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/*

    		 Crown Copyright (c) 1997

    This TenDRA(r) Computer Program is subject to Copyright

    owned by the United Kingdom Secretary of State for Defence

    acting through the Defence Evaluation and Research Agency

    (DERA).  It is made available to Recipients with a

    royalty-free licence for its use, reproduction, transfer

    to other parties and amendment for any purpose not excluding

    product development provided that any such use et cetera

    shall be deemed to be acceptance of the following conditions:-

        (1) Its Recipients shall ensure that this Notice is

        reproduced upon any copies or amended versions of it;

        (2) Any amended version of it shall be clearly marked to

        show both the nature of and the organisation responsible

        for the relevant amendment or amendments;

        (3) Its onward transfer from a recipient to another

        party shall be deemed to be that party's acceptance of

        these conditions;

        (4) DERA gives no warranty or assurance as to its

        quality or suitability for any purpose and DERA accepts

        no liability whatsoever in relation to any use to which

        it may be put.

*/

#include "config.h"

#include "types.h"

#include "binding.h"

#include "capsule.h"

#include "tdf.h"

#include "tree.h"

#include "utility.h"

/*

    CREATE A NEW OBJECT

    This routine allocates a new object of type v.

*/

object *new_object

    PROTO_N ( ( v ) )

    PROTO_T ( long v )

{

    static object *free_objs = null ;

    static int objs_left = 0 ;

    object *p ;

    if ( objs_left == 0 ) {

	objs_left = 200 ;

	free_objs = alloc_nof ( object, objs_left ) ;

    }

    objs_left-- ;

    p = free_objs + objs_left ;

    p->named = 0 ;

    p->id = ( var_count [v] )++ ;

    p->order = -1 ;

    p->aux = null ;

    if ( v == var_tag ) {

	var ( p ) = 3 ;

    } else if ( v == var_token ) {

	is_foreign ( p ) = 0 ;

	res_sort ( p ) = sort_unknown ;

	implicit_sort ( p ) = sort_unknown ;

	arg_sorts ( p ) = null ;

    }

    return ( p ) ;

}

/*

    SPARE BINDING TABLE

    In fact only two binding tables are ever needed.  The one not in use

    is stored in spare_bt.

*/

static binding *spare_bt = null ;

/*

    CREATE A NEW BINDING TABLE

    This routine allocates a new binding table and initializes its entries.

*/

binding *new_binding_table

    PROTO_Z ()

{

    binding *bt ;

    long i, n = no_variables ;

    if ( n == 0 ) return ( null ) ;

    if ( spare_bt ) {

	bt = spare_bt ;

	spare_bt = null ;

	for ( i = 0 ; i < n ; i++ ) {

	    bt [i].max_no = 0 ;

	}

    } else {

	bt = alloc_nof ( binding, n ) ;

	for ( i = 0 ; i < n ; i++ ) {

	    bt [i].max_no = 0 ;

	    bt [i].sz = 0 ;

	    bt [i].table = null ;

	}

    }

    return ( bt ) ;

}

/*

    FREE A BINDING

    The binding bt is returned to free.

*/

void free_binding_table

    PROTO_N ( ( bt ) )

    PROTO_T ( binding *bt )

{

    spare_bt = bt ;

    return ;

}

/*

    SET THE SIZE OF A BINDING

    The vth entry of bt is set to size n.

*/

void set_binding_size

    PROTO_N ( ( bt, v, n ) )

    PROTO_T ( binding *bt X long v X long n )

{

    object **p ;

    binding *b ;

    long i, m = n + 10 ;

    if ( v < 0 || v >= no_variables ) {

	input_error ( "Illegal binding sort" ) ;

	return ;

    }

    b = bt + v ;

    b->max_no = n ;

    if ( b->sz < m ) {

	p = realloc_nof ( b->table, object *, m ) ;

	b->sz = m ;

	b->table = p ;

    } else {

	p = b->table ;

    }

    for ( i = 0 ; i < b->sz ; i++ ) p [i] = null ;

    return ;

}

/*

    SET AN ENTRY IN A BINDING

    The nth entry of the vth entry of the binding bt is set to p.

