b2allocator.H

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//------------------------------------------------------------------------
// b2allocator.H --
//
// written by Mathias Doreille
//            Thomas Blome <thomas.blome@dlr.de>
//            Harald Klimach <harald.klimach@dlr.de>
//
// Copyright (c) 2004-2012 SMR Engineering & Development SA
//                         2502 Bienne, Switzerland
//
// Copyright (c) 2023-2024 Deutsches Zentrum für Luft- und Raumfahrt (DLR) e.V.
//                    Linder Höhe, 51147 Köln
//
// All Rights Reserved.  Proprietary source code.  The contents of
// this file may not be disclosed to third parties, copied or
// duplicated in any form, in whole or in part, without the prior
// written permission of SMR.
//------------------------------------------------------------------------
 
#ifndef B2ALLOCATOR_H_
#define B2ALLOCATOR_H_
 
#include <new>
#include <stdlib.h>
 
#include <forward_list>
 
#include "b2ppconfig.h"
 
namespace b2000 {
 
using std::size_t;
 
class Allocator {
public:
    Allocator() { no_debug_alloc = getenv("GLIBCXX_FORCE_NEW") == nullptr; }
 
    explicit Allocator(size_t block_size_) : block_size(block_size_) {
        no_debug_alloc = getenv("GLIBCXX_FORCE_NEW") == nullptr;
    }
 
    ~Allocator() {
        for (list_block_t::iterator i = list_block.begin(); i != list_block.end(); ++i) {
            ::operator delete(*i);
        }
    }
 
    void* allocate(size_t size) {
    void* res{nullptr};
        if (no_debug_alloc) {
            res = start;
            const size_t aligned{(size + align_comp) & ~align_comp};
            start += aligned;
            if (start > end) {
                while (block_size < 8 * aligned) { block_size *= 2; }
                start = (char*)::operator new(block_size, block_alignment);
                end = start + block_size;
                list_block.push_front(start);
                res = start;
                start += size;
            }
        } else {
            res = (char*)::operator new(size);
            list_block.push_front((char*)res);
        }
        return res;
    }
 
    void deallocate(void* ptr, size_t size) {}
 
private:
    // Ensure 64-byte (AVX-512) alignment in starting addresses
    static constexpr size_t align_comp{63};
    static constexpr std::align_val_t block_alignment{align_comp+1};
    using list_block_t = std::forward_list<char*>;
    list_block_t list_block;
    char* start{};
    char* end{};
    size_t block_size{65536};
    bool no_debug_alloc;
};
 
}  // namespace b2000
 
#endif // B2ALLOCATOR_H_