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 enum env_op {
  36         env_op_create,
  37         env_op_delete,
  38         env_op_overwrite,
  39 };
  40
  41 /* Action which shall be performed in the call the hsearch.  */
  42 typedef enum {
  43         FIND,
  44         ENTER
  45 } ACTION;
  46
  47 typedef struct entry {
  48         const char *key;
  49         char *data;
  50         int (*callback)(const char *name, const char *value, enum env_op op,
  51                 int flags);
  52         int flags;
  53 } ENTRY;
  54
  55 /* Opaque type for internal use.  */
  56 struct _ENTRY;
  57
  58 /*
  59  * Family of hash table handling functions.  The functions also
  60  * have reentrant counterparts ending with _r.  The non-reentrant
  61  * functions all work on a signle internal hashing table.
  62  */
  63
  64 /* Data type for reentrant functions.  */
  65 struct hsearch_data {
  66         struct _ENTRY *table;
  67         unsigned int size;
  68         unsigned int filled;
  69 /*
  70  * Callback function which will check whether the given change for variable
  71  * "item" to "newval" may be applied or not, and possibly apply such change.
  72  * When (flag & H_FORCE) is set, it shall not print out any error message and
  73  * shall force overwriting of write-once variables.
  74 .* Must return 0 for approval, 1 for denial.
  75  */
  76         int (*change_ok)(const ENTRY *__item, const char *newval, enum env_op,
  77                 int flag);
  78 };
  79
  80 /* Create a new hashing table which will at most contain NEL elements.  */
  81 extern int hcreate_r(size_t __nel, struct hsearch_data *__htab);
  82
  83 /* Destroy current internal hashing table.  */
  84 extern void hdestroy_r(struct hsearch_data *__htab);
  85
  86 /*
  87  * Search for entry matching ITEM.key in internal hash table.  If
  88  * ACTION is `FIND' return found entry or signal error by returning
  89  * NULL.  If ACTION is `ENTER' replace existing data (if any) with
  90  * ITEM.data.
  91  * */
  92 extern int hsearch_r(ENTRY __item, ACTION __action, ENTRY ** __retval,
  93                      struct hsearch_data *__htab, int __flag);
  94
  95 /*
  96  * Search for an entry matching `MATCH'.  Otherwise, Same semantics
  97  * as hsearch_r().
  98  */
  99 extern int hmatch_r(const char *__match, int __last_idx, ENTRY ** __retval,
 100                     struct hsearch_data *__htab);
 101 /*
 102  * Search for an entry whose key or data contains `MATCH'.  Otherwise,
 103  * Same semantics as hsearch_r().
 104  */
 105 extern int hstrstr_r(const char *__match, int __last_idx, ENTRY ** __retval,
 106                     struct hsearch_data *__htab);
 107
 108 /* Search and delete entry matching ITEM.key in internal hash table. */
 109 extern int hdelete_r(const char *__key, struct hsearch_data *__htab,
 110                      int __flag);
 111
 112 extern ssize_t hexport_r(struct hsearch_data *__htab,
 113                      const char __sep, int __flag, char **__resp, size_t __size,
 114                      int argc, char * const argv[]);
 115
 116 /*
 117  * nvars: length of vars array
 118  * vars: array of strings (variable names) to import (nvars == 0 means all)
 119  * do_apply: whether to call callback function to check the new argument,
 120  * and possibly apply changes (false means accept everything)
 121  */
 122 extern int himport_r(struct hsearch_data *__htab,
 123                      const char *__env, size_t __size, const char __sep,
 124                      int __flag, int nvars, char * const vars[]);
 125
 126 /* Walk the whole table calling the callback on each element */
 127 extern int hwalk_r(struct hsearch_data *__htab, int (*callback)(ENTRY *));
 128
 129 /* Flags for himport_r(), hexport_r(), hdelete_r(), and hsearch_r() */
 130 #define H_NOCLEAR       (1 << 0) /* do not clear hash table before importing */
 131 #define H_FORCE         (1 << 1) /* overwrite read-only/write-once variables */
 132 #define H_INTERACTIVE   (1 << 2) /* indicate that an import is user directed */
 133 #define H_HIDE_DOT      (1 << 3) /* don't print env vars that begin with '.' */
 134
 135 #endif /* search.h */