/* i4remove.c   (c)Copyright Sequiter Software Inc., 1990-1994.  All rights reserved. */

#include "d4all.h"
#ifndef S4UNIX
#ifdef __TURBOC__
#pragma hdrstop
#endif
#endif

#ifndef S4OFF_WRITE
#ifndef S4INDEX_OFF

int S4FUNCTION t4remove( TAG4 *t4, char *ptr, long rec )
{
  int rc ;

#ifdef S4DEBUG
  if ( t4 == 0 )
    e4severe( e4parm, E4_T4REMOVE ) ;
#endif

  rc = t4go( t4, ptr, rec ) ;   /* returns -1 if code_base->error_code < 0 */
  if ( rc < 0 )
    return rc ;
  if ( rc )
    return r4entry ;

  return t4remove_current( t4 ) ;
}

int S4FUNCTION t4remove_calc( TAG4 *t4, long rec )
{
  char *ptr ;

#ifdef S4DEBUG
  if ( t4 == 0 )
    e4severe( e4parm, E4_T4REM_CALC ) ;
#endif

  if ( t4->code_base->error_code < 0 )
    return -1 ;

  t4expr_key( t4, &ptr ) ;
  return t4remove( t4, ptr, rec ) ;
}

#ifndef N4OTHER

#ifdef S4FOX
/* remove the (current) branch block */
void S4FUNCTION t4remove_branch( TAG4 *t4, B4BLOCK *block_on )
{
  long l_node, r_node ;
  INDEX4 *i4 ;
#ifdef S4BYTE_SWAP
  char *swap_ptr ;
  S4LONG long_val ;
  short short_val ;
  int i ;
#endif

  i4 = t4->index ;

  if ( block_on == (B4BLOCK *)l4first( &t4->blocks ) )
  {
    /* Root Block, do not delete */
#ifdef S4DEBUG
    if ( block_on->header.left_node != -1 || block_on->header.right_node != -1 || block_on->header.n_keys != 1 )
      e4severe( e4info, E4_INFO_CIB ) ;
#endif
    memset( block_on->data, 0, B4BLOCK_SIZE - sizeof(B4STD_HEADER) - sizeof(B4NODE_HEADER) ) ;
    if ( !b4leaf( block_on ) )   /* if not a leaf, then reset node_hdr too */
    {
      memset( (void *)&block_on->node_hdr, 0, sizeof(B4NODE_HEADER) ) ;
      b4leaf_init( block_on ) ;
    }
    else
      block_on->node_hdr.free_space = B4BLOCK_SIZE - sizeof( B4STD_HEADER ) - sizeof( B4NODE_HEADER ) ;
    block_on->header.n_keys = 0 ;
    block_on->header.left_node = -1 ;
    block_on->header.right_node = -1 ;
    block_on->key_on = -1 ;
    block_on->built_on = -1 ;
    block_on->header.node_attribute = 3 ;  /* root and leaf */
    block_on->changed = 1 ;
  }
  else /* This block is to be deleted */
  {
    l_node = block_on->header.left_node ;
    r_node = block_on->header.right_node ;
    l4remove( &t4->blocks, block_on ) ;
    if ( i4shrink( i4, block_on->file_block ) < 0 )
      return ;
    block_on->changed = 0 ;

    if ( l_node != -1L )
    {
      if ( file4read_all( &i4->file, I4MULTIPLY*l_node, &block_on->header, B4BLOCK_SIZE) < 0 )
        return ;

#ifdef S4BYTE_SWAP
      block_on->header.node_attribute = x4reverse_short( (void *)&block_on->header.node_attribute ) ;
      block_on->header.n_keys = x4reverse_short( (void *)&block_on->header.n_keys ) ;
      block_on->header.left_node = x4reverse_long( (void *)&block_on->header.left_node ) ;
      block_on->header.right_node = x4reverse_long( (void *)&block_on->header.right_node ) ;

      /* if block is a leaf */
      if (block_on->header.node_attribute >= 2 )
      {
        block_on->node_hdr.free_space = x4reverse_short( (void *)&block_on->node_hdr.free_space ) ;
        long_val = x4reverse_long( (void *)&block_on->node_hdr.rec_num_mask[0] ) ;
        memcpy( (void *)&block_on->node_hdr.rec_num_mask[0], (void *)&long_val, sizeof(S4LONG) ) ;
      }
      else                /* if block is a branch */
      {
        short_val = block_on->tag->header.key_len + sizeof(S4LONG) ;
        /* position swap_ptr to end of first key expression */
        swap_ptr = (char *) &block_on->node_hdr.free_space + block_on->tag->header.key_len ;

