
  array[i] = elem;              /* add elem to array */
  arraylen++;

  if (realret != retval)
  {
    error("add: retval was %p expected %p", realret, retval);
  }

  verify();
}

void addtest(void *elem)
{
  int i;
  void *realret;

  realret = add234(tree, elem);

  i = 0;
  while (i < arraylen && cmp(elem, array[i]) > 0)
    i++;
  if (i < arraylen && !cmp(elem, array[i]))
  {
    void *retval = array[i];    /* expect that returned not elem */
    if (realret != retval)
    {
      error("add: retval was %p expected %p", realret, retval);
    }
  } else
    internal_addtest(elem, i, realret);
}

void addpostest(void *elem, int i)
{
  void *realret;

  realret = addpos234(tree, elem, i);

  internal_addtest(elem, i, realret);
}

void delpostest(int i)
{
  int index = i;
  void *elem = array[i], *ret;

  /* i points to the right element */
  while (i < arraylen - 1)
  {
    array[i] = array[i + 1];
    i++;
  }
  arraylen--;                   /* delete elem from array */

  if (tree->cmp)
    ret = del234(tree, elem);
  else
    ret = delpos234(tree, index);

  if (ret != elem)
  {
    error("del returned %p, expected %p", ret, elem);
  }

  verify();
}

void deltest(void *elem)
{
  int i;

  i = 0;
  while (i < arraylen && cmp(elem, array[i]) > 0)
    i++;
  if (i >= arraylen || cmp(elem, array[i]) != 0)
    return;                     /* don't do it! */
  delpostest(i);
}

/* A sample data set and test utility. Designed for pseudo-randomness,
 * and yet repeatability. */

/*
 * This random number generator uses the `portable implementation'
 * given in ANSI C99 draft N869. It assumes `unsigned' is 32 bits;
 * change it if not.
 */
int randomnumber(unsigned *seed)
{
  *seed *= 1103515245;
  *seed += 12345;
  return ((*seed) / 65536) % 32768;
}

int mycmp(void *av, void *bv)
{
  char const *a = (char const *) av;
  char const *b = (char const *) bv;
  return strcmp(a, b);
}

#define lenof(x) ( sizeof((x)) / sizeof(*(x)) )

char *strings[] = {
  "0", "2", "3", "I", "K", "d", "H", "J", "Q", "N", "n", "q", "j", "i",
  "7", "G", "F", "D", "b", "x", "g", "B", "e", "v", "V", "T", "f", "E",
  "S", "8", "A", "k", "X", "p", "C", "R", "a", "o", "r", "O", "Z", "u",
  "6", "1", "w", "L", "P", "M", "c", "U", "h", "9", "t", "5", "W", "Y",
  "m", "s", "l", "4",
#if 0
  "a", "ab", "absque", "coram", "de",
  "palam", "clam", "cum", "ex", "e",
  "sine", "tenus", "pro", "prae",
  "banana", "carrot", "cabbage", "broccoli", "onion", "zebra",
  "penguin", "blancmange", "pangolin", "whale", "hedgehog",
  "giraffe", "peanut", "bungee", "foo", "bar", "baz", "quux",
  "murfl", "spoo", "breen", "flarn", "octothorpe",
  "snail", "tiger", "elephant", "octopus", "warthog", "armadillo",
  "aardvark", "wyvern", "dragon", "elf", "dwarf", "orc", "goblin",
  "pixie", "basilisk", "warg", "ape", "lizard", "newt", "shopkeeper",
  "wand", "ring", "amulet"
#endif
};

#define NSTR lenof(strings)

void findtest(void)
{
  static const int rels[] = {
    REL234_EQ, REL234_GE, REL234_LE, REL234_LT, REL234_GT
  };
  static const char *const relnames[] = {
    "EQ", "GE", "LE", "LT", "GT"
  };
  int i, j, rel, index;
  char *p, *ret, *realret, *realret2;
  int lo, hi, mid, c;

  for (i = 0; i < (int) NSTR; i++)
  {
    p = strings[i];
    for (j = 0; j < (int) (sizeof(rels) / sizeof(*rels)); j++)
    {
      rel = rels[j];

      lo = 0;
      hi = arraylen - 1;
      while (lo <= hi)
      {
        mid = (lo + hi) / 2;
        c = strcmp(p, array[mid]);
        if (c < 0)
          hi = mid - 1;
        else if (c > 0)
          lo = mid + 1;
        else
          break;
      }

