1 | /* list.c - Functions for manipulating linked lists of objects. */ |
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2 | |
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3 | /* Copyright (C) 1996 |
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4 | Free Software Foundation, Inc. |
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5 | |
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6 | This file is part of GNU Bash, the Bourne Again SHell. |
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7 | |
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8 | Bash is free software; you can redistribute it and/or modify it under |
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9 | the terms of the GNU General Public License as published by the Free |
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10 | Software Foundation; either version 2, or (at your option) any later |
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11 | version. |
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12 | |
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13 | Bash is distributed in the hope that it will be useful, but WITHOUT ANY |
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14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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16 | for more details. |
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17 | |
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18 | You should have received a copy of the GNU General Public License along |
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19 | with Bash; see the file COPYING. If not, write to the Free Software |
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20 | Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */ |
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21 | |
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22 | #include "config.h" |
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23 | |
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24 | #if defined (HAVE_UNISTD_H) |
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25 | # ifdef _MINIX |
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26 | # include <sys/types.h> |
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27 | # endif |
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28 | # include <unistd.h> |
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29 | #endif |
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30 | |
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31 | #include "shell.h" |
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32 | |
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33 | /* A global variable which acts as a sentinel for an `error' list return. */ |
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34 | GENERIC_LIST global_error_list; |
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35 | |
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36 | #ifdef INCLUDE_UNUSED |
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37 | /* Call FUNCTION on every member of LIST, a generic list. */ |
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38 | void |
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39 | list_walk (list, function) |
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40 | GENERIC_LIST *list; |
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41 | sh_glist_func_t *function; |
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42 | { |
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43 | for ( ; list; list = list->next) |
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44 | if ((*function) (list) < 0) |
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45 | return; |
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46 | } |
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47 | |
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48 | /* Call FUNCTION on every string in WORDS. */ |
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49 | void |
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50 | wlist_walk (words, function) |
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51 | WORD_LIST *words; |
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52 | sh_icpfunc_t *function; |
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53 | { |
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54 | for ( ; words; words = words->next) |
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55 | if ((*function) (words->word->word) < 0) |
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56 | return; |
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57 | } |
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58 | #endif /* INCLUDE_UNUSED */ |
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59 | |
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60 | /* Reverse the chain of structures in LIST. Output the new head |
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61 | of the chain. You should always assign the output value of this |
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62 | function to something, or you will lose the chain. */ |
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63 | GENERIC_LIST * |
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64 | list_reverse (list) |
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65 | GENERIC_LIST *list; |
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66 | { |
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67 | register GENERIC_LIST *next, *prev; |
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68 | |
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69 | for (prev = (GENERIC_LIST *)NULL; list; ) |
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70 | { |
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71 | next = list->next; |
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72 | list->next = prev; |
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73 | prev = list; |
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74 | list = next; |
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75 | } |
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76 | return (prev); |
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77 | } |
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78 | |
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79 | /* Return the number of elements in LIST, a generic list. */ |
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80 | int |
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81 | list_length (list) |
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82 | GENERIC_LIST *list; |
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83 | { |
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84 | register int i; |
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85 | |
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86 | for (i = 0; list; list = list->next, i++); |
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87 | return (i); |
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88 | } |
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89 | |
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90 | /* Append TAIL to HEAD. Return the header of the list. */ |
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91 | GENERIC_LIST * |
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92 | list_append (head, tail) |
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93 | GENERIC_LIST *head, *tail; |
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94 | { |
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95 | register GENERIC_LIST *t_head; |
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96 | |
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97 | if (head == 0) |
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98 | return (tail); |
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99 | |
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100 | for (t_head = head; t_head->next; t_head = t_head->next) |
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101 | ; |
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102 | t_head->next = tail; |
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103 | return (head); |
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104 | } |
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105 | |
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106 | #ifdef INCLUDE_UNUSED |
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107 | /* Delete the element of LIST which satisfies the predicate function COMPARER. |
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108 | Returns the element that was deleted, so you can dispose of it, or -1 if |
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109 | the element wasn't found. COMPARER is called with the list element and |
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110 | then ARG. Note that LIST contains the address of a variable which points |
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111 | to the list. You might call this function like this: |
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112 | |
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113 | SHELL_VAR *elt = list_remove (&variable_list, check_var_has_name, "foo"); |
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114 | dispose_variable (elt); |
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115 | */ |
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116 | GENERIC_LIST * |
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117 | list_remove (list, comparer, arg) |
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118 | GENERIC_LIST **list; |
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119 | Function *comparer; |
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120 | char *arg; |
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121 | { |
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122 | register GENERIC_LIST *prev, *temp; |
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123 | |
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124 | for (prev = (GENERIC_LIST *)NULL, temp = *list; temp; prev = temp, temp = temp->next) |
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125 | { |
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126 | if ((*comparer) (temp, arg)) |
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127 | { |
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128 | if (prev) |
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129 | prev->next = temp->next; |
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130 | else |
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131 | *list = temp->next; |
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132 | return (temp); |
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133 | } |
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134 | } |
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135 | return ((GENERIC_LIST *)&global_error_list); |
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136 | } |
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137 | #endif |
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