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Functions
avl.c File Reference
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "avl.h"

Go to the source code of this file.

Functions

struct avl_tableavl_create (avl_comparison_func *compare, void *param, struct libavl_allocator *allocator)
voidavl_find (const struct avl_table *tree, const void *item)
void ** avl_probe (struct avl_table *tree, void *item)
voidavl_insert (struct avl_table *table, void *item)
voidavl_replace (struct avl_table *table, void *item)
voidavl_delete (struct avl_table *tree, const void *item)
static void trav_refresh (struct avl_traverser *trav)
void avl_t_init (struct avl_traverser *trav, struct avl_table *tree)
voidavl_t_first (struct avl_traverser *trav, struct avl_table *tree)
voidavl_t_last (struct avl_traverser *trav, struct avl_table *tree)
voidavl_t_find (struct avl_traverser *trav, struct avl_table *tree, void *item)
voidavl_t_insert (struct avl_traverser *trav, struct avl_table *tree, void *item)
voidavl_t_copy (struct avl_traverser *trav, const struct avl_traverser *src)
voidavl_t_next (struct avl_traverser *trav)
voidavl_t_prev (struct avl_traverser *trav)
voidavl_t_cur (struct avl_traverser *trav)
voidavl_t_replace (struct avl_traverser *trav, void *new)
static void copy_error_recovery (struct avl_node **stack, int height, struct avl_table *new, avl_item_func *destroy)
struct avl_tableavl_copy (const struct avl_table *org, avl_copy_func *copy, avl_item_func *destroy, struct libavl_allocator *allocator)
void avl_destroy (struct avl_table *tree, avl_item_func *destroy)
voidavl_malloc (struct libavl_allocator *allocator, size_t size)
void avl_free (struct libavl_allocator *allocator, void *block)
void() avl_assert_insert (struct avl_table *table, void *item)
void *() avl_assert_delete (struct avl_table *table, void *item)

Function Documentation

void*() avl_assert_delete ( struct avl_table table,
void item 
)

Definition at line 884 of file avl.c.

{
  void *p = avl_delete (table, item);
  assert (p != NULL);
  return p;
}

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void() avl_assert_insert ( struct avl_table table,
void item 
)

Definition at line 875 of file avl.c.

{
  void **p = avl_probe (table, item);
  assert (p != NULL && *p == item);
}

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struct avl_table* avl_copy ( const struct avl_table org,
avl_copy_func copy,
avl_item_func destroy,
struct libavl_allocator allocator 
) [read]

Definition at line 727 of file avl.c.

{
  struct avl_node *stack[2 * (AVL_MAX_HEIGHT + 1)];
  int height = 0;

  struct avl_table *new;
  const struct avl_node *x;
  struct avl_node *y;

  assert (org != NULL);
  new = avl_create (org->avl_compare, org->avl_param,
                    allocator != NULL ? allocator : org->avl_alloc);
  if (new == NULL)
    return NULL;
  new->avl_count = org->avl_count;
  if (new->avl_count == 0)
    return new;

  x = (const struct avl_node *) &org->avl_root;
  y = (struct avl_node *) &new->avl_root;
  for (;;)
    {
      while (x->avl_link[0] != NULL)
        {
          assert (height < 2 * (AVL_MAX_HEIGHT + 1));

          y->avl_link[0] =
            new->avl_alloc->libavl_malloc (new->avl_alloc,
                                           sizeof *y->avl_link[0]);
          if (y->avl_link[0] == NULL)
            {
              if (y != (struct avl_node *) &new->avl_root)
                {
                  y->avl_data = NULL;
                  y->avl_link[1] = NULL;
                }

              copy_error_recovery (stack, height, new, destroy);
              return NULL;
            }

          stack[height++] = (struct avl_node *) x;
          stack[height++] = y;
          x = x->avl_link[0];
          y = y->avl_link[0];
        }
      y->avl_link[0] = NULL;

