small readme changes

[smdp.git] / cstack.c

diff --git a/cstack.c b/cstack.c
index 6474436..f56ee2c 100644 (file)
--- a/cstack.c
+++ b/cstack.c
@@ -1,3 +1,24 @@
+/*
+ * An implementation of a char stack in heap memory.
+ * Copyright (C) 2014 Michael Goehler
+ *
+ * This file is part of mdp.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
 #include <stdlib.h> // malloc, realloc
 
 #include "include/cstack.h"
@@ -29,8 +50,10 @@ char cstack_pop(cstack_t *self) {
     return self->content[self->head--];
 }
 
-char cstack_top(cstack_t *self) {
-    return self->content[self->head];
+int cstack_top(cstack_t *self, char c) {
+    if(self->head >= 0 && self->content[self->head] == c)
+        return 1;
+    return 0;
 }
 
 int cstack_empty(cstack_t *self)  {