Adding upstream version 4.2.

Signed-off-by: Daniel Baumann <daniel@debian.org>

dlink.c

@@ -0,0 +1,74 @@
+
+/* doubly linked lists */
+/* This is free software. No strings attached. No copyright claimed */
+
+#include	<unistd.h>
+#include	<stdlib.h>
+#include	<string.h>
+#ifdef __dietlibc__
+char *strncpy(char *dest, const char *src, size_t n) __THROW;
+#endif
+void *xcalloc(size_t num, size_t size);
+#include	"dlink.h"
+
+void *dl_head()
+{
+    void *h;
+    h = dl_alloc(0);
+    dl_next(h) = h;
+    dl_prev(h) = h;
+    return h;
+}
+
+void dl_free(void *v)
+{
+    struct __dl_head *vv  = v;
+    free(vv-1);
+}
+
+void dl_init(void *v)
+{
+    dl_next(v) = v;
+    dl_prev(v) = v;
+}
+
+void dl_insert(void *head, void *val)
+{
+    dl_next(val) = dl_next(head);
+    dl_prev(val) = head;
+    dl_next(dl_prev(val)) = val;
+    dl_prev(dl_next(val)) = val;
+}
+
+void dl_add(void *head, void *val)
+{
+    dl_prev(val) = dl_prev(head);
+    dl_next(val) = head;
+    dl_next(dl_prev(val)) = val;
+    dl_prev(dl_next(val)) = val;
+}
+
+void dl_del(void *val)
+{
+    if (dl_prev(val) == 0 || dl_next(val) == 0)
+	return;
+    dl_prev(dl_next(val)) = dl_prev(val);
+    dl_next(dl_prev(val)) = dl_next(val);
+    dl_prev(val) = dl_next(val) = 0;
+}
+
+char *dl_strndup(char *s, int l)
+{
+    char *n;
+    if (s == NULL)
+	return NULL;
+    n = dl_newv(char, l+1);
+    strncpy(n, s, l+1);
+    n[l] = 0;
+    return n;
+}
+
+char *dl_strdup(char *s)
+{
+    return dl_strndup(s, (int)strlen(s));
+}