1 files changed, 126 insertions, 0 deletions
diff --git a/libs/libc/stack.c b/libs/libc/stack.c
new file mode 100644
index 0000000..0cbb69d
--- /dev/null
+++ b/libs/libc/stack.c
@@ -0,0 +1,126 @@
+// MIT License, Copyright (c) 2020 Marvin Borner
+
+#include <def.h>
+#include <mem.h>
+#include <stack.h>
+
+static int nonce = 0;
+
+struct stack *stack_new(void)
+{
+	struct stack *stack = malloc(sizeof(*stack));
+	stack->tail = NULL;
+	return stack;
+}
+
+void stack_destroy(struct stack *stack)
+{
+	struct stack_node *iterator = stack->tail;
+	while (iterator) {
+		if (!iterator->prev) {
+			free(iterator);
+			break;
+		}
+		iterator = iterator->prev;
+		free(iterator->next);
+	}
+	stack->tail = NULL;
+	free(stack);
+	stack = NULL;
+}
+
+static struct stack_node *stack_new_node(void)
+{
+	struct stack_node *node = malloc(sizeof(*node));
+	node->data = NULL;
+	node->prev = NULL;
+	node->next = NULL;
+	node->nonce = nonce++;
+	return node;
+}
+
+static u32 stack_push_bot_node(struct stack *stack, struct stack_node *node)
+{
+	if (!stack || !node)
+		return 0;
+
+	if (stack->tail) {
+		struct stack_node *iterator = stack->tail;
+		while (iterator) {
+			if (!iterator->prev)
+				break;
+			iterator = iterator->prev;
+		}
+		iterator->prev = node;
+		node->next = iterator;
+	} else {
+		stack->tail = node;
+	}
+
+	return 1;
+}
+
+static u32 stack_push_node(struct stack *stack, struct stack_node *node)
+{
+	if (!stack || !node)
+		return 0;
+
+	if (stack->tail) {
+		stack->tail->next = node;
+		node->prev = stack->tail;
+		stack->tail = node;
+	} else {
+		stack->tail = node;
+	}
+
+	return 1;
+}
+
+u32 stack_empty(struct stack *stack)
+{
+	return !stack->tail;
+}
+
+u32 stack_push_bot(struct stack *stack, void *data)
+{
+	struct stack_node *node = stack_new_node();
+	node->data = data;
+	return stack_push_bot_node(stack, node);
+}
+
+u32 stack_push(struct stack *stack, void *data)
+{
+	struct stack_node *node = stack_new_node();
+	node->data = data;
+	return stack_push_node(stack, node);
+}
+
+void *stack_pop(struct stack *stack)
+{
+	if (!stack || !stack->tail)
+		return NULL;
+
+	struct stack_node *prev = stack->tail;
+
+	if (stack->tail->prev)
+		stack->tail->prev->next = NULL;
+	stack->tail = stack->tail->prev;
+
+	void *data = prev->data;
+	free(prev);
+	return data;
+}
+
+void *stack_peek(struct stack *stack)
+{
+	if (!stack || !stack->tail)
+		return NULL;
+
+	return stack->tail->data;
+}
+
+void stack_clear(struct stack *stack)
+{
+	while (stack_pop(stack))
+		;
+}