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cmake_minimum_required(VERSION 3.10)
set(CMAKE_C_STANDARD 99)
project(
ht
VERSION 1.0
LANGUAGES C)
if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
include(CTest)
endif()
# add_compile_options(-fsanitize=address,leak,undefined)
# add_link_options(-fsanitize=address,leak,undefined)
add_library(ht src/ht.c)
target_include_directories(ht PUBLIC include/)
target_compile_options(ht PRIVATE -Wall -Wpedantic)
if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME AND BUILD_TESTING)
add_subdirectory(test/)
endif()

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GNU GENERAL PUBLIC LICENSE
Version 3, 29 June 2007
Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
Preamble
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If the Program specifies that a proxy can decide which future
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15. Disclaimer of Warranty.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
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HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
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IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
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GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
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DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
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17. Interpretation of Sections 15 and 16.
If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
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copy of the Program in return for a fee.
END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.
<one line to give the program's name and a brief idea of what it does.>
Copyright (C) <year> <name of author>
This program 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 3 of the License, or
(at your option) any later version.
This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
Also add information on how to contact you by electronic and paper mail.
If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:
<program> Copyright (C) <year> <name of author>
This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License. Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".
You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<https://www.gnu.org/licenses/>.
The GNU General Public License does not permit incorporating your program
into proprietary programs. If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library. If this is what you want to do, use the GNU Lesser General
Public License instead of this License. But first, please read
<https://www.gnu.org/licenses/why-not-lgpl.html>.

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# ht
ht (official name is lowercase) is a hash table library written in standard
C99. It takes inspiration from the [GLib GHashTable
type](https://docs.gtk.org/glib/struct.HashTable.html).
For examples of usage, see `test/test_ht.c`.
### Building
CMake is the only dependency as it is nessesary for building.
```sh
cmake -B build
make -C build
```
Once built, you can run tests with
```sh
make -C build test
```
### Documentation
you can build documentation with:
```
doxygen
```
The generated documentation is available in the `docs/` directory.

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/**
* @file
* Hash table library for standard C99.
*/
#ifndef INCLUDED_HT_HT_H
#define INCLUDED_HT_HT_H
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* Structure holding memory allocation functions as well as extra data to pass
* to the functions when allocating.
*/
typedef struct HTAllocator {
/**
* Analogous to the standard library function of the same name. The
* user_data field of the allocator is passed as the second argument. This
* should return NULL or exit the program if allocation fails. If it
* attempts to longjmp, it might cause memory leaks (unless allocated memory
* is tracked separately).
*/
void *(*malloc)(size_t size, void *user_data);
/**
* Analogous to the standard library function of the same name. The
* user_data field of the allocator is passed as the second argument. This
* should be able to accept a ptr of NULL.
*/
void (*free)(void *ptr, void *user_data);
/**
* Extra data to pass to the allocation functions.
*/
void *user_data;
} HTAllocator;
/**
* Values used to determine when to grow and shrink the hash table.
*/
typedef struct HTThreshold {
/**
* Initial size of the table. Cannot be 0.
*/
size_t initial_size;
/**
* How much to grow the table by. A value of 2, for example, means to double
* the table size every time it is expanded.
*/
float growth_factor;
/**
* Once at least this percentage of the table is filled, the table will be
* grown. Should be a value in the range (0, 1].
*/
float growth_threshold;
/**
* Once less than this percentage of the table is filled, the table will be
* shrunk. Should be a value in the range (0, 1].
*/
float shrink_threshold;
} HTThreshold;
typedef struct HTTable HTTable;
/**
* Stuff an integer into a pointer. This just casts n to a uintptr_t and then to
* a void *.
*/
#define HT_STUFF(n) ((void *) (uintptr_t) (n))
/**
* Undo HT_STUFF and retrieve the value as an intptr_t.
*/
#define HT_UNSTUFF(n) ((intptr_t) (void *) (n))
/**
* Undo HT_STUFF and retrieve the value as a uintptr_t.
*/
#define HT_UUNSTUFF(n) ((uintptr_t) (void *) (n))
/**
* Hash function for the hash table.
*/
typedef uint64_t (*ht_hash_callback_t)(const void *key, void *user_data);
/**
* Equality function for the hash table. If key1\ ==\ key2, then
* hash(key1)\ ==\ hash(key2). However, the reverse is not true. That is, things
* that are equal have the same hash, but things with the same hash are not
* necessarily equal.
*/
typedef bool (*ht_equal_callback_t)(const void *key1, const void *key2,
void *user_data);
/**
* Function to free a hash table key or value.
*/
typedef void (*ht_destroy_callback_t)(void *ptr, void *user_data);
/**
* The set of functions used by a hash table. Each function will have the
* user_data member passed as its last argument.
