misc/search.h

   1 /* Declarations for System V style searching functions.
   2    Copyright (C) 1995-1999, 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _SEARCH_H
  21 #define _SEARCH_H 1
  22
  23 #include <features.h>
  24
  25 #define __need_size_t
  26 #include <stddef.h>
  27
  28 __BEGIN_DECLS
  29
  30 #if defined __USE_SVID || defined __USE_XOPEN_EXTENDED
  31 /* Prototype structure for a linked-list data structure.
  32    This is the type used by the `insque' and `remque' functions.  */
  33
  34 # ifdef __USE_GNU
  35 struct qelem
  36   {
  37     struct qelem *q_forw;
  38     struct qelem *q_back;
  39     char q_data[1];
  40   };
  41 # endif
  42
  43
  44 /* Insert ELEM into a doubly-linked list, after PREV.  */
  45 extern void insque (void *__elem, void *__prev) __THROW;
  46
  47 /* Unlink ELEM from the doubly-linked list that it is in.  */
  48 extern void remque (void *__elem) __THROW;
  49 #endif
  50
  51
  52 /* For use with hsearch(3).  */
  53 #ifndef __COMPAR_FN_T
  54 # define __COMPAR_FN_T
  55 typedef int (*__compar_fn_t) (__const void *, __const void *);
  56
  57 # ifdef __USE_GNU
  58 typedef __compar_fn_t comparison_fn_t;
  59 # endif
  60 #endif
  61
  62 /* Action which shall be performed in the call the hsearch.  */
  63 typedef enum
  64   {
  65     FIND,
  66     ENTER
  67   }
  68 ACTION;
  69
  70 typedef struct entry
  71   {
  72     char *key;
  73     void *data;
  74   }
  75 ENTRY;
  76
  77 /* Opaque type for internal use.  */
  78 struct _ENTRY;
  79
  80 /* Family of hash table handling functions.  The functions also
  81    have reentrant counterparts ending with _r.  The non-reentrant
  82    functions all work on a signle internal hashing table.  */
  83
  84 /* Search for entry matching ITEM.key in internal hash table.  If
  85    ACTION is `FIND' return found entry or signal error by returning
  86    NULL.  If ACTION is `ENTER' replace existing data (if any) with
  87    ITEM.data.  */
  88 extern ENTRY *hsearch (ENTRY __item, ACTION __action) __THROW;
  89
  90 /* Create a new hashing table which will at most contain NEL elements.  */
  91 extern int hcreate (size_t __nel) __THROW;
  92
  93 /* Destroy current internal hashing table.  */
  94 extern void hdestroy (void) __THROW;
  95
  96 #ifdef __USE_GNU
  97 /* Data type for reentrant functions.  */
  98 struct hsearch_data
  99   {
 100     struct _ENTRY *table;
 101     unsigned int size;
 102     unsigned int filled;
 103   };
 104
 105 /* Reentrant versions which can handle multiple hashing tables at the
 106    same time.  */
 107 extern int hsearch_r (ENTRY __item, ACTION __action, ENTRY **__retval,
 108                       struct hsearch_data *__htab) __THROW;
 109 extern int hcreate_r (size_t __nel, struct hsearch_data *__htab) __THROW;
 110 extern void hdestroy_r (struct hsearch_data *__htab) __THROW;
 111 #endif
 112
 113
 114 /* The tsearch routines are very interesting. They make many
 115    assumptions about the compiler.  It assumes that the first field
 116    in node must be the "key" field, which points to the datum.
 117    Everything depends on that.  */
 118 /* For tsearch */
 119 typedef enum
 120 {
 121   preorder,
 122   postorder,
 123   endorder,
 124   leaf
 125 }
 126 VISIT;
 127
 128 /* Search for an entry matching the given KEY in the tree pointed to
 129    by *ROOTP and insert a new element if not found.  */
 130 extern void *tsearch (__const void *__key, void **__rootp,
 131                       __compar_fn_t __compar);
 132
 133 /* Search for an entry matching the given KEY in the tree pointed to
 134    by *ROOTP.  If no matching entry is available return NULL.  */
 135 extern void *tfind (__const void *__key, void *__const *__rootp,
 136                     __compar_fn_t __compar);
 137
 138 /* Remove the element matching KEY from the tree pointed to by *ROOTP.  */
 139 extern void *tdelete (__const void *__restrict __key,
 140                       void **__restrict __rootp,
 141                       __compar_fn_t __compar);
 142
 143 #ifndef __ACTION_FN_T
 144 # define __ACTION_FN_T
 145 typedef void (*__action_fn_t) (__const void *__nodep, VISIT __value,
 146                                int __level);
 147 #endif
 148
 149 /* Walk through the whole tree and call the ACTION callback for every node
 150    or leaf.  */
 151 extern void twalk (__const void *__root, __action_fn_t __action);
 152
 153 #ifdef __USE_GNU
 154 /* Callback type for function to free a tree node.  If the keys are atomic
 155    data this function should do nothing.  */
 156 typedef void (*__free_fn_t) (void *__nodep);
 157
 158 /* Destroy the whole tree, call FREEFCT for each node or leaf.  */
 159 extern void tdestroy (void *__root, __free_fn_t __freefct);
 160 #endif
 161
 162
 163 /* Perform linear search for KEY by comparing by COMPAR in an array
 164    [BASE,BASE+NMEMB*SIZE).  */
 165 extern void *lfind (__const void *__key, __const void *__base,
 166                     size_t *__nmemb, size_t __size, __compar_fn_t __compar);
 167
 168 /* Perform linear search for KEY by comparing by COMPAR function in
 169    array [BASE,BASE+NMEMB*SIZE) and insert entry if not found.  */
 170 extern void *lsearch (__const void *__key, void *__base,
 171                       size_t *__nmemb, size_t __size, __compar_fn_t __compar);
 172
 173 __END_DECLS
 174
 175 #endif /* search.h */