      if (c == 0)
      {
        if (rel == REL234_LT)
          ret = (mid > 0 ? array[--mid] : NULL);
        else if (rel == REL234_GT)
          ret = (mid < arraylen - 1 ? array[++mid] : NULL);
        else
          ret = array[mid];
      } else
      {
        assert(lo == hi + 1);
        if (rel == REL234_LT || rel == REL234_LE)
        {
          mid = hi;
          ret = (hi >= 0 ? array[hi] : NULL);
        } else if (rel == REL234_GT || rel == REL234_GE)
        {
          mid = lo;
          ret = (lo < arraylen ? array[lo] : NULL);
        } else
          ret = NULL;
      }

      realret = findrelpos234(tree, p, NULL, rel, &index);
      if (realret != ret)
      {
        error("find(\"%s\",%s) gave %s should be %s",
              p, relnames[j], realret, ret);
      }
      if (realret && index != mid)
      {
        error("find(\"%s\",%s) gave %d should be %d",
              p, relnames[j], index, mid);
      }
      if (realret && rel == REL234_EQ)
      {
        realret2 = index234(tree, index);
        if (realret2 != realret)
        {
          error("find(\"%s\",%s) gave %s(%d) but %d -> %s",
                p, relnames[j], realret, index, index, realret2);
        }
      }
#if 0
      printf("find(\"%s\",%s) gave %s(%d)\n", p, relnames[j],
             realret, index);
#endif
    }
  }

  realret = findrelpos234(tree, NULL, NULL, REL234_GT, &index);
  if (arraylen && (realret != array[0] || index != 0))
  {
    error("find(NULL,GT) gave %s(%d) should be %s(0)",
          realret, index, array[0]);
  } else if (!arraylen && (realret != NULL))
  {
    error("find(NULL,GT) gave %s(%d) should be NULL", realret, index);
  }

  realret = findrelpos234(tree, NULL, NULL, REL234_LT, &index);
  if (arraylen
      && (realret != array[arraylen - 1] || index != arraylen - 1))
  {
    error("find(NULL,LT) gave %s(%d) should be %s(0)", realret, index,
          array[arraylen - 1]);
  } else if (!arraylen && (realret != NULL))
  {
    error("find(NULL,LT) gave %s(%d) should be NULL", realret, index);
  }
}

void splittest(tree234 * tree, void **array, int arraylen)
{
  int i;
  tree234 *tree3, *tree4;
  for (i = 0; i <= arraylen; i++)
  {
    tree3 = copytree234(tree, NULL, NULL);
    tree4 = splitpos234(tree3, i, 0);
    verifytree(tree3, array, i);
    verifytree(tree4, array + i, arraylen - i);
    join234(tree3, tree4);
    freetree234(tree4);         /* left empty by join */
    verifytree(tree3, array, arraylen);
    freetree234(tree3);
  }
}

int main(void)
{
  int in[NSTR];
  int i, j, k;
  int tworoot, tmplen;
  unsigned seed = 0;
  tree234 *tree2, *tree3, *tree4;
  int c;

  setvbuf(stdout, NULL, _IOLBF, 0);

  for (i = 0; i < (int) NSTR; i++)
    in[i] = 0;
  array = NULL;
  arraylen = arraysize = 0;
  tree = newtree234(mycmp);
  cmp = mycmp;

  verify();
  for (i = 0; i < 10000; i++)
  {
    j = randomnumber(&seed);
    j %= NSTR;
    printf("trial: %d\n", i);
    if (in[j])
    {
      printf("deleting %s (%d)\n", strings[j], j);
      deltest(strings[j]);
      in[j] = 0;
    } else
    {
      printf("adding %s (%d)\n", strings[j], j);
      addtest(strings[j]);
      in[j] = 1;
    }
    disptree(tree);
    findtest();
  }

  while (arraylen > 0)
  {
    j = randomnumber(&seed);
    j %= arraylen;
    deltest(array[j]);
  }

  freetree234(tree);

  /*
   * Now try an unsorted tree. We don't really need to test
   * delpos234 because we know del234 is based on it, so it's
   * already been tested in the above sorted-tree code; but for
   * completeness we'll use it to tear down our unsorted tree
   * once we've built it.
   */
  tree = newtree234(NULL);
  cmp = NULL;
  verify();
  for (i = 0; i < 1000; i++)
  {
    printf("trial: %d\n", i);
    j = randomnumber(&seed);
    j %= NSTR;
    k = randomnumber(&seed);
    k %= count234(tree) + 1;
    printf("adding string %s at index %d\n", strings[j], k);
    addpostest(strings[j], k);
  }