*/
typedef struct HTTableFunctions {
/**
* Hash function.
*/
ht_hash_callback_t hash;
/**
* Equality predicate function.
*/
ht_equal_callback_t equal;
/**
* Function to call to cleanup keys when they are removed from the
* table. This can be NULL. In that case, no cleanup is performed.
*/
ht_destroy_callback_t destroy_key;
/**
* Function to call to cleanup values when they are removed from the
* table. This can be NULL. In that case, no cleanup is performed.
*/
ht_destroy_callback_t destroy_value;
/**
* This will be passed as a final argument to each other function.
*/
void *user_data;
} HTTableFunctions;
/**
* Call back used to copy values.
* @see ht_copy
*/
typedef void *(*ht_copy_callback_t)(const void *original, void *user_data);
/**
* Callback used for looping functions. The meaning of the return value depends
* on the function used.
* @see ht_foreach
* @see ht_foreach_remove
* @see ht_foreach_steal
*/
typedef bool (*ht_foreach_callback_t)(void *key, void *value, void *user_data);
HTTable *ht_new(const HTTableFunctions *fns, const HTAllocator *alloc,
const HTThreshold *thresh);
HTTable *ht_copy(const HTTable *ht, ht_copy_callback_t copy_key_callback,
ht_copy_callback_t copy_value_callback, void *user_data);
void ht_free(HTTable *ht);
size_t ht_count(const HTTable *ht);
bool ht_equal(const HTTable *ht1, const HTTable *ht2);
bool ht_insert(HTTable *ht, void *key, void *value);
bool ht_clear(HTTable *ht);
bool ht_remove(HTTable *ht, const void *key);
bool ht_steal(HTTable *ht, const void *key, void **stolen_key,
void **stolen_value);
bool ht_steal_all(HTTable *ht, void ***keys, void ***values);
void *ht_get_extended(const HTTable *ht, const void *key, void **found_key);
/**
* Lookup a value in a hash table from its key.
* @param ht The hash table
* @param key The key
* @return The value associated with the key, or NULL if the key is absent
*/
static inline void *ht_get(const HTTable *ht, const void *key) {
return ht_get_extended(ht, key, NULL);
}
bool ht_has_extended(const HTTable *ht, const void *key, void **found_key);
/**
* Test for the presence of a key in a hash table.
* @param ht The hash table
* @param key The key
* @return Whether the table contained a mapping for the key
*/
static inline bool ht_has(const HTTable *ht, const void *key) {
return ht_has_extended(ht, key, NULL);
}
void ht_foreach(const HTTable *ht, ht_foreach_callback_t callback,
void *user_data);
bool ht_foreach_remove(HTTable *ht, ht_foreach_callback_t callback,
void *user_data);
bool ht_foreach_steal(HTTable *ht, ht_foreach_callback_t callback,
void *user_data);
bool ht_find(HTTable *ht, ht_foreach_callback_t callback, void *user_data,
void **key, void **value);
bool ht_steal_from(HTTable *ht, HTTable *src);
bool ht_get_keys_and_values(const HTTable *ht, void ***keys, void ***values);
void **ht_get_keys(const HTTable *ht);
void **ht_get_values(const HTTable *ht);
uint64_t ht_string_hash_callback(const void *str, void *user_data);
bool ht_string_equal_callback(const void *str1, const void *str2,
void *user_data);
uint64_t ht_intptr_hash_callback(const void *num, void *user_data);
bool ht_intptr_equal_callback(const void *n1, const void *n2, void *user_data);
#ifdef __cplusplus
}
#endif
#endif

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/**
* @file
* Hash table library for standard C99.
*/
#include "ht.h"
#include <stdlib.h>
#include <string.h>
/**
* Allocator callback that calls the standard C malloc.
* @param size The number of bytes to allocate
* @param user_data Ignored
* @return The result of malloc(size)
*/
static void *default_allocator_malloc(size_t size, void *user_data) {
return malloc(size);
}
/**
* Allocator callback that calls the standard C free.
* @param ptr The pointer to free
* @param user_data Ignored
*/
static void default_allocator_free(void *ptr, void *user_data) {
free(ptr);
}
/**
* HTAllocator that delegates to to the standard library's malloc and free
* functions.
*/
const static HTAllocator DEFAULT_ALLOCATOR = {
.malloc = default_allocator_malloc,
.free = default_allocator_free,
.user_data = NULL,
};
/**
* Default HTThreshold values if none are provided.
