/*
========================================================================
  bisl_sym - symbol-table handling for BISL compiler.  Uses Plank's 
             rb-tree library.

  Global routines:

    add_cstr  - add named constraint to the symbol-table
    add_tupl  - add named tuple to the symbol-table
    find_cstr - find named constraint in table
    find_tupl - find named tupl in table
    init_syms - initialize symbol-table

  Copyright 1996     Micah Beck / Simon D. Levy  University of Tennessee
  All distributions of this product must include source code.  Source 
  code is not to be distributed in any modified form.
========================================================================
*/

#include "bisl.h"
#include "rb.h"		/* red-black tree for symbol table */

static Rb_node m_etab,	/* root of constraint symbol table */
               m_ttab;	/* root of tuple symbol table */


/*
------------------------------------------------------------------------
  kill_insert - destructively insert item in table using name-key
------------------------------------------------------------------------
*/

static void kill_insert( Rb_node tab, char *name, char *ptr)
{
  int fnd;
  Rb_node n = rb_find_key_n(tab, name, &fnd);

  if (fnd)					
    rb_delete_node(n);

  rb_insert(tab, name, ptr);

} /* kill_insert */


/*
------------------------------------------------------------------------
  add_cstr - add named constraint to the symbol-table
------------------------------------------------------------------------
*/

void add_cstr(char *name, CSTR *cstr)
{
  kill_insert(m_etab, name, (char *)cstr);	/* insert in tree */
  cstr->name = name;				/* store name */

} /* add_cstr */



/*
------------------------------------------------------------------------
  add_tupl - add named tuple to the symbol-table
------------------------------------------------------------------------
*/

void add_tupl(char *name, TUPL *tupl)
{
  kill_insert(m_ttab, name, (char *)tupl);	/* insert in tree */

} /* add_tupl */


/*
------------------------------------------------------------------------
  find_cstr - find named constraint in table, and return it a pointer to
              it, or zero if not found
------------------------------------------------------------------------
*/

CSTR *find_cstr(char *name)
{
  int fnd;
  Rb_node n = rb_find_key_n(m_etab, name, &fnd);

  if (fnd)					
    return (CSTR *)n->v.val;
  else 					
    return 0;


} /* find_cstr */


/*
------------------------------------------------------------------------
  find_tupl - find named tupl in table, and return a pointer to
              it, or zero if not found
------------------------------------------------------------------------
*/

TUPL *find_tupl(char *name)
{
  int fnd;
  Rb_node n = rb_find_key_n(m_ttab, name, &fnd);

  if (fnd)					
    return (TUPL *)n->v.val;
  else 					
    return 0;


} /* find_tupl */


/*
------------------------------------------------------------------------
  init_syms - initialize symbol-table
------------------------------------------------------------------------
*/

void init_syms(void)
{
  m_etab = make_rb();
  m_ttab = make_rb();

} /* init_syms */