parser.c

这是有名的＜＜嵌入式系统TCP/IP应用层协议＞＞,M.Tim Jones 著

/*
 *  Embedded CLI Command Parser (Tokenizer)
 *
 *  ./software/ch9/emcli/emclid/parser.c
 *
 *  [e-mail]
 *
 */

#include <stdio.h>

#define MAX_ARGS	20

static char vector[MAX_ARGS];
static char *ibuf;
static int  numArgs;

/*
 *  parseCommand()
 *
 *  Identifies and logs the independent arguments of the command
 *  line and puts their index into the vector indexed by the
 *  particular arguments.
 *
 *  Returns the number of arguments parsed for the particular
 *  command.  If the return is -1, then an error occured, otherwise
 *  a return of 0 represents no arguments, > 0 is the number of args.
 *
 *  NOTE:  This module keeps user-local information local to this
 *         module.  Therefore, the user should not modify the command
 *         buffer after it has been passed to parseCommand.
 *
 */

int parseCommand( char *buf ) 
{
  int i=0;
  int len = strlen(buf);

  ibuf = buf;
  numArgs = 0;

  /* First, skip the command */
  while ((i < len) && (buf[i] != ' ')) i++;
  buf[i++] = 0;
  while ((i < len) && (buf[i] == ' ')) i++;
  if (i >= len) return 0;

  while (1) {

    if (numArgs >= MAX_ARGS) return -1;

    vector[numArgs] = i;

    if (i >= len) break;

    while ((i < len) && (buf[i] != ' ')) i++;
    buf[i++] = 0;

    while ((i < len) && (buf[i] == ' ')) i++;

    numArgs++;

  }

  return numArgs;
}


char *getArg( int arg )
{
  if (ibuf) {
    return (char *)(&ibuf[vector[arg]]);
  } else {
    return NULL;
  }
}


int getArgCount ( void )
{
  return numArgs;
}

/*
 *  Copyright (c) 2002 Charles River Media.  All rights reserved.
 * 
 *  Redistribution and use in source and binary forms, with or 
 *  without modification, is hereby granted without fee 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.  Neither the name of Charles River Media nor the names of 
 *        its contributors may be used to endorse or promote products 
 *        derived from this software without specific prior 
 *        written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY CHARLES RIVER MEDIA AND CONTRIBUTERS 
 * 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS 
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL CHARLES
 * RIVER MEDIA OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
 * INCIDENTAL, SPECIAL, EXEMPLARAY, 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.
 */