  /*
   * While we have this tree in its full form, we'll take a copy
   * of it to use in split and join testing.
   */
  tree2 = copytree234(tree, NULL, NULL);
  verifytree(tree2, array, arraylen);   /* check the copy is accurate */
  /*
   * Split tests. Split the tree at every possible point and
   * check the resulting subtrees.
   */
  tworoot = (!tree2->root->elems[1]);   /* see if it has a 2-root */
  splittest(tree2, array, arraylen);
  /*
   * Now do the split test again, but on a tree that has a 2-root
   * (if the previous one didn't) or doesn't (if the previous one
   * did).
   */
  tmplen = arraylen;
  while ((!tree2->root->elems[1]) == tworoot)
  {
    delpos234(tree2, --tmplen);
  }
  printf("now trying splits on second tree\n");
  splittest(tree2, array, tmplen);
  freetree234(tree2);

  /*
   * Back to the main testing of uncounted trees.
   */
  while (count234(tree) > 0)
  {
    printf("cleanup: tree size %d\n", count234(tree));
    j = randomnumber(&seed);
    j %= count234(tree);
    printf("deleting string %s from index %d\n", (char *) array[j], j);
    delpostest(j);
  }
  freetree234(tree);

  /*
   * Finally, do some testing on split/join on _sorted_ trees. At
   * the same time, we'll be testing split on very small trees.
   */
  tree = newtree234(mycmp);
  cmp = mycmp;
  arraylen = 0;
  for (i = 0; i < 16; i++)
  {
    addtest(strings[i]);
    tree2 = copytree234(tree, NULL, NULL);
    splittest(tree2, array, arraylen);
    freetree234(tree2);
  }
  freetree234(tree);

  /*
   * Test silly cases of join: join(emptytree, emptytree), and
   * also ensure join correctly spots when sorted trees fail the
   * ordering constraint.
   */
  tree = newtree234(mycmp);
  tree2 = newtree234(mycmp);
  tree3 = newtree234(mycmp);
  tree4 = newtree234(mycmp);
  assert(mycmp(strings[0], strings[1]) < 0);    /* just in case :-) */
  add234(tree2, strings[1]);
  add234(tree4, strings[0]);
  array[0] = strings[0];
  array[1] = strings[1];
  verifytree(tree, array, 0);
  verifytree(tree2, array + 1, 1);
  verifytree(tree3, array, 0);
  verifytree(tree4, array, 1);

  /*
   * So:
   *  - join(tree,tree3) should leave both tree and tree3 unchanged.
   *  - joinr(tree,tree2) should leave both tree and tree2 unchanged.
   *  - join(tree4,tree3) should leave both tree3 and tree4 unchanged.
   *  - join(tree, tree2) should move the element from tree2 to tree.
   *  - joinr(tree4, tree3) should move the element from tree4 to tree3.
   *  - join(tree,tree3) should return NULL and leave both unchanged.
   *  - join(tree3,tree) should work and create a bigger tree in tree3.
   */
  assert(tree == join234(tree, tree3));
  verifytree(tree, array, 0);
  verifytree(tree3, array, 0);
  assert(tree2 == join234r(tree, tree2));
  verifytree(tree, array, 0);
  verifytree(tree2, array + 1, 1);
  assert(tree4 == join234(tree4, tree3));
  verifytree(tree3, array, 0);
  verifytree(tree4, array, 1);
  assert(tree == join234(tree, tree2));
  verifytree(tree, array + 1, 1);
  verifytree(tree2, array, 0);
  assert(tree3 == join234r(tree4, tree3));
  verifytree(tree3, array, 1);
  verifytree(tree4, array, 0);
  assert(NULL == join234(tree, tree3));
  verifytree(tree, array + 1, 1);
  verifytree(tree3, array, 1);
  assert(tree3 == join234(tree3, tree));
  verifytree(tree3, array, 2);
  verifytree(tree, array, 0);

  return 0;
}

#endif

#if 0                           /* sorted list of strings might be useful */
{
"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D",
      "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P",
      "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "a", "b",
      "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n",
      "o", "p", "q", "r", "s", "t", "u", "v", "w", "x",}
#endif
