uspace/app/sbi/src/strtab.c

   1 /*
   2  * Copyright (c) 2010 Jiri Svoboda
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @file String table.
  30  *
  31  * Converts strings to more compact SID (string ID, integer) and back.
  32  * (The point is that this deduplicates the strings. Using SID might actually
  33  * not be such a big win.)
  34  *
  35  * The string table is a singleton as there will never be a need for
  36  * more than one.
  37  *
  38  * Current implementation uses a linked list and thus it is slow.
  39  */
  40
  41 #include <stdlib.h>
  42 #include "mytypes.h"
  43 #include "os/os.h"
  44 #include "list.h"
  45
  46 #include "strtab.h"
  47
  48 static list_t str_list;
  49
  50 /** Initialize string table. */
  51 void strtab_init(void)
  52 {
  53         list_init(&str_list);
  54 }
  55
  56 /** Get SID of a string.
  57  *
  58  * Return SID of @a str. If @a str is not in the string table yet,
  59  * it is added and thus a new SID is assigned.
  60  *
  61  * @param str   String
  62  * @return      SID of @a str.
  63  */
  64 sid_t strtab_get_sid(const char *str)
  65 {
  66         list_node_t *node;
  67         sid_t sid;
  68
  69         sid = 0;
  70         node = list_first(&str_list);
  71
  72         while (node != NULL) {
  73                 ++sid;
  74                 if (os_str_cmp(str, list_node_data(node, char *)) == 0)
  75                         return sid;
  76
  77                 node = list_next(&str_list, node);
  78         }
  79
  80         ++sid;
  81         list_append(&str_list, os_str_dup(str));
  82
  83         return sid;
  84 }
  85
  86 /** Get string with the given SID.
  87  *
  88  * Returns string that has SID @a sid. If no such string exists, this
  89  * causes a fatal error in the interpreter.
  90  *
  91  * @param sid   SID of the string.
  92  * @return      Pointer to the string.
  93  */
  94 char *strtab_get_str(sid_t sid)
  95 {
  96         list_node_t *node;
  97         sid_t cnt;
  98
  99         node = list_first(&str_list);
 100         cnt = 1;
 101         while (node != NULL && cnt < sid) {
 102                 node = list_next(&str_list, node);
 103                 cnt += 1;
 104         }
 105
 106         if (node == NULL) {
 107                 printf("Internal error: Invalid SID %d", sid);
 108                 abort();
 109         }
 110
 111         return list_node_data(node, char *);
 112 }