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  * SPDX-License-Identifier:     LGPL-2.1+
   7  */
   8
   9 /*
  10  * Based on code from uClibc-0.9.30.3
  11  * Extensions for use within U-Boot
  12  * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
  13  */
  14
  15 #ifndef _SEARCH_H
  16 #define _SEARCH_H 1
  17
  18 #include <stddef.h>
  19
  20 #define __set_errno(val) do { errno = val; } while (0)
  21
  22 enum env_op {
  23         env_op_create,
  24         env_op_delete,
  25         env_op_overwrite,
  26 };
  27
  28 /* Action which shall be performed in the call the hsearch.  */
  29 typedef enum {
  30         FIND,
  31         ENTER
  32 } ACTION;
  33
  34 typedef struct entry {
  35         const char *key;
  36         char *data;
  37         int (*callback)(const char *name, const char *value, enum env_op op,
  38                 int flags);
  39         int flags;
  40 } ENTRY;
  41
  42 /* Opaque type for internal use.  */
  43 struct _ENTRY;
  44
  45 /*
  46  * Family of hash table handling functions.  The functions also
  47  * have reentrant counterparts ending with _r.  The non-reentrant
  48  * functions all work on a signle internal hashing table.
  49  */
  50
  51 /* Data type for reentrant functions.  */
  52 struct hsearch_data {
  53         struct _ENTRY *table;
  54         unsigned int size;
  55         unsigned int filled;
  56 /*
  57  * Callback function which will check whether the given change for variable
  58  * "item" to "newval" may be applied or not, and possibly apply such change.
  59  * When (flag & H_FORCE) is set, it shall not print out any error message and
  60  * shall force overwriting of write-once variables.
  61 .* Must return 0 for approval, 1 for denial.
  62  */
  63         int (*change_ok)(const ENTRY *__item, const char *newval, enum env_op,
  64                 int flag);
  65 };
  66
  67 /* Create a new hashing table which will at most contain NEL elements.  */
  68 extern int hcreate_r(size_t __nel, struct hsearch_data *__htab);
  69
  70 /* Destroy current internal hashing table.  */
  71 extern void hdestroy_r(struct hsearch_data *__htab);
  72
  73 /*
  74  * Search for entry matching ITEM.key in internal hash table.  If
  75  * ACTION is `FIND' return found entry or signal error by returning
  76  * NULL.  If ACTION is `ENTER' replace existing data (if any) with
  77  * ITEM.data.
  78  * */
  79 extern int hsearch_r(ENTRY __item, ACTION __action, ENTRY ** __retval,
  80                      struct hsearch_data *__htab, int __flag);
  81
  82 /*
  83  * Search for an entry matching `MATCH'.  Otherwise, Same semantics
  84  * as hsearch_r().
  85  */
  86 extern int hmatch_r(const char *__match, int __last_idx, ENTRY ** __retval,
  87                     struct hsearch_data *__htab);
  88
  89 /* Search and delete entry matching ITEM.key in internal hash table. */
  90 extern int hdelete_r(const char *__key, struct hsearch_data *__htab,
  91                      int __flag);
  92
  93 extern ssize_t hexport_r(struct hsearch_data *__htab,
  94                      const char __sep, int __flag, char **__resp, size_t __size,
  95                      int argc, char * const argv[]);
  96
  97 /*
  98  * nvars: length of vars array
  99  * vars: array of strings (variable names) to import (nvars == 0 means all)
 100  * do_apply: whether to call callback function to check the new argument,
 101  * and possibly apply changes (false means accept everything)
 102  */
 103 extern int himport_r(struct hsearch_data *__htab,
 104                      const char *__env, size_t __size, const char __sep,
 105                      int __flag, int __crlf_is_lf, int nvars,
 106                      char * const vars[]);
 107
 108 /* Walk the whole table calling the callback on each element */
 109 extern int hwalk_r(struct hsearch_data *__htab, int (*callback)(ENTRY *));
 110
 111 /* Flags for himport_r(), hexport_r(), hdelete_r(), and hsearch_r() */
 112 #define H_NOCLEAR       (1 << 0) /* do not clear hash table before importing */
 113 #define H_FORCE         (1 << 1) /* overwrite read-only/write-once variables */
 114 #define H_INTERACTIVE   (1 << 2) /* indicate that an import is user directed */
 115 #define H_HIDE_DOT      (1 << 3) /* don't print env vars that begin with '.' */
 116 #define H_MATCH_KEY     (1 << 4) /* search/grep key  = variable names        */
 117 #define H_MATCH_DATA    (1 << 5) /* search/grep data = variable values       */
 118 #define H_MATCH_BOTH    (H_MATCH_KEY | H_MATCH_DATA) /* search/grep both     */
 119 #define H_MATCH_IDENT   (1 << 6) /* search for indentical strings            */
 120 #define H_MATCH_SUBSTR  (1 << 7) /* search for substring matches             */
 121 #define H_MATCH_REGEX   (1 << 8) /* search for regular expression matches    */
 122 #define H_MATCH_METHOD  (H_MATCH_IDENT | H_MATCH_SUBSTR | H_MATCH_REGEX)
 123 #define H_PROGRAMMATIC  (1 << 9) /* indicate that an import is from setenv() */
 124 #define H_ORIGIN_FLAGS  (H_INTERACTIVE | H_PROGRAMMATIC)
 125
 126 #endif /* search.h */