pmt: initial 3.0.2 update
This commit is contained in:
273
include/libgnulib/hash.h
Executable file
273
include/libgnulib/hash.h
Executable file
@@ -0,0 +1,273 @@
|
||||
/* hash - hashing table processing.
|
||||
Copyright (C) 1998-1999, 2001, 2003, 2009-2024 Free Software Foundation,
|
||||
Inc.
|
||||
Written by Jim Meyering <meyering@ascend.com>, 1998.
|
||||
|
||||
This file is free software: you can redistribute it and/or modify
|
||||
it under the terms of the GNU Lesser General Public License as
|
||||
published by the Free Software Foundation; either version 2.1 of the
|
||||
License, or (at your option) any later version.
|
||||
|
||||
This file 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 Lesser General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU Lesser General Public License
|
||||
along with this program. If not, see <https://www.gnu.org/licenses/>. */
|
||||
|
||||
/* A generic hash table package. */
|
||||
|
||||
/* Make sure USE_OBSTACK is defined to 1 if you want the allocator to use
|
||||
obstacks instead of malloc, and recompile 'hash.c' with same setting. */
|
||||
|
||||
#ifndef HASH_H_
|
||||
# define HASH_H_
|
||||
|
||||
/* This file uses _GL_ATTRIBUTE_DEALLOC, _GL_ATTRIBUTE_DEPRECATED,
|
||||
_GL_ATTRIBUTE_MALLOC, _GL_ATTRIBUTE_NODISCARD, _GL_ATTRIBUTE_PURE,
|
||||
_GL_ATTRIBUTE_RETURNS_NONNULL. */
|
||||
#if !_GL_CONFIG_H_INCLUDED
|
||||
#error "Please include config.h first."
|
||||
#endif
|
||||
|
||||
# include <stdio.h>
|
||||
|
||||
# ifdef __cplusplus
|
||||
extern "C" {
|
||||
# endif
|
||||
|
||||
struct hash_tuning
|
||||
{
|
||||
/* This structure is mainly used for 'hash_initialize', see the block
|
||||
documentation of 'hash_reset_tuning' for more complete comments. */
|
||||
|
||||
float shrink_threshold; /* ratio of used buckets to trigger a shrink */
|
||||
float shrink_factor; /* ratio of new smaller size to original size */
|
||||
float growth_threshold; /* ratio of used buckets to trigger a growth */
|
||||
float growth_factor; /* ratio of new bigger size to original size */
|
||||
bool is_n_buckets; /* if CANDIDATE really means table size */
|
||||
};
|
||||
|
||||
typedef struct hash_tuning Hash_tuning;
|
||||
|
||||
struct hash_table;
|
||||
|
||||
typedef struct hash_table Hash_table;
|
||||
|
||||
/*
|
||||
* Information and lookup.
|
||||
*/
|
||||
|
||||
/* The following few functions provide information about the overall hash
|
||||
table organization: the number of entries, number of buckets and maximum
|
||||
length of buckets. */
|
||||
|
||||
/* Return the number of buckets in the hash table. The table size, the total
|
||||
number of buckets (used plus unused), or the maximum number of slots, are
|
||||
the same quantity. */
|
||||
extern size_t hash_get_n_buckets (const Hash_table *table)
|
||||
_GL_ATTRIBUTE_PURE;
|
||||
|
||||
/* Return the number of slots in use (non-empty buckets). */
|
||||
extern size_t hash_get_n_buckets_used (const Hash_table *table)
|
||||
_GL_ATTRIBUTE_PURE;
|
||||
|
||||
/* Return the number of active entries. */
|
||||
extern size_t hash_get_n_entries (const Hash_table *table)
|
||||
_GL_ATTRIBUTE_PURE;
|
||||
|
||||
/* Return the length of the longest chain (bucket). */
|
||||
extern size_t hash_get_max_bucket_length (const Hash_table *table)
|
||||
_GL_ATTRIBUTE_PURE;
|
||||
|
||||
/* Do a mild validation of a hash table, by traversing it and checking two
|
||||
statistics. */
|
||||
extern bool hash_table_ok (const Hash_table *table)
|
||||
_GL_ATTRIBUTE_PURE;
|
||||
|
||||
extern void hash_print_statistics (const Hash_table *table, FILE *stream);
|
||||
|
||||
/* If ENTRY matches an entry already in the hash table, return the
|
||||
entry from the table. Otherwise, return NULL. */
|
||||
extern void *hash_lookup (const Hash_table *table, const void *entry);
|
||||
|
||||
/*
|
||||
* Walking.