      for (;;)
        {
          y->avl_balance = x->avl_balance;
          if (copy == NULL)
            y->avl_data = x->avl_data;
          else
            {
              y->avl_data = copy (x->avl_data, org->avl_param);
              if (y->avl_data == NULL)
                {
                  y->avl_link[1] = NULL;
                  copy_error_recovery (stack, height, new, destroy);
                  return NULL;
                }
            }

          if (x->avl_link[1] != NULL)
            {
              y->avl_link[1] =
                new->avl_alloc->libavl_malloc (new->avl_alloc,
                                               sizeof *y->avl_link[1]);
              if (y->avl_link[1] == NULL)
                {
                  copy_error_recovery (stack, height, new, destroy);
                  return NULL;
                }

              x = x->avl_link[1];
              y = y->avl_link[1];
              break;
            }
          else
            y->avl_link[1] = NULL;

          if (height <= 2)
            return new;

          y = stack[--height];
          x = stack[--height];
        }
    }
}

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struct avl_table* avl_create ( avl_comparison_func compare,
void param,
struct libavl_allocator allocator 
) [read]

Definition at line 37 of file avl.c.

{
  struct avl_table *tree;

  assert (compare != NULL);

  if (allocator == NULL)
    allocator = &avl_allocator_default;

  tree = allocator->libavl_malloc (allocator, sizeof *tree);
  if (tree == NULL)
    return NULL;

  tree->avl_root = NULL;
  tree->avl_compare = compare;
  tree->avl_param = param;
  tree->avl_alloc = allocator;
  tree->avl_count = 0;
  tree->avl_generation = 0;

  return tree;
}

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void* avl_delete ( struct avl_table tree,
const void item 
)

Definition at line 228 of file avl.c.

{
  /* Stack of nodes. */
  struct avl_node *pa[AVL_MAX_HEIGHT]; /* Nodes. */
  unsigned char da[AVL_MAX_HEIGHT];    /* |avl_link[]| indexes. */
  int k;                               /* Stack pointer. */

  struct avl_node *p;   /* Traverses tree to find node to delete. */
  int cmp;              /* Result of comparison between |item| and |p|. */

  assert (tree != NULL && item != NULL);

  k = 0;
  p = (struct avl_node *) &tree->avl_root;
  for (cmp = -1; cmp != 0;
       cmp = tree->avl_compare (item, p->avl_data, tree->avl_param))
    {
      int dir = cmp > 0;

      pa[k] = p;
      da[k++] = dir;

      p = p->avl_link[dir];
      if (p == NULL)
        return NULL;
    }
  item = p->avl_data;

  if (p->avl_link[1] == NULL)
    pa[k - 1]->avl_link[da[k - 1]] = p->avl_link[0];
  else
    {
      struct avl_node *r = p->avl_link[1];
      if (r->avl_link[0] == NULL)
        {
          r->avl_link[0] = p->avl_link[0];
          r->avl_balance = p->avl_balance;
          pa[k - 1]->avl_link[da[k - 1]] = r;
          da[k] = 1;
          pa[k++] = r;
        }
      else
        {
          struct avl_node *s;
          int j = k++;

          for (;;)
            {
              da[k] = 0;
              pa[k++] = r;
              s = r->avl_link[0];
              if (s->avl_link[0] == NULL)
                break;

              r = s;
            }

          s->avl_link[0] = p->avl_link[0];
          r->avl_link[0] = s->avl_link[1];
          s->avl_link[1] = p->avl_link[1];
          s->avl_balance = p->avl_balance;

          pa[j - 1]->avl_link[da[j - 1]] = s;
          da[j] = 1;
          pa[j] = s;
        }
    }

  tree->avl_alloc->libavl_free (tree->avl_alloc, p);

  assert (k > 0);
  while (--k > 0)
    {
      struct avl_node *y = pa[k];

