Move stack.h and stack.c to lib

lib/stack.c

@@ -0,0 +1,40 @@
+#include "stack.h"
+#include "../lib/xalloc.h"
+
+#include <stdlib.h>
+
+struct stack {
+	size_t max_size;
+	size_t cur_size;
+	void** arr;
+};
+
+stack_t* alloc_stack(size_t size)
+{
+	stack_t* stack = xmalloc(sizeof(stack_t));
+	stack->arr = xcalloc(size, sizeof(void*));
+	stack->max_size = size;
+	stack->cur_size = 0;
+	return stack;
+}
+
+void free_stack(stack_t* stack)
+{
+	xfree(stack->arr);
+	xfree(stack);
+}
+
+void push(stack_t* stack, void* elt)
+{
+	if (stack->cur_size == stack->max_size) {
+		stack->max_size *= 2;
+		xrealloc(stack->arr, stack->max_size);
+	}
+	stack->arr[stack->cur_size++] = elt;
+}
+
+void* pop(stack_t* stack)
+{
+	void* res = stack->arr[--stack->cur_size];
+	return res;
+}

lib/stack.h

@@ -0,0 +1,15 @@
+#ifndef ZMAP_STACK_H
+#define ZMAP_STACK_H
+
+#include <stddef.h>
+
+struct stack;
+typedef struct stack stack_t;
+
+stack_t* alloc_stack(size_t size);
+void free_stack(stack_t* stack);
+
+void push(stack_t* stack, void* elt);
+void* pop(stack_t* stack);
+
+#endif /* ZMAP_STACK_H */