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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 "object.h"

#include "hash.h"

#include "type.h"

#include "utility.h"

/*

    STANDARD HASH TABLES

    These hash tables represent the various namespaces permitted in C

    plus the TDF token namespace.

*/

hash_table *exps ;

hash_table *files ;

hash_table *keywords ;

hash_table *subsets ;

hash_table *tags ;

hash_table *tag_fields ;

hash_table *tokens ;

hash_table *types ;

hash_table *type_fields ;

/*

    INITIALISATION ROUTINE

    This routine initialises the standard hash tables and sets a few

    miscellaneous variables.

*/

void init_hash

    PROTO_Z ()

{

    buffer = alloc_nof ( char, buffsize + 100 ) ;

    exps = make_hash_table ( "Expression" ) ;

    files = make_hash_table ( "Output file" ) ;

    keywords = make_hash_table ( "Keyword" ) ;

    subsets = make_hash_table ( "Set" ) ;

    tags = make_hash_table ( "Tag" ) ;

    tag_fields = make_hash_table ( "Field selector struct/union" ) ;

    tokens = make_hash_table ( "Token" ) ;

    types = make_hash_table ( "Type" ) ;

    type_fields = make_hash_table ( "Field selector" ) ;

    return ;

}

/*

    HASHING ROUTINE

    This routine finds the hash value of the string nm.  This value must

    lie in the range [ 0, hash_size ).

*/

static int hash

    PROTO_N ( ( nm ) )

    PROTO_T ( char *nm )

{

    char *s ;

    int n = 0 ;

    for ( s = nm ; *s ; s++ ) n += *s ;

    return ( n % hash_size ) ;

}

/*

    CREATE A NEW HASH TABLE

    This routine creates a new hash table called nm.

*/

hash_table *make_hash_table

    PROTO_N ( ( nm ) )

    PROTO_T ( char *nm )

{

    int i ;

    hash_table *t = alloc_nof ( hash_table, 1 ) ;

    t->name = nm ;

    for ( i = 0 ; i < hash_size ; i++ ) t->array [i] = null ;

    return ( t ) ;

}

/*

    LOOK UP A NAME IN A HASH TABLE

    This routine looks up the object nm (version v) in the hth column

    of hash table t.  It returns the object if it is found, or null

    otherwise.

*/

static object *lookup_hash

    PROTO_N ( ( t, nm, v, h ) )

    PROTO_T ( hash_table *t X char *nm X int v X int h )

{

    hash_elem *e = t->array [h] ;

    while ( e ) {

	if ( streq ( nm, e->obj->name ) ) {

	    if ( v == e->vers || v == any_version ) return ( e->obj ) ;

	}

	e = e->next ;

    }

    return ( null ) ;

}

/*

    ADD AN OBJECT TO A HASH TABLE

    This routine adds the object p (version v) to the hash table t,

    reporting an error and returning the old value if it is already

    defined.  Otherwise it returns p.

*/

object *add_hash

    PROTO_N ( ( t, p, v ) )

    PROTO_T ( hash_table *t X object *p X int v )

{

    hash_elem *e ;

    char *nm = p->name ;

    int h = hash ( nm ) ;

    object *q = lookup_hash ( t, nm, v, h ) ;

    if ( q != null ) {

	char *fn = q->filename ;

	if ( fn ) {

	    char *err = "%s '%s' already defined (%s, line %d)" ;

	    error ( ERR_SERIOUS, err, t->name, nm, fn, q->line_no ) ;

	} else {

	    error ( ERR_SERIOUS, "%s '%s' already defined", t->name, nm ) ;

	}

	return ( q ) ;

    }

    alloc_variable ( e, hash_elem, 1000 ) ;

    e->obj = p ;

    e->vers = v ;

    e->next = t->array [h] ;

    t->array [h] = e ;

    return ( p ) ;

}

/*

    SEARCH A HASH TABLE FOR AN OBJECT

    This routine searches the hash table t for the object named nm

    (version v), returning it if it is found.  If it is not found then

    null is returned.

*/

object *search_hash

    PROTO_N ( ( t, nm, v ) )

    PROTO_T ( hash_table *t X char *nm X int v )

{

    int h = hash ( nm ) ;

    return ( lookup_hash ( t, nm, v, h ) ) ;

}

/*

    SORT THE ELEMENTS OF A HASH LIST

    This routine sorts the elements of the hash table t into a single

    alphabetical list.  The table cannot be used subsequently.

*/

hash_elem *sort_hash

    PROTO_N ( ( t ) )

    PROTO_T ( hash_table *t )

{

    int i ;

    hash_elem *r = null ;

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

	hash_elem *p = t->array [i]  ;

	while ( p ) {

	    hash_elem *pn = p->next ;

	    hash_elem *q = r, *s = null ;

	    while ( q ) {

		if ( strcmp ( p->obj->name, q->obj->name ) <= 0 ) break ;

		s = q ;

		q = q->next ;

	    }

	    if ( s == null ) {

		p->next = r ;

		r = p ;

	    } else {

		p->next = s->next ;

		s->next = p ;

	    }

	    p = pn ;

	}

    }

    return ( r ) ;

}