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Diffstat (limited to 'list.c')
| -rw-r--r-- | list.c | 128 |
1 files changed, 128 insertions, 0 deletions
@@ -0,0 +1,128 @@ +/* list.c - Functions for manipulating linked lists of objects. */ + +/* Copyright (C) 1996 + Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne Again SHell. + + Bash is free software; you can redistribute it and/or modify it under + the terms of the GNU General Public License as published by the Free + Software Foundation; either version 2, or (at your option) any later + version. + + Bash is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License along + with Bash; see the file COPYING. If not, write to the Free Software + Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#include "config.h" + +#if defined (HAVE_UNISTD_H) +# include <unistd.h> +#endif + +#include "shell.h" + +/* A global variable which acts as a sentinel for an `error' list return. */ +GENERIC_LIST global_error_list; + +/* Call FUNCTION on every member of LIST, a generic list. */ +void +map_over_list (list, function) + GENERIC_LIST *list; + Function *function; +{ + for ( ; list; list = list->next) + (*function) (list); +} + +/* Call FUNCTION on every string in WORDS. */ +void +map_over_words (words, function) + WORD_LIST *words; + Function *function; +{ + for ( ; words; words = words->next) + (*function) (words->word->word); +} + +/* Reverse the chain of structures in LIST. Output the new head + of the chain. You should always assign the output value of this + function to something, or you will lose the chain. */ +GENERIC_LIST * +reverse_list (list) + GENERIC_LIST *list; +{ + register GENERIC_LIST *next, *prev; + + for (prev = (GENERIC_LIST *)NULL; list; ) + { + next = list->next; + list->next = prev; + prev = list; + list = next; + } + return (prev); +} + +/* Return the number of elements in LIST, a generic list. */ +int +list_length (list) + GENERIC_LIST *list; +{ + register int i; + + for (i = 0; list; list = list->next, i++); + return (i); +} + +/* Append TAIL to HEAD. Return the header of the list. */ +GENERIC_LIST * +list_append (head, tail) + GENERIC_LIST *head, *tail; +{ + register GENERIC_LIST *t_head; + + if (head == 0) + return (tail); + + for (t_head = head; t_head->next; t_head = t_head->next) + ; + t_head->next = tail; + return (head); +} + +/* Delete the element of LIST which satisfies the predicate function COMPARER. + Returns the element that was deleted, so you can dispose of it, or -1 if + the element wasn't found. COMPARER is called with the list element and + then ARG. Note that LIST contains the address of a variable which points + to the list. You might call this function like this: + + SHELL_VAR *elt = delete_element (&variable_list, check_var_has_name, "foo"); + dispose_variable (elt); +*/ +GENERIC_LIST * +delete_element (list, comparer, arg) + GENERIC_LIST **list; + Function *comparer; + char *arg; +{ + register GENERIC_LIST *prev, *temp; + + for (prev = (GENERIC_LIST *)NULL, temp = *list; temp; prev = temp, temp = temp->next) + { + if ((*comparer) (temp, arg)) + { + if (prev) + prev->next = temp->next; + else + *list = temp->next; + return (temp); + } + } + return ((GENERIC_LIST *)&global_error_list); +} |