        /* move through all B4KEY's to swap 'long's */
        for ( i = 0 ; i < (int) block_on->header.n_keys ; i++ )
        {
          long_val = x4reverse_long( (void *)swap_ptr ) ;
          memcpy( swap_ptr, (void *) &long_val, sizeof(S4LONG) ) ;
          swap_ptr += sizeof(S4LONG) ;
          long_val = x4reverse_long( (void *)swap_ptr ) ;
          memcpy( swap_ptr, (void *) &long_val, sizeof(S4LONG) ) ;
          swap_ptr += short_val ;
        }
      }
#endif

      block_on->file_block = l_node ;
      block_on->header.right_node = r_node ;
      block_on->changed = 1 ;
      b4flush( block_on ) ;
    }

    if ( r_node != -1L )
    {
      if ( file4read_all( &i4->file, I4MULTIPLY*r_node, &block_on->header, B4BLOCK_SIZE) < 0 )
        return ;

#ifdef S4BYTE_SWAP
      block_on->header.node_attribute = x4reverse_short( (void *)&block_on->header.node_attribute ) ;
      block_on->header.n_keys = x4reverse_short( (void *)&block_on->header.n_keys ) ;
      block_on->header.left_node = x4reverse_long( (void *)&block_on->header.left_node ) ;
      block_on->header.right_node = x4reverse_long( (void *)&block_on->header.right_node ) ;

      /* if block is a leaf */
      if (block_on->header.node_attribute >= 2 )
      {
        block_on->node_hdr.free_space = x4reverse_short( (void *)&block_on->node_hdr.free_space ) ;
        long_val = x4reverse_long( (void *)block_on->node_hdr.rec_num_mask ) ;
        memcpy( (void *)block_on->node_hdr.rec_num_mask, (void *)&long_val, sizeof(S4LONG) ) ;
      }
      else                /* if block is a branch */
      {
        short_val = block_on->tag->header.key_len + sizeof(S4LONG) ;
        /* position swap_ptr to end of first key expression */
        swap_ptr = (char *) &block_on->node_hdr.free_space + block_on->tag->header.key_len ;

        /* move through all B4KEY's to swap 'long's */
        for ( i = 0 ; i < (int) block_on->header.n_keys ; i++ )
        {
          long_val = x4reverse_long( (void *)swap_ptr ) ;
          memcpy( swap_ptr, (void *) &long_val, sizeof(S4LONG) ) ;
          swap_ptr += sizeof(S4LONG) ;
          long_val = x4reverse_long( (void *)swap_ptr ) ;
          memcpy( swap_ptr, (void *) &long_val, sizeof(S4LONG) ) ;
          swap_ptr += short_val ;
        }
      }
#endif

      block_on->file_block = r_node ;
      block_on->header.left_node = l_node ;
      block_on->changed = 1 ;
      b4flush( block_on ) ;
    }

    b4free( block_on ) ;
  }
}
#endif

/* Remove the current key */
int S4FUNCTION t4remove_current( TAG4 *t4 )
{
  B4BLOCK *block_on ;
  INDEX4 *i4 ;
#ifdef S4FOX
  void *new_key_info ;
  long rec ;
  int bl_removed, less_than_last ;
#else
  int remove_done, update_reqd ;
  B4BLOCK *block_iterate ;
#endif

  i4 = t4->index ;

#ifdef S4FOX
  i4->tag_index->header.version = i4->version_old+1 ;
  new_key_info = 0 ;

  for ( block_on = (B4BLOCK *)t4->blocks.last_node ; block_on ; )
  {
    bl_removed = 0 ;
    if ( new_key_info == 0 )  /* then delete entry */
    {
      if ( b4lastpos( block_on ) == 0 )
      {
        if ( block_on != (B4BLOCK *)l4first( &t4->blocks ) )
          bl_removed = 1 ;
        t4remove_branch( t4, block_on ) ;
        block_on = (B4BLOCK *)t4->blocks.last_node ;
      }
      else
      {
        less_than_last = 0 ;
        if ( block_on->key_on < b4lastpos( block_on ) )
          less_than_last = 1 ;
        b4remove( block_on ) ;
        if ( less_than_last )
          return 0 ;

        /* On last entry */
        b4go_eof( block_on ) ;
        block_on->key_on-- ;  /* update key_on for goint to last spot */
        new_key_info = b4key_key( block_on, block_on->key_on ) ;
        rec = b4recno( block_on, block_on->key_on ) ;
      }
    }
    else  /* Adjust entry */
    {
      b4br_replace( block_on, (char *)new_key_info, rec ) ;
      if ( block_on->key_on != b4lastpos( block_on ) )  /* not on end key, so exit, else continue */
        return 0 ;
    }

    if ( !bl_removed )
    {
      block_on = (B4BLOCK *)block_on->link.p ;
      if ( block_on == (B4BLOCK *)t4->blocks.last_node )
        break ;
    }
  }
#endif

