usr/src/usr.bin/make/hash.h

/*
 * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
 * Copyright (c) 1988, 1989 by Adam de Boor
 * Copyright (c) 1989 by Berkeley Softworks
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam de Boor.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)hash.h      5.4 (Berkeley) %G%
 */

/* hash.h --
 *
 *      This file contains definitions used by the hash module,
 *      which maintains hash tables.
 */

#ifndef _HASH
#define _HASH

/*
 * The following defines one entry in the hash table.
 */

typedef struct Hash_Entry {
    struct Hash_Entry *next;            /* Used to link together all the
                                         * entries associated with the same
                                         * bucket. */
    ClientData        clientData;       /* Arbitrary piece of data associated
                                         * with key. */
    unsigned          namehash;         /* hash value of key */
    char              name[1];          /* key string */
} Hash_Entry;

typedef struct Hash_Table {
    struct Hash_Entry **bucketPtr;/* Pointers to Hash_Entry, one
                                 * for each bucket in the table. */
    int         size;           /* Actual size of array. */
    int         numEntries;     /* Number of entries in the table. */
    int         mask;           /* Used to select bits for hashing. */
} Hash_Table;

/*
 * The following structure is used by the searching routines
 * to record where we are in the search.
 */

typedef struct Hash_Search {
    Hash_Table  *tablePtr;      /* Table being searched. */
    int         nextIndex;      /* Next bucket to check (after current). */
    Hash_Entry  *hashEntryPtr;  /* Next entry to check in current bucket. */
} Hash_Search;

/*
 * Macros.
 */

/*
 * ClientData Hash_GetValue(h)
 *     Hash_Entry *h;
 */

#define Hash_GetValue(h) ((h)->clientData)

/*
 * Hash_SetValue(h, val);
 *     Hash_Entry *h;
 *     char *val;
 */

#define Hash_SetValue(h, val) ((h)->clientData = (ClientData) (val))

/*
 * Hash_Size(n) returns the number of words in an object of n bytes
 */

#define Hash_Size(n)    (((n) + sizeof (int) - 1) / sizeof (int))

/*
 * The following procedure declarations and macros
 * are the only things that should be needed outside
 * the implementation code.
 */

extern Hash_Entry *     Hash_CreateEntry();
extern void             Hash_DeleteTable();
extern void             Hash_DeleteEntry();
extern void             Hash_DeleteTable();
extern Hash_Entry *     Hash_EnumFirst();
extern Hash_Entry *     Hash_EnumNext();
extern Hash_Entry *     Hash_FindEntry();
extern void             Hash_InitTable();
extern void             Hash_PrintStats();

#endif _HASH