      if (da[k] == 0)
        {
          y->avl_balance++;
          if (y->avl_balance == +1)
            break;
          else if (y->avl_balance == +2)
            {
              struct avl_node *x = y->avl_link[1];
              if (x->avl_balance == -1)
                {
                  struct avl_node *w;
                  assert (x->avl_balance == -1);
                  w = x->avl_link[0];
                  x->avl_link[0] = w->avl_link[1];
                  w->avl_link[1] = x;
                  y->avl_link[1] = w->avl_link[0];
                  w->avl_link[0] = y;
                  if (w->avl_balance == +1)
                    x->avl_balance = 0, y->avl_balance = -1;
                  else if (w->avl_balance == 0)
                    x->avl_balance = y->avl_balance = 0;
                  else /* |w->avl_balance == -1| */
                    x->avl_balance = +1, y->avl_balance = 0;
                  w->avl_balance = 0;
                  pa[k - 1]->avl_link[da[k - 1]] = w;
                }
              else
                {
                  y->avl_link[1] = x->avl_link[0];
                  x->avl_link[0] = y;
                  pa[k - 1]->avl_link[da[k - 1]] = x;
                  if (x->avl_balance == 0)
                    {
                      x->avl_balance = -1;
                      y->avl_balance = +1;
                      break;
                    }
                  else
                    x->avl_balance = y->avl_balance = 0;
                }
            }
        }
      else
        {
          y->avl_balance--;
          if (y->avl_balance == -1)
            break;
          else if (y->avl_balance == -2)
            {
              struct avl_node *x = y->avl_link[0];
              if (x->avl_balance == +1)
                {
                  struct avl_node *w;
                  assert (x->avl_balance == +1);
                  w = x->avl_link[1];
                  x->avl_link[1] = w->avl_link[0];
                  w->avl_link[0] = x;
                  y->avl_link[0] = w->avl_link[1];
                  w->avl_link[1] = y;
                  if (w->avl_balance == -1)
                    x->avl_balance = 0, y->avl_balance = +1;
                  else if (w->avl_balance == 0)
                    x->avl_balance = y->avl_balance = 0;
                  else /* |w->avl_balance == +1| */
                    x->avl_balance = -1, y->avl_balance = 0;
                  w->avl_balance = 0;
                  pa[k - 1]->avl_link[da[k - 1]] = w;
                }
              else
                {
                  y->avl_link[0] = x->avl_link[1];
                  x->avl_link[1] = y;
                  pa[k - 1]->avl_link[da[k - 1]] = x;
                  if (x->avl_balance == 0)
                    {
                      x->avl_balance = +1;
                      y->avl_balance = -1;
                      break;
                    }
                  else
                    x->avl_balance = y->avl_balance = 0;
                }
            }
        }
    }

  tree->avl_count--;
  tree->avl_generation++;
  return (void *) item;
}

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void avl_destroy ( struct avl_table tree,
avl_item_func destroy 
)

Definition at line 822 of file avl.c.

{
  struct avl_node *p, *q;

  assert (tree != NULL);

  for (p = tree->avl_root; p != NULL; p = q)
    if (p->avl_link[0] == NULL)
      {
        q = p->avl_link[1];
        if (destroy != NULL && p->avl_data != NULL)
          destroy (p->avl_data, tree->avl_param);
        tree->avl_alloc->libavl_free (tree->avl_alloc, p);
      }
    else
      {
        q = p->avl_link[0];
        p->avl_link[0] = q->avl_link[1];
        q->avl_link[1] = p;
      }

  tree->avl_alloc->libavl_free (tree->avl_alloc, tree);
}

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void* avl_find ( const struct avl_table tree,
const void item 
)

Definition at line 64 of file avl.c.

{
  const struct avl_node *p;

  assert (tree != NULL && item != NULL);
  for (p = tree->avl_root; p != NULL; )
    {
      int cmp = tree->avl_compare (item, p->avl_data, tree->avl_param);

      if (cmp < 0)
        p = p->avl_link[0];
      else if (cmp > 0)
        p = p->avl_link[1];
      else /* |cmp == 0| */
        return p->avl_data;
    }

  return NULL;
}

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void avl_free ( struct libavl_allocator allocator,
void block 
)

Definition at line 857 of file avl.c.

{
  assert (allocator != NULL && block != NULL);
  free (block);
}

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void* avl_insert ( struct avl_table table,
void item 
)

Definition at line 201 of file avl.c.

