1 files changed, 188 insertions, 0 deletions
diff --git a/contrib/cvs/src/stack.c b/contrib/cvs/src/stack.c
new file mode 100644
index 0000000..22a1088
--- /dev/null
+++ b/contrib/cvs/src/stack.c
@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2004-2005 The Free Software Foundation, Inc.
+ *
+ * Portions Copyright (C) 2004-2005 Derek Price, Ximbiot <http://ximbiot.com>,
+ *                                  and others.
+ * 
+ * You may distribute under the terms of the GNU General Public License as
+ * specified in the README file that comes with the CVS source distribution.
+ *
+ * This module uses the hash.c module to implement a stack.
+ */
+
+#include "cvs.h"
+#include <assert.h>
+
+
+
+static void
+do_push (stack, elem, isstring)
+    List *stack;
+    void *elem;
+    int isstring;
+{
+    Node *p = getnode();
+
+    if (isstring)
+	p->key = elem;
+    else
+	p->data = elem;
+
+    addnode(stack, p);
+}
+
+
+
+void
+push (stack, elem)
+    List *stack;
+    void *elem;
+{
+    do_push (stack, elem, 0);
+}
+
+
+
+void
+push_string (stack, elem)
+    List *stack;
+    char *elem;
+{
+    do_push (stack, elem, 1);
+}
+
+
+
+static void *
+do_pop (stack, isstring)
+    List *stack;
+    int isstring;
+{
+    void *elem;
+
+    if (isempty (stack)) return NULL;
+
+    if (isstring)
+    {
+	elem = stack->list->prev->key;
+	stack->list->prev->key = NULL;
+    }
+    else
+    {
+	elem = stack->list->prev->data;
+	stack->list->prev->data = NULL;
+    }
+
+    delnode (stack->list->prev);
+    return elem;
+}
+
+
+
+void *
+pop (stack)
+    List *stack;
+{
+    return do_pop (stack, 0);
+}
+
+
+
+char *
+pop_string (stack)
+    List *stack;
+{
+    return do_pop (stack, 1);
+}
+
+
+
+static void
+do_unshift (stack, elem, isstring)
+    List *stack;
+    void *elem;
+    int isstring;
+{
+    Node *p = getnode();
+
+    if (isstring)
+	p->key = elem;
+    else
+	p->data = elem;
+
+    addnode_at_front(stack, p);
+}
+
+
+
+void
+unshift (stack, elem)
+    List *stack;
+    void *elem;
+{
+    do_unshift (stack, elem, 0);
+}
+
+
+
+void
+unshift_string (stack, elem)
+    List *stack;
+    char *elem;
+{
+    do_unshift (stack, elem, 1);
+}
+
+
+
+static void *
+do_shift (stack, isstring)
+    List *stack;
+    int isstring;
+{
+    void *elem;
+
+    if (isempty (stack)) return NULL;
+
+    if (isstring)
+    {
+	elem = stack->list->next->key;
+	stack->list->next->key = NULL;
+    }
+    else
+    {
+	elem = stack->list->next->data;
+	stack->list->next->data = NULL;
+    }
+    delnode (stack->list->next);
+    return elem;
+}
+
+
+
+void *
+shift (stack)
+    List *stack;
+{
+    return do_shift (stack, 0);
+}
+
+
+
+char *
+shift_string (stack)
+    List *stack;
+{
+    return do_shift (stack, 1);
+}
+
+
+
+int
+isempty (stack)
+    List *stack;
+{
+    if (stack->list == stack->list->next)
+	return 1;
+    return 0;
+}