X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Flist.c;h=0f4f2f84b91618cf95b6525e0aef9392d7d198e5;hb=f7eaaeba017b2442edd730b929d4713ba4375b1e;hp=8aedd7573656cbc4beedd514019c42a855bdb686;hpb=a14bc59fb8f27db193d74662dc9c5cb8237177ef;p=sliver-openvswitch.git diff --git a/lib/list.c b/lib/list.c index 8aedd7573..0f4f2f84b 100644 --- a/lib/list.c +++ b/lib/list.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009 Nicira Networks. + * Copyright (c) 2008, 2009, 2010 Nicira Networks. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -24,14 +24,22 @@ list_init(struct list *list) list->next = list->prev = list; } +/* Initializes 'list' with pointers that will (probably) cause segfaults if + * dereferenced and, better yet, show up clearly in a debugger. */ +void +list_poison(struct list *list) +{ + memset(list, 0xcc, sizeof *list); +} + /* Inserts 'elem' just before 'before'. */ void list_insert(struct list *before, struct list *elem) { - elem->prev = before->prev; - elem->next = before; - before->prev->next = elem; - before->prev = elem; + elem->prev = before->prev; + elem->next = before; + before->prev->next = elem; + before->prev = elem; } /* Removes elements 'first' though 'last' (exclusive) from their current list, @@ -39,19 +47,19 @@ list_insert(struct list *before, struct list *elem) void list_splice(struct list *before, struct list *first, struct list *last) { - if (first == last) - return; - last = last->prev; - - /* Cleanly remove 'first'...'last' from its current list. */ - first->prev->next = last->next; - last->next->prev = first->prev; - - /* Splice 'first'...'last' into new list. */ - first->prev = before->prev; - last->next = before; - before->prev->next = first; - before->prev = last; + if (first == last) + return; + last = last->prev; + + /* Cleanly remove 'first'...'last' from its current list. */ + first->prev->next = last->next; + last->next->prev = first->prev; + + /* Splice 'first'...'last' into new list. */ + first->prev = before->prev; + last->next = before; + before->prev->next = first; + before->prev = last; } /* Inserts 'elem' at the beginning of 'list', so that it becomes the front in @@ -59,7 +67,7 @@ list_splice(struct list *before, struct list *first, struct list *last) void list_push_front(struct list *list, struct list *elem) { - list_insert(list->next, elem); + list_insert(list->next, elem); } /* Inserts 'elem' at the end of 'list', so that it becomes the back in @@ -67,7 +75,7 @@ list_push_front(struct list *list, struct list *elem) void list_push_back(struct list *list, struct list *elem) { - list_insert(list, elem); + list_insert(list, elem); } /* Puts 'elem' in the position currently occupied by 'position'. @@ -94,9 +102,9 @@ list_moved(struct list *list) struct list * list_remove(struct list *elem) { - elem->prev->next = elem->next; - elem->next->prev = elem->prev; - return elem->next; + elem->prev->next = elem->next; + elem->next->prev = elem->prev; + return elem->next; } /* Removes the front element from 'list' and returns it. Undefined behavior if @@ -104,9 +112,9 @@ list_remove(struct list *elem) struct list * list_pop_front(struct list *list) { - struct list *front = list->next; - list_remove(front); - return front; + struct list *front = list->next; + list_remove(front); + return front; } /* Removes the back element from 'list' and returns it. @@ -114,27 +122,31 @@ list_pop_front(struct list *list) struct list * list_pop_back(struct list *list) { - struct list *back = list->prev; - list_remove(back); - return back; + struct list *back = list->prev; + list_remove(back); + return back; } -/* Returns the front element in 'list'. - Undefined behavior if 'list' is empty. */ +/* Returns the front element in 'list_'. + Undefined behavior if 'list_' is empty. */ struct list * -list_front(struct list *list) +list_front(const struct list *list_) { - assert(!list_is_empty(list)); - return list->next; + struct list *list = (struct list *) list_; + + assert(!list_is_empty(list)); + return list->next; } -/* Returns the back element in 'list'. - Undefined behavior if 'list' is empty. */ +/* Returns the back element in 'list_'. + Undefined behavior if 'list_' is empty. */ struct list * -list_back(struct list *list) +list_back(const struct list *list_) { - assert(!list_is_empty(list)); - return list->prev; + struct list *list = (struct list *) list_; + + assert(!list_is_empty(list)); + return list->prev; } /* Returns the number of elements in 'list'. @@ -142,17 +154,17 @@ list_back(struct list *list) size_t list_size(const struct list *list) { - const struct list *e; - size_t cnt = 0; + const struct list *e; + size_t cnt = 0; - for (e = list->next; e != list; e = e->next) - cnt++; - return cnt; + for (e = list->next; e != list; e = e->next) + cnt++; + return cnt; } /* Returns true if 'list' is empty, false otherwise. */ bool list_is_empty(const struct list *list) { - return list->next == list; + return list->next == list; }