busybox/libbb/inode_hash.c

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) many different people.
 * If you wrote this, please acknowledge your work.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"

typedef struct ino_dev_hash_bucket_struct {
	struct ino_dev_hash_bucket_struct *next;
	ino_t ino;
	dev_t dev;
	char name[1];
} ino_dev_hashtable_bucket_t;

#define HASH_SIZE	311		/* Should be prime */
#define hash_inode(i)	((i) % HASH_SIZE)

/* array of [HASH_SIZE] elements */
static ino_dev_hashtable_bucket_t **ino_dev_hashtable;

/*
 * Return name if statbuf->st_ino && statbuf->st_dev are recorded in
 * ino_dev_hashtable, else return NULL
 */
char* FAST_FUNC is_in_ino_dev_hashtable(const struct stat *statbuf)
{
	ino_dev_hashtable_bucket_t *bucket;

	if (!ino_dev_hashtable)
		return NULL;

	bucket = ino_dev_hashtable[hash_inode(statbuf->st_ino)];
	while (bucket != NULL) {
		if ((bucket->ino == statbuf->st_ino)
		 && (bucket->dev == statbuf->st_dev)
		) {
			return bucket->name;
		}
		bucket = bucket->next;
	}
	return NULL;
}

/* Add statbuf to statbuf hash table */
void FAST_FUNC add_to_ino_dev_hashtable(const struct stat *statbuf, const char *name)
{
	int i;
	ino_dev_hashtable_bucket_t *bucket;

	i = hash_inode(statbuf->st_ino);
	if (!name)
		name = "";
	bucket = xmalloc(sizeof(ino_dev_hashtable_bucket_t) + strlen(name));
	bucket->ino = statbuf->st_ino;
	bucket->dev = statbuf->st_dev;
	strcpy(bucket->name, name);

	if (!ino_dev_hashtable)
		ino_dev_hashtable = xzalloc(HASH_SIZE * sizeof(*ino_dev_hashtable));

	bucket->next = ino_dev_hashtable[i];
	ino_dev_hashtable[i] = bucket;
}

#if ENABLE_FEATURE_CLEAN_UP
/* Clear statbuf hash table */
void FAST_FUNC reset_ino_dev_hashtable(void)
{
	int i;
	ino_dev_hashtable_bucket_t *bucket;

	for (i = 0; ino_dev_hashtable && i < HASH_SIZE; i++) {
		while (ino_dev_hashtable[i] != NULL) {
			bucket = ino_dev_hashtable[i]->next;
			free(ino_dev_hashtable[i]);
			ino_dev_hashtable[i] = bucket;
		}
	}
	free(ino_dev_hashtable);
	ino_dev_hashtable = NULL;
}
#endif
1	niro	532	/* vi: set sw=4 ts=4: */
2			/*
3			* Utility routines.
4			*
5			* Copyright (C) many different people.
6			* If you wrote this, please acknowledge your work.
7			*
8			* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
9			*/
10
11			#include "libbb.h"
12
13	niro	816	typedef struct ino_dev_hash_bucket_struct {
14			struct ino_dev_hash_bucket_struct *next;
15			ino_t ino;
16			dev_t dev;
17			char name[1];
18			} ino_dev_hashtable_bucket_t;
19
20	niro	532	#define HASH_SIZE 311 /* Should be prime */
21			#define hash_inode(i) ((i) % HASH_SIZE)
22
23	niro	816	/* array of [HASH_SIZE] elements */
24			static ino_dev_hashtable_bucket_t **ino_dev_hashtable;
25	niro	532
26			/*
27	niro	816	* Return name if statbuf->st_ino && statbuf->st_dev are recorded in
28			* ino_dev_hashtable, else return NULL
29	niro	532	*/
30	niro	816	char* FAST_FUNC is_in_ino_dev_hashtable(const struct stat *statbuf)
31	niro	532	{
32			ino_dev_hashtable_bucket_t *bucket;
33
34	niro	816	if (!ino_dev_hashtable)
35			return NULL;
36
37	niro	532	bucket = ino_dev_hashtable[hash_inode(statbuf->st_ino)];
38			while (bucket != NULL) {
39	niro	816	if ((bucket->ino == statbuf->st_ino)
40			&& (bucket->dev == statbuf->st_dev)
41			) {
42			return bucket->name;
43			}
44			bucket = bucket->next;
45	niro	532	}
46	niro	816	return NULL;
47	niro	532	}
48
49			/* Add statbuf to statbuf hash table */
50	niro	816	void FAST_FUNC add_to_ino_dev_hashtable(const struct stat statbuf, const char name)
51	niro	532	{
52			int i;
53			ino_dev_hashtable_bucket_t *bucket;
54
55			i = hash_inode(statbuf->st_ino);
56	niro	816	if (!name)
57			name = "";
58			bucket = xmalloc(sizeof(ino_dev_hashtable_bucket_t) + strlen(name));
59	niro	532	bucket->ino = statbuf->st_ino;
60			bucket->dev = statbuf->st_dev;
61	niro	816	strcpy(bucket->name, name);
62
63			if (!ino_dev_hashtable)
64			ino_dev_hashtable = xzalloc(HASH_SIZE * sizeof(*ino_dev_hashtable));
65
66	niro	532	bucket->next = ino_dev_hashtable[i];
67			ino_dev_hashtable[i] = bucket;
68			}
69
70	niro	816	#if ENABLE_FEATURE_CLEAN_UP
71	niro	532	/* Clear statbuf hash table */
72	niro	816	void FAST_FUNC reset_ino_dev_hashtable(void)
73	niro	532	{
74			int i;
75			ino_dev_hashtable_bucket_t *bucket;
76
77	niro	816	for (i = 0; ino_dev_hashtable && i < HASH_SIZE; i++) {
78	niro	532	while (ino_dev_hashtable[i] != NULL) {
79			bucket = ino_dev_hashtable[i]->next;
80			free(ino_dev_hashtable[i]);
81			ino_dev_hashtable[i] = bucket;
82			}
83			}
84	niro	816	free(ino_dev_hashtable);
85			ino_dev_hashtable = NULL;
86	niro	532	}
87			#endif