erl_marshal.c

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      }
      else { /* list: 5 + len(elem1) + len(elem2) ... */
	for (len = 5; ERL_TYPE(ep) == ERL_LIST; ep =  TAIL(ep)) {
	  len += erl_term_len_helper(HEAD(ep), dist);
	}
	len += erl_term_len_helper(ep, dist); /* last element */
      }
      break;

    case ERL_TUPLE:
      /* (2 or 5) + len(elem1) + len(elem2) ... */
      i = ep->uval.tval.size;
      if (i <= 0xff) len = 2;
      else len = 5;
      
      for (i=0; i<ep->uval.tval.size; i++) {
	len += erl_term_len_helper(ep->uval.tval.elems[i], dist);
      }
      break;

    case ERL_FLOAT:
      len = 32;
      break;

    case ERL_BINARY:
      i = ep->uval.bval.size;
      len = 5 + i;
      break;

    case ERL_FUNCTION:
      if (ERL_FUN_ARITY(ep) == -1) {
	  len = 1 + 4;
	  len += erl_term_len_helper(ERL_FUN_CREATOR(ep),dist);
	  len += erl_term_len_helper(ERL_FUN_MODULE(ep),dist);
	  len += erl_term_len_helper(ERL_FUN_INDEX(ep),dist);
	  len += erl_term_len_helper(ERL_FUN_UNIQ(ep),dist);
	  for (i = 0; i < ERL_CLOSURE_SIZE(ep); i++)
	      len += erl_term_len_helper(ERL_CLOSURE_ELEMENT(ep,i), dist);
      } else {
	  len = 1 + 4 + 16 + 4 + 4;
	  len += erl_term_len_helper(ERL_FUN_MODULE(ep),dist);
	  len += erl_term_len_helper(ERL_FUN_INDEX(ep),dist);
	  len += erl_term_len_helper(ERL_FUN_UNIQ(ep),dist);
	  len += erl_term_len_helper(ERL_FUN_CREATOR(ep),dist);
	  for (i = 0; i < ERL_CLOSURE_SIZE(ep); i++)
	      len += erl_term_len_helper(ERL_CLOSURE_ELEMENT(ep,i), dist);
      }
      break;

    default:
#ifdef DEBUG
	fprintf(stderr, "Shouldn't happen: erl_term_len, unknown term type: '%c'\n",ERL_TYPE(ep));
#endif
      erl_errno = EINVAL;
      exit(1);
    }
  }

  return len;
}

/* 
 * This one makes it easy to ENCODE several CONSECUTIVE
 * ETERM's into the same buffer. 
 */
int erl_encode_buf(ETERM *ep, unsigned char **ext)
{
  unsigned char *start=*ext;
  
  *(*ext)++ = ERL_VERSION_MAGIC;
  if (erl_encode_it(ep, ext, 0)) {
#ifdef DEBUG
    erl_err_msg("<ERROR> erl_encode_buf: Error while encoding\n");
#endif
    return 0;
  }
  return (*ext - start);

} /* erl_encode_buf */

/*
 * A nice macro to make it look cleaner in the 
 * cases of PID's,PORT's and REF's below. 
 * It reads the NODE name from a buffer.
 */
#define READ_THE_NODE(ext,cp,len,i) \
/* eat first atom, repr. the node */ \
if (**ext != ERL_ATOM_EXT) \
  return (ETERM *) NULL; \
*ext += 1; \
i = (**ext << 8) | (*ext)[1]; \
cp = (char *) *(ext) + 2; \
*ext += (i + 2); \
len = i

#define STATIC_NODE_BUF_SZ 30

#define SET_NODE(node,node_buf,cp,len) \
if (len >= STATIC_NODE_BUF_SZ) node = malloc(len+1); \
else node = node_buf; \
memcpy(node, cp, len); \
node[len] = '\0'

#define RESET_NODE(node,len) \
if (len >= STATIC_NODE_BUF_SZ) free(node)

/*
 * The actual DECODE engine.
 * Returns NULL in case of failure.
 */
static ETERM *erl_decode_it(unsigned char **ext)
{
    char *cp;
    ETERM *ep,*tp,*np;
    unsigned int u,sign;
    int i,j,len,arity;
    double ff;
    
