db/dbmi_base/token.c

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/*!
   \file db/dbmi_base/token.c
 
   \brief DBMI Library (base) - tokens management
 
   (C) 1999-2009 by the GRASS Development Team
 
   This program is free software under the GNU General Public
   License (>=v2). Read the file COPYING that comes with GRASS
   for details.
 
   \author Joel Jones (CERL/UIUC), Radim Blazek
 */
#include <grass/dbmi.h>
 
/* these routines manage a mapping between tokens (ints) and memory addresses */
#define NONE ((dbAddress)NULL)
 
static dbAddress *list = NONE;
static dbToken count = 0;
 
/*!
   \brief Find token
 
   \param token pointer to dbToken
 
   \return dbAddress
   \return NULL if no token found
 */
dbAddress db_find_token(dbToken token)
{
    if (token >= 0 && token < count)
        return list[token];
    return (NONE);
}
 
/*!
   \brief Drop token
 
   \param token pointer to dbToken
 */
void db_drop_token(dbToken token)
{
    if (token >= 0 && token < count)
        list[token] = NONE;
}
 
/*!
   \brief Add new token
 
   \param address dbAddress of token to be added
 
   \return dbToken
 */
dbToken db_new_token(dbAddress address)
{
    dbToken token;
    dbAddress *p;
 
    for (token = 0; token < count; token++)
        if (list[token] == NONE) {
            list[token] = address;
            return token;
        }
 
    p = (dbAddress *)db_realloc((void *)list, sizeof(*list) * (count + 1));
    if (p == NULL)
        return -1;
 
    list = p;
    token = count++;
    list[token] = address;
    return (token);
}