{
  void **p = avl_probe (table, item);
  return p == NULL || *p == item ? NULL : *p;
}

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void* avl_malloc ( struct libavl_allocator allocator,
size_t  size 
)

Definition at line 849 of file avl.c.

{
  assert (allocator != NULL && size > 0);
  return malloc (size);
}
void** avl_probe ( struct avl_table tree,
void item 
)

Definition at line 89 of file avl.c.

{
  struct avl_node *y, *z; /* Top node to update balance factor, and parent. */
  struct avl_node *p, *q; /* Iterator, and parent. */
  struct avl_node *n;     /* Newly inserted node. */
  struct avl_node *w;     /* New root of rebalanced subtree. */
  int dir;                /* Direction to descend. */

  unsigned char da[AVL_MAX_HEIGHT]; /* Cached comparison results. */
  int k = 0;              /* Number of cached results. */

  assert (tree != NULL && item != NULL);

  z = (struct avl_node *) &tree->avl_root;
  y = tree->avl_root;
  dir = 0;
  for (q = z, p = y; p != NULL; q = p, p = p->avl_link[dir])
    {
      int cmp = tree->avl_compare (item, p->avl_data, tree->avl_param);
      if (cmp == 0)
        return &p->avl_data;

      if (p->avl_balance != 0)
        z = q, y = p, k = 0;
      da[k++] = dir = cmp > 0;
    }

  n = q->avl_link[dir] =
    tree->avl_alloc->libavl_malloc (tree->avl_alloc, sizeof *n);
  if (n == NULL)
    return NULL;

  tree->avl_count++;
  n->avl_data = item;
  n->avl_link[0] = n->avl_link[1] = NULL;
  n->avl_balance = 0;
  if (y == NULL)
    return &n->avl_data;

  for (p = y, k = 0; p != n; p = p->avl_link[da[k]], k++)
    if (da[k] == 0)
      p->avl_balance--;
    else
      p->avl_balance++;

  if (y->avl_balance == -2)
    {
      struct avl_node *x = y->avl_link[0];
      if (x->avl_balance == -1)
        {
          w = x;
          y->avl_link[0] = x->avl_link[1];
          x->avl_link[1] = y;
          x->avl_balance = y->avl_balance = 0;
        }
      else
        {
          assert (x->avl_balance == +1);
          w = x->avl_link[1];
          x->avl_link[1] = w->avl_link[0];
          w->avl_link[0] = x;
          y->avl_link[0] = w->avl_link[1];
          w->avl_link[1] = y;
          if (w->avl_balance == -1)
            x->avl_balance = 0, y->avl_balance = +1;
          else if (w->avl_balance == 0)
            x->avl_balance = y->avl_balance = 0;
          else /* |w->avl_balance == +1| */
            x->avl_balance = -1, y->avl_balance = 0;
          w->avl_balance = 0;
        }
    }
  else if (y->avl_balance == +2)
    {
      struct avl_node *x = y->avl_link[1];
      if (x->avl_balance == +1)
        {
          w = x;
          y->avl_link[1] = x->avl_link[0];
          x->avl_link[0] = y;
          x->avl_balance = y->avl_balance = 0;
        }
      else
        {
          assert (x->avl_balance == -1);
          w = x->avl_link[0];
          x->avl_link[0] = w->avl_link[1];
          w->avl_link[1] = x;
          y->avl_link[1] = w->avl_link[0];
          w->avl_link[0] = y;
          if (w->avl_balance == +1)
            x->avl_balance = 0, y->avl_balance = -1;
          else if (w->avl_balance == 0)
            x->avl_balance = y->avl_balance = 0;
          else /* |w->avl_balance == -1| */
            x->avl_balance = +1, y->avl_balance = 0;
          w->avl_balance = 0;
        }
    }
  else
    return &n->avl_data;
  z->avl_link[y != z->avl_link[0]] = w;

  tree->avl_generation++;
  return &n->avl_data;
}

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void* avl_replace ( struct avl_table table,
void item 
)

Definition at line 212 of file avl.c.

