#ifndef __STDC_WANT_LIB_EXT1__

#define __STDC_WANT_LIB_EXT1__ 1  // C11's bounds-checking interface.

#endif

#include <string.h>

#ifdef _WIN32

#include <windows.h>

#endif

#ifdef __unix__

#include <strings.h>

#include <sys/param.h>

#endif

// C11's bounds-checking interface.

#if defined(__STDC_LIB_EXT1__)

#define HAVE_MEMSET_S 1

#endif

// GNU C Library version 2.25 or later.

#if defined(__GLIBC__) && \

    (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 25))

#define HAVE_EXPLICIT_BZERO 1

#endif

// Newlib

#if defined(__NEWLIB__)

#define HAVE_EXPLICIT_BZERO 1

#endif

// FreeBSD version 11.0 or later.

#if defined(__FreeBSD__) && __FreeBSD_version >= 1100037

#define HAVE_EXPLICIT_BZERO 1

#endif

// OpenBSD version 5.5 or later.

#if defined(__OpenBSD__) && OpenBSD >= 201405

#define HAVE_EXPLICIT_BZERO 1

#endif

// NetBSD version 7.2 or later.

#if defined(__NetBSD__) && __NetBSD_Version__ >= 702000000

#define HAVE_EXPLICIT_MEMSET 1

#endif

// Adapted from

// https://github.com/jedisct1/libsodium/blob/1647f0d53ae0e370378a9195477e3df0a792408f/src/libsodium/sodium/utils.c#L102-L130

void memzero(void *const pnt, const size_t len) {

#ifdef _WIN32

  SecureZeroMemory(pnt, len);

#elif defined(HAVE_MEMSET_S)

  memset_s(pnt, (rsize_t)len, 0, (rsize_t)len);

#elif defined(HAVE_EXPLICIT_BZERO)

  explicit_bzero(pnt, len);

#elif defined(HAVE_EXPLICIT_MEMSET)

  explicit_memset(pnt, 0, len);

#else

  volatile unsigned char *volatile pnt_ = (volatile unsigned char *volatile)pnt;

  size_t i = (size_t)0U;

  while (i < len) {

    pnt_[i++] = 0U;

  }

#endif

  // explicitly mark the memory as overwritten for the Clang MemorySanitizer

  // this is only included at compile time if MemorySanitizer is enabled and

  // should not come with any downsides during regular builds

#if defined(__has_feature)

#if __has_feature(memory_sanitizer)

  memset(pnt, 0, len);

#endif

#endif

}