util.c

操作系统源代码

	      (*root)->balance = 0;
	    }
	}     
	} 
    }
  else
    {
      /* Insert it on the right. */
      if (insert_id_rec (&((*root)->right), new_id))
	{
	  /* The height increased. */
	  (*root)->balance ++;
	  switch ((*root)->balance)
	    {
	    case 0:  /* no height increase. */
	      return (FALSE);
	    case 1:  /* height increase. */
	      return (FALSE);
	    case 2:  /* we need to do a rebalancing act. */
	      A = *root;
	      B = (*root)->right;
	      if (B->balance >= 0)
		{
		  /* Single Rotate. */
		  A->right = B->left;
		  B->left = A;
		  *root = B;
		  A->balance = 0;
		  B->balance = 0;
		}
	      else
		{
		  /* Double Rotate. */
		  *root = B->left;
		  B->left = (*root)->right;
		  A->right = (*root)->left;
		  (*root)->left = A;
		  (*root)->right = B;
		  switch ((*root)->balance)
		    {
		    case -1:
		      A->balance = 0;
		      B->balance = 1;
		      break;
		    case  0:
		      A->balance = 0;
		      B->balance = 0;
		      break;
		    case  1:
		      A->balance = -1;
		      B->balance = 0;
		      break;
		    }
		  (*root)->balance = 0;
		}
	    }     
	} 
    }
  
  /* If we fall through to here, the tree did not grow in height. */
  return (FALSE);
}


/* Initialize variables for the symbol table tree. */

void
init_tree()
{
  name_tree  = NULL;
  next_array = 1;
  next_func  = 1;
  next_var   = 4;  /* 0 => ibase, 1 => obase, 2 => scale, 3 => last. */
}


/* Lookup routines for symbol table names. */

int
lookup (name, namekind)
     char *name;
     int  namekind;
{
  id_rec *id;

  /* Warn about non-standard name. */
  if (strlen(name) != 1)
    warn ("multiple letter name - %s", name);

  /* Look for the id. */
  id = find_id (name_tree, name);
  if (id == NULL)
    {
      /* We need to make a new item. */
      id = (id_rec *) bc_malloc (sizeof (id_rec));
      id->id = strcopyof (name);
      id->a_name = 0;
      id->f_name = 0;
      id->v_name = 0;
      insert_id_rec (&name_tree, id);
    }

  /* Return the correct value. */
  switch (namekind)
    {
      
    case ARRAY:
      /* ARRAY variable numbers are returned as negative numbers. */
      if (id->a_name != 0)
	{
	  free (name);
	  return (-id->a_name);
	}
      id->a_name = next_array++;
      a_names[id->a_name] = name;
      if (id->a_name < MAX_STORE)
	{
	  if (id->a_name >= a_count)
	    more_arrays ();
	  return (-id->a_name);
	}
      yyerror ("Too many array variables");
      exit (1);

    case FUNCT:
      if (id->f_name != 0)
	{
	  free(name);
	  return (id->f_name);
	}
      id->f_name = next_func++;
      f_names[id->f_name] = name;
      if (id->f_name < MAX_STORE)
	{
	  if (id->f_name >= f_count)
	    more_functions ();
	  return (id->f_name);
	}
      yyerror ("Too many functions");
      exit (1);

    case SIMPLE:
      if (id->v_name != 0)
	{
	  free(name);
	  return (id->v_name);
	}
      id->v_name = next_var++;
      v_names[id->v_name - 1] = name;
      if (id->v_name <= MAX_STORE)
	{
	  if (id->v_name >= v_count)
	    more_variables ();
	  return (id->v_name);
	}
      yyerror ("Too many variables");
      exit (1);
    }
}


/* Print the welcome banner. */

void 
welcome()
{
#if !__minix
  printf ("This is free software with ABSOLUTELY NO WARRANTY.\n");
  printf ("For details type `warranty'. \n");
#endif
}


/* Print out the warranty information. */

void 
warranty(prefix)
     char *prefix;
{
  printf ("\n%s%s\n\n", prefix, BC_VERSION);
  printf ("%s%s%s%s%s%s%s%s%s%s%s",
"    This program is free software; you can redistribute it and/or modify\n",
"    it under the terms of the GNU General Public License as published by\n",
"    the Free Software Foundation; either version 2 of the License , or\n",
"    (at your option) any later version.\n\n",
"    This program is distributed in the hope that it will be useful,\n",
"    but WITHOUT ANY WARRANTY; without even the implied warranty of\n",
"    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n",
"    GNU General Public License for more details.\n\n",
"    You should have received a copy of the GNU General Public License\n",
"    along with this program. If not, write to the Free Software\n",
"    Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.\n\n");
}

