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