byte_order_helpers.h

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// Copyright (c) 2023, 2024, Oracle and/or its affiliates.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License, version 2.0,
// as published by the Free Software Foundation.
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#ifndef MYSQL_SERIALIZATION_BYTE_ORDER_HELPERS_H
#define MYSQL_SERIALIZATION_BYTE_ORDER_HELPERS_H
 
#include <bitset>
#include <sstream>
#include <vector>
#include "my_byteorder.h"
 
#ifdef HAVE_ENDIAN_CONVERSION_MACROS
#include <endian.h>
#endif
 
/// @file
/// Experimental API header
/// Conversions between different number representations. MySQL writes
/// binary data in LE, therefore this header defines the following conversions:
/// host -> LE (for writing)
/// LE -> host (for reading)
 
#if !defined(le64toh)
/**
  Converting a 64 bit integer from little-endian byte order to host byteorder
 
  @param x  64-bit integer in little endian byte order
  @return  64-bit integer in host byte order
*/
uint64_t inline le64toh(uint64_t x) {
#ifndef WORDS_BIGENDIAN
  return x;
#else
  x = ((x << 8) & 0xff00ff00ff00ff00ULL) | ((x >> 8) & 0x00ff00ff00ff00ffULL);
  x = ((x << 16) & 0xffff0000ffff0000ULL) | ((x >> 16) & 0x0000ffff0000ffffULL);
  return (x << 32) | (x >> 32);
#endif
}
#endif
 
#if !defined(htole64)
/**
  Converting a 64 bit integer from host's byte order to little-endian byte
  order.
 
  @param x  64-bit integer in host's byte order
  @return  64-bit integer in little endian byte order
*/
 
uint64_t inline htole64(uint64_t x) {
#ifndef WORDS_BIGENDIAN
  return x;
#else
  x = ((x << 8) & 0xff00ff00ff00ff00ULL) | ((x >> 8) & 0x00ff00ff00ff00ffULL);
  x = ((x << 16) & 0xffff0000ffff0000ULL) | ((x >> 16) & 0x0000ffff0000ffffULL);
  return (x << 32) | (x >> 32);
#endif
}
#endif
 
#endif  // MYSQL_SERIALIZATION_BYTE_ORDER_HELPERS_H