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158 lines
4.9 KiB
C
158 lines
4.9 KiB
C
#ifndef HASH_H
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#define HASH_H
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/* hash.h */
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/************************************************************************
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Copyright 1988, 1991 by Carnegie Mellon University
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted, provided
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that the above copyright notice appear in all copies and that both that
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copyright notice and this permission notice appear in supporting
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documentation, and that the name of Carnegie Mellon University not be used
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in advertising or publicity pertaining to distribution of the software
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without specific, written prior permission.
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CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
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SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
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IN NO EVENT SHALL CMU BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
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DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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SOFTWARE.
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************************************************************************/
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/*
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* Generalized hash table ADT
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*
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* Provides multiple, dynamically-allocated, variable-sized hash tables on
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* various data and keys.
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*
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* This package attempts to follow some of the coding conventions suggested
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* by Bob Sidebotham and the AFS Clean Code Committee.
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*/
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/*
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* The user must supply the following:
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*
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* 1. A comparison function which is declared as:
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*
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* int compare(data1, data2)
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* hash_datum *data1, *data2;
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*
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* This function must compare the desired fields of data1 and
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* data2 and return TRUE (1) if the data should be considered
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* equivalent (i.e. have the same key value) or FALSE (0)
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* otherwise. This function is called through a pointer passed to
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* the various hashtable functions (thus pointers to different
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* functions may be passed to effect different tests on different
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* hash tables).
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*
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* Internally, all the functions of this package always call the
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* compare function with the "key" parameter as the first parameter,
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* and a full data element as the second parameter. Thus, the key
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* and element arguments to functions such as hash_Lookup() may
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* actually be of different types and the programmer may provide a
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* compare function which compares the two different object types
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* as desired.
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*
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* Example:
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*
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* int compare(key, element)
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* char *key;
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* struct some_complex_structure *element;
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* {
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* return !strcmp(key, element->name);
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* }
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*
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* key = "John C. Doe"
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* element = &some_complex_structure
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* hash_Lookup(table, hashcode, compare, key);
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*
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* 2. A hash function yielding an unsigned integer value to be used
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* as the hashcode (index into the hashtable). Thus, the user
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* may hash on whatever data is desired and may use several
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* different hash functions for various different hash tables.
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* The actual hash table index will be the passed hashcode modulo
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* the hash table size.
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*
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* A generalized hash function, hash_HashFunction(), is included
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* with this package to make things a little easier. It is not
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* guarenteed to use the best hash algorithm in existence. . . .
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*/
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/*
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* Various hash table definitions
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*/
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/*
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* Define "hash_datum" as a universal data type
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*/
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#ifdef __STDC__
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typedef void hash_datum;
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#else
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typedef char hash_datum;
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#endif
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typedef struct hash_memberstruct hash_member;
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typedef struct hash_tblstruct hash_tbl;
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typedef struct hash_tblstruct_hdr hash_tblhdr;
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struct hash_memberstruct {
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hash_member *next;
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hash_datum *data;
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};
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struct hash_tblstruct_hdr {
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unsigned size, bucketnum;
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hash_member *member;
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};
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struct hash_tblstruct {
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unsigned size, bucketnum;
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hash_member *member; /* Used for linear dump */
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hash_member *table[1]; /* Dynamically extended */
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};
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/* ANSI function prototypes or empty arg list? */
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#ifdef __STDC__
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#define P(args) args
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#else
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#define P(args) ()
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#endif
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typedef int (*hash_cmpfp) P((hash_datum *, hash_datum *));
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typedef void (*hash_freefp) P((hash_datum *));
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extern hash_tbl *hash_Init P((u_int tablesize));
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extern void hash_Reset P((hash_tbl *tbl, hash_freefp));
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extern unsigned hash_HashFunction P((u_char *str, u_int len));
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extern int hash_Exists P((hash_tbl *, u_int code,
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hash_cmpfp, hash_datum *key));
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extern int hash_Insert P((hash_tbl *, u_int code,
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hash_cmpfp, hash_datum *key,
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hash_datum *element));
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extern int hash_Delete P((hash_tbl *, u_int code,
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hash_cmpfp, hash_datum *key,
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hash_freefp));
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extern hash_datum *hash_Lookup P((hash_tbl *, u_int code,
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hash_cmpfp, hash_datum *key));
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extern hash_datum *hash_FirstEntry P((hash_tbl *));
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extern hash_datum *hash_NextEntry P((hash_tbl *));
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#undef P
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#endif /* HASH_H */
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