#ifdef S4MDX
  remove_done = 0 ;
  update_reqd = 0 ;
  i4->changed = 1 ;
  t4->changed = 1 ;
  t4->header.version++ ;

  block_iterate = (B4BLOCK *)l4last( &t4->blocks ) ;
  for ( ;; )
  {
    block_on = block_iterate ;
    if ( block_on == 0 )
      break ;
    block_iterate = (B4BLOCK *)l4prev( &t4->blocks, block_iterate ) ;  /* Calculate the previous block while the current block exists. */

    if ( !remove_done )  /* either removing or else updating */
    {
      if ( b4lastpos( block_on ) == 0 )  /* delete block */
      {
        if ( block_on == (B4BLOCK *)l4first( &t4->blocks ) )  /* root block, don't delete */
        {
          block_on->changed = 1 ;
          block_on->key_on = 0 ;
          memset( (void *)&block_on->n_keys, 0, i4->header.block_rw ) ;
          if (t4->filter )  /* must modify the filter setting for dBASE IV compatibility */
          {
            file4write(&t4->index->file, t4->header_offset+sizeof(t4->header)+222, (char *)"\0", (int)1 ) ;
            t4->has_keys = 0 ;
#ifdef S4MDX
            t4->had_keys = 1 ;
#endif
          }
          return 0 ;
        }
else
{
  l4remove( &t4->blocks, block_on ) ;
  if ( i4shrink( i4, block_on->file_block) < 0 )
    return -1 ;
  b4free( block_on ) ;
}
}
else  /* just remove entry */
{
  if ( block_iterate && block_on->key_on == b4lastpos( block_on ) && b4lastpos( block_on ) > 0 )  /* save to become last key of the block for parent update */
  {
    memcpy( t4->code_base->saved_key, b4key_key( block_on, block_on->n_keys - 1 - b4leaf(block_on) ), t4->header.key_len ) ;
    update_reqd = 1 ;
  }
  else
    update_reqd = 0 ;

  b4remove( block_on ) ;
  if ( !b4leaf( block_on ) && b4lastpos( block_on ) == 0 )  /* branch with only one entry, so have the entry take place of this block */
  {
    if (block_on == (B4BLOCK *)l4first( &t4->blocks ) )   /* the entry becomes the new root */
    {
      /* first update the tags root */
      t4->header.root = b4key( block_on, 0 )->num ;
#ifdef S4BYTE_SWAP
      t4->header.root = x4reverse_long( (void *)&t4->header.root ) ;
#endif
      file4write( &t4->index->file, t4->header_offset, (void *)&t4->header.root, sizeof(t4->header.root) ) ;
#ifdef S4BYTE_SWAP
      t4->header.root = x4reverse_long( (void *)&t4->header.root ) ;
#endif
      update_reqd = 0 ;
    }
    else  /* remove this branch block */
    {
      block_iterate->changed = 1 ;
      b4key( block_iterate, block_iterate->key_on )->num = b4key( block_on, 0 )->num ;
    }
    l4remove( &t4->blocks, block_on ) ;
    if ( i4shrink( t4->index, block_on->file_block) < 0 )
      return -1 ;
    block_on->changed = 0 ;
    b4free( block_on ) ;
  }
  else
    block_on->key_on = b4lastpos( block_on ) ;

  if ( !update_reqd )
    return 0 ;
  remove_done = 1 ;
}
}
else  /* Adjust entry - at most one update will be required in MDX */
{
  if ( block_on->key_on < b4lastpos( block_on ) )
  {
    block_on->changed = 1 ;
    memcpy( b4key_key( block_on, block_on->key_on), t4->code_base->saved_key, t4->header.key_len ) ;
    return 0 ;
  }
}
}
#endif

return 0 ;
}

#endif   /* ifndef N4OTHER  */

#ifdef N4OTHER

#ifdef S4NDX
int S4FUNCTION t4remove_current( TAG4 *t4 )
{
  B4BLOCK *block_on, *block_iterate ;
  int remove_done, update_reqd ;
#ifdef S4USE_OLD
  void *new_key_info ;
  long shrink_br = 0 ;
  B4BLOCK *shrink_block = 0 ;
  new_key_info = 0 ;
#endif

  t4->header.version = t4->header.old_version+1 ;

  remove_done = 0 ;
  update_reqd = 0 ;
  t4->header.version++ ;

  block_iterate = (B4BLOCK *)l4last( &t4->blocks ) ;
  for ( ;; )
  {
    block_on = block_iterate ;
    if ( block_on == 0 )
      break ;
    block_iterate = (B4BLOCK *)l4prev( &t4->blocks, block_iterate ) ;  /* Calculate the previous block while the current block exists. */

    if ( !remove_done )  /* either removing or else updating */
    {
      if ( b4lastpos( block_on ) == 0 )  /* delete block */
      {
        block_on->changed = 1 ;
        block_on->key_on = 0 ;
        memset( (void *)&block_on->n_keys, 0, B4BLOCK_SIZE ) ;
        if ( block_on == (B4BLOCK *)l4first( &t4->blocks ) )  /* root block, don't delete */
          return 0 ;
else
{
  l4remove( &t4->blocks, block_on ) ;
  if ( b4flush( block_on ) < 0 )
    return -1 ;
  b4free( block_on ) ;
}
}
else  /* just remove entry */
{
  if ( block_iterate && block_on->key_on == b4lastpos( block_on ) && b4lastpos( block_on ) > 0 )  /* save to become last key of the block for parent update */
  {
    memcpy( t4->code_base->saved_key, b4key_key( block_on, block_on->n_keys - 1 - b4leaf(block_on) ), t4->header.key_len ) ;
    update_reqd = 1 ;
  }
  else
    update_reqd = 0 ;