*/
const static HTThreshold DEFAULT_THRESHOLD = {
.initial_size = 32,
.growth_factor = 2.0f,
.growth_threshold = 0.75f,
.shrink_threshold = 0.25f,
};
/**
* Hash table buckets, stored as a singly linked list.
*/
typedef struct Bucket {
uint64_t hash; //!< Hash for the key.
void *key; //!< Key for the entry.
void *value; //!< Value for the entry.
struct Bucket *next; //!< Next entry in the bucket.
} Bucket;
/**
* A hash table.
*/
struct HTTable {
const HTTableFunctions *fns; //!< Set of functions to use for hashing, etc.
const HTAllocator *alloc; //!< Set of memory allocation functions.
const HTThreshold *thresh; //!< Thresholds for resizing, etc.
size_t table_size; //<! Number of buckets.
size_t count; //<! Number of elements.
Bucket **buckets; //!< Array of all buckets. Has table_size entries.
};
/**
* Call the table's allocator's malloc function with the user_data argument.
* @param ht The hash table
* @param size The number of bytes to allocate
* @return The newly allocated memory, or NULL if an error occurred
*/
static inline void *malloc_for_table(const HTTable *ht, size_t size) {
return ht->alloc->malloc(size, ht->alloc->user_data);
}
/**
* Call malloc_for_table, then zero the newly allocated buffer.
* @param ht The hash table
* @param size The number of bytes to allocate
* @return The newly allocated memory, or NULL if an error occurred
*/
static void *zeroed_malloc(const HTTable *ht, size_t size) {
void *p = malloc_for_table(ht, size);
if (!p) {
return NULL;
}
memset(p, 0, size);
return p;
}
/**
* Call the table's allocator's free function with the user_data argument.
* @param ht The hash table
* @param ptr The pointer to free
*/
static inline void free_for_table(const HTTable *ht, void *ptr) {
ht->alloc->free(ptr, ht->alloc->user_data);
}
/**
* The the table's key destruction function, if it has one.
* @param ht The hash table
* @param key The key to free
*/
static inline void free_table_key(const HTTable *ht, void *key) {
if (ht->fns->destroy_key) {
ht->fns->destroy_key(key, ht->fns->user_data);
}
}
/**
* The the table's value destruction function, if it has one.
* @param ht The hash table
* @param value The value to free
*/
static inline void free_table_value(const HTTable *ht, void *value) {
if (ht->fns->destroy_value) {
ht->fns->destroy_value(value, ht->fns->user_data);
}
}
/**
* Create and return a new hash table.
* @param fns The HTTableFunctions to use for the table
* @param alloc The HTAllocator to use, or NULL to use the standard C malloc and
* free
* @param thresh The HTThreshold to use, or NULL to use the default
* @return The new, empty hash table, or NULL if an error occured
*/
HTTable *ht_new(const HTTableFunctions *fns, const HTAllocator *alloc,
const HTThreshold *thresh) {
if (!alloc) {
alloc = &DEFAULT_ALLOCATOR;
}
if (!thresh) {
thresh = &DEFAULT_THRESHOLD;
}
HTTable *ht = alloc->malloc(sizeof(HTTable), alloc->user_data);
if (!ht) {
return NULL;
}
ht->fns = fns;
ht->alloc = alloc;
ht->thresh = thresh;
ht->count = 0;
ht->table_size = ht->thresh->initial_size;
ht->buckets = zeroed_malloc(ht, sizeof(Bucket *) * ht->table_size);
if (!ht->buckets) {
free_for_table(ht, ht);
return NULL;
}
return ht;
}
/**
* Execute the following block or statement once for each bucket in a hash
* table. Note that as this uses two loops, you cannot use a `break` statement
* inside it.
* @param bvar The variable name to put the bucket in. It is safe to modify this
* variable in almost any way, including freeing it.
* @param ht The hash table
*/
#define FOR_EACH_BUCKET(bvar, ht) \
for (struct { \
const HTTable *t; \
size_t i; \
} __l = {.t = (ht), .i = 0}; \
__l.i < __l.t->table_size; ++__l.i) \
for (Bucket *bvar = __l.t->buckets[__l.i], \
*__n = bvar ? bvar->next : NULL; \
bvar; bvar = __n, __n = bvar ? bvar->next : NULL)
/**
* Make a copy of a hash table. The HTTableFunctions, HTAllocator, and
* HTTreshold are copied from the old table.
