1/* list.c - Functions for manipulating linked lists of objects. */ 2 3/* Copyright (C) 1996 4 Free Software Foundation, Inc. 5 6 This file is part of GNU Bash, the Bourne Again SHell. 7 8 Bash is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free 10 Software Foundation; either version 2, or (at your option) any later 11 version. 12 13 Bash is distributed in the hope that it will be useful, but WITHOUT ANY 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16 for more details. 17 18 You should have received a copy of the GNU General Public License along 19 with Bash; see the file COPYING. If not, write to the Free Software 20 Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */ 21 22#include "config.h" 23 24#if defined (HAVE_UNISTD_H) 25# ifdef _MINIX 26# include <sys/types.h> 27# endif 28# include <unistd.h> 29#endif 30 31#include "shell.h" 32 33/* A global variable which acts as a sentinel for an `error' list return. */ 34GENERIC_LIST global_error_list; 35 36#ifdef INCLUDE_UNUSED 37/* Call FUNCTION on every member of LIST, a generic list. */ 38void 39list_walk (list, function) 40 GENERIC_LIST *list; 41 sh_glist_func_t *function; 42{ 43 for ( ; list; list = list->next) 44 if ((*function) (list) < 0) 45 return; 46} 47 48/* Call FUNCTION on every string in WORDS. */ 49void 50wlist_walk (words, function) 51 WORD_LIST *words; 52 sh_icpfunc_t *function; 53{ 54 for ( ; words; words = words->next) 55 if ((*function) (words->word->word) < 0) 56 return; 57} 58#endif /* INCLUDE_UNUSED */ 59 60/* Reverse the chain of structures in LIST. Output the new head 61 of the chain. You should always assign the output value of this 62 function to something, or you will lose the chain. */ 63GENERIC_LIST * 64list_reverse (list) 65 GENERIC_LIST *list; 66{ 67 register GENERIC_LIST *next, *prev; 68 69 for (prev = (GENERIC_LIST *)NULL; list; ) 70 { 71 next = list->next; 72 list->next = prev; 73 prev = list; 74 list = next; 75 } 76 return (prev); 77} 78 79/* Return the number of elements in LIST, a generic list. */ 80int 81list_length (list) 82 GENERIC_LIST *list; 83{ 84 register int i; 85 86 for (i = 0; list; list = list->next, i++); 87 return (i); 88} 89 90/* Append TAIL to HEAD. Return the header of the list. */ 91GENERIC_LIST * 92list_append (head, tail) 93 GENERIC_LIST *head, *tail; 94{ 95 register GENERIC_LIST *t_head; 96 97 if (head == 0) 98 return (tail); 99 100 for (t_head = head; t_head->next; t_head = t_head->next) 101 ; 102 t_head->next = tail; 103 return (head); 104} 105 106#ifdef INCLUDE_UNUSED 107/* Delete the element of LIST which satisfies the predicate function COMPARER. 108 Returns the element that was deleted, so you can dispose of it, or -1 if 109 the element wasn't found. COMPARER is called with the list element and 110 then ARG. Note that LIST contains the address of a variable which points 111 to the list. You might call this function like this: 112 113 SHELL_VAR *elt = list_remove (&variable_list, check_var_has_name, "foo"); 114 dispose_variable (elt); 115*/ 116GENERIC_LIST * 117list_remove (list, comparer, arg) 118 GENERIC_LIST **list; 119 Function *comparer; 120 char *arg; 121{ 122 register GENERIC_LIST *prev, *temp; 123 124 for (prev = (GENERIC_LIST *)NULL, temp = *list; temp; prev = temp, temp = temp->next) 125 { 126 if ((*comparer) (temp, arg)) 127 { 128 if (prev) 129 prev->next = temp->next; 130 else 131 *list = temp->next; 132 return (temp); 133 } 134 } 135 return ((GENERIC_LIST *)&global_error_list); 136} 137#endif 138