/* $Header: /CVSROOT/debris/drisbuf.h,v 1.4 2005/08/15 01:04:52 tino Exp $
 *
 * DebRIS: DEBian Remote Install Scripter
 * Data buffers
 *
 * $Log: drisbuf.h,v $
 * Revision 1.4  2005/08/15 01:04:52  tino
 * all functions now have a prefix (dris_)
 *
 * Revision 1.3  2005/07/25 03:12:36  tino
 * added dris_buf_printf
 *
 * Revision 1.2  2005/07/24 22:14:27  tino
 * added dris_buf_pull
 *
 * Revision 1.1  2005/06/01 02:12:34  tino
 * first version.  As SirbeD is missing, this just does nothing yet.
 */

struct dris_buf
  {
    size_t	len, max;
    char	*buf;
  };

static void *
alloc(void *ptr, size_t len)
{
  void	*tmp;

  if ((tmp=(ptr ? realloc(ptr, len) : malloc(len)))==0)
    dris_ex("out of memory");
  return tmp;
}

static struct dris_buf *
dris_buf_extend(struct dris_buf *buf, size_t len)
{
  buf->buf		= alloc(buf->buf, (buf->max=buf->len+len)+1);
  buf->buf[buf->len]	= 0;
  return buf;
}

static struct dris_buf *
dris_buf_printf(struct dris_buf *buf, const char *s, va_list list)
{
  size_t	n;

  for (n=BUFSIZ;; n+=BUFSIZ)
    {
      int	k;

      dris_buf_extend(buf, n);
      k	= vsnprintf(buf->buf+buf->len, buf->max-buf->len+1, s, list);
      if (k>=0 && k<n)
	{
	  buf->len	+= k;
	  return buf;
	}
    }
}

static struct dris_buf *
dris_buf_new(void)
{
  struct dris_buf	*tmp;

  tmp		= alloc(NULL, sizeof *tmp);
  tmp->len	= 0;
  tmp->max	= 0;
  tmp->buf	= 0;
  return dris_buf_extend(tmp, BUFSIZ);
}

static struct dris_buf *
dris_buf_add(struct dris_buf *buf, const void *ptr, size_t len)
{
  buf	= dris_buf_extend(buf, len);
  memcpy(buf->buf+buf->len, ptr, len);
  buf->len		+= len;
  buf->buf[buf->len]	= 0;
  return buf;
}

static struct dris_buf *
dris_buf_add_s(struct dris_buf *buf, const char *s)
{
  return dris_buf_add(buf, s, strlen(s));
}

static struct dris_buf *
dris_buf_reset(struct dris_buf *buf)
{
  buf->len	= 0;
  buf->buf[0]	= 0;
  return buf;
}

static struct dris_buf *
dris_buf_pull(struct dris_buf *buf, int n)
{
  if (n>=buf->len)
    return dris_buf_reset(buf);
  memmove(buf->buf, buf->buf+n, buf->len-=n);
  buf->buf[buf->len]	= 0;
  return buf;
}