* @param ht The hash table to copy
* @param copy_key_callback Function to use to copy each key, or NULL to just
* use the same pointer
* @param copy_value_callback Function to use to copy each value, or NULL to
* just use the same pointer
* @param user_data Extra data to pass to the copy functions
* @return A copy of ht, or NULL if an error occurred
*/
HTTable *ht_copy(const HTTable *ht, ht_copy_callback_t copy_key_callback,
ht_copy_callback_t copy_value_callback, void *user_data) {
HTTable *copy = malloc_for_table(ht, sizeof(HTTable));
if (!copy) {
return NULL;
}
copy->fns = ht->fns;
copy->alloc = ht->alloc;
copy->thresh = ht->thresh;
copy->count = ht->count;
copy->table_size = ht->table_size;
copy->buckets = zeroed_malloc(ht, sizeof(Bucket *) * copy->table_size);
if (!copy->buckets) {
free_for_table(ht, copy);
return NULL;
}
FOR_EACH_BUCKET(bucket, ht) {
uint64_t hash = bucket->hash;
size_t index = hash % copy->table_size;
Bucket *new_bucket = malloc_for_table(ht, sizeof(Bucket));
if (!new_bucket) {
ht_free(copy);
return NULL;
}
new_bucket->hash = hash;
new_bucket->key = copy_key_callback(bucket->key, user_data);
new_bucket->value = copy_value_callback(bucket->key, user_data);
new_bucket->next = copy->buckets[index];
copy->buckets[index] = new_bucket;
}
return copy;
}
/**
* Free a bucket and its associated key and value.
* @param ht The hash table
* @param bucket The bucket to free
*/
static inline void free_bucket(HTTable *ht, Bucket *bucket) {
free_table_key(ht, bucket->key);
free_table_value(ht, bucket->value);
free_for_table(ht, bucket);
}
/**
* Free a hash table as well as all of it's keys and values.
* @param ht The hash table
*/
void ht_free(HTTable *ht) {
if (ht->buckets) {
FOR_EACH_BUCKET(bucket, ht) {
free_bucket(ht, bucket);
}
}
free_for_table(ht, ht->buckets);
free_for_table(ht, ht);
}
/**
* Get the number of key-value pairs in a hash table.
* @return The number of pairs
*/
size_t ht_count(const HTTable *ht) {
return ht->count;
}
/**
* Check weather two hash tables are equal. That is, they are the same size and
* all elements in ht2 are present in ht1. This uses the hash and comparison
* functions from ht1 on the elements of ht2.
* @param ht1 The first hash table
* @param ht2 The second hash table
* @return True if the two tables were equal
*/
bool ht_equal(const HTTable *ht1, const HTTable *ht2) {
if (ht1->count != ht2->count) {
return false;
}
FOR_EACH_BUCKET(bucket, ht2) {
if (!ht_has(ht1, bucket->key)) {
return false;
}
}
return true;
}
/**
* Calculate the minimum number of elements to be present before a hash table
* should be grown.
* @param ht The hash table
* @return The growth threshold
*/
static inline size_t calculate_growth_threshold(HTTable *ht) {
return (size_t) (ht->table_size * ht->thresh->growth_threshold);
}
/**
* Calculate the maximum number of elements to be present before a hash table
* should be shrunk.
* @param ht The hash table
* @return The shrink threshold
*/
static inline size_t calculate_shrink_threshold(HTTable *ht) {
return (size_t) (ht->table_size * ht->thresh->shrink_threshold);
}
/**
* Expand or shrink a hash table to new_size buckets and then rehashes it.
* @param ht The hash table
* @param new_size The size to change to
* @return Wether the operation succeeded (true means success)
*/
static bool resize_to(HTTable *ht, size_t new_size) {
if (new_size < ht->thresh->initial_size) {
new_size = ht->thresh->initial_size;
}
if (ht->table_size == new_size) {
return true;
}
Bucket **new_buckets = zeroed_malloc(ht, sizeof(Bucket *) * new_size);
if (!new_size) {
return false;
}
FOR_EACH_BUCKET(bucket, ht) {
size_t index = bucket->hash % new_size;
bucket->next = new_buckets[index];
new_buckets[index] = bucket;
}
free_for_table(ht, ht->buckets);
ht->buckets = new_buckets;
ht->table_size = new_size;
return true;
}
/**
* Resize a hash table if it has reached one of its thresholds.
* @param ht The hash table
* @param delta The amount to add to the table's element count before checking
* @return False if an error occurred, true otherwise
*/
static bool maybe_resize(HTTable *ht, size_t delta) {
size_t new_count = ht->count + delta;
if (new_count >= calculate_growth_threshold(ht)) {
size_t new_size = ht->table_size * ht->thresh->growth_factor;
return resize_to(ht, new_size);
} else if (new_count <= calculate_shrink_threshold(ht)
&& ht->table_size != ht->thresh->initial_size) {
size_t new_size = ht->table_size / ht->thresh->growth_factor;
return resize_to(ht, new_size);
}
return true;
}
/**
* Check weather an entry matches a given key.
