include/search.h

   1 /*
   2  * Declarations for System V style searching functions.
   3  * Copyright (C) 1995-1999, 2000 Free Software Foundation, Inc.
   4  * This file is part of the GNU C Library.
   5  *
   6  * The GNU C Library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * The GNU C Library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with the GNU C Library; if not, write to the Free
  18  * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19  * 02111-1307 USA.
  20  */
  21
  22 /*
  23  * Based on code from uClibc-0.9.30.3
  24  * Extensions for use within U-Boot
  25  * Copyright (C) 2010 Wolfgang Denk <wd@denx.de>
  26  */
  27
  28 #ifndef _SEARCH_H
  29 #define _SEARCH_H 1
  30
  31 #include <stddef.h>
  32
  33 #define __set_errno(val) do { errno = val; } while (0)
  34
  35 /* Action which shall be performed in the call the hsearch.  */
  36 typedef enum {
  37         FIND,
  38         ENTER
  39 } ACTION;
  40
  41 typedef struct entry {
  42         const char *key;
  43         char *data;
  44 } ENTRY;
  45
  46 /* Opaque type for internal use.  */
  47 struct _ENTRY;
  48
  49 /*
  50  * Family of hash table handling functions.  The functions also
  51  * have reentrant counterparts ending with _r.  The non-reentrant
  52  * functions all work on a signle internal hashing table.
  53  */
  54
  55 /* Data type for reentrant functions.  */
  56 struct hsearch_data {
  57         struct _ENTRY *table;
  58         unsigned int size;
  59         unsigned int filled;
  60 /*
  61  * Callback function which will check whether the given change for variable
  62  * "name" from "oldval" to "newval" may be applied or not, and possibly apply
  63  * such change.
  64  * When (flag & H_FORCE) is set, it shall not print out any error message and
  65  * shall force overwriting of write-once variables.
  66 .* Must return 0 for approval, 1 for denial.
  67  */
  68         int (*apply)(const char *name, const char *oldval,
  69                         const char *newval, int flag);
  70 };
  71
  72 /* Create a new hashing table which will at most contain NEL elements.  */
  73 extern int hcreate_r(size_t __nel, struct hsearch_data *__htab);
  74
  75 /* Destroy current internal hashing table.  */
  76 extern void hdestroy_r(struct hsearch_data *__htab);
  77
  78 /*
  79  * Search for entry matching ITEM.key in internal hash table.  If
  80  * ACTION is `FIND' return found entry or signal error by returning
  81  * NULL.  If ACTION is `ENTER' replace existing data (if any) with
  82  * ITEM.data.
  83  * */
  84 extern int hsearch_r(ENTRY __item, ACTION __action, ENTRY ** __retval,
  85                      struct hsearch_data *__htab);
  86
  87 /*
  88  * Search for an entry matching `MATCH'.  Otherwise, Same semantics
  89  * as hsearch_r().
  90  */
  91 extern int hmatch_r(const char *__match, int __last_idx, ENTRY ** __retval,
  92                     struct hsearch_data *__htab);
  93 /*
  94  * Search for an entry whose key or data contains `MATCH'.  Otherwise,
  95  * Same semantics as hsearch_r().
  96  */
  97 extern int hstrstr_r(const char *__match, int __last_idx, ENTRY ** __retval,
  98                     struct hsearch_data *__htab);
  99
 100 /* Search and delete entry matching ITEM.key in internal hash table. */
 101 extern int hdelete_r(const char *__key, struct hsearch_data *__htab);
 102
 103 extern ssize_t hexport_r(struct hsearch_data *__htab,
 104                      const char __sep, char **__resp, size_t __size,
 105                      int argc, char * const argv[]);
 106
 107 /*
 108  * nvars: length of vars array
 109  * vars: array of strings (variable names) to import (nvars == 0 means all)
 110  * do_apply: whether to call callback function to check the new argument,
 111  * and possibly apply changes (false means accept everything)
 112  */
 113 extern int himport_r(struct hsearch_data *__htab,
 114                      const char *__env, size_t __size, const char __sep,
 115                      int __flag, int nvars, char * const vars[], int do_apply);
 116
 117 /* Flags for himport_r() */
 118 #define H_NOCLEAR       (1 << 0) /* do not clear hash table before importing */
 119 #define H_FORCE         (1 << 1) /* overwrite read-only/write-once variables */
 120
 121 #endif /* search.h */