encode_string.c

来自「OTP是开放电信平台的简称」· C语言 代码 · 共 77 行

/* ``The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved via the world wide web at http://www.erlang.org/.
 * 
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 * 
 * The Initial Developer of the Original Code is Ericsson Utvecklings AB.
 * Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
 * AB. All Rights Reserved.''
 * 
 *     $Id$
 */
#include <string.h>
#include "eidef.h"
#include "eiext.h"
#include "putget.h"


int ei_encode_string(char *buf, int *index, const char *p)
{
    return ei_encode_string_len(buf, index, p, strlen(p));
}

int ei_encode_string_len(char *buf, int *index, const char *p, int len)
{
    char *s = buf + *index;
    char *s0 = s;
    int i;

    if (len == 0) {

      if (!buf) {
	s += 1;
      } else {
	put8(s,ERL_NIL_EXT);
      }

    } else if (len <= 0xffff) {

      if (!buf) {
	s += 3;
      } else {
	put8(s,ERL_STRING_EXT);
	put16be(s,len);
	memmove(s,p,len);	/* unterminated string */
      }
      s += len;

    } else {

      if (!buf) {
	s += 5 + (2*len) + 1;
      } else {
	/* strings longer than 65535 are encoded as lists */
	put8(s,ERL_LIST_EXT);
	put32be(s,len);

	for (i=0; i<len; i++) {
	  put8(s,ERL_SMALL_INTEGER_EXT);
	  put8(s,p[i]);
	}
	put8(s,ERL_NIL_EXT);
      }

    }

    *index += s-s0; 

    return 0; 
}