* @param ht The hash table
* @param bucket The bucket to check, or NULL
* @param hash The key's hash
* @param key The key
* @return True the bucket contains the given key, false otherwise
*/
static bool bucket_matches(const HTTable *ht, Bucket *bucket, uint64_t hash,
const void *key) {
return bucket && bucket->hash == hash
&& ht->fns->equal(bucket->key, key, ht->fns->user_data);
}
/**
* Find a given entry in a hash table. As this returns a double pointer, you
* can use it to remove or insert entries.
* @param ht The hash table
* @param hash The key's hash
* @param key The key
* @return A double pointer to a bucket, or NULL if no bucket was found
*/
static Bucket **find_bucket(const HTTable *ht, uint64_t hash, const void *key) {
size_t index = hash % ht->table_size;
Bucket *bucket = ht->buckets[index];
if (!bucket) {
return NULL;
} else if (bucket_matches(ht, bucket, hash, key)) {
return &ht->buckets[index];
}
for (; bucket->next; bucket = bucket->next) {
if (bucket_matches(ht, bucket->next, hash, key)) {
return &bucket->next;
}
}
// add new entries to the start
return NULL;
}
/**
* Calculate the hash of a given key.
* @param ht The hash table
* @param key The key
* @return The key's hash
*/
static inline uint64_t hash_for_table(const HTTable *ht, const void *key) {
return ht->fns->hash(key, ht->fns->user_data);
}
/**
* Insert a new key-value pair into a hash table, or update an existing pair
* @param ht The hash table
* @param key The key to insert
* @param value The value to associate with the key
* @return True if the insertion was successful, false if an allocation error
* occurred
*/
bool ht_insert(HTTable *ht, void *key, void *value) {
if (!maybe_resize(ht, 1)) {
return false;
}
uint64_t hash = hash_for_table(ht, key);
Bucket **bucket_ptr = find_bucket(ht, hash, key);
if (bucket_ptr) {
free_table_key(ht, (*bucket_ptr)->key);
(*bucket_ptr)->key = key;
free_table_value(ht, (*bucket_ptr)->value);
(*bucket_ptr)->value = value;
return true;
} else {
size_t index = hash % ht->table_size;
Bucket *new_bucket = malloc_for_table(ht, sizeof(Bucket));
if (!new_bucket) {
return false;
}
new_bucket->hash = hash;
new_bucket->key = key;
new_bucket->value = value;
new_bucket->next = ht->buckets[index];
ht->buckets[index] = new_bucket;
++ht->count;
return true;
}
}
/**
* Remove all entries from a hash table and free their keys and values.
* @param ht The hash table
* @return True if the operation was successful, false otherwise
*/
bool ht_clear(HTTable *ht) {
FOR_EACH_BUCKET(bucket, ht) {
free_bucket(ht, bucket);
}
free_for_table(ht, ht->buckets);
ht->table_size = ht->thresh->initial_size;
ht->buckets = zeroed_malloc(ht, sizeof(Bucket) * ht->table_size);
ht->count = 0;
if (!ht->buckets) {
ht->table_size = 0;
}
return ht->buckets;
}
/**
* Remove an entry from a hash table and free it's key and value.
* @param ht The hash table
* @param key The key to remove
* @return True if the operation was successful, false if an allocation error
* occurred
*/
bool ht_remove(HTTable *ht, const void *key) {
uint64_t hash = hash_for_table(ht, key);
Bucket **bucket_ptr = find_bucket(ht, hash, key);
if (!bucket_ptr) {
return true;
}
Bucket *to_remove = *bucket_ptr;
*bucket_ptr = to_remove->next;
free_bucket(ht, to_remove);
--ht->count;
if (!maybe_resize(ht, 0)) {
return false;
}
return true;
}
/**
* Store the key and value of an entry into stolen_key and stolen_value. Either
* of these can be NULL, in which case the respective key or value is instead
* freed.
* @param ht The hash table
* @param bucket The entry
* @param stolen_key Where to store the key, or NULL
* @param stolen_value Where to store the value, or NULL
*/
static inline void steal_bucket(HTTable *ht, Bucket *bucket, void **stolen_key,
void **stolen_value) {
if (stolen_key) {
*stolen_key = bucket->key;
} else {
free_table_key(ht, bucket->key);
}
if (stolen_value) {
*stolen_value = bucket->value;
} else {
free_table_value(ht, bucket->value);
}
free_for_table(ht, bucket);
}
/**
* Remove a key and value from a hash table without freeing them.