{
  void **p = avl_probe (table, item);
  if (p == NULL || *p == item)
    return NULL;
  else
    {
      void *r = *p;
      *p = item;
      return r;
    }
}

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void* avl_t_copy ( struct avl_traverser trav,
const struct avl_traverser src 
)

Definition at line 557 of file avl.c.

{
  assert (trav != NULL && src != NULL);

  if (trav != src)
    {
      trav->avl_table = src->avl_table;
      trav->avl_node = src->avl_node;
      trav->avl_generation = src->avl_generation;
      if (trav->avl_generation == trav->avl_table->avl_generation)
        {
          trav->avl_height = src->avl_height;
          memcpy (trav->avl_stack, (const void *) src->avl_stack,
                  sizeof *trav->avl_stack * trav->avl_height);
        }
    }

  return trav->avl_node != NULL ? trav->avl_node->avl_data : NULL;
}

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void* avl_t_cur ( struct avl_traverser trav)

Definition at line 685 of file avl.c.

{
  assert (trav != NULL);

  return trav->avl_node != NULL ? trav->avl_node->avl_data : NULL;
}
void* avl_t_find ( struct avl_traverser trav,
struct avl_table tree,
void item 
)

Definition at line 493 of file avl.c.

{
  struct avl_node *p, *q;

  assert (trav != NULL && tree != NULL && item != NULL);
  trav->avl_table = tree;
  trav->avl_height = 0;
  trav->avl_generation = tree->avl_generation;
  for (p = tree->avl_root; p != NULL; p = q)
    {
      int cmp = tree->avl_compare (item, p->avl_data, tree->avl_param);

      if (cmp < 0)
        q = p->avl_link[0];
      else if (cmp > 0)
        q = p->avl_link[1];
      else /* |cmp == 0| */
        {
          trav->avl_node = p;
          return p->avl_data;
        }

      assert (trav->avl_height < AVL_MAX_HEIGHT);
      trav->avl_stack[trav->avl_height++] = p;
    }

  trav->avl_height = 0;
  trav->avl_node = NULL;
  return NULL;
}

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void* avl_t_first ( struct avl_traverser trav,
struct avl_table tree 
)

Definition at line 437 of file avl.c.

{
  struct avl_node *x;

  assert (tree != NULL && trav != NULL);

  trav->avl_table = tree;
  trav->avl_height = 0;
  trav->avl_generation = tree->avl_generation;

  x = tree->avl_root;
  if (x != NULL)
    while (x->avl_link[0] != NULL)
      {
        assert (trav->avl_height < AVL_MAX_HEIGHT);
        trav->avl_stack[trav->avl_height++] = x;
        x = x->avl_link[0];
      }
  trav->avl_node = x;

  return x != NULL ? x->avl_data : NULL;
}

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void avl_t_init ( struct avl_traverser trav,
struct avl_table tree 
)

Definition at line 425 of file avl.c.

{
  trav->avl_table = tree;
  trav->avl_node = NULL;
  trav->avl_height = 0;
  trav->avl_generation = tree->avl_generation;
}

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void* avl_t_insert ( struct avl_traverser trav,
struct avl_table tree,
void item 
)

Definition at line 532 of file avl.c.

{
  void **p;

  assert (trav != NULL && tree != NULL && item != NULL);

  p = avl_probe (tree, item);
  if (p != NULL)
    {
      trav->avl_table = tree;
      trav->avl_node =
        ((struct avl_node *)
         ((char *) p - offsetof (struct avl_node, avl_data)));
      trav->avl_generation = tree->avl_generation - 1;
      return *p;
    }
  else
    {
      avl_t_init (trav, tree);
      return NULL;
    }
}

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void* avl_t_last ( struct avl_traverser trav,
struct avl_table tree 
)

Definition at line 464 of file avl.c.

{
  struct avl_node *x;

  assert (tree != NULL && trav != NULL);

  trav->avl_table = tree;
  trav->avl_height = 0;
  trav->avl_generation = tree->avl_generation;

  x = tree->avl_root;
  if (x != NULL)
    while (x->avl_link[1] != NULL)
      {
        assert (trav->avl_height < AVL_MAX_HEIGHT);
        trav->avl_stack[trav->avl_height++] = x;
        x = x->avl_link[1];
      }
  trav->avl_node = x;

  return x != NULL ? x->avl_data : NULL;
}

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void* avl_t_next ( struct avl_traverser trav)

Definition at line 581 of file avl.c.