|
||||
*/
|
||||
|
||||
/* The functions in this page traverse the hash table and process the
|
||||
contained entries. For the traversal to work properly, the hash table
|
||||
should not be resized nor modified while any particular entry is being
|
||||
processed. In particular, entries should not be added, and an entry
|
||||
may be removed only if there is no shrink threshold and the entry being
|
||||
removed has already been passed to hash_get_next. */
|
||||
|
||||
/* Return the first data in the table, or NULL if the table is empty. */
|
||||
extern void *hash_get_first (const Hash_table *table)
|
||||
_GL_ATTRIBUTE_PURE;
|
||||
|
||||
/* Return the user data for the entry following ENTRY, where ENTRY has been
|
||||
returned by a previous call to either 'hash_get_first' or 'hash_get_next'.
|
||||
Return NULL if there are no more entries. */
|
||||
extern void *hash_get_next (const Hash_table *table, const void *entry);
|
||||
|
||||
/* Fill BUFFER with pointers to active user entries in the hash table, then
|
||||
return the number of pointers copied. Do not copy more than BUFFER_SIZE
|
||||
pointers. */
|
||||
extern size_t hash_get_entries (const Hash_table *table, void **buffer,
|
||||
size_t buffer_size);
|
||||
|
||||
typedef bool (*Hash_processor) (void *entry, void *processor_data);
|
||||
|
||||
/* Call a PROCESSOR function for each entry of a hash table, and return the
|
||||
number of entries for which the processor function returned success. A
|
||||
pointer to some PROCESSOR_DATA which will be made available to each call to
|
||||
the processor function. The PROCESSOR accepts two arguments: the first is
|
||||
the user entry being walked into, the second is the value of PROCESSOR_DATA
|
||||
as received. The walking continue for as long as the PROCESSOR function
|
||||
returns nonzero. When it returns zero, the walking is interrupted. */
|
||||
extern size_t hash_do_for_each (const Hash_table *table,
|
||||
Hash_processor processor, void *processor_data);
|
||||
|
||||
/*
|
||||
* Allocation and clean-up.
|
||||
*/
|
||||
|
||||
/* Return a hash index for a NUL-terminated STRING between 0 and N_BUCKETS-1.
|
||||
This is a convenience routine for constructing other hashing functions. */
|
||||
extern size_t hash_string (const char *string, size_t n_buckets)
|
||||
_GL_ATTRIBUTE_PURE;
|
||||
|
||||
extern void hash_reset_tuning (Hash_tuning *tuning);
|
||||
|
||||
typedef size_t (*Hash_hasher) (const void *entry, size_t table_size);
|
||||
typedef bool (*Hash_comparator) (const void *entry1, const void *entry2);
|
||||
typedef void (*Hash_data_freer) (void *entry);
|
||||
|
||||
/* Reclaim all storage associated with a hash table. If a data_freer
|
||||
function has been supplied by the user when the hash table was created,
|
||||
this function applies it to the data of each entry before freeing that
|
||||
entry. This function preserves errno, like 'free'. */
|
||||
extern void hash_free (Hash_table *table);
|
||||
|
||||
/* Allocate and return a new hash table, or NULL upon failure. The initial
|
||||
number of buckets is automatically selected so as to _guarantee_ that you
|
||||
may insert at least CANDIDATE different user entries before any growth of
|
||||
the hash table size occurs. So, if have a reasonably tight a-priori upper
|
||||
bound on the number of entries you intend to insert in the hash table, you
|
||||
may save some table memory and insertion time, by specifying it here. If
|
||||
the IS_N_BUCKETS field of the TUNING structure is true, the CANDIDATE
|
||||
argument has its meaning changed to the wanted number of buckets.
|
||||
|
||||
TUNING points to a structure of user-supplied values, in case some fine
|
||||
tuning is wanted over the default behavior of the hasher. If TUNING is
|
||||
NULL, the default tuning parameters are used instead. If TUNING is
|
||||
provided but the values requested are out of bounds or might cause
|
||||
rounding errors, return NULL.
|
||||
|
||||
The user-supplied HASHER function, when not NULL, accepts two
|
||||
arguments ENTRY and TABLE_SIZE. It computes, by hashing ENTRY contents, a
|
||||
slot number for that entry which should be in the range 0..TABLE_SIZE-1.
|
||||
This slot number is then returned.
|
||||
|
||||
The user-supplied COMPARATOR function, when not NULL, accepts two
|
||||
arguments pointing to user data, it then returns true for a pair of entries
|
||||
that compare equal, or false otherwise. This function is internally called
|
||||
on entries which are already known to hash to the same bucket index,
|
||||
but which are distinct pointers.
|
||||
|
||||
The user-supplied DATA_FREER function, when not NULL, may be later called
|
||||
with the user data as an argument, just before the entry containing the
|
||||
data gets freed. This happens from within 'hash_free' or 'hash_clear'.
|
||||
You should specify this function only if you want these functions to free
|
||||
all of your 'data' data. This is typically the case when your data is
|
||||
simply an auxiliary struct that you have malloc'd to aggregate several
|
||||
values.