  b4remove( block_on ) ;
  if ( !b4leaf( block_on ) && b4lastpos( block_on ) == 0 )  /* branch with only one entry, so have the entry take place of this block */
  {
    if (block_on == (B4BLOCK *)l4first( &t4->blocks ) )   /* the entry becomes the new root */
    {
      /* first update the tags root */
      t4->header.root = b4key( block_on, 0 )->num ;
#ifdef S4BYTE_SWAP
      t4->header.root = x4reverse_long( (void *)&t4->header.root ) ;
#endif
      file4write( &t4->file, t4->header_offset, (void *)&t4->header.root, sizeof(t4->header.root) ) ;
#ifdef S4BYTE_SWAP
      t4->header.root = x4reverse_long( (void *)&t4->header.root ) ;
#endif
      update_reqd = 0 ;
    }
    else  /* remove this branch block */
    {
      block_iterate->changed = 1 ;
      b4key( block_iterate, block_iterate->key_on )->pointer = b4key( block_on, 0 )->pointer ;
    }
    l4remove( &t4->blocks, block_on ) ;
    block_on->changed = 1 ;
    memset( &block_on->n_keys, 0, B4BLOCK_SIZE ) ;
    if ( b4flush( block_on ) < 0 )
      return -1 ;
    b4free( block_on ) ;
  }
  else
    block_on->key_on = b4lastpos( block_on ) ;

  if ( !update_reqd )
    return 0 ;
  remove_done = 1 ;
}
}
else  /* Adjust entry - at most one update will be required in MDX */
{
  if ( block_on->key_on < b4lastpos( block_on ) )
  {
    block_on->changed = 1 ;
    memcpy( b4key_key( block_on, block_on->key_on), t4->code_base->saved_key, t4->header.key_len ) ;
    return 0 ;
  }
}
}

return 0 ;
}
#else
#ifdef S4CLIPPER
int S4FUNCTION t4balance_branch( TAG4 *, B4BLOCK * ) ;

int S4FUNCTION t4remove_ref( TAG4 *t4 )
{
  B4KEY_DATA *my_key_data ;
  B4BLOCK *block_on, *block_up ;
  long reference ;
  int i ;
  int rc ;

  my_key_data = (B4KEY_DATA *)u4alloc_er( t4->code_base, t4->header.group_len ) ;
  if ( my_key_data == 0 )
    return -1 ;
  block_on = (B4BLOCK *)t4->blocks.last_node ;

  /*  no longer required...
      #ifdef S4DEBUG
      if ( block_on->n_keys )
      e4severe( e4info, E4_INFO_DEL ) ;
      #endif
      */

  t4up( t4 ) ;
  block_up = (B4BLOCK *)t4->blocks.last_node ;

  if ( block_up == 0 )  /* root block only, so reference doesn't exist */
  {
    /* reset the block */
    short offset = ( t4->header.keys_max + 2 + ( (t4->header.keys_max/2)*2 != t4->header.keys_max ) ) * sizeof(short) ;
    for ( i = 0 ; i <= t4->header.keys_max ; i++ )
      block_on->pointers[i] = (short)( t4->header.group_len * i ) + offset ;
    return 0 ;
  }
else  /* delete the block */
{
  t4shrink( t4, block_on->file_block ) ;
  l4pop( &t4->saved ) ;
  block_on->changed = 0 ;
  b4free( block_on ) ;
}
block_on = block_up ;

if ( block_on->key_on >= block_on->n_keys )
  memcpy( &(my_key_data->num), &( b4key( block_on, block_on->key_on - 1 )->num), sizeof(long) + t4->header.key_len ) ;
else
memcpy( &(my_key_data->num), &( b4key( block_on, block_on->key_on )->num), sizeof(long) + t4->header.key_len ) ;

if ( block_on->n_keys == 1 )
{
  /* take the branch, and put in place of me, then delete and add me */
  if ( block_on->key_on >= block_on->n_keys )
    reference = (long) b4key( block_on, 0 )->pointer ;
  else
    reference = (long) b4key( block_on, 1 )->pointer ;
  t4shrink( t4, block_on->file_block ) ;
  t4up( t4 ) ;
  l4pop(&t4->saved ) ;
  block_on->changed = 0 ;
  b4free( block_on ) ;
  block_on = (B4BLOCK *)t4->blocks.last_node ;
  if ( block_on == 0 )  /* just removed root, so make reference root! */
    t4->header.root = reference ;
  else
  {
    memcpy( &(b4key( block_on, block_on->key_on )->pointer), &reference, sizeof( reference ) )  ;
    block_on->changed = 1 ;
  }
}
else    /* just remove myself, add later */
{
  b4remove( block_on ) ;
  if ( block_on->n_keys < t4->header.keys_half && block_on->file_block != t4->header.root )  /* if not root may have to balance the tree */
  {
    if ( t4balance_branch( t4, block_on ) < 0 )
      return -1 ;
  }
}