    /* Assume we are going to decode an integer */
    ep = erl_alloc_eterm(ERL_INTEGER);
    ERL_COUNT(ep) = 1;
    
    switch (*(*ext)++) 
    {
    case ERL_INTEGER_EXT:
	i = (int) (**ext << 24) | ((*ext)[1] << 16) |
	    ((*ext)[2] << 8) | (*ext)[3];
	*ext += 4;
	ep->uval.ival.i = i;
	return ep;

    case ERL_SMALL_INTEGER_EXT:
	i = *(*ext)++;
	ep->uval.ival.i = i;
	return ep;

        /* NOTE: The arity below for bigs is not really the arity (= number of digits) */
        /*       It is the byte count and this might cause problems in other parts...  */
    case ERL_SMALL_BIG_EXT:
        arity = *(*ext)++; 
	goto big_cont;
    case ERL_LARGE_BIG_EXT:
	arity = (**ext << 24) | ((*ext)[1])<< 16 | 
	    ((*ext)[2]) << 8 |((*ext)[3]); 
	*ext += 4;
    big_cont:
	sign = *(*ext)++; 
	if (arity != 4)             
	    goto big_truncate;
	if ((*ext)[3] & 0x80) { 
	    /* MSB already occupied ! */
	    if (sign)
		goto big_truncate;
	    else {                
		/* It will fit into an unsigned int !! */
		u = (((*ext)[3] << 24)|((*ext)[2])<< 16|((*ext)[1]) << 8 |(**ext));
		ERL_TYPE(ep) = ERL_U_INTEGER;
		ep->uval.uival.u = u;
		/* *ext += i; */
		*ext += arity;
		return ep;
	    }
	}
	else {       
	    /* It will fit into an int !! 
	     * Note: It comes in "one's-complement notation" 
	     */
	    if (sign)
		i = (int) (~(((*ext)[3] << 24) | ((*ext)[2])<< 16 |
			     ((*ext)[1]) << 8 | (**ext)) | (unsigned int) sign);
	    else
		i = (int) (((*ext)[3] << 24) | ((*ext)[2])<< 16 |
			   ((*ext)[1]) << 8 | (**ext));
	    ep->uval.ival.i = i;
	    *ext += arity;
	    return ep;
	}
    big_truncate: 
	/* truncate to: (+/-) 1 */
#ifdef DEBUG
	erl_err_msg("<WARNING> erl_decode_it: Integer truncated...");
#endif
	ep->uval.ival.i = sign?-1:1;
	*ext += arity;
	return ep;
      
    case ERL_ATOM_EXT:
	ERL_TYPE(ep) = ERL_ATOM;
	i = (**ext << 8) | (*ext)[1];
	cp = (char *) *(ext) + 2;
	*ext += (i + 2);
	ep->uval.aval.len = i;
	ep->uval.aval.a = (char *) erl_malloc(i+1);
	memcpy(ep->uval.aval.a, cp, i);
	ep->uval.aval.a[i]='\0';
	return ep;
      
    case ERL_PID_EXT:
	erl_free_term(ep);
	{			/* Why not use the constructors? */
	    char *node;
	    char node_buf[STATIC_NODE_BUF_SZ];
	    unsigned int number, serial;
	    unsigned char creation;
	    ETERM *eterm_p;

	    READ_THE_NODE(ext,cp,len,i);
	    SET_NODE(node,node_buf,cp,len);

	    /* get the integers */
#if 0
	    /* FIXME: Remove code or whatever....
               Ints on the wire are big-endian (== network byte order)
               so use ntoh[sl]. (But some are little-endian! Arrrgh!)
               Also, the libc authors can be expected to optimize them
               heavily. However, the marshalling makes no guarantees
               about alignments -- so it won't work at all. */
	    number = ntohl(*((unsigned int *)*ext)++);
	    serial = ntohl(*((unsigned int *)*ext)++);
#else
	    number = ((*ext)[0] << 24) | ((*ext)[1]) << 16 | 
		((*ext)[2]) << 8 | ((*ext)[3]);	
	    *ext += 4;
	    serial = ((*ext)[0] << 24) | ((*ext)[1]) << 16 | 
		((*ext)[2]) << 8 | ((*ext)[3]);	
	    *ext += 4;
#endif
	    creation =  *(*ext)++; 
	    eterm_p = erl_mk_pid(node, number, serial, creation);
	    RESET_NODE(node,len);
	    return eterm_p;
	}
    case ERL_REFERENCE_EXT:
	erl_free_term(ep);
	{
	    char *node;
	    char node_buf[STATIC_NODE_BUF_SZ];
	    unsigned int number;
	    unsigned char creation;
	    ETERM *eterm_p;

	    READ_THE_NODE(ext,cp,len,i);
	    SET_NODE(node,node_buf,cp,len);

