4 files changed, 144 insertions, 5 deletions

diff --git a/lib/libc/stdlib/Makefile.inc b/lib/libc/stdlib/Makefile.inc
index a65ef1ee1684..b04c2da8184d 100644
--- a/lib/libc/stdlib/Makefile.inc
+++ b/lib/libc/stdlib/Makefile.inc
@@ -6,12 +6,12 @@
 
 MISRCS+=_Exit.c abort.c abs.c atexit.c atof.c atoi.c atol.c atoll.c \
 	bsearch.c calloc.c div.c exit.c getenv.c getopt.c getopt_long.c \
-	getsubopt.c hcreate.c heapsort.c imaxabs.c imaxdiv.c \
+	getsubopt.c hcreate.c heapsort.c imaxabs.c imaxdiv.c insque.c \
 	labs.c ldiv.c llabs.c lldiv.c malloc.c merge.c putenv.c \
 	qsort.c qsort_r.c radixsort.c rand.c random.c reallocf.c realpath.c \
-	setenv.c strfmon.c strhash.c strtod.c strtoimax.c strtol.c strtoll.c \
-	strtoq.c strtoul.c strtoull.c strtoumax.c strtouq.c system.c \
-	tdelete.c tfind.c tsearch.c twalk.c
+	remque.c setenv.c strfmon.c strhash.c strtod.c strtoimax.c strtol.c \
+	strtoll.c strtoq.c strtoul.c strtoull.c strtoumax.c strtouq.c \
+	system.c tdelete.c tfind.c tsearch.c twalk.c
 
 # machine-dependent stdlib sources
 .if exists(${.CURDIR}/../libc/${MACHINE_ARCH}/stdlib/Makefile.inc)
@@ -21,7 +21,7 @@ MISRCS+=_Exit.c abort.c abs.c atexit.c atof.c atoi.c atol.c atoll.c \
 .if ${LIB} == "c"
 MAN+=	abort.3 abs.3 alloca.3 atexit.3 atof.3 atoi.3 atol.3 bsearch.3 \
 	div.3 exit.3 getenv.3 getopt.3 getopt_long.3 getsubopt.3 hcreate.3 \
-	imaxabs.3 imaxdiv.3 labs.3 ldiv.3 llabs.3 lldiv.3 \
+	imaxabs.3 imaxdiv.3 insque.3 labs.3 ldiv.3 llabs.3 lldiv.3 \
 	malloc.3 memory.3 qsort.3 radixsort.3 rand.3 random.3 \
 	realpath.3 strfmon.3 strtod.3 strtol.3 strtoul.3 system.3 tsearch.3
 
@@ -29,6 +29,7 @@ MLINKS+=atol.3 atoll.3
 MLINKS+=exit.3 _Exit.3
 MLINKS+=getenv.3 putenv.3 getenv.3 setenv.3 getenv.3 unsetenv.3
 MLINKS+=hcreate.3 hdestroy.3 hcreate.3 hsearch.3
+MLINKS+=insque.3 remque.3
 MLINKS+=qsort.3 heapsort.3 qsort.3 mergesort.3 qsort.3 qsort_r.3
 MLINKS+=rand.3 rand_r.3 rand.3 srand.3 rand.3 sranddev.3
 MLINKS+=random.3 initstate.3 random.3 setstate.3 random.3 srandom.3 \
diff --git a/lib/libc/stdlib/insque.3 b/lib/libc/stdlib/insque.3
new file mode 100644
index 000000000000..7df48f018652
--- /dev/null
+++ b/lib/libc/stdlib/insque.3
@@ -0,0 +1,59 @@
+.\"
+.\" Initial implementation:
+.\" Copyright (c) 2002 Robert Drehmel
+.\" All rights reserved.
+.\"
+.\" As long as the above copyright statement and this notice remain
+.\" unchanged, you can do what ever you want with this file. 
+.\"
+.\" $FreeBSD$
+.\"
+.Dd October 10, 2002
+.Dt INSQUE 3
+.Os
+.Sh NAME
+.Nm insque ,
+.Nm remque
+.Nd doubly-linked list management
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In search.h
+.Ft void
+.Fn insque "void *element1" "void *pred"
+.Ft void
+.Fn remque "void *element"
+.Sh DESCRIPTION
+.Pp
+The
+.Fn insque
+and
+.Fn remque
+functions encapsulate the ever-repeating task of doing insertion and
+removal operations on doubly linked lists.  The functions expect their
+arguments to point to a structure whose first and second members are
+pointers to the next and previous element, respectively.
+The
+.Fn insque
+functions also allows the
+.Fa pred
+argument to be a NULL pointer for the initialization of a new list's
+head element.
+.Sh HISTORY
+The
+.Fn insque
+and
+.Fn remque
+functions appeared in
+.Bx 4.2 .
+In
+.Fx 5.0 ,
+they reappeared conforming to
+.St -p1003.1-2001 .
+.Sh STANDARDS
+The
+.Fn insque
+and
+.Fn remque
+functions conform to
+.St -p1003.1-2001 .
diff --git a/lib/libc/stdlib/insque.c b/lib/libc/stdlib/insque.c
new file mode 100644
index 000000000000..08d179a5f988
--- /dev/null
+++ b/lib/libc/stdlib/insque.c
@@ -0,0 +1,48 @@
+/*
+ * Initial implementation:
+ * Copyright (c) 2002 Robert Drehmel
+ * All rights reserved.
+ *
+ * As long as the above copyright statement and this notice remain
+ * unchanged, you can do what ever you want with this file. 
+ *
+ * $FreeBSD$
+ */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#define	_SEARCH_PRIVATE
+#include <search.h>
+#ifdef DEBUG
+#include <stdio.h>
+#else
+#include <stdlib.h>	/* for NULL */
+#endif
+
+void insque(void *element, void *pred)
+{
+	struct que_elem *prev, *next, *elem;
+
+	elem = (struct que_elem *)element;
+	prev = (struct que_elem *)pred;
+
+	if (prev == NULL) {
+		elem->prev = elem->next = NULL;
+		return;
+	}
+
+	next = prev->next;
+	if (next != NULL) {
+#ifdef DEBUG
+		if (next->prev != prev) {
+			fprintf(stderr, "insque: Inconsistency detected:"
+			    " next(%p)->prev(%p) != prev(%p)\n",
+			    next, next->prev, prev);
+		}
+#endif
+		next->prev = elem;
+	}
+	prev->next = elem;
+	elem->prev = prev;
+	elem->next = next;
+}
diff --git a/lib/libc/stdlib/remque.c b/lib/libc/stdlib/remque.c
new file mode 100644
index 000000000000..234118876891
--- /dev/null
+++ b/lib/libc/stdlib/remque.c
@@ -0,0 +1,31 @@
+/*
+ * Initial implementation:
+ * Copyright (c) 2002 Robert Drehmel
+ * All rights reserved.
+ *
+ * As long as the above copyright statement and this notice remain
+ * unchanged, you can do what ever you want with this file. 
+ *
+ * $FreeBSD$
+ */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#define	_SEARCH_PRIVATE
+#include <search.h>
+#include <stdlib.h>	/* for NULL */
+
+void remque(void *element)
+{
+	struct que_elem *prev, *next, *elem;
+
+	elem = (struct que_elem *)element;
+
+	prev = elem->prev;
+	next = elem->next;
+
+	if (prev != NULL)
+		prev->next = next;
+	if (next != NULL)
+		next->prev = prev;
+}