* @param ht The hash table
* @param key The key to use for the lookup
* @param stolen_key A pointer to a `void *` to fill with the retrieved key, or
* NULL if the key is to be freed
* @param stolen_value A pointer to a `void *` to fill with the retrieved value,
* or NULL if the value is to be freed
* @return True if the operation succeeded, false if an error occurred
*/
bool ht_steal(HTTable *ht, const void *key, void **stolen_key,
void **stolen_value) {
uint64_t hash = hash_for_table(ht, key);
Bucket **bucket_ptr = find_bucket(ht, hash, key);
if (!bucket_ptr) {
return true;
}
Bucket *to_remove = *bucket_ptr;
*bucket_ptr = to_remove->next;
steal_bucket(ht, to_remove, stolen_key, stolen_value);
--ht->count;
return maybe_resize(ht, 0);
}
/**
* Clear a hash table without calling any destructor. The returned arrays are
* allocated with the hash table's allocator.
* @param ht The hash table
* @param keys A pointer to a `void **` to fill with the array of keys in the
* table. If this is NULL, the keys will instead be freed.
* @param values The same as the keys parameter, but for the table's values
* @return True if the operation succeeded, false if an allocation error
* occurred. In the case of an error, the table is not modified and the values
* of *keys and *values are undefined.
*/
bool ht_steal_all(HTTable *ht, void ***keys, void ***values) {
if (keys) {
*keys = malloc_for_table(ht, sizeof(void *) * ht->count);
if (!*keys) {
return false;
}
}
if (values) {
*values = malloc_for_table(ht, sizeof(void *) * ht->count);
if (!*values) {
if (keys) {
free_for_table(ht, *keys);
}
return false;
}
}
Bucket **new_buckets =
zeroed_malloc(ht, sizeof(Bucket) * ht->thresh->initial_size);
if (!new_buckets) {
if (keys) {
free_for_table(ht, *keys);
}
if (values) {
free_for_table(ht, *values);
}
return false;
}
size_t old_table_size = ht->table_size;
Bucket **old_buckets = ht->buckets;
ht->table_size = ht->thresh->initial_size;
ht->count = 0;
ht->buckets = new_buckets;
size_t out_i = 0;
for (size_t i = 0; i < old_table_size; ++i) {
Bucket *bucket = old_buckets[i];
while (bucket) {
Bucket *next = bucket->next;
steal_bucket(ht, bucket, keys ? &(*keys)[out_i] : NULL,
values ? &(*values)[out_i] : NULL);
bucket = next;
++out_i;
}
}
free_for_table(ht, old_buckets);
return true;
}
/**
* Lookup a value in a hash table from its key.
* @param ht The hash table
* @param key The key
* @param found_key A pointer to a `void *` to fill with the key that was
* actually in the table. This can be NULL.
* @return The value associated with the key, or NULL if the key is absent
*/
void *ht_get_extended(const HTTable *ht, const void *key, void **found_key) {
uint64_t hash = hash_for_table(ht, key);
Bucket **bucket_ptr = find_bucket(ht, hash, key);
if (!bucket_ptr) {
if (found_key) {
*found_key = NULL;
}
return NULL;
}
if (found_key) {
*found_key = (*bucket_ptr)->key;
}
return (*bucket_ptr)->value;
}
/**
* Test for the presence of a key in a hash table.
* @param ht The hash table
* @param key The key
* @param found_key A pointer to a `void *` to fill with the key that was
* actually in the table. This can be NULL.
* @return Whether the table contained a mapping for the key
*/
bool ht_has_extended(const HTTable *ht, const void *key, void **found_key) {
uint64_t hash = hash_for_table(ht, key);
Bucket **bucket_ptr = find_bucket(ht, hash, key);
if (found_key) {
if (bucket_ptr) {
*found_key = (*bucket_ptr)->key;
} else {
*found_key = NULL;
}
}
return bucket_ptr;
}
/**
* Run a function for each entry in a hash table. The function should return a
* `bool`. If it returns true the iteration is stopped. You must not alter the
* table during the iteration.
* @param ht The hash table
* @param callback The function to call
* @param user_data Extra data to pass to the function
* @see ht_foreach_remove
*/
void ht_foreach(const HTTable *ht, ht_foreach_callback_t callback,
void *user_data) {
FOR_EACH_BUCKET(bucket, ht) {
if (callback(bucket->key, bucket->value, user_data)) {
return;
}
}
}
/**
* Run a function for each entry in a hash table. The function should return a
* `bool`. If it returns true the key-value pair passed to the function is
* removed from the table and their destructors called. You must not make any
* other alterations to the table during iteration.