/* now add the removed reference back into the index */
rc = t4add( t4, (unsigned char *)my_key_data->value, my_key_data->num ) ;
u4free( my_key_data ) ;

return rc ;
}

static int t4balance_block( TAG4 *t4, B4BLOCK *parent, B4BLOCK *b4, B4BLOCK *b4temp, char is_right, char balance_mode )
{
  B4KEY_DATA *bdata, *bdata2 ;
  int avg, i ;
  long temp_fb ;

  if ( balance_mode == 2 && b4leaf( b4temp ) )
  {
#ifdef S4DEBUG
    e4severe( e4info, E4_INFO_CIF ) ;
#endif
    return -1 ;
  }
  else
  {
    if ( b4temp->n_keys + b4->n_keys < t4->header.keys_max )  /* join the two */
    {
      if ( is_right )
      {
        if ( balance_mode == 2 )
        {
          b4->key_on = 0 ;
          parent->key_on-- ;
          bdata = b4key( parent, parent->key_on ) ;
          b4insert( b4, bdata->value, bdata->num, b4key( b4temp, b4temp->n_keys )->pointer / 512 ) ;
          for ( i = b4temp->n_keys - 1 ; i >= 0 ; i-- )
          {
            b4->key_on = 0 ;
            bdata = b4key( b4temp, i ) ;
            b4insert( b4, bdata->value, bdata->num, bdata->pointer / 512 ) ;
          }
          b4temp->changed = 0 ;
          t4shrink( t4, b4temp->file_block ) ;
          b4remove( parent ) ;
          if ( parent->n_keys < t4->header.keys_half )
            t4balance_branch( t4, parent ) ;
        }
        else
        {
          for ( i = 0 ; i < b4->n_keys ; i++ )
          {
            b4go_eof( b4temp ) ;
            bdata = b4key( b4, i ) ;
            b4insert( b4temp, bdata->value, bdata->num, 0L ) ;
          }

          t4->index->code_base->do_index_verify = 0 ;  /* avoid verify errors due to our partial removal */
          do
          {
            t4down( t4 ) ;
          } while( !b4leaf( t4block( t4 ) ) ) ;
          t4->index->code_base->do_index_verify = 1 ;

          b4flush( b4temp ) ;
          if ( t4remove_ref( t4 ) != 0 )  /* will delete b4 and will remove and re-add the reference if required */
            return -1 ;
        }
      }
      else
      {
        /* put parent entry, then all but one child, then last child to parent */
        b4go_eof( b4 ) ;
        if ( balance_mode == 2 )
        {
          b4temp->key_on = 0 ;
          bdata = b4key( parent, parent->key_on ) ;
          b4insert( b4temp, bdata->value, bdata->num, b4key( b4, b4->n_keys )->pointer / 512 ) ;
          for ( i = b4->n_keys - 1 ; i >= 0 ; i-- )
          {
            b4temp->key_on = 0 ;
            bdata = b4key( b4, i ) ;
            b4insert( b4temp, bdata->value, bdata->num, bdata->pointer / 512 ) ;
          }
          t4shrink( t4, b4->file_block ) ;
          l4pop( &t4->saved ) ;
          b4->changed = 0 ;
          b4free( b4 ) ;
          b4flush( b4temp ) ;
          b4remove( parent ) ;
          if ( parent->n_keys < t4->header.keys_half )
            t4balance_branch( t4, parent ) ;
        }
        else
        {
          bdata = b4key( parent, parent->key_on ) ;
          b4insert( b4, bdata->value, bdata->num, 0L ) ;
          for ( i = 0 ; i < b4temp->n_keys - 1 ; i++ )
          {
            b4go_eof( b4 ) ;
            bdata = b4key( b4temp, i ) ;
            b4insert( b4, bdata->value, bdata->num, 0L ) ;
          }
          bdata = b4key( parent, parent->key_on ) ;
          bdata2 = b4key( b4temp, b4temp->n_keys - 1 ) ;
          memcpy( bdata->value, bdata2->value, t4->header.key_len )  ;
          memcpy( &( bdata->num ), &bdata2->num, sizeof( long ) )  ;

          parent->key_on++ ;
          parent->changed = 1 ;