	    /* get the integers */
#if 0
	    number = ntohl(*((unsigned int *)*ext)++);
#else
	    number = ((*ext)[0] << 24) | ((*ext)[1]) << 16 | 
		((*ext)[2]) << 8 | ((*ext)[3]);	
	    *ext += 4;
#endif
	    creation =  *(*ext)++; 
	    eterm_p = erl_mk_ref(node, number, creation);
	    RESET_NODE(node,len);
	    return eterm_p;
	}

    case ERL_NEW_REFERENCE_EXT: 
	erl_free_term(ep);
	{
	    char *node;
	    char node_buf[STATIC_NODE_BUF_SZ];
	    size_t cnt, i;
	    unsigned int n[3];
	    unsigned char creation;
	    ETERM *eterm_p;

#if 0
	    cnt = ntohs(*((unsigned short *)*ext)++);
#else
	    cnt = ((*ext)[0] << 8) | (*ext)[1];
	    *ext += 2;
#endif

	    READ_THE_NODE(ext,cp,len,i);
	    SET_NODE(node,node_buf,cp,len);

	    /* get the integers */
	    creation =  *(*ext)++; 
	    for(i = 0; i < cnt; i++)
	    {
#if 0
		n[i] = ntohl(*((unsigned int *)*ext)++);
#else
		n[i] = ((*ext)[0] << 24) | ((*ext)[1]) << 16 | 
		    ((*ext)[2]) << 8 | ((*ext)[3]);	
		*ext += 4;
#endif
	    }
	    eterm_p = __erl_mk_reference(node, cnt, n, creation);
	    RESET_NODE(node,len);
	    return eterm_p;
	}

    case ERL_PORT_EXT:
	erl_free_term(ep);
	{
	    char *node;
	    char node_buf[STATIC_NODE_BUF_SZ];
	    unsigned int number;
	    unsigned char creation;
	    ETERM *eterm_p;

	    READ_THE_NODE(ext,cp,len,i);
	    SET_NODE(node,node_buf,cp,len);

	    /* get the integers */
#if 0
	    number = ntohl(*((unsigned int *)*ext)++);
#else
	    number = ((*ext)[0] << 24) | ((*ext)[1]) << 16 | 
		((*ext)[2]) << 8 | ((*ext)[3]);	
	    *ext += 4;
#endif
	    creation =  *(*ext)++; 
	    eterm_p = erl_mk_port(node, number, creation);
	    RESET_NODE(node,len);
	    return eterm_p;
	}

    case ERL_NIL_EXT:
	ERL_TYPE(ep) = ERL_EMPTY_LIST;
	return ep;

    case ERL_LIST_EXT:
	ERL_TYPE(ep) = ERL_LIST;
	i = (**ext << 24) | ((*ext)[1] << 16) |((*ext)[2] << 8) | (*ext)[3];
	*ext += 4;	
	/* ASSERT(i != 0);	*/	/* Should be represented by ERL_NIL_EXT. */
	tp = ep;
	for (j = 0; j < i; j++) 
	    if ((HEAD(tp) = erl_decode_it(ext)) == NULL) 
		goto failure;
	    else if (j + 1 < i) {
		/* We have to watch out for how we allocates the
		 * last tail element since we may encounter non-
		 * well formed lists.
		 */
		np = erl_alloc_eterm(ERL_LIST);
		ERL_COUNT(np) = 1;
		TAIL(tp) = np;
		tp = np;
	    }
	if ((TAIL(tp) = erl_decode_it(ext)) == NULL) 
	    goto failure;
	return ep;

    case ERL_STRING_EXT:
	{
	    unsigned char* s;
	  
	    ERL_TYPE(ep) = ERL_EMPTY_LIST;
	    i = (**ext << 8) | ((*ext)[1]);
	    *ext += 2;
	    s = *ext+i;

	    while (*ext < s) {
		ETERM* integer;
		ETERM* cons;

		integer = erl_alloc_eterm(ERL_INTEGER);
		ERL_COUNT(integer) = 1;
		integer->uval.ival.i = *--s;

		cons = erl_alloc_eterm(ERL_LIST);
		ERL_COUNT(cons) = 1;
		HEAD(cons) = integer;
		TAIL(cons) = ep;
		ep = cons;
	    }
	    *ext += i;
	    return ep;
	}

    case ERL_SMALL_TUPLE_EXT:
	ERL_TYPE(ep) = ERL_TUPLE;
	i = *(*ext)++;
	goto decode_tuple;

