API Reference — pma/MemoryResource

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class PMAAPI MemoryResource

Abstract base for polymorphic memory allocation. Implement this interface to supply a custom allocator across API boundaries without modifying the signatures of the APIs that consume it.

When to use this

Use MemoryResource when you need to pass a custom allocator into a subsystem that you do not own — for example, to redirect all pma allocations to a pool, arena, or tracking wrapper. Because it decouples the allocator policy from the API surface, you can swap implementations at runtime without touching call sites.

Example

#include "pma/MemoryResource.h"
#include <cstdlib>

class MallocResource : public pma::MemoryResource {
public:
    void* allocate(std::size_t size, std::size_t alignment) override {
        // Use aligned_alloc or platform equivalent
        return std::aligned_alloc(alignment, size);
    }

    void deallocate(void* ptr, std::size_t /*size*/, std::size_t /*alignment*/) override {
        std::free(ptr);
    }
};

// Pass to any pma API that accepts a MemoryResource*
MallocResource resource;
auto* reader = pma::BinaryStreamReader::create(&stream, &resource);

Watch out for

• Both allocate and deallocate are pure virtual — any concrete subclass must implement both or the compiler will reject instantiation.
• allocate receives an explicit alignment argument. Ignoring it and using a plain malloc will produce undefined behavior for over-aligned types. Use std::aligned_alloc, _aligned_malloc, or a platform equivalent.