/*
   * Declarations for System V style searching functions.
   * Copyright (C) 1995-1999, 2000 Free Software Foundation, Inc.
   * This file is part of the GNU C Library.
   *
   * SPDX-License-Identifier:	LGPL-2.1+
   */
  
  /*
   * Based on code from uClibc-0.9.30.3
   * Extensions for use within U-Boot
   * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
   */
  
  #ifndef _SEARCH_H
  #define	_SEARCH_H 1
  
  #include <stddef.h>
  
  #define __set_errno(val) do { errno = val; } while (0)
  
  enum env_op {
  	env_op_create,
  	env_op_delete,
  	env_op_overwrite,
  };
  
  /* Action which shall be performed in the call the hsearch.  */
  typedef enum {
  	FIND,
  	ENTER
  } ACTION;
  
  typedef struct entry {
  	const char *key;
  	char *data;
  	int (*callback)(const char *name, const char *value, enum env_op op,
  		int flags);
  	int flags;
  } ENTRY;
  
  /* Opaque type for internal use.  */
  struct _ENTRY;
  
  /*
   * Family of hash table handling functions.  The functions also
   * have reentrant counterparts ending with _r.  The non-reentrant
   * functions all work on a signle internal hashing table.
   */
  
  /* Data type for reentrant functions.  */
  struct hsearch_data {
  	struct _ENTRY *table;
  	unsigned int size;
  	unsigned int filled;
  /*
   * Callback function which will check whether the given change for variable
   * "item" to "newval" may be applied or not, and possibly apply such change.
   * When (flag & H_FORCE) is set, it shall not print out any error message and
   * shall force overwriting of write-once variables.
  .* Must return 0 for approval, 1 for denial.
   */
  	int (*change_ok)(const ENTRY *__item, const char *newval, enum env_op,
  		int flag);
  };
  
  /* Create a new hashing table which will at most contain NEL elements.  */
  extern int hcreate_r(size_t __nel, struct hsearch_data *__htab);
  
  /* Destroy current internal hashing table.  */
  extern void hdestroy_r(struct hsearch_data *__htab);
  
  /*
   * Search for entry matching ITEM.key in internal hash table.  If
   * ACTION is `FIND' return found entry or signal error by returning
   * NULL.  If ACTION is `ENTER' replace existing data (if any) with
   * ITEM.data.
   * */
  extern int hsearch_r(ENTRY __item, ACTION __action, ENTRY ** __retval,
  		     struct hsearch_data *__htab, int __flag);
  
  /*
   * Search for an entry matching `MATCH'.  Otherwise, Same semantics
   * as hsearch_r().
   */
  extern int hmatch_r(const char *__match, int __last_idx, ENTRY ** __retval,
  		    struct hsearch_data *__htab);
  
  /* Search and delete entry matching ITEM.key in internal hash table. */
  extern int hdelete_r(const char *__key, struct hsearch_data *__htab,
  		     int __flag);
  
  extern ssize_t hexport_r(struct hsearch_data *__htab,
  		     const char __sep, int __flag, char **__resp, size_t __size,
  		     int argc, char * const argv[]);
  
  /*
   * nvars: length of vars array
   * vars: array of strings (variable names) to import (nvars == 0 means all)
   * do_apply: whether to call callback function to check the new argument,
   * and possibly apply changes (false means accept everything)
   */
  extern int himport_r(struct hsearch_data *__htab,
  		     const char *__env, size_t __size, const char __sep,
  		     int __flag, int __crlf_is_lf, int nvars,
  		     char * const vars[]);
  
  /* Walk the whole table calling the callback on each element */
  extern int hwalk_r(struct hsearch_data *__htab, int (*callback)(ENTRY *));
  
  /* Flags for himport_r(), hexport_r(), hdelete_r(), and hsearch_r() */
  #define H_NOCLEAR	(1 << 0) /* do not clear hash table before importing */
  #define H_FORCE		(1 << 1) /* overwrite read-only/write-once variables */
  #define H_INTERACTIVE	(1 << 2) /* indicate that an import is user directed */
  #define H_HIDE_DOT	(1 << 3) /* don't print env vars that begin with '.' */
  #define H_MATCH_KEY	(1 << 4) /* search/grep key  = variable names	     */
  #define H_MATCH_DATA	(1 << 5) /* search/grep data = variable values	     */
  #define H_MATCH_BOTH	(H_MATCH_KEY | H_MATCH_DATA) /* search/grep both     */
  #define H_MATCH_IDENT	(1 << 6) /* search for indentical strings	     */
  #define H_MATCH_SUBSTR	(1 << 7) /* search for substring matches	     */
  #define H_MATCH_REGEX	(1 << 8) /* search for regular expression matches    */
  #define H_MATCH_METHOD	(H_MATCH_IDENT | H_MATCH_SUBSTR | H_MATCH_REGEX)
  
  #endif /* search.h */