217 lines
6.5 KiB
C
217 lines
6.5 KiB
C
/* Hash tables for Objective C method dispatch.
|
|
Copyright (C) 1993, 1995, 1996, 2004 Free Software Foundation, Inc.
|
|
|
|
This file is part of GCC.
|
|
|
|
GCC is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2, or (at your option)
|
|
any later version.
|
|
|
|
GCC is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with GCC; see the file COPYING. If not, write to
|
|
the Free Software Foundation, 51 Franklin Street, Fifth Floor,
|
|
Boston, MA 02110-1301, USA. */
|
|
|
|
/* As a special exception, if you link this library with files
|
|
compiled with GCC to produce an executable, this does not cause
|
|
the resulting executable to be covered by the GNU General Public License.
|
|
This exception does not however invalidate any other reasons why
|
|
the executable file might be covered by the GNU General Public License. */
|
|
|
|
|
|
#ifndef __hash_INCLUDE_GNU
|
|
#define __hash_INCLUDE_GNU
|
|
|
|
#include <stddef.h>
|
|
#include <string.h>
|
|
#include "objc.h"
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif /* __cplusplus */
|
|
|
|
/*
|
|
* This data structure is used to hold items
|
|
* stored in a hash table. Each node holds
|
|
* a key/value pair.
|
|
*
|
|
* Items in the cache are really of type void *.
|
|
*/
|
|
typedef struct cache_node
|
|
{
|
|
struct cache_node *next; /* Pointer to next entry on the list.
|
|
NULL indicates end of list. */
|
|
const void *key; /* Key used to locate the value. Used
|
|
to locate value when more than one
|
|
key computes the same hash
|
|
value. */
|
|
void *value; /* Value stored for the key. */
|
|
} *node_ptr;
|
|
|
|
|
|
/*
|
|
* This data type is the function that computes a hash code given a key.
|
|
* Therefore, the key can be a pointer to anything and the function specific
|
|
* to the key type.
|
|
*
|
|
* Unfortunately there is a mutual data structure reference problem with this
|
|
* typedef. Therefore, to remove compiler warnings the functions passed to
|
|
* objc_hash_new will have to be casted to this type.
|
|
*/
|
|
typedef unsigned int (*hash_func_type) (void *, const void *);
|
|
|
|
/*
|
|
* This data type is the function that compares two hash keys and returns an
|
|
* integer greater than, equal to, or less than 0, according as the first
|
|
* parameter is lexicographically greater than, equal to, or less than the
|
|
* second.
|
|
*/
|
|
|
|
typedef int (*compare_func_type) (const void *, const void *);
|
|
|
|
|
|
/*
|
|
* This data structure is the cache.
|
|
*
|
|
* It must be passed to all of the hashing routines
|
|
* (except for new).
|
|
*/
|
|
typedef struct cache
|
|
{
|
|
/* Variables used to implement the hash itself. */
|
|
node_ptr *node_table; /* Pointer to an array of hash nodes. */
|
|
/* Variables used to track the size of the hash table so to determine
|
|
when to resize it. */
|
|
unsigned int size; /* Number of buckets allocated for the hash table
|
|
(number of array entries allocated for
|
|
"node_table"). Must be a power of two. */
|
|
unsigned int used; /* Current number of entries in the hash table. */
|
|
unsigned int mask; /* Precomputed mask. */
|
|
|
|
/* Variables used to implement indexing through the hash table. */
|
|
|
|
unsigned int last_bucket; /* Tracks which entry in the array where
|
|
the last value was returned. */
|
|
/* Function used to compute a hash code given a key.
|
|
This function is specified when the hash table is created. */
|
|
hash_func_type hash_func;
|
|
/* Function used to compare two hash keys to see if they are equal. */
|
|
compare_func_type compare_func;
|
|
} *cache_ptr;
|
|
|
|
|
|
/* Two important hash tables. */
|
|
extern cache_ptr module_hash_table, class_hash_table;
|
|
|
|
/* Allocate and initialize a hash table. */
|
|
|
|
cache_ptr objc_hash_new (unsigned int size,
|
|
hash_func_type hash_func,
|
|
compare_func_type compare_func);
|
|
|
|
/* Deallocate all of the hash nodes and the cache itself. */
|
|
|
|
void objc_hash_delete (cache_ptr cache);
|
|
|
|
/* Add the key/value pair to the hash table. If the
|
|
hash table reaches a level of fullness then it will be resized.
|
|
|
|
assert if the key is already in the hash. */
|
|
|
|
void objc_hash_add (cache_ptr *cachep, const void *key, void *value);
|
|
|
|
/* Remove the key/value pair from the hash table.
|
|
assert if the key isn't in the table. */
|
|
|
|
void objc_hash_remove (cache_ptr cache, const void *key);
|
|
|
|
/* Used to index through the hash table. Start with NULL
|
|
to get the first entry.
|
|
|
|
Successive calls pass the value returned previously.
|
|
** Don't modify the hash during this operation ***
|
|
|
|
Cache nodes are returned such that key or value can
|
|
be extracted. */
|
|
|
|
node_ptr objc_hash_next (cache_ptr cache, node_ptr node);
|
|
|
|
/* Used to return a value from a hash table using a given key. */
|
|
|
|
void *objc_hash_value_for_key (cache_ptr cache, const void *key);
|
|
|
|
/* Used to determine if the given key exists in the hash table */
|
|
|
|
BOOL objc_hash_is_key_in_hash (cache_ptr cache, const void *key);
|
|
|
|
/************************************************
|
|
|
|
Useful hashing functions.
|
|
|
|
Declared inline for your pleasure.
|
|
|
|
************************************************/
|
|
|
|
/* Calculate a hash code by performing some
|
|
manipulation of the key pointer. (Use the lowest bits
|
|
except for those likely to be 0 due to alignment.) */
|
|
|
|
static inline unsigned int
|
|
objc_hash_ptr (cache_ptr cache, const void *key)
|
|
{
|
|
return ((size_t)key / sizeof (void *)) & cache->mask;
|
|
}
|
|
|
|
|
|
/* Calculate a hash code by iterating over a NULL
|
|
terminate string. */
|
|
static inline unsigned int
|
|
objc_hash_string (cache_ptr cache, const void *key)
|
|
{
|
|
unsigned int ret = 0;
|
|
unsigned int ctr = 0;
|
|
const char *ckey = (const char *) key;
|
|
|
|
while (*ckey) {
|
|
ret ^= *ckey++ << ctr;
|
|
ctr = (ctr + 1) % sizeof (void *);
|
|
}
|
|
|
|
return ret & cache->mask;
|
|
}
|
|
|
|
|
|
/* Compare two pointers for equality. */
|
|
static inline int
|
|
objc_compare_ptrs (const void *k1, const void *k2)
|
|
{
|
|
return (k1 == k2);
|
|
}
|
|
|
|
|
|
/* Compare two strings. */
|
|
static inline int
|
|
objc_compare_strings (const void *k1, const void *k2)
|
|
{
|
|
if (k1 == k2)
|
|
return 1;
|
|
else if (k1 == 0 || k2 == 0)
|
|
return 0;
|
|
else
|
|
return ! strcmp ((const char *) k1, (const char *) k2);
|
|
}
|
|
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif /* __cplusplus */
|
|
|
|
|
|
#endif /* not __hash_INCLUDE_GNU */
|