          t4->index->code_base->do_index_verify = 0 ;  /* avoid verify errors due to our partial removal */
          b4flush( b4 ) ;
          do
          {
            if ( t4down( t4 ) == 1 )
              break ;
          } while( ((B4BLOCK *)t4->blocks.last_node)->file_block != b4temp->file_block ) ;
          t4->index->code_base->do_index_verify = 1 ;
          if ( t4remove_ref( t4 ) != 0 )  /* will delete b4temp and will remove and re-add the reference if required */
            return -1 ;
          b4temp->changed = 0 ;
        }
      }
    }
    else  /* will have to redistribute keys */
    {
      avg = ( b4->n_keys + b4temp->n_keys + 1 ) / 2 ;
      if ( avg < t4->header.keys_half )
        avg = t4->header.keys_half ;
      if ( is_right )
      {
        b4->key_on = 0 ;
        parent->key_on-- ;
        bdata = b4key( parent, parent->key_on ) ;

        if ( balance_mode == 2 )
        {
          if ( b4->n_keys == 0 )
          {
            temp_fb = b4key( b4, 0 )->pointer ;
            b4insert( b4, bdata->value, bdata->num, b4key( b4temp, b4temp->n_keys )->pointer / 512 ) ;
            b4append( b4, temp_fb / 512 ) ;
          }
          else
            b4insert( b4, bdata->value, bdata->num, b4key( b4temp, b4temp->n_keys )->pointer / 512 ) ;
        }
        else
          b4insert( b4, bdata->value, bdata->num, 0L ) ;

        while ( b4temp->n_keys > avg && b4->n_keys < avg )
        {
          b4->key_on = 0 ;
          b4temp->key_on = b4temp->n_keys - 1 ;
          bdata = b4key( b4temp, b4temp->key_on ) ;
          if ( balance_mode == 2 )
            b4insert( b4, bdata->value, bdata->num, bdata->pointer / 512 ) ;
          else
            b4insert( b4, bdata->value, bdata->num, 0L ) ;
          b4remove( b4temp ) ;
        }
        b4temp->key_on = b4temp->n_keys - 1 ;
      }
      else
      {
        b4go_eof( b4 ) ;
        if ( balance_mode == 2 )
        {
          bdata = b4key( b4, b4->n_keys ) ;
          bdata2 = b4key( parent, parent->key_on ) ;
          memcpy( bdata->value, bdata2->value, t4->header.key_len )  ;
          memcpy( &(bdata->num), &bdata2->num, sizeof( long ) )  ;
          b4->n_keys++ ;
        }
        else
        {
          bdata = b4key( parent, parent->key_on ) ;
          b4insert( b4, bdata->value, bdata->num, 0L ) ;
        }

        while ( b4->n_keys - (balance_mode == 2) < avg )
        {
          b4go_eof( b4 ) ;
          b4temp->key_on = 0 ;
          bdata = b4key( b4temp, b4temp->key_on ) ;
          if ( balance_mode == 2 )
            b4insert( b4, bdata->value, bdata->num, bdata->pointer / 512 ) ;
          else
            b4insert( b4, bdata->value, bdata->num, 0L ) ;
          b4remove( b4temp ) ;
        }

        if ( balance_mode == 2 )
        {
          b4->n_keys-- ;
          b4->key_on-- ;
        }
        b4temp->key_on = 0 ;
      }
      /* and add a key back to the parent */
      bdata = b4key( parent, parent->key_on ) ;
      if ( balance_mode == 2 )
      {
        if ( is_right )
          bdata2 = b4key( b4temp, b4temp->n_keys - 1 ) ;
        else
          bdata2 = b4key( b4, b4->n_keys ) ;
        memcpy( bdata->value, bdata2->value, t4->header.key_len )  ;
        memcpy( &(bdata->num), &bdata2->num, sizeof( long ) )  ;
        if ( is_right )
        {
          b4temp->key_on = b4temp->n_keys ;
          b4remove( b4temp ) ;
        }
      }
      else
      {
        bdata2 = b4key( b4temp, b4temp->key_on ) ;
        memcpy( bdata->value, bdata2->value, t4->header.key_len )  ;
        memcpy( &(bdata->num), &bdata2->num, sizeof( long ) )  ;
        b4remove( b4temp ) ;
      }
      parent->changed = 1 ;
      b4flush( b4temp ) ;
    }
  }
  return 0 ;
}

static int t4balance_branch_leaf( TAG4 *t4, B4BLOCK *parent, B4BLOCK *branch, B4BLOCK *leaf )
{
  B4BLOCK *b4temp ;
  long new_file_block ;
  B4KEY_DATA *key ;

  t4->header.version++ ;
  new_file_block = t4extend( t4 ) ;
  b4temp = b4alloc( t4, new_file_block ) ;
  if ( b4temp == 0 )
    return -1 ;

  key = b4key( b4temp, 0 ) ;
  key->pointer =  leaf->file_block * I4MULTIPLY ;
  b4temp->changed = 1 ;
  key = b4key( parent, parent->key_on ) ;
#ifdef S4DEBUG_DEV
  if ( key->pointer != leaf->file_block * I4MULTIPLY )
    e4severe( e4info, "t4balance_branch_leaf - corruption" ) ;
#endif
  key->pointer = new_file_block * I4MULTIPLY ;
  parent->changed = 1 ;
  l4add( &t4->blocks, b4temp ) ;