/* Print out the limits of this program. */

void
limits()
{
  printf ("BC_BASE_MAX     = %d\n",  BC_BASE_MAX);
  printf ("BC_DIM_MAX      = %ld\n", (long) BC_DIM_MAX);
  printf ("BC_SCALE_MAX    = %d\n",  BC_SCALE_MAX);
  printf ("BC_STRING_MAX   = %d\n",  BC_STRING_MAX);
  printf ("MAX Exponent    = %ld\n", (long) LONG_MAX);
  printf ("MAX code        = %ld\n", (long) BC_MAX_SEGS * (long) BC_SEG_SIZE);
  printf ("multiply digits = %ld\n", (long) LONG_MAX / (long) 90);
  printf ("Number of vars  = %ld\n", (long) MAX_STORE);
#ifdef OLD_EQ_OP
  printf ("Old assignment operatiors are valid. (=-, =+, ...)\n");
#endif 
}

/* bc_malloc will check the return value so all other places do not
   have to do it!  SIZE is the number of types to allocate. */

char *
bc_malloc (size)
     int size;
{
  char *ptr;

  ptr = (char *) malloc (size);
  if (ptr == NULL)
    out_of_memory ();

  return ptr;
}


/* The following routines are error routines for various problems. */

/* Malloc could not get enought memory. */

void
out_of_memory()
{
  fprintf (stderr, "Fatal error: Out of memory for malloc.\n");
  exit (1);
}



/* The standard yyerror routine.  Built with variable number of argumnets. */

#ifndef VARARGS
#ifdef __STDC__
void
yyerror (char *str, ...)
#else
void
yyerror (str)
     char *str;
#endif
#else
void
yyerror (str, va_alist)
     char *str;
#endif
{
  char *name;
  va_list args;

#ifndef VARARGS   
   va_start (args, str);
#else
   va_start (args);
#endif
  if (is_std_in)
    name = "(standard_in)";
  else
    name = g_argv[optind-1];
  fprintf (stderr,"%s %d: ",name,line_no);
  vfprintf (stderr, str, args);
  fprintf (stderr, "\n");
  had_error = TRUE;
  va_end (args);
}


/* The routine to produce warnings about non-standard features
   found during parsing. */

#ifndef VARARGS
#ifdef __STDC__
void 
warn (char *mesg, ...)
#else
void
warn (mesg)
     char *mesg;
#endif
#else
void
warn (mesg, va_alist)
     char *mesg;
#endif
{
  char *name;
  va_list args;

#ifndef VARARGS   
  va_start (args, mesg);
#else
  va_start (args);
#endif
  if (std_only)
    {
      if (is_std_in)
	name = "(standard_in)";
      else
	name = g_argv[optind-1];
      fprintf (stderr,"%s %d: ",name,line_no);
      vfprintf (stderr, mesg, args);
      fprintf (stderr, "\n");
      had_error = TRUE;
    }
  else
    if (warn_not_std)
      {
	if (is_std_in)
	  name = "(standard_in)";
	else
	  name = g_argv[optind-1];
	fprintf (stderr,"%s %d: (Warning) ",name,line_no);
	vfprintf (stderr, mesg, args);
	fprintf (stderr, "\n");
      }
  va_end (args);
}

/* Runtime error will  print a message and stop the machine. */

#ifndef VARARGS
#ifdef __STDC__
void
rt_error (char *mesg, ...)
#else
void
rt_error (mesg)
     char *mesg;
#endif
#else
void
rt_error (mesg, va_alist)
     char *mesg;
#endif
{
  va_list args;
  char error_mesg [255];

#ifndef VARARGS   
  va_start (args, mesg);
#else
  va_start (args);
#endif
  vsprintf (error_mesg, mesg, args);
  va_end (args);
  
  fprintf (stderr, "Runtime error (func=%s, adr=%d): %s\n",
	   f_names[pc.pc_func], pc.pc_addr, error_mesg);
  runtime_error = TRUE;
}


/* A runtime warning tells of some action taken by the processor that
   may change the program execution but was not enough of a problem
   to stop the execution. */

#ifndef VARARGS
#ifdef __STDC__
void
rt_warn (char *mesg, ...)
#else
void
rt_warn (mesg)
     char *mesg;
#endif
#else
void
rt_warn (mesg, va_alist)
     char *mesg;
#endif
{
  va_list args;
  char error_mesg [255];

#ifndef VARARGS   
  va_start (args, mesg);
#else
  va_start (args);
#endif
  vsprintf (error_mesg, mesg, args);
  va_end (args);

  fprintf (stderr, "Runtime warning (func=%s, adr=%d): %s\n",
	   f_names[pc.pc_func], pc.pc_addr, error_mesg);
}