text: /****************************************************************************
   * Copyright 2020 Thomas E. Dickey                                          *
   * Copyright 1998-2009,2010 Free Software Foundation, Inc.                  *
   *                                                                          *
   * 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, distribute with modifications, 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 THE ABOVE COPYRIGHT HOLDERS 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.                               *
   *                                                                          *
   * Except as contained in this notice, the name(s) of the above copyright   *
   * holders shall not be used in advertising or otherwise to promote the     *
   * sale, use or other dealings in this Software without prior written       *
   * authorization.                                                           *
   ****************************************************************************/
  
  /****************************************************************************
   *  Author: Thomas E. Dickey <dickey@clark.net> 1997                        *
   ****************************************************************************/
  
  /*
  **	tries.c
  **
  **	Functions to manage the tree of partial-completions for keycodes.
  **
  */
  
  #include <curses.priv.h>
  
  MODULE_ID("$Id: tries.c,v 1.31 2020/02/02 23:34:34 tom Exp $")
  
  /*
   * Expand a keycode into the string that it corresponds to, returning null if
   * no match was found, otherwise allocating a string of the result.
   */
  NCURSES_EXPORT(char *)
  _nc_expand_try(TRIES * tree, unsigned code, int *count, size_t len)
  {
      TRIES *ptr = tree;
      char *result = 0;
  
      if (code != 0) {
  	while (ptr != 0) {
  	    if ((result = _nc_expand_try(ptr->child, code, count, len + 1))
  		!= 0) {
  		break;
  	    }
  	    if (ptr->value == code) {
  		*count -= 1;
  		if (*count == -1) {
  		    result = typeCalloc(char, len + 2);
  		    break;
  		}
  	    }
  	    ptr = ptr->sibling;
  	}
      }
      if (result != 0) {
  	if (ptr != 0 && (result[len] = (char) ptr->ch) == 0)
  	    *((unsigned char *) (result + len)) = 128;
  #ifdef TRACE
  	if (len == 0 && USE_TRACEF(TRACE_MAXIMUM)) {
  	    _tracef("expand_key %s %s",
  		    _nc_tracechar(CURRENT_SCREEN, (int) code),
  		    _nc_visbuf(result));
  	    _nc_unlock_global(tracef);
  	}
  #endif
      }
      return result;
  }
  
  /*
   * Remove a code from the specified tree, freeing the unused nodes.  Returns
   * true if the code was found/removed.
   */
  NCURSES_EXPORT(int)
  _nc_remove_key(TRIES ** tree, unsigned code)
  {
      T((T_CALLED("_nc_remove_key(%p,%d)"), (void *) tree, code));
  
      if (code == 0)
  	returnCode(FALSE);
  
      while (*tree != 0) {
  	if (_nc_remove_key(&(*tree)->child, code)) {
  	    returnCode(TRUE);
  	}
  	if ((*tree)->value == code) {
  	    if ((*tree)->child) {
  		/* don't cut the whole sub-tree */
  		(*tree)->value = 0;
  	    } else {
  		TRIES *to_free = *tree;
  		*tree = (*tree)->sibling;
  		free(to_free);
  	    }
  	    returnCode(TRUE);
  	}
  	tree = &(*tree)->sibling;
      }
      returnCode(FALSE);
  }
  
  /*
   * Remove a string from the specified tree, freeing the unused nodes.  Returns
   * true if the string was found/removed.
   */
  NCURSES_EXPORT(int)
  _nc_remove_string(TRIES ** tree, const char *string)
  {
      T((T_CALLED("_nc_remove_string(%p,%s)"), (void *) tree, _nc_visbuf(string)));
  
      if (string == 0 || *string == 0)
  	returnCode(FALSE);
  
      while (*tree != 0) {
  	if (UChar((*tree)->ch) == UChar(*string)) {
  	    if (string[1] != 0)
  		returnCode(_nc_remove_string(&(*tree)->child, string + 1));
  	    if ((*tree)->child == 0) {
  		TRIES *to_free = *tree;
  		*tree = (*tree)->sibling;
  		free(to_free);
  		returnCode(TRUE);
  	    } else {
  		returnCode(FALSE);
  	    }
  	}
  	tree = &(*tree)->sibling;
      }
      returnCode(FALSE);
  }
  