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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libiberty/insque.c
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Diffstat (limited to 'libiberty/insque.c')
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diff --git a/libiberty/insque.c b/libiberty/insque.c
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+++ b/libiberty/insque.c
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+/* insque(3C) routines
+ This file is in the public domain. */
+
+/*
+
+@deftypefn Supplemental void insque (struct qelem *@var{elem}, @
+ struct qelem *@var{pred})
+@deftypefnx Supplemental void remque (struct qelem *@var{elem})
+
+Routines to manipulate queues built from doubly linked lists. The
+@code{insque} routine inserts @var{elem} in the queue immediately
+after @var{pred}. The @code{remque} routine removes @var{elem} from
+its containing queue. These routines expect to be passed pointers to
+structures which have as their first members a forward pointer and a
+back pointer, like this prototype (although no prototype is provided):
+
+@example
+struct qelem @{
+ struct qelem *q_forw;
+ struct qelem *q_back;
+ char q_data[];
+@};
+@end example
+
+@end deftypefn
+
+*/
+
+
+struct qelem {
+ struct qelem *q_forw;
+ struct qelem *q_back;
+};
+
+
+void
+insque (struct qelem *elem, struct qelem *pred)
+{
+ elem -> q_forw = pred -> q_forw;
+ pred -> q_forw -> q_back = elem;
+ elem -> q_back = pred;
+ pred -> q_forw = elem;
+}
+
+
+void
+remque (struct qelem *elem)
+{
+ elem -> q_forw -> q_back = elem -> q_back;
+ elem -> q_back -> q_forw = elem -> q_forw;
+}