    case ERL_LARGE_TUPLE_EXT:
	i = (**ext << 24) | ((*ext)[1]) << 16 | 
	    ((*ext)[2]) << 8 | ((*ext)[3]) ;	
	*ext += 4;
    decode_tuple:
	ep->uval.tval.size = i;
	j = (i + 1) * sizeof(ETERM*);
	ep->uval.tval.elems = (ETERM**) erl_malloc(j);
	memset(ep->uval.tval.elems, 0, j); /* in case of failure below... */
	for (i=0; i<ep->uval.tval.size; i++)
	    if ((tp = erl_decode_it(ext)) == NULL)
		goto failure;
	    else
		ep->uval.tval.elems[i] = tp;
	return ep;

    case ERL_FLOAT_EXT:
	ERL_TYPE(ep) = ERL_FLOAT;
	if (sscanf((char *) *ext, "%lf", &ff) != 1)
	    goto failure;
	*ext += 31;
	ep->uval.fval.f = ff;
	return ep;

    case ERL_BINARY_EXT:
	ERL_TYPE(ep) = ERL_BINARY;
	i = (**ext << 24) | ((*ext)[1] << 16) |
	    ((*ext)[2] << 8) | (*ext)[3];
	*ext += 4;
	ep->uval.bval.size = i;
	ep->uval.bval.b = (unsigned char *) erl_malloc(i);
	memcpy(ep->uval.bval.b, *ext, i);
	*ext += i;
	return ep;

    case ERL_FUN_EXT:		/* FIXME: error checking */
	ERL_TYPE(ep) = ERL_FUNCTION;
	i = get32be(*ext);
	/*i = *(**ext << 24) | ((*ext)[1] << 16) | ((*ext)[2] << 8) | (*ext)[3];
	 *ext += 4; */
	ERL_FUN_ARITY(ep) = -1;
	ERL_CLOSURE_SIZE(ep) = i;
	ERL_FUN_CREATOR(ep) = erl_decode_it(ext);
	ERL_FUN_MODULE(ep) = erl_decode_it(ext);
	ERL_FUN_INDEX(ep) = erl_decode_it(ext);
	ERL_FUN_UNIQ(ep) = erl_decode_it(ext);
	j = i * sizeof(ETERM*);
	ERL_CLOSURE(ep) = (ETERM**) erl_malloc(j);
	memset(ERL_CLOSURE(ep), 0, j);
	for (i = 0; i < ERL_CLOSURE_SIZE(ep); i++)
	    ERL_CLOSURE_ELEMENT(ep,i) = erl_decode_it(ext);
	return ep;

    case ERL_NEW_FUN_EXT:	/* FIXME: error checking */
	ERL_TYPE(ep) = ERL_FUNCTION;
	i = get32be(*ext);	/* size, we don't use it here */
	ERL_FUN_ARITY(ep) = get8(*ext);
	memcpy(ERL_FUN_MD5(ep), *ext, 16);
	*ext += 16;
	ERL_FUN_NEW_INDEX(ep) = get32be(*ext);
	i = get32be(*ext);
	ERL_CLOSURE_SIZE(ep) = i;
	ERL_FUN_MODULE(ep) = erl_decode_it(ext);
	ERL_FUN_INDEX(ep) = erl_decode_it(ext);
	ERL_FUN_UNIQ(ep) = erl_decode_it(ext);
	ERL_FUN_CREATOR(ep) = erl_decode_it(ext);
	j = i * sizeof(ETERM*);
	ERL_CLOSURE(ep) = (ETERM**) erl_malloc(j);
	memset(ERL_CLOSURE(ep), 0, j);
	for (i = 0; i < ERL_CLOSURE_SIZE(ep); i++)
	    ERL_CLOSURE_ELEMENT(ep,i) = erl_decode_it(ext);
	return ep;

    } /* switch */
    
 failure:
    erl_free_term(ep);
    return (ETERM *) NULL;
    
} /* erl_decode_it */

/*
 * DECODE a buffer of BYTES into an ETERM.
 * Returns NULL in case of failure.
 */
ETERM *erl_decode(unsigned char *t) 
{
  ETERM *ep;
  unsigned char *ext;

  ext = t;

  /* We ignore the version magic since it might be
   * possible that the buffer has been manipulated
   * with erl_peek_ext.
   */
  if (*ext == ERL_VERSION_MAGIC) 
    ext++;  

  ep = NULL;
  ep = erl_decode_it(&ext);