Crank/arena.hpp

#pragma once
#include "buffer.hpp"
#include "stdlib.h"
#include "string.h"

class arena{
	ksdk::buffer<char> data;
	size_t last;
	size_t count;
public: 
	arena()
	:last(0)
	,count(0)
	,data(ksdk::buffer<char>(nullptr,(size_t)0))
	{}

	arena(size_t sz)
	:last(0)
	,count(0)
	,data(ksdk::buffer<char>(nullptr,(size_t)0))
	{
		if(sz!=0)
		{
			auto v=malloc(sz);
			if(v!=nullptr)
			{
				data=ksdk::buffer<char>((char*)v,sz);
			}
		}
	}

	arena(char* pos,size_t sz)
	:last(0)
	,count(0)
	,data(ksdk::buffer<char>(pos,(size_t)sz))
	{
	}

	void* allocate(size_t sz)
	{
		auto ret=data.begin()+last;
		if(ret<data.end())
		{
			count++;
			last+=sz;
			return ret;
		}
		else
		{
			return nullptr;
		}
	}

	bool desallocate(void* ptr)
	{
		if(ptr>=data.begin() && ptr<data.end())
		{
			count--;
			if(count==0)
			{
				memset(data.begin(),data.size(),0);
				last=0;
			}
			return true;
		}
		return false;
	}
};