include/search.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /*
   3  * Declarations for System V style searching functions.
   4  * Copyright (C) 1995-1999, 2000 Free Software Foundation, Inc.
   5  * This file is part of the GNU C Library.
   6  */
   7
   8 /*
   9  * Based on code from uClibc-0.9.30.3
  10  * Extensions for use within U-Boot
  11  * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
  12  */
  13
  14 #ifndef _SEARCH_H_
  15 #define _SEARCH_H_
  16
  17 #include <stddef.h>
  18
  19 #define __set_errno(val) do { errno = val; } while (0)
  20
  21 enum env_op {
  22         env_op_create,
  23         env_op_delete,
  24         env_op_overwrite,
  25 };
  26
  27 /* Action which shall be performed in the call to hsearch.  */
  28 typedef enum {
  29         FIND,
  30         ENTER
  31 } ACTION;
  32
  33 typedef struct entry {
  34         const char *key;
  35         char *data;
  36         int (*callback)(const char *name, const char *value, enum env_op op,
  37                 int flags);
  38         int flags;
  39 } ENTRY;
  40
  41 /* Opaque type for internal use.  */
  42 struct _ENTRY;
  43
  44 /*
  45  * Family of hash table handling functions.  The functions also
  46  * have reentrant counterparts ending with _r.  The non-reentrant
  47  * functions all work on a single internal hash table.
  48  */
  49
  50 /* Data type for reentrant functions.  */
  51 struct hsearch_data {
  52         struct _ENTRY *table;
  53         unsigned int size;
  54         unsigned int filled;
  55 /*
  56  * Callback function which will check whether the given change for variable
  57  * "__item" to "newval" may be applied or not, and possibly apply such change.
  58  * When (flag & H_FORCE) is set, it shall not print out any error message and
  59  * shall force overwriting of write-once variables.
  60  * Must return 0 for approval, 1 for denial.
  61  */
  62         int (*change_ok)(const ENTRY *__item, const char *newval, enum env_op,
  63                 int flag);
  64 };
  65
  66 /* Create a new hash table which will contain at most "__nel" elements.  */
  67 extern int hcreate_r(size_t __nel, struct hsearch_data *__htab);
  68
  69 /* Destroy current internal hash table.  */
  70 extern void hdestroy_r(struct hsearch_data *__htab);
  71
  72 /*
  73  * Search for entry matching __item.key in internal hash table.  If
  74  * ACTION is `FIND' return found entry or signal error by returning
  75  * NULL.  If ACTION is `ENTER' replace existing data (if any) with
  76  * __item.data.
  77  * */
  78 extern int hsearch_r(ENTRY __item, ACTION __action, ENTRY ** __retval,
  79                      struct hsearch_data *__htab, int __flag);
  80
  81 /*
  82  * Search for an entry matching "__match".  Otherwise, Same semantics
  83  * as hsearch_r().
  84  */
  85 extern int hmatch_r(const char *__match, int __last_idx, ENTRY ** __retval,
  86                     struct hsearch_data *__htab);
  87
  88 /* Search and delete entry matching "__key" in internal hash table. */
  89 extern int hdelete_r(const char *__key, struct hsearch_data *__htab,
  90                      int __flag);
  91
  92 extern ssize_t hexport_r(struct hsearch_data *__htab,
  93                      const char __sep, int __flag, char **__resp, size_t __size,
  94                      int argc, char * const argv[]);
  95
  96 /*
  97  * nvars: length of vars array
  98  * vars: array of strings (variable names) to import (nvars == 0 means all)
  99  */
 100 extern int himport_r(struct hsearch_data *__htab,
 101                      const char *__env, size_t __size, const char __sep,
 102                      int __flag, int __crlf_is_lf, int nvars,
 103                      char * const vars[]);
 104
 105 /* Walk the whole table calling the callback on each element */
 106 extern int hwalk_r(struct hsearch_data *__htab, int (*callback)(ENTRY *));
 107
 108 /* Flags for himport_r(), hexport_r(), hdelete_r(), and hsearch_r() */
 109 #define H_NOCLEAR       (1 << 0) /* do not clear hash table before importing */
 110 #define H_FORCE         (1 << 1) /* overwrite read-only/write-once variables */
 111 #define H_INTERACTIVE   (1 << 2) /* indicate that an import is user directed */
 112 #define H_HIDE_DOT      (1 << 3) /* don't print env vars that begin with '.' */
 113 #define H_MATCH_KEY     (1 << 4) /* search/grep key  = variable names        */
 114 #define H_MATCH_DATA    (1 << 5) /* search/grep data = variable values       */
 115 #define H_MATCH_BOTH    (H_MATCH_KEY | H_MATCH_DATA) /* search/grep both     */
 116 #define H_MATCH_IDENT   (1 << 6) /* search for indentical strings            */
 117 #define H_MATCH_SUBSTR  (1 << 7) /* search for substring matches             */
 118 #define H_MATCH_REGEX   (1 << 8) /* search for regular expression matches    */
 119 #define H_MATCH_METHOD  (H_MATCH_IDENT | H_MATCH_SUBSTR | H_MATCH_REGEX)
 120 #define H_PROGRAMMATIC  (1 << 9) /* indicate that an import is from env_set() */
 121 #define H_ORIGIN_FLAGS  (H_INTERACTIVE | H_PROGRAMMATIC)
 122
 123 #endif /* _SEARCH_H_ */