b2_growable_stack.h

// 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