inetaddr.c

来自「用于嵌入式系统的TCP/IP协议栈」· C语言 代码 · 共 70 行

/***********************************************************************/
/*                                                                     */
/*   Module:  inetaddr.c                                               */
/*   Release: 2001.3                                                   */
/*   Version: 99.0                                                     */
/*   Purpose: inet_addr() implementation                               */
/*                                                                     */
/*---------------------------------------------------------------------*/
/*                                                                     */
/*               Copyright 1999, Blunk Microsystems                    */
/*                      ALL RIGHTS RESERVED                            */
/*                                                                     */
/*   Licensees have the non-exclusive right to use, modify, or extract */
/*   this computer program for software development at a single site.  */
/*   This program may be resold or disseminated in executable format   */
/*   only. The source code may not be redistributed or resold.         */
/*                                                                     */
/***********************************************************************/
#include "../tcp_ipp.h"
#include <ctype.h>

/***********************************************************************/
/* Global Function Definitions                                         */
/***********************************************************************/

/***********************************************************************/
/*   inet_addr: Convert dotted-decimal address to integer              */
/*                                                                     */
/*       Input: ptr = pointer to dotted decimal IP address string      */
/*                                                                     */
/*     Returns: integer IP address                                     */
/*                                                                     */
/*        Note: Address is returned in network byte order              */
/*                                                                     */
/***********************************************************************/
ui32 inet_addr(const char *ptr)
{
  int i, n;
  ui32 lword = 0;

  /*-------------------------------------------------------------------*/
  /* Loop once for each byte converted.                                */
  /*-------------------------------------------------------------------*/
  for (n = 4;; lword <<= 8)
  {
    /*-----------------------------------------------------------------*/
    /* Convert one byte's worth and write OR to 32-bit word.           */
    /*-----------------------------------------------------------------*/
    for (i = 0; isdigit(*ptr); ++ptr)
      i = (10 * i) + (*ptr - '0');
    lword |= (i & 0xFF);

    /*-----------------------------------------------------------------*/
    /* If finished, return long word IP address.                       */
    /*-----------------------------------------------------------------*/
    if (--n == 0)
      return htonl(lword);

    /*-----------------------------------------------------------------*/
    /* Check for '.' between each decimal number.                      */
    /*-----------------------------------------------------------------*/
    if (*ptr++ != '.')
    {
      NetError(NULL, EFAULT);
      return (ui32)-1;
    }
  }
}