1 files changed, 82 insertions, 0 deletions
diff --git a/src/rapidjson/internal/stack.h b/src/rapidjson/internal/stack.h
new file mode 100755
index 0000000000..966893b3fc
--- /dev/null
+++ b/src/rapidjson/internal/stack.h
@@ -0,0 +1,82 @@
+#ifndef RAPIDJSON_INTERNAL_STACK_H_
+#define RAPIDJSON_INTERNAL_STACK_H_
+
+namespace rapidjson {
+namespace internal {
+
+///////////////////////////////////////////////////////////////////////////////
+// Stack
+
+//! A type-unsafe stack for storing different types of data.
+/*! \tparam Allocator Allocator for allocating stack memory.
+*/
+template <typename Allocator>
+class Stack {
+public:
+	Stack(Allocator* allocator, size_t stack_capacity) : allocator_(allocator), own_allocator_(0), stack_(0), stack_top_(0), stack_end_(0), stack_capacity_(stack_capacity) {
+		RAPIDJSON_ASSERT(stack_capacity_ > 0);
+		if (!allocator_)
+			own_allocator_ = allocator_ = new Allocator();
+		stack_top_ = stack_ = (char*)allocator_->Malloc(stack_capacity_);
+		stack_end_ = stack_ + stack_capacity_;
+	}
+
+	~Stack() {
+		Allocator::Free(stack_);
+		delete own_allocator_; // Only delete if it is owned by the stack
+	}
+
+	void Clear() { /*stack_top_ = 0;*/ stack_top_ = stack_; }
+
+	template<typename T>
+	T* Push(size_t count = 1) {
+		 // Expand the stack if needed
+		if (stack_top_ + sizeof(T) * count >= stack_end_) {
+			size_t new_capacity = stack_capacity_ * 2;
+			size_t size = GetSize();
+			size_t new_size = GetSize() + sizeof(T) * count;
+			if (new_capacity < new_size)
+				new_capacity = new_size;
+			stack_ = (char*)allocator_->Realloc(stack_, stack_capacity_, new_capacity);
+			stack_capacity_ = new_capacity;
+			stack_top_ = stack_ + size;
+			stack_end_ = stack_ + stack_capacity_;
+		}
+		T* ret = (T*)stack_top_;
+		stack_top_ += sizeof(T) * count;
+		return ret;
+	}
+
+	template<typename T>
+	T* Pop(size_t count) {
+		RAPIDJSON_ASSERT(GetSize() >= count * sizeof(T));
+		stack_top_ -= count * sizeof(T);
+		return (T*)stack_top_;
+	}
+
+	template<typename T>
+	T* Top() { 
+		RAPIDJSON_ASSERT(GetSize() >= sizeof(T));
+		return (T*)(stack_top_ - sizeof(T));
+	}
+
+	template<typename T>
+	T* Bottom() { return (T*)stack_; }
+
+	Allocator& GetAllocator() { return *allocator_; }
+	size_t GetSize() const { return stack_top_ - stack_; }
+	size_t GetCapacity() const { return stack_capacity_; }
+
+private:
+	Allocator* allocator_;
+	Allocator* own_allocator_;
+	char *stack_;
+	char *stack_top_;
+	char *stack_end_;
+	size_t stack_capacity_;
+};
+
+} // namespace internal
+} // namespace rapidjson
+
+#endif // RAPIDJSON_STACK_H_