1 files changed, 165 insertions, 0 deletions
diff --git a/base/dbl_list.hh b/base/dbl_list.hh
new file mode 100644
index 000000000..4f6d61a45
--- /dev/null
+++ b/base/dbl_list.hh
@@ -0,0 +1,165 @@
+/*
+ * Copyright (c) 2003 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __DBL_LIST_HH__
+#define __DBL_LIST_HH__
+
+class DblListEl {
+    DblListEl *next;
+    DblListEl *prev;
+
+    // remove this from list
+    void remove() {
+        prev->next = next;
+        next->prev = prev;
+    }
+
+    // insert this before old_el
+    void insertBefore(DblListEl *old_el) {
+        prev = old_el->prev;
+        next = old_el;
+        prev->next = this;
+        next->prev = this;
+    }
+
+    // insert this after old_el
+    void insertAfter(DblListEl *old_el) {
+        next = old_el->next;
+        prev = old_el;
+        next->prev = this;
+        prev->next = this;
+    }
+
+    friend class DblListBase;
+};
+
+
+//
+// doubly-linked list of DblListEl objects
+//
+class DblListBase {
+    // dummy list head element: dummy.next is head, dummy.prev is tail
+    DblListEl dummy;
+
+    // length counter
+    unsigned length;
+
+    DblListEl *valid_or_null(DblListEl *el) {
+        // make sure users never see the dummy element
+        return (el == &dummy) ? NULL : el;
+    }
+
+  public:
+
+    DblListEl *head() {
+        return valid_or_null(dummy.next);
+    }
+
+    DblListEl *tail() {
+        return valid_or_null(dummy.prev);
+    }
+
+    DblListEl *next(DblListEl *el) {
+        return valid_or_null(el->next);
+    }
+
+    DblListEl *prev(DblListEl *el) {
+        return valid_or_null(el->prev);
+    }
+
+    bool is_empty() {
+        return (dummy.next == &dummy);
+    }
+
+    void remove(DblListEl *el) {
+        el->remove();
+        --length;
+    }
+
+    void insertBefore(DblListEl *new_el, DblListEl *old_el) {
+        new_el->insertBefore(old_el);
+        ++length;
+    }
+
+    void insertAfter(DblListEl *new_el, DblListEl *old_el) {
+        new_el->insertAfter(old_el);
+        ++length;
+    }
+
+    // append to end of list, i.e. as dummy.prev
+    void append(DblListEl *el) {
+        insertBefore(el, &dummy);
+    }
+
+    // prepend to front of list (push), i.e. as dummy.next
+    void prepend(DblListEl *el) {
+        insertAfter(el, &dummy);
+    }
+
+    DblListEl *pop() {
+        DblListEl *hd = head();
+        if (hd != NULL)
+            remove(hd);
+        return hd;
+    }
+
+    // constructor
+    DblListBase() {
+        dummy.next = dummy.prev = &dummy;
+        length = 0;
+    }
+};
+
+
+//
+// Template class serves solely to cast args & return values
+// to appropriate type (T *)
+//
+template<class T> class DblList : private DblListBase {
+
+  public:
+
+    T *head() { return (T *)DblListBase::head(); }
+    T *tail() { return (T *)DblListBase::tail(); }
+
+    T *next(T *el) { return (T *)DblListBase::next(el); }
+    T *prev(T *el) { return (T *)DblListBase::prev(el); }
+
+    bool is_empty() { return DblListBase::is_empty(); }
+
+    void remove(T *el) { DblListBase::remove(el); }
+
+    void append(T *el) { DblListBase::append(el); }
+    void prepend(T *el) { DblListBase::prepend(el); }
+
+    T *pop() { return (T *)DblListBase::pop(); }
+
+    DblList<T>() { }
+};
+
+#endif // __DBL_LIST_HH__