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/*

 * Copyright (c) 2002-2005 The TenDRA Project <http://www.tendra.org/>.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 * 1. Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 * 3. Neither the name of The TenDRA Project nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific, prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS

 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;

 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF

 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * $Id$

 */

/*

    		 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(void)

{

    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(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(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(hash_table *t, char *nm, int v, 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(hash_table *t, object *p, 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(hash_table *t, char *nm, 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(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);

}