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/* SPDX-License-Identifier: LGPL-2.1 */
/*
* Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
* Copyright (C) 2018 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
*
*/
#ifndef _TRACE_FILTER_HASH_H
#define _TRACE_FILTER_HASH_H
#include <stdint.h>
struct tracecmd_filter_id_item {
struct tracecmd_filter_id_item *next;
int id;
};
struct tracecmd_filter_id {
struct tracecmd_filter_id_item **hash;
int count;
};
/**
* tracecmd_quick_hash - A quick (non secured) hash alogirthm
* @val: The value to perform the hash on
* @bits: The size in bits you need to return
*
* This is a quick hashing function adapted from Donald E. Knuth's 32
* bit multiplicative hash. See The Art of Computer Programming (TAOCP).
* Multiplication by the Prime number, closest to the golden ratio of
* 2^32.
*
* @bits is used to max the result for use cases that require
* a power of 2 return value that is less than 32 bits. Any value
* of @bits greater than 31 (or zero), will simply return the full hash on @val.
*/
static inline uint32_t tracecmd_quick_hash(uint32_t val, unsigned int bits)
{
val *= UINT32_C(2654435761);
if (!bits || bits > 31)
return val;
return val & ((1 << bits) - 1);
}
struct tracecmd_filter_id_item *
tracecmd_filter_id_find(struct tracecmd_filter_id *hash, int id);
void tracecmd_filter_id_add(struct tracecmd_filter_id *hash, int id);
void tracecmd_filter_id_remove(struct tracecmd_filter_id *hash, int id);
void tracecmd_filter_id_clear(struct tracecmd_filter_id *hash);
struct tracecmd_filter_id *tracecmd_filter_id_hash_alloc(void);
void tracecmd_filter_id_hash_free(struct tracecmd_filter_id *hash);
struct tracecmd_filter_id *
tracecmd_filter_id_hash_copy(struct tracecmd_filter_id *hash);
int *tracecmd_filter_ids(struct tracecmd_filter_id *hash);
int tracecmd_filter_id_compare(struct tracecmd_filter_id *hash1,
struct tracecmd_filter_id *hash2);
static inline int tracecmd_filter_task_count(struct tracecmd_filter_id *hash)
{
return hash->count;
}
#endif /* _TRACE_FILTER_HASH_H */
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