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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 "check.h"
#include "node.h"
#include "shape.h"
#include "table.h"
#include "tdf.h"
#include "utility.h"


/*
    BASIC ALIGNMENTS

    These are the basic alignments from the TDF specification.
*/

node *al_code = null ;
node *al_frame =  null ;
node *al_alloca = null ;
node *al_var_param = null ;
node *al_top =  null ;
static node *al_offset = null ;
static node *al_pointer = null ;
static node *al_proc = null ;


/*
    FIND THE ALIGNMENT OF A SHAPE

    For the node p, representing a shape or an alignment, this returns
    the alignment of p.
*/

node *al_shape
    PROTO_N ( ( p ) )
    PROTO_T ( node *p )
{
    node *q ;
    sortname s ;
    if ( p == null ) return ( null ) ;
    s = p->cons->sortnum ;
    if ( s == SORT_alignment ) {
        switch ( p->cons->encoding ) {
            case ENC_alignment : {
                return ( al_shape ( p->son ) ) ;
            }
            case ENC_alignment_apply_token : {
                return ( al_shape ( expand_tok ( p ) ) ) ;
            }
        }
        return ( copy_node ( p ) ) ;
    }
    if ( s == SORT_shape ) {
        switch ( p->cons->encoding ) {
            case ENC_bottom : {
                is_fatal = 0 ;
                input_error ( "Can't have alignment of bottom in %s",
                              checking ) ;
                return ( null ) ;
            }
            case ENC_offset : return ( copy_node ( al_offset ) ) ;
            case ENC_pointer : return ( copy_node ( al_pointer ) ) ;
            case ENC_proc : return ( copy_node ( al_proc ) ) ;
            case ENC_top : return ( copy_node ( al_top ) ) ;
            case ENC_nof : return ( al_shape ( p->son->bro ) ) ;
            case ENC_shape_apply_token : {
                return ( al_shape ( expand_tok ( p ) ) ) ;
            }
        }
    }
    q = new_node () ;
    q->cons = cons_no ( SORT_alignment, ENC_alignment ) ;
    q->son = copy_node ( p ) ;
    return ( null ) ;
}


/*
    FIND WHAT A POINTER POINTS TO

    For the node p of the form ( pointer a ) this routine returns a.
*/

node *ptr_to
    PROTO_N ( ( p ) )
    PROTO_T ( node *p )
{
    p = expand_tok ( p ) ;
    if ( p && p->cons == cons_no ( SORT_shape, ENC_pointer ) ) {
        return ( p->son ) ;
    }
    return ( null ) ;
}


/*
    FIND THE FIRST COMPONENT OF AN OFFSET

    For the node p of the form ( offset a b ) this routine returns a.
*/

node *offset_from
    PROTO_N ( ( p ) )
    PROTO_T ( node *p )
{
    p = expand_tok ( p ) ;
    if ( p && p->cons == cons_no ( SORT_shape, ENC_offset ) ) {
        return ( p->son ) ;
    }
    return ( null ) ;
}


/*
    FIND THE SECOND COMPONENT OF AN OFFSET

    For the node p of the form ( offset a b ) this routine returns b.
*/

node *offset_to
    PROTO_N ( ( p ) )
    PROTO_T ( node *p )
{
    p = expand_tok ( p ) ;
    if ( p && p->cons == cons_no ( SORT_shape, ENC_offset ) ) {
        return ( p->son->bro ) ;
    }
    return ( null ) ;
}


/*
    CHECK THAT TWO ALIGNMENTS ARE EQUAL

    This routine is not yet implemented.
*/

void al_equals
    PROTO_N ( ( p, q ) )
    PROTO_T ( node *p X node *q )
{
    UNUSED ( p ) ;
    UNUSED ( q ) ;
    return ;
}


/*
    CHECK THAT ONE ALIGNMENT CONTAINS ANOTHER

    This routine is not yet implemented.
*/

void al_includes
    PROTO_N ( ( p, q ) )
    PROTO_T ( node *p X node *q )
{
    UNUSED ( p ) ;
    UNUSED ( q ) ;
    return ;
}


/*
    FIND THE UNIONS OF TWO ALIGNMENTS

    The value of ( unite_alignments p q ) is returned.
*/

node *al_union
    PROTO_N ( ( p, q ) )
    PROTO_T ( node *p X node *q )
{
    if ( p == null || p->cons->sortnum != SORT_alignment ) return ( null ) ;
    if ( q == null || q->cons->sortnum != SORT_alignment ) return ( null ) ;
    if ( p->cons->encoding == ENC_alignment &&
         p->son->cons == cons_no ( SORT_shape, ENC_top ) ) return ( q ) ;
    if ( q->cons->encoding == ENC_alignment &&
         q->son->cons == cons_no ( SORT_shape, ENC_top ) ) return ( p ) ;
    return ( null ) ;
}


/*
    INITIALIZE BASIC ALIGNMENTS

    The basic alignments, al_top, al_offset, al_pointer and al_proc, are
    initialized.
*/

void init_alignments
    PROTO_Z ()
{
    /* Set up al_top */
    al_top =  new_node () ;
    al_top->cons = cons_no ( SORT_alignment, ENC_alignment ) ;
    al_top->son = copy_node ( sh_top ) ;

    /* Set up al_offset */
    al_offset =  new_node () ;
    al_offset->cons = cons_no ( SORT_alignment, ENC_alignment ) ;
    al_offset->son = sh_offset ( al_top, al_top ) ;

    /* Set up al_pointer */
    al_pointer =  new_node () ;
    al_pointer->cons = cons_no ( SORT_alignment, ENC_alignment ) ;
    al_pointer->son = sh_pointer ( al_top ) ;

    /* Set up al_proc */
    al_proc =  new_node () ;
    al_proc->cons = cons_no ( SORT_alignment, ENC_alignment ) ;
    al_proc->son = copy_node ( sh_proc ) ;
    return ;
}