{
  struct avl_node *x;

  assert (trav != NULL);

  if (trav->avl_generation != trav->avl_table->avl_generation)
    trav_refresh (trav);

  x = trav->avl_node;
  if (x == NULL)
    {
      return avl_t_first (trav, trav->avl_table);
    }
  else if (x->avl_link[1] != NULL)
    {
      assert (trav->avl_height < AVL_MAX_HEIGHT);
      trav->avl_stack[trav->avl_height++] = x;
      x = x->avl_link[1];

      while (x->avl_link[0] != NULL)
        {
          assert (trav->avl_height < AVL_MAX_HEIGHT);
          trav->avl_stack[trav->avl_height++] = x;
          x = x->avl_link[0];
        }
    }
  else
    {
      struct avl_node *y;

      do
        {
          if (trav->avl_height == 0)
            {
              trav->avl_node = NULL;
              return NULL;
            }

          y = x;
          x = trav->avl_stack[--trav->avl_height];
        }
      while (y == x->avl_link[1]);
    }
  trav->avl_node = x;

  return x->avl_data;
}

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void* avl_t_prev ( struct avl_traverser trav)

Definition at line 634 of file avl.c.

{
  struct avl_node *x;

  assert (trav != NULL);

  if (trav->avl_generation != trav->avl_table->avl_generation)
    trav_refresh (trav);

  x = trav->avl_node;
  if (x == NULL)
    {
      return avl_t_last (trav, trav->avl_table);
    }
  else if (x->avl_link[0] != NULL)
    {
      assert (trav->avl_height < AVL_MAX_HEIGHT);
      trav->avl_stack[trav->avl_height++] = x;
      x = x->avl_link[0];

      while (x->avl_link[1] != NULL)
        {
          assert (trav->avl_height < AVL_MAX_HEIGHT);
          trav->avl_stack[trav->avl_height++] = x;
          x = x->avl_link[1];
        }
    }
  else
    {
      struct avl_node *y;

      do
        {
          if (trav->avl_height == 0)
            {
              trav->avl_node = NULL;
              return NULL;
            }

          y = x;
          x = trav->avl_stack[--trav->avl_height];
        }
      while (y == x->avl_link[0]);
    }
  trav->avl_node = x;

  return x->avl_data;
}

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void* avl_t_replace ( struct avl_traverser trav,
void new 
)

Definition at line 696 of file avl.c.

{
  void *old;

  assert (trav != NULL && trav->avl_node != NULL && new != NULL);
  old = trav->avl_node->avl_data;
  trav->avl_node->avl_data = new;
  return old;
}
static void copy_error_recovery ( struct avl_node **  stack,
int  height,
struct avl_table new,
avl_item_func destroy 
) [static]

Definition at line 707 of file avl.c.

{
  assert (stack != NULL && height >= 0 && new != NULL);

  for (; height > 2; height -= 2)
    stack[height - 1]->avl_link[1] = NULL;
  avl_destroy (new, destroy);
}

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static void trav_refresh ( struct avl_traverser trav) [static]

Definition at line 397 of file avl.c.

{
  assert (trav != NULL);

  trav->avl_generation = trav->avl_table->avl_generation;

  if (trav->avl_node != NULL)
    {
      avl_comparison_func *cmp = trav->avl_table->avl_compare;
      void *param = trav->avl_table->avl_param;
      struct avl_node *node = trav->avl_node;
      struct avl_node *i;

      trav->avl_height = 0;
      for (i = trav->avl_table->avl_root; i != node; )
        {
          assert (trav->avl_height < AVL_MAX_HEIGHT);
          assert (i != NULL);

          trav->avl_stack[trav->avl_height++] = i;
          i = i->avl_link[cmp (node->avl_data, i->avl_data, param) > 0];
        }
    }
}

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