  return t4balance_block( t4, parent, b4temp, branch, 1, 2 ) ;
}

/* if do_full is true, the whole branch set will be balanced, not just the current leaf block and reqd.  Also, this will balance top down instead of the other way. */
int S4FUNCTION t4balance( TAG4 *t4, B4BLOCK *b4, int do_full )
{
  B4BLOCK *b4temp, *parent ;
  long temp_fb ;
  int rc, i ;
  char is_right, balance_mode ;  /* balance_mode = 0 for done, 1 for leaf, and 2 for branch */

  if ( !b4leaf( b4 ) )
    return 0 ;

  b4temp = b4alloc( t4, 0L ) ;
  if ( b4temp == 0 )
    return -1 ;

  if ( do_full )
  {
    t4up_to_root( t4 ) ;
    balance_mode = 2 ;  /* branch */
  }
  else
    balance_mode = 1 ;  /* leaf */

  while ( balance_mode != 0 || do_full )
  {
    if ( do_full )
    {
      parent = (B4BLOCK *)t4->blocks.last_node ;
      parent->key_on = parent->n_keys ;
      rc = t4down( t4 ) ;
      if ( rc == 1 )  /* make sure siblings are also leafs */
      {
        t4up( t4 ) ;
        parent = (B4BLOCK *)t4->blocks.last_node ;
        if ( parent != 0 )
        {
          if ( parent->key_on > 0 )
          {
            temp_fb = (long)b4key( parent, parent->key_on - 1 )->pointer ;
            if ( i4read_block( &t4->file, temp_fb, 0, b4temp ) < 0 )
            {
              b4free( b4temp ) ;
              return -1 ;
            }
            if ( b4leaf( b4temp ) == 0 &&  b4leaf( b4 ) == 1 )
            {
              rc = t4balance_branch_leaf( t4, parent, b4temp, b4 ) ;
              b4free( b4temp ) ;
              return rc ;
            }
          }
        }

        break ;
      }
      if ( rc < 0 )
        return -1 ;

      b4 = (B4BLOCK *)t4->blocks.last_node ;
      b4->key_on = b4->n_keys ;

      if ( b4->n_keys >= t4->header.keys_half )
        continue ;

      if ( b4leaf( b4 ) )
        balance_mode = 1 ;
      temp_fb = b4key( parent, parent->key_on - 1 )->pointer ;
      is_right = 1 ;
    }
    else
    {
      if ( balance_mode == 2 )  /* branch */
      {
        b4 = parent ;
        while( t4->blocks.last_node != (LINK4 *)b4 )  /* re-align ourselves */
          t4up( t4 ) ;
      }
      t4up( t4 ) ;
      parent = (B4BLOCK *)t4->blocks.last_node ;

      if ( parent == 0 )  /* root block */
      {
        t4down( t4 ) ;
        parent = (B4BLOCK *)t4->blocks.last_node ;
        if ( !b4leaf( parent ) && parent->n_keys == 0 )  /* remove */
        {
          temp_fb = (long)b4key( parent, 0 )->pointer ;
          t4shrink( t4, parent->file_block ) ;
          t4up( t4 ) ;
          l4pop( &t4->saved ) ;
          parent->changed = 0 ;
          b4free( parent ) ;
          t4->header.root = temp_fb ;
          t4down( t4 ) ;
        }
        break ;
      }

      if ( parent->n_keys == 0 )  /* try to replace parent with ourself */
      {
#ifdef S4DEBUG
        e4severe( e4info, E4_INFO_CIF ) ;
#endif
        return -1 ;
      }

      if ( b4->n_keys >= t4->header.keys_half )
      {
        balance_mode = 0 ;
        continue ;
      }
      is_right = (parent->key_on == parent->n_keys ) ;
      if ( is_right )
        temp_fb = b4key( parent, parent->key_on - 1 )->pointer ;
      else
        temp_fb = b4key( parent, parent->key_on + 1 )->pointer ;
    }

    b4temp->file_block = temp_fb ;
    for ( ;; )
    {
      if ( i4read_block( &t4->file, temp_fb, 0, b4temp ) < 0 )
      {
        b4free( b4temp ) ;
        return -1 ;
      }

      if ( balance_mode == 2 || b4leaf( b4temp ) )  /* if branch mode or leaf mode and leaf block found */
        break ;

      if ( is_right )
        temp_fb = b4key( b4temp, b4temp->n_keys )->pointer ;
      else
        temp_fb = b4key( b4temp, 0 )->pointer ;
    }

    if ( t4balance_block( t4, parent, b4, b4temp, is_right, balance_mode ) < 0 )
      return -1 ;

    if ( do_full )
    {
      if ( b4leaf( b4 ) )
        balance_mode = 0 ;
    }
    else
    {
      if ( parent->n_keys < t4->header.keys_half )  /* do parent as well */
        balance_mode = 2 ;
      else
        balance_mode = 0 ;
    }
  }


