text: /**
   * @file
   * various utility macros
   */
  
  /*
   * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without modification,
   * are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice,
   *    this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   * 3. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
   * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
   * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
   * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
   * OF SUCH DAMAGE.
   *
   * This file is part of the lwIP TCP/IP stack.
   *
   * Author: Adam Dunkels <adam@sics.se>
   *
   */
  #ifndef LWIP_HDR_DEF_H
  #define LWIP_HDR_DEF_H
  
  /* arch.h might define NULL already */
  #include "lwip/arch.h"
  #include "lwip/opt.h"
  #if LWIP_PERF
  #include "arch/perf.h"
  #else /* LWIP_PERF */
  #define PERF_START    /* null definition */
  #define PERF_STOP(x)  /* null definition */
  #endif /* LWIP_PERF */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #define LWIP_MAX(x , y)  (((x) > (y)) ? (x) : (y))
  #define LWIP_MIN(x , y)  (((x) < (y)) ? (x) : (y))
  
  /* Get the number of entries in an array ('x' must NOT be a pointer!) */
  #define LWIP_ARRAYSIZE(x) (sizeof(x)/sizeof((x)[0]))
  
  #ifndef NULL
  #ifdef __cplusplus
  #define NULL 0
  #else
  #define NULL ((void *)0)
  #endif
  #endif
  
  /* Endianess-optimized shifting of two u8_t to create one u16_t */
  #if BYTE_ORDER == LITTLE_ENDIAN
  #define LWIP_MAKE_U16(a, b) ((a << 8) | b)
  #else
  #define LWIP_MAKE_U16(a, b) ((b << 8) | a)
  #endif
  
  #if BYTE_ORDER == BIG_ENDIAN
  #define lwip_htons(x) (x)
  #define lwip_ntohs(x) (x)
  #define lwip_htonl(x) (x)
  #define lwip_ntohl(x) (x)
  #define PP_HTONS(x) (x)
  #define PP_NTOHS(x) (x)
  #define PP_HTONL(x) (x)
  #define PP_NTOHL(x) (x)
  #else /* BYTE_ORDER != BIG_ENDIAN */
  #ifndef lwip_htons
  u16_t lwip_htons(u16_t x);
  #endif
  #define lwip_ntohs(x) lwip_htons(x)
  
  #ifndef lwip_htonl
  u32_t lwip_htonl(u32_t x);
  #endif
  #define lwip_ntohl(x) lwip_htonl(x)
  
  /* Provide usual function names as macros for users, but this can be turned off */
  #ifndef LWIP_DONT_PROVIDE_BYTEORDER_FUNCTIONS
  #ifndef htons
  #define htons(x) lwip_htons(x)
  #endif
  
  #ifndef ntohs
  #define ntohs(x) lwip_ntohs(x)
  #endif
  
  #ifndef htonl
  #define htonl(x) lwip_htonl(x)
  #endif
  
  #ifndef ntohl
  #define ntohl(x) lwip_ntohl(x)
  #endif
  #endif
  
  /* These macros should be calculated by the preprocessor and are used
     with compile-time constants only (so that there is no little-endian
     overhead at runtime). */
  #define PP_HTONS(x) ((((x) & 0xff) << 8) | (((x) & 0xff00) >> 8))
  #define PP_NTOHS(x) PP_HTONS(x)
  #define PP_HTONL(x) ((((x) & 0xff) << 24) | \
                       (((x) & 0xff00) << 8) | \
                       (((x) & 0xff0000UL) >> 8) | \
                       (((x) & 0xff000000UL) >> 24))
  #define PP_NTOHL(x) PP_HTONL(x)
  
  #endif /* BYTE_ORDER == BIG_ENDIAN */
  
  /* Functions that are not available as standard implementations.
   * In cc.h, you can #define these to implementations available on
   * your platform to save some code bytes if you use these functions
   * in your application, too.
   */
  
  #ifndef lwip_itoa
  /* This can be #defined to itoa() or snprintf(result, bufsize, "%d", number) depending on your platform */
  void  lwip_itoa(char* result, size_t bufsize, int number);
  #endif
  #ifndef lwip_strnicmp
  /* This can be #defined to strnicmp() or strncasecmp() depending on your platform */
  int   lwip_strnicmp(const char* str1, const char* str2, size_t len);
  #endif
  #ifndef lwip_stricmp
  /* This can be #defined to stricmp() or strcasecmp() depending on your platform */
  int   lwip_stricmp(const char* str1, const char* str2);
  #endif
  #ifndef lwip_strnstr
  /* This can be #defined to strnstr() depending on your platform */
  char* lwip_strnstr(const char* buffer, const char* token, size_t n);
  #endif
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* LWIP_HDR_DEF_H */
  