* @param ht The hash table
* @param callback The function to call
* @param user_data Extra data to pass to the function
*/
bool ht_foreach_remove(HTTable *ht, ht_foreach_callback_t callback,
void *user_data) {
for (size_t i = 0; i < ht->table_size; ++i) {
Bucket **bucket_ptr = &ht->buckets[i];
while (*bucket_ptr) {
Bucket *bucket = *bucket_ptr;
if (callback((*bucket_ptr)->key, (*bucket_ptr)->value, user_data)) {
*bucket_ptr = bucket->next;
free_bucket(ht, bucket);
--ht->count;
} else {
bucket_ptr = &bucket->next;
}
}
}
return maybe_resize(ht, 0);
}
/**
* This is the same as ht_foreach_remove except that the key-value pair's
* destructors are not called.
* @param ht The hash table
* @param callback The function to call
* @param user_data Extra data to pass to the function
*/
bool ht_foreach_steal(HTTable *ht, ht_foreach_callback_t callback,
void *user_data) {
for (size_t i = 0; i < ht->table_size; ++i) {
Bucket **bucket_ptr = &ht->buckets[i];
while (*bucket_ptr) {
Bucket *bucket = *bucket_ptr;
if (callback((*bucket_ptr)->key, (*bucket_ptr)->value, user_data)) {
*bucket_ptr = bucket->next;
free_for_table(ht, bucket);
--ht->count;
} else {
bucket_ptr = &bucket->next;
}
}
}
return maybe_resize(ht, 0);
}
/**
* Call callback on every entry in a table until it returns true. When it does,
* put the key and value passed to callback into the key and value parameters.
* @param ht The hash table
* @param callback The functions to call
* @param user_data Extra data to pass to the callback
* @param key A pointer to a `void *` to store the key, or NULL
* @param value A pointer to a `void *` to store the value, or NULL
* @return True callback returned true, false otherwise
*/
bool ht_find(HTTable *ht, ht_foreach_callback_t callback, void *user_data,
void **key, void **value) {
FOR_EACH_BUCKET(bucket, ht) {
if (callback(bucket->key, bucket->value, user_data)) {
if (key) {
*key = bucket->key;
}
if (value) {
*value = bucket->value;
}
return true;
}
}
if (key) {
*key = NULL;
}
if (value) {
*value = NULL;
}
return false;
}
/**
* Add all entries from one hash table into another. No destructor are
* called. The entries are removed from the source table. Weather or not the
* operations succeeds, the source table is cleared. In the case of a failure,
* all entries that could not be inserted are freed.
* @param ht The destination table
* @param src The source table
* @return True if the operation was successful, false otherwise
*/
bool ht_steal_from(HTTable *ht, HTTable *src) {
Bucket **new_buckets =
zeroed_malloc(src, sizeof(Bucket) * src->thresh->initial_size);
if (!new_buckets) {
return NULL;
}
size_t old_table_size = src->table_size;
Bucket **old_buckets = src->buckets;
src->buckets = new_buckets;
src->count = 0;
src->table_size = src->thresh->initial_size;
bool no_errors = true;
for (size_t i = 0; i < old_table_size; ++i) {
Bucket *bucket = old_buckets[i];
while (bucket) {
if (no_errors) {
no_errors = ht_insert(ht, bucket->key, bucket->value);
}
Bucket *next = bucket->next;
if (no_errors) {
free_for_table(src, bucket);
} else {
free_bucket(src, bucket);
}
bucket = next;
}
}
free_for_table(src, old_buckets);
return no_errors;
}
/**
* Get the keys and value of a table as a list. This does not modify the table
* or transfer ownership of the keys or values. The returned arrays are
* allocated with the hash table's allocator.
* @param ht The hash table
* @param keys A pointer to a `void **` to fill with the table's keys, or NULL
* @param values A pointer to a `void **` to fill with the table's values, or
* NULL
* @return True if the operation succeeded, false otherwise. If it failed, the
* value of *keys and *values is undefined.
*/
bool ht_get_keys_and_values(const HTTable *ht, void ***keys, void ***values) {
if (!keys && !values) {
return true;
}
if (keys) {
*keys = malloc_for_table(ht, sizeof(void *) * ht->count);
if (!*keys) {
return false;
}
}
if (values) {
*values = malloc_for_table(ht, sizeof(void *) * ht->count);
if (!*values) {
if (keys) {
free_for_table(ht, *keys);
}
return false;
}
}
size_t i = 0;
FOR_EACH_BUCKET(bucket, ht) {
if (keys) {
if (keys) {
(*keys)[i] = bucket->key;
}
if (values) {
(*values)[i] = bucket->value;
}
++i;
}
}
return true;
}
/**
* Same as ht_get_keys_and_values, but only get the keys.
* @param ht The hash table
* @return The array of keys, or NULL if an allocation error occurred. It is the
* caller's responsibility to free this.