  b4free( b4temp ) ;
  return 0 ;
}

int S4FUNCTION t4get_replace_entry( TAG4 *t4, B4KEY_DATA *insert_spot, B4BLOCK *save_block )
{
  int rc ;
  B4BLOCK *block_on ;

  block_on = save_block ;

  if ( b4leaf( block_on ) )
    return 0 ;

  block_on->key_on = block_on->key_on + 1 ;
  while ( !b4leaf( block_on ) )
  {
    rc = t4down( t4 ) ;
    if ( rc < 0 || rc == 2 )
      return -1 ;
    block_on = (B4BLOCK *)t4->blocks.last_node ;
  }
  memcpy( &insert_spot->num, &(b4key( block_on, block_on->key_on )->num), sizeof(long) + t4->header.key_len ) ;
  save_block->changed = 1 ;
  b4remove( block_on ) ;
  if ( block_on->n_keys < t4->header.keys_half && block_on->file_block != t4->header.root )  /* if not root may have to balance the tree */
    if ( t4balance( t4, block_on, 0 ) < 0 )
      return -1 ;
  return 1 ;
}

int S4FUNCTION t4balance_branch( TAG4 *t4, B4BLOCK *b4 )
{
  B4BLOCK *parent, *b4temp ;
  int is_right ;
  long temp_fb, reference ;

#ifdef S4DEBUG
  if ( b4leaf( b4 ) )
    e4severe( e4info, E4_T4BALANCE_BR ) ;
#endif

  if ( b4 == (B4BLOCK *)l4first( &t4->blocks ) )
  {
    if ( b4->n_keys == 0 )   /* empty, so just remove */
    {
      reference = (long)b4key( b4, 0 )->pointer ;
      b4->changed = 0 ;
      t4shrink( t4, b4->file_block ) ;
      t4up( t4 ) ;
      l4pop(&t4->saved ) ;
      t4->header.root = reference ;
    }
    return 0 ;
  }

#ifdef S4DEBUG
  if (  b4->n_keys < 2 )
    e4severe( e4info, E4_T4BALANCE_BR ) ;
#endif

  t4up( t4 ) ;
  parent = (B4BLOCK *)t4->blocks.last_node ;

#ifdef S4DEBUG
  if ( b4key( parent, parent->key_on )->pointer != I4MULTIPLY * b4->file_block )
    e4severe( e4info, E4_T4BALANCE_BR ) ;
#endif

  if ( parent->key_on == parent->n_keys )
  {
    temp_fb = b4key( parent, parent->key_on - 1 )->pointer ;
    is_right = 1 ;
  }
  else
  {
    temp_fb = b4key( parent, parent->key_on + 1 )->pointer ;
    is_right = 0 ;

  }

  b4temp = b4alloc( t4, 0L ) ;
  if ( b4temp == 0 )
    return -1 ;

  if ( i4read_block( &t4->file, temp_fb, 0, b4temp ) < 0 )
  {
    b4free( b4temp ) ;
    return -1 ;
  }

  if ( t4balance_block( t4, parent, b4, b4temp, is_right, 2 ) < 0 )
    return -1 ;

  b4free( b4temp ) ;
  return 0 ;
}

int S4FUNCTION t4remove_current( TAG4 *t4 )
{
  B4BLOCK *block_on ;

  t4->header.version = (short)( t4->header.old_version + 1L ) ;

  block_on = (B4BLOCK *)t4->blocks.last_node ;

#ifdef S4DEBUG
  if ( b4lastpos( block_on ) == -b4leaf( block_on ) )
    e4severe( e4info, E4_INFO_UNE ) ;
#endif

  switch( t4get_replace_entry( t4, b4key( block_on, block_on->key_on ), block_on ) )
  {
  case 0 :   /* leaf delete */
    b4remove( block_on ) ;
    if ( block_on->n_keys == 0 )  /* last entry deleted! -- remove upward reference */
    {
      if ( t4remove_ref( t4 ) != 0 )
        return -1 ;
    }
    else
    {
      if ( block_on->n_keys < t4->header.keys_half && block_on->file_block != t4->header.root )  /* if not root may have to balance the tree */
        return t4balance( t4, block_on, 0 ) ;
    }
    break ;

  case 1 :   /* branch delete */
    /*         block_on->changed = 1 ;*/  /* mark as changed for all entries */
    if( t4block( t4 )->n_keys == 0 )    /* removed the last key of */
      if ( t4remove_ref( t4 ) != 0 )
        return -1 ;
    break ;

  default:
    e4severe( e4info, E4_INFO_INT ) ;
    break ;
  }
  return 0 ;
}
#endif  /* S4CLIPPER */
#endif  /* S4NDX */
#endif  /* N4OTHER */

#endif  /* S4INDEX_OFF */
#endif  /* S4OFF_WRITE */