#ifndef SCL_HASH_H
#define SCL_HASH_H

/*
* NIST Utils Class Library
* clutils/scl_hash.h
* April 1997
* David Sauder
* K. C. Morris

* Development of this software was funded by the United States Government,
* and is not subject to copyright.
*/

/************************************************************************
** Hash_Table:    Hash_Table
** Description:
**
** Largely based on code written by ejp@ausmelb.oz
**
** Constants:
**    HASH_TABLE_NULL    - the null Hash_Table
**
************************************************************************/

/*
 * This work was supported by the United States Government, and is
 * not subject to copyright.
 *
 * $Log: scl_hash.h,v $
 * Revision 3.0.1.2  1997/11/05 22:33:49  sauderd
 * Adding a new state DP3.1 and associated revision
 *
 * Revision 3.0.1.1  1997/07/28 19:35:28  sauderd
 * Adding a new state DP3.0.1 and associated revision
 *
 * Revision 3.0.1.0  1997/04/16 19:14:12  dar
 * Setting the first branch
 *
 * Revision 3.0  1997/04/16  19:14:11  dar
 * STEP Class Library Pre Release 3.0
 *
 * Revision 2.2.1.0  1997/09/20  20:59:02  sauderd
 * Setting the first branch
 *
 * Revision 2.2  1997/09/20 20:59:01  sauderd
 * STEP Class Library Pre Release 2.2
 *
 * Revision 2.1.0.1  1997/05/16 14:35:29  lubell
 * setting state to dp21
 *
 * Revision 2.1.0.0  1997/05/12  14:13:33  lubell
 * setting branch
 *
 * Revision 2.1  1997/05/12  14:13:32  lubell
 * changing version to 2.1
 *
 * Revision 2.0.1.2  1997/05/09  20:04:42  lubell
 * Changed the date from 2/94 to 5/95
 *
 * Revision 2.0.1.1  1994/04/05  16:44:11  sauderd
 * Changed the date from 1993 to 1994
 *
 * Revision 2.0.1.0  1994/02/04  21:32:20  sauderd
 * Setting the first branch
 *
 * Revision 2.0  1994/02/04  21:32:18  sauderd
 * STEP Class Library Release 2.0
 *
 * Revision 1.3  1994/09/30  20:58:22  sauderd
 * Administrative stuff for the release.  Added the name of the file, library,
 * the date, contact people, and $id $ for RCS.  Did general cleaning, etc.
 *
 * Revision 1.2  1992/12/15  14:07:52  kc
 * made parameters to HASHfind and HASHinsert const
 *
 * Revision 1.1  1992/10/07  18:37:20  kc
 * Initial revision
 *
 * Revision 1.1  1992/10/06  22:06:30  kc
 * Initial revision
 *
 * Revision 1.1  1992/09/29  15:44:19  libes
 * Initial revision
 *
 * Revision 1.1  1992/08/19  18:49:59  libes
 * Initial revision
 *
 * Revision 1.2  1992/05/31  08:36:48  libes
 * multiple files
 *
 */

#include <scl_export.h>

typedef enum { HASH_FIND, HASH_INSERT, HASH_DELETE } Action;

struct Element {
    char      *      key;
    void      *      data;
    struct Element * next;
    struct Symbol  * symbol;   //for debugging hash conflicts
    char            type;      //user-supplied type
};

struct Hash_Table {
    unsigned int    p;                 // Next bucket to be split
    unsigned int    maxp;              // upper bound on p during expansion
    long            KeyCount;          // current # keys
    unsigned int    SegmentCount;      // current # segments
    unsigned int    MinLoadFactor;
    unsigned int    MaxLoadFactor;
#define DIRECTORY_SIZE        256
#define DIRECTORY_SIZE_SHIFT    8    // log2(DIRECTORY_SIZE)
    struct Element ** Directory[DIRECTORY_SIZE];
};

typedef struct {
    unsigned int i;         // segment index (i think)
    unsigned int j;         // key index in segment (ditto)
    struct Element * p;     // usually the next element to be returned
    struct Hash_Table * table;
    char type;
    struct Element * e;   /* originally thought of as a place for */
    /* the caller of HASHlist to temporarily stash the return value */
    /* to allow the caller (i.e., DICTdo) to be macroized, but now */
    /* conveniently used by HASHlist, which both stores the ultimate */
    /* value here as well as returns it via the return value of HASHlist */
} HashEntry;

#ifdef __cplusplus
extern "C" {
#endif

    SCL_UTILS_EXPORT struct Hash_Table * HASHcreate( unsigned );
    SCL_UTILS_EXPORT void               HASHinitialize( void );
    SCL_UTILS_EXPORT void       *       HASHfind( struct Hash_Table *,  char * );
    SCL_UTILS_EXPORT void               HASHinsert( struct Hash_Table *, char *, void * );
    SCL_UTILS_EXPORT void               HASHdestroy( struct Hash_Table * );
    SCL_UTILS_EXPORT struct Element  *  HASHsearch( struct Hash_Table *, const struct Element *, Action );
    SCL_UTILS_EXPORT void               HASHlistinit( struct Hash_Table *, HashEntry * );
    SCL_UTILS_EXPORT void               HASHlistinit_by_type( struct Hash_Table *, HashEntry *, char );
    SCL_UTILS_EXPORT struct Element  *  HASHlist( HashEntry * );

#ifdef __cplusplus
}
#endif

#endif /* SCL_HASH_H */
