b2_growable_stack.h

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// MIT License

// Copyright (c) 2019 Erin Catto

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#ifndef B2_GROWABLE_STACK_H
#define B2_GROWABLE_STACK_H

#include <string.h>

#include "b2_settings.h"

template <typename T, int32 N>
class b2GrowableStack
{
public:
        b2GrowableStack()
        {
                m_stack = m_array;
                m_count = 0;
                m_capacity = N;
        }

        ~b2GrowableStack()
        {
                if (m_stack != m_array)
                {
                        b2Free(m_stack);
                        m_stack = nullptr;
                }
        }

        void Push(const T& element)
        {
                if (m_count == m_capacity)
                {
                        T* old = m_stack;
                        m_capacity *= 2;
                        m_stack = (T*)b2Alloc(m_capacity * sizeof(T));
                        memcpy(m_stack, old, m_count * sizeof(T));
                        if (old != m_array)
                        {
                                b2Free(old);
                        }
                }

                m_stack[m_count] = element;
                ++m_count;
        }

        T Pop()
        {
                b2Assert(m_count > 0);
                --m_count;
                return m_stack[m_count];
        }

        int32 GetCount()
        {
                return m_count;
        }

private:
        T* m_stack;
        T m_array[N];
        int32 m_count;
        int32 m_capacity;
};


#endif