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// license:GPL-2.0+
// copyright-holders:Couriersud
/*
* palloc.h
*
*/
#ifndef PMEMPOOL_H_
#define PMEMPOOL_H_
#include "palloc.h"
#include "pstream.h"
#include "pstring.h"
#include "ptypes.h"
#include "putil.h"
#include <algorithm>
#include <cstddef>
#include <memory>
#include <unordered_map>
#include <utility>
#include <vector>
namespace plib {
//============================================================
// Memory pool
//============================================================
class mempool
{
private:
struct block
{
block(mempool *mp)
: m_num_alloc(0)
, m_free(mp->m_min_alloc)
, m_cur(0)
, m_data(nullptr)
, m_mempool(mp)
{
std::size_t alloc_bytes = (mp->m_min_alloc + mp->m_min_align - 1) & ~(mp->m_min_align - 1);
m_data_allocated = static_cast<char *>(::operator new(alloc_bytes));
void *r = m_data_allocated;
std::align(mp->m_min_align, mp->m_min_alloc, r, alloc_bytes);
m_data = reinterpret_cast<char *>(r);
}
std::size_t m_num_alloc;
std::size_t m_free;
std::size_t m_cur;
char *m_data;
char *m_data_allocated;
mempool *m_mempool;
};
struct info
{
info(block *b, std::size_t p) : m_block(b), m_pos(p) { }
info(const info &) = default;
info(info &&) = default;
block * m_block;
std::size_t m_pos;
};
block * new_block()
{
auto *b = new block(this);
m_blocks.push_back(b);
return b;
}
static std::unordered_map<void *, info> &sinfo()
{
static std::unordered_map<void *, info> spinfo;
return spinfo;
}
size_t m_min_alloc;
size_t m_min_align;
std::vector<block *> m_blocks;
public:
mempool(size_t min_alloc, size_t min_align)
: m_min_alloc(min_alloc), m_min_align(min_align)
{
}
COPYASSIGNMOVE(mempool, delete)
~mempool()
{
for (auto & b : m_blocks)
{
if (b->m_num_alloc != 0)
{
plib::perrlogger("Found block with {} dangling allocations\n", b->m_num_alloc);
}
::operator delete(b->m_data);
}
}
void *alloc(size_t size)
{
size_t rs = (size + m_min_align - 1) & ~(m_min_align - 1);
for (auto &b : m_blocks)
{
if (b->m_free > rs)
{
b->m_free -= rs;
b->m_num_alloc++;
auto ret = reinterpret_cast<void *>(b->m_data + b->m_cur);
sinfo().insert({ ret, info(b, b->m_cur)});
b->m_cur += rs;
return ret;
}
}
{
block *b = new_block();
b->m_num_alloc = 1;
b->m_free = m_min_alloc - rs;
auto ret = reinterpret_cast<void *>(b->m_data + b->m_cur);
sinfo().insert({ ret, info(b, b->m_cur)});
b->m_cur += rs;
return ret;
}
}
void free(void *ptr)
{
info i = sinfo().find(ptr)->second;
block *b = i.m_block;
if (b->m_num_alloc == 0)
throw plib::pexception("mempool::free - double free was called\n");
else
{
//b->m_free = m_min_alloc;
//b->cur_ptr = b->data;
}
b->m_num_alloc--;
}
};
} // namespace plib
#endif /* PMEMPOOL_H_ */
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