|
||||
|
||||
Set errno on failure; otherwise errno is unspecified. */
|
||||
_GL_ATTRIBUTE_NODISCARD
|
||||
extern Hash_table *hash_initialize (size_t candidate,
|
||||
const Hash_tuning *tuning,
|
||||
Hash_hasher hasher,
|
||||
Hash_comparator comparator,
|
||||
Hash_data_freer data_freer)
|
||||
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_DEALLOC (hash_free, 1);
|
||||
|
||||
/* Like hash_initialize, but invokes xalloc_die instead of returning NULL. */
|
||||
/* This function is defined by module 'xhash'. */
|
||||
_GL_ATTRIBUTE_NODISCARD
|
||||
extern Hash_table *hash_xinitialize (size_t candidate,
|
||||
const Hash_tuning *tuning,
|
||||
Hash_hasher hasher,
|
||||
Hash_comparator comparator,
|
||||
Hash_data_freer data_freer)
|
||||
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_DEALLOC (hash_free, 1)
|
||||
_GL_ATTRIBUTE_RETURNS_NONNULL;
|
||||
|
||||
/* Make all buckets empty, placing any chained entries on the free list.
|
||||
Apply the user-specified function data_freer (if any) to the data of any
|
||||
affected entries. */
|
||||
extern void hash_clear (Hash_table *table);
|
||||
|
||||
/*
|
||||
* Insertion and deletion.
|
||||
*/
|
||||
|
||||
/* For an already existing hash table, change the number of buckets through
|
||||
specifying CANDIDATE. The contents of the hash table are preserved. The
|
||||
new number of buckets is automatically selected so as to _guarantee_ that
|
||||
the table may receive at least CANDIDATE different user entries, including
|
||||
those already in the table, before any other growth of the hash table size
|
||||
occurs. If TUNING->IS_N_BUCKETS is true, then CANDIDATE specifies the
|
||||
exact number of buckets desired. Return true iff the rehash succeeded,
|
||||
false (setting errno) otherwise. */
|
||||
_GL_ATTRIBUTE_NODISCARD
|
||||
extern bool hash_rehash (Hash_table *table, size_t candidate);
|
||||
|
||||
/* If ENTRY matches an entry already in the hash table, return the pointer
|
||||
to the entry from the table. Otherwise, insert ENTRY and return ENTRY.
|
||||
Return NULL (setting errno) if the storage required for insertion
|
||||
cannot be allocated. This implementation does not support
|
||||
duplicate entries or insertion of NULL. */
|
||||
_GL_ATTRIBUTE_NODISCARD
|
||||
extern void *hash_insert (Hash_table *table, const void *entry);
|
||||
|
||||
/* Same as hash_insert, but invokes xalloc_die instead of returning NULL. */
|
||||
/* This function is defined by module 'xhash'. */
|
||||
extern void *hash_xinsert (Hash_table *table, const void *entry);
|
||||
|
||||
/* Insert ENTRY into hash TABLE if there is not already a matching entry.
|
||||
|
||||
Return -1 (setting errno) upon memory allocation failure.
|
||||
Return 1 if insertion succeeded.
|
||||
Return 0 if there is already a matching entry in the table,
|
||||
and in that case, if MATCHED_ENT is non-NULL, set *MATCHED_ENT
|
||||
to that entry.
|
||||
|
||||
This interface is easier to use than hash_insert when you must
|
||||
distinguish between the latter two cases. More importantly,
|
||||
hash_insert is unusable for some types of ENTRY values. When using
|
||||
hash_insert, the only way to distinguish those cases is to compare
|
||||
the return value and ENTRY. That works only when you can have two
|
||||
different ENTRY values that point to data that compares "equal". Thus,
|
||||
when the ENTRY value is a simple scalar, you must use
|
||||
hash_insert_if_absent. ENTRY must not be NULL. */
|
||||
extern int hash_insert_if_absent (Hash_table *table, const void *entry,
|
||||
const void **matched_ent);
|
||||
|
||||
/* If ENTRY is already in the table, remove it and return the just-deleted
|
||||
data (the user may want to deallocate its storage). If ENTRY is not in the
|
||||
table, don't modify the table and return NULL. */
|
||||
extern void *hash_remove (Hash_table *table, const void *entry);
|
||||
|
||||
/* Same as hash_remove. This interface is deprecated.
|
||||
FIXME: Remove in 2022. */
|
||||
_GL_ATTRIBUTE_DEPRECATED
|
||||
extern void *hash_delete (Hash_table *table, const void *entry);
|
||||
|
||||
# ifdef __cplusplus
|
||||
}
|
||||
# endif
|
||||
|
||||
#endif
|
||||
Reference in New Issue
Block a user