dstring.c

/*
 * hfsutils - tools for reading and writing Macintosh HFS volumes
 * Copyright (C) 1996-1998 Robert Leslie
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id: dstring.c,v 1.7 1998/11/02 22:08:28 rob Exp $
 */

# ifdef HAVE_CONFIG_H
#  include "config.h"
# endif

# include <stdlib.h>
# include <string.h>

# include "dstring.h"

/*
 * NAME:	dstring->init()
 * DESCRIPTION:	initialize a new dynamic string
 */
void dstr_init(dstring *string)
{
  string->str     = string->sbuf;
  string->len     = 0;
  string->space   = sizeof(string->sbuf);
  string->sbuf[0] = 0;
}

/*
 * NAME:	dstring->append()
 * DESCRIPTION:	append to a dynamic string
 */
int dstr_append(dstring *string, const char *str, size_t len)
{
  size_t newlen;

  if (len == (size_t) -1)
    len = strlen(str);

  newlen = string->len + len;

  /* make sure there is room */

  if (newlen >= string->space)
    {
      char *new;

      newlen *= 2;

      new = malloc(newlen);
      if (new == 0)
	return -1;

      string->space = newlen;

      memcpy(new, string->str, string->len);

      if (string->str != string->sbuf)
	free(string->str);

      string->str = new;
    }

  /* append the string */

  memcpy(string->str + string->len, str, len);

  string->len += len;
  string->str[string->len] = 0;

  return 0;
}

/*
 * NAME:	dstring->string()
 * DESCRIPTION:	return a pointer to a dynamic string's content
 */
char *dstr_string(dstring *string)
{
  return string->str;
}

/*
 * NAME:	dstring->length()
 * DESCRIPTION:	return the length of a dynamic string
 */
int dstr_length(dstring *string)
{
  return string->len;
}

/*
 * NAME:	dstring->shrink()
 * DESCRIPTION:	truncate a dynamic string to a shorter length
 */
void dstr_shrink(dstring *string, size_t len)
{
  if (len < string->len)
    string->len = len;
}

/*
 * NAME:	dstring->free()
 * DESCRIPTION:	free a dynamic string
 */
void dstr_free(dstring *string)
{
  if (string->str != string->sbuf)
    free(string->str);
}