*/

void set_binding

    PROTO_N ( ( bt, v, n, p ) )

    PROTO_T ( binding *bt X long v X long n X object *p )

{

    binding *b ;

    if ( v < 0 || v >= no_variables ) {

	input_error ( "Illegal binding sort" ) ;

	return ;

    }

    b = bt + v ;

    if ( n >= b->max_no || n < 0 ) {

	out ( "<error>" ) ;

	input_error ( "Object number %ld (%s) too big", n, var_types [v] ) ;

	while ( n >= b->sz ) {

	    /* Table is extended (errors only) */

	    long i, m = b->sz + 100 ;

	    b->sz = m ;

	    b->table = realloc_nof ( b->table, object *, m ) ;

	    for ( i = 1 ; i <= 100 ; i++ ) b->table [ m - i ] = null ;

	}

    }

    if ( b->table [n] ) {

	input_error ( "Object %s (%s) already bound", object_name ( v, n ),

		      var_types [v] ) ;

    }

    b->table [n] = p ;

    return ;

}

/*

    FILL IN BLANK ENTRIES IN A BINDING

    Objects are allocated for all the entries in the binding bt which

    are not associated with an existing object.

*/

void complete_binding

    PROTO_N ( ( bt ) )

    PROTO_T ( binding *bt )

{

    long v ;

    for ( v = 0 ; v < no_variables ; v++ ) {

	long i ;

	binding *b = bt + v ;

	for ( i = 0 ; i < b->max_no ; i++ ) {

	    if ( b->table [i] == null ) {

		b->table [i] = new_object ( v ) ;

	    }

	}

    }

    return ;

}

/*

    FIND AN ENTRY IN A BINDING

    The nth entry of the vth entry of binding bt is returned.

*/

object *find_binding

    PROTO_N ( ( bt, v, n ) )

    PROTO_T ( binding *bt X long v X long n )

{

    binding *b ;

    if ( v < 0 || v >= no_variables ) {

	input_error ( "Illegal binding sort" ) ;

	return ( null ) ;

    }

    b = bt + v ;

    if ( n >= b->max_no || n < 0 ) {

	out ( "<error>" ) ;

	input_error ( "Object number %ld (%s) too big", n, var_types [v] ) ;

    }

    if ( n >= b->sz ) return ( null ) ;

    return ( b->table [n] ) ;

}

/*

    OUTPUT AN OBJECT

    The object p of type v and number n is output.

*/

void out_object

    PROTO_N ( ( n, p, v ) )

    PROTO_T ( long n X object *p X long v )

{

    if ( v < 0 || v >= no_variables ) {

	out ( "<error>" ) ;

	input_error ( "Illegal binding sort" ) ;

	return ;

    }

    if ( dumb_mode ) {

	word *w ;

	out_string ( var_types [v] ) ;

	w = new_word ( HORIZ_BRACKETS ) ;

	out_int ( n ) ;

	end_word ( w ) ;

	return ;

    }

    if ( p == null ) {

	p = find_binding ( crt_binding, v, n ) ;

	if ( p == null ) {

	    p = new_object ( v ) ;

	    set_binding ( crt_binding, v, n, p ) ;

	}

    }

    if ( p->named ) {

	if ( p->name.simple ) {

	    out ( p->name.val.str ) ;

	} else {

	    out_unique ( p->name.val.uniq ) ;

	}

	return ;

    }

    out_char ( '~' ) ;

    out_string ( var_types [v] ) ;

    out_char ( '_' ) ;

    out_int ( p->id ) ;

    return ;

}

/*

    RETURN AN OBJECT NAME (FOR ERROR REPORTING)

    The name of object type v and number n is returned.

*/

char *object_name

    PROTO_N ( ( v, n ) )

    PROTO_T ( long v X long n )

{

    object *p ;

    char *buff = alloc_nof ( char, 1000 ) ;

    if ( dumb_mode ) {

	IGNORE sprintf ( buff, "%ld", n ) ;

	return ( buff ) ;

    }

    p = find_binding ( crt_binding, v, n ) ;

    if ( p->named ) {

	if ( p->name.simple ) {

	    IGNORE sprintf ( buff, "%s", p->name.val.str ) ;

	} else {

	    IGNORE sprintf ( buff, "unique(%ld)", p->id ) ;

	}

    } else {

	IGNORE sprintf ( buff, "%ld", p->id ) ;

    }

    return ( buff ) ;

}