Add hash table support as base for new environment code

[people/ms/u-boot.git] / include / search.h

/*
 * 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.
 *
 * The GNU C Library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * The GNU C Library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the GNU C Library; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 * 02111-1307 USA.
 */

/*
 * Based on code from uClibc-0.9.30.3
 * Extensions for use within U-Boot
 * Copyright (C) 2010 Wolfgang Denk <wd@denx.de>
 */

#ifndef _SEARCH_H
#define	_SEARCH_H 1

#include <stddef.h>

#define __set_errno(val) do { errno = val; } while (0)

/*
 * Prototype structure for a linked-list data structure.
 * This is the type used by the `insque' and `remque' functions.
 */

/* For use with hsearch(3).  */
typedef int (*__compar_fn_t) (__const void *, __const void *);
typedef __compar_fn_t comparison_fn_t;

/* Action which shall be performed in the call the hsearch.  */
typedef enum {
	FIND,
	ENTER
} ACTION;

typedef struct entry {
	char *key;
	char *data;
} 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;
};

/* Create a new hashing table which will at most contain NEL elements.  */
extern int hcreate(size_t __nel);
extern int hcreate_r(size_t __nel, struct hsearch_data *__htab);

/* Destroy current internal hashing table.  */
extern void hdestroy(void);
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 ENTRY *hsearch(ENTRY __item, ACTION __action);
extern int hsearch_r(ENTRY __item, ACTION __action, ENTRY ** __retval,
		     struct hsearch_data *__htab);

/* Search and delete entry matching ITEM.key in internal hash table. */
extern int hdelete(const char *__key);
extern int hdelete_r(const char *__key, struct hsearch_data *__htab);

extern ssize_t hexport(const char __sep, char **__resp, size_t __size);
extern ssize_t hexport_r(struct hsearch_data *__htab,
		     const char __sep, char **__resp, size_t __size);

extern int himport(const char *__env, size_t __size, const char __sep,
		   int __flag);
extern int himport_r(struct hsearch_data *__htab,
		     const char *__env, size_t __size, const char __sep,
		     int __flag);

/* Flags for himport() / himport_r() */
#define	H_NOCLEAR	1	/* do not clear hash table before importing */

#endif /* search.h */