memory.h

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/*
  Memory utlities
 */

#ifndef LBCRYPTO_UTILS_MEMORY_H
#define LBCRYPTO_UTILS_MEMORY_H

#include <cstdint>
#include <cstddef>
#include <iterator>
#include <utility>
#include <vector>

namespace lbcrypto {

template <class X>
void MoveAppend(std::vector<X>& dst, std::vector<X>& src) {
    if (dst.empty()) {
        dst = std::move(src);
    }
    else {
        dst.reserve(dst.size() + src.size());
        std::move(std::begin(src), std::end(src), std::back_inserter(dst));
        src.clear();
    }
}

/**
 * @brief secure_memset() is a function with the same functionality provided by std::memset.
 *        Usually, the compiler optimizes a call to std::memset out if it is called for a memory which goes out of scope.
 *        This function is never optimized out and used to re-initialize a memory for security reasons.
 */
void secure_memset(volatile void* mem, uint8_t c, size_t len);

/**
 * @brief AllocTrim() returns free (unused) heap memory to the operating system.
 *        It is the companion to OpenFHE's retain-by-default malloc tuning: call it at a quiescent point after a large
 *        transient-footprint operation (e.g., EvalBootstrap) to reclaim peak scratch memory.
 *
 *        This is a performance/RSS utility, NOT a security primitive: it does not erase data. Use
 *        secure_memset() to wipe sensitive memory before freeing. It is not async-signal-safe.
 *
 * @return true if a trim was attempted, false on unsupported platforms.
 */
bool AllocTrim();

}  // namespace lbcrypto

#endif  // LBCRYPTO_UTILS_MEMORY_H