manip.c

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

/*
 *  Embedded SLP Message Manipulation Functions
 *
 *  ./software/ch10/emslp
 *
 *  [e-mail]
 *
 */

#include <stdio.h>
#include "manip.h"

/*
 *  emitByte()
 *
 *  Emit an octet into an slpMsg stream.
 *
 */

void emitByte( slpMsgType *slpMsg, uint8_t value)
{
  if (slpMsg == NULL) return;
  slpMsg->buffer[slpMsg->index++] = value;
  slpMsg->len++;
}


/*
 *  emitShort()
 *
 *  Emit a short (16 bits) into an slpMsg stream.
 *
 */

void emitShort( slpMsgType *slpMsg, uint16_t value)
{
  if (slpMsg == NULL) return;
  slpMsg->buffer[slpMsg->index++] = (unsigned char )(value >> 8);
  slpMsg->buffer[slpMsg->index++] = (unsigned char )(value & 0xff);
  slpMsg->len+=2;
}


/*
 *  emitString()
 *
 *  Emit a variable length string into an slpMsg stream.
 *
 */

void emitString( slpMsgType *slpMsg, const char *string)
{
  int i, len = strlen(string);

  if ((slpMsg == NULL) || (string == NULL)) return;
  for (i = 0 ; i < len ; i++) emitByte(slpMsg, string[i]);
}


/*
 *  getByte()
 *
 *  Get an octet from an slpMsg stream.
 *
 */

int getByte( slpMsgType *slpMsg, uint8_t *value)
{
  int ret = -1;
  if (slpMsg == NULL) return -1;
  if (slpMsg->index < slpMsg->len) {
    if (value) {
      *value = slpMsg->buffer[slpMsg->index++];
    } else {
      slpMsg->index++;
    }
    ret = 0;
  } 

  return ret;
}


/*
 *  getShort()
 *
 *  Get a short from an slpMsg stream.
 *
 */

int getShort( slpMsgType *slpMsg, uint16_t *value)
{
  int ret = -1;
  if (slpMsg == NULL) return -1;
  if (slpMsg->index+1 < slpMsg->len) {
    if (value) {
      *value  = slpMsg->buffer[slpMsg->index++] << 8;
      *value |= slpMsg->buffer[slpMsg->index++];
    } else {
      slpMsg->index+=2;
    }
    ret = 0;
  }

  return ret;
}


/*
 *  getTriOctet()
 *
 *  Get a 3 octet word from the slpMsg stream.
 *
 */

int getTriOctet( slpMsgType *slpMsg, uint32_t *value)
{
  int ret = -1;
  if (slpMsg == NULL) return -1;
  if (slpMsg->index+2 < slpMsg->len) {
    if (value) {
      *value  = slpMsg->buffer[slpMsg->index++] << 16;
      *value |= slpMsg->buffer[slpMsg->index++] <<  8;
      *value |= slpMsg->buffer[slpMsg->index++];
    } else {
      slpMsg->index+=3;
    }
    ret = 0;
  } 

  return ret;
}


/*
 *  getString()
 *
 *  Get a variable length string from an slpMsg stream.
 *
 */

int getString( slpMsgType *slpMsg, int len, char *string)
{
  int i, ret = -1;

  if (slpMsg == NULL) return -1;

  if (slpMsg->index+len < slpMsg->len) {
    if (string) {
      for (i = 0 ; i < len ; i++) {
        string[i] = slpMsg->buffer[slpMsg->index+i];
      }
      string[i] = 0;
    }
    slpMsg->index += len;

    ret = 0;
  }

  return ret;
}

/*
 *  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.
 */