*/
void **ht_get_keys(const HTTable *ht) {
void **keys = NULL;
ht_get_keys_and_values(ht, &keys, NULL);
return keys;
}
/**
* Same as ht_get_keys_and_values, but only get the values.
* @param ht The hash table
* @return The array of values, or NULL if an allocation error occurred. It is
* the caller's responsibility to free this.
*/
void **ht_get_values(const HTTable *ht) {
void **values = NULL;
ht_get_keys_and_values(ht, &values, NULL);
return values;
}
/**
* HTTableFunctions hash function that hashes a null-terminated c-string.
* @param str The string to hash
* @param user_data The extra data stored in the HTTableFunctions
* @return The string's hash
*/
uint64_t ht_string_hash_callback(const void *str, void *user_data) {
if (!str) {
return 0;
}
const char *s = str;
uint64_t hash = 5381;
for (int c; (c = *(s++));) {
hash = ((hash << 5) + hash) + c;
}
return hash;
}
/**
* HTTableFunctions equality function that compares two null-terminated
* c-strings.
* @param str1 The first string, or NULL
* @param str2 The second string, or NULL
* @param user_data The extra data stored in the HTTableFunctions
* @return Weather the string where equal or both NULL
*/
bool ht_string_equal_callback(const void *str1, const void *str2,
void *user_data) {
if (!str1 || !str2) {
return str1 == str2;
}
return strcmp(str1, str2) == 0;
}
/**
* HTTableFunctions hash function that hashes a intptr_t or uintptr_t.
* @param num The number
* @param user_data The extra data stored in the HTTableFunctions
* @return The number (possibly under a modulo if it would overflow)
*/
uint64_t ht_intptr_hash_callback(const void *num, void *user_data) {
uintptr_t n = (uintptr_t) num;
#if UINTPTR_MAX > UINT64_MAX
// I know of no architectures where this is true, but just in case.
return n % UINT64_MAX;
#else
return n;
#endif
}
/**
* HTTableFunctions equality function that compares two intptr_t or uintptr_t
* values.
* @param n1 The first number
* @param n2 The second number
* @param user_data The extra data stored in the HTTableFunctions
* @return Weather the numbers were equal
*/
bool ht_intptr_equal_callback(const void *n1, const void *n2, void *user_data) {
return n1 == n2;
}

5
test/CMakeLists.txt Normal file
View File

@ -0,0 +1,5 @@
link_libraries(ht)
add_compile_options(-Wall -Wpedantic)
add_executable(test_ht test_ht.c)
add_test(NAME ht COMMAND test_ht)

308
test/test_ht.c Normal file
View File

@ -0,0 +1,308 @@
// this will certainly fail if NDEBUG is defined
#undef NDEBUG
#include <assert.h>
#include <ht.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void *counting_malloc(size_t size, void *count_ptr) {
int64_t *count = count_ptr;
void *ptr = malloc(size);
if (!ptr) {
return NULL;
}
++*count;
return ptr;
}
void counting_free(void *ptr, void *count_ptr) {
int64_t *count = count_ptr;
if (ptr) {
--*count;
}
free(ptr);
}
// this is void so it is standards compliant to pass this as a callback
void *counting_strdup(const void *str, void *count_ptr) {
size_t len = strlen(str) + 1;
char *buf = counting_malloc(len, count_ptr);
if (!buf) {
return NULL;
}
memcpy(buf, str, len);
return buf;
}
struct count_and_strs {
char **strs;
int count;
};
bool foreach_test_callback(void *key, void *value, void *user_data) {
struct count_and_strs *data = user_data;
char *index_str = (char *) key + sizeof("str") - 1;
int num = atoi(index_str) - 1;
assert(strcmp(key, data->strs[num]) == 0);
assert(strcmp(value, data->strs[num]) == 0);
return ++data->count >= 50;
}
bool foreach_remove_test_callback(void *key, void *value, void *user_data) {
bool *flag = user_data;
return *flag = !*flag;
}
struct alloc_count_and_flag {
bool flag;
int64_t *count;
};
bool foreach_steal_test_callback(void *key, void *value, void *user_data) {
struct alloc_count_and_flag *data = user_data;
if (data->flag) {
counting_free(key, data->count);
counting_free(value, data->count);
}
data->flag = !data->flag;
return !data->flag;
}
int main() {
int64_t allocation_count = 0;
const HTTableFunctions ONE_STR_FNS = {
.hash = ht_string_hash_callback,
.equal = ht_string_equal_callback,
.destroy_key = counting_free,
.destroy_value = NULL,
.user_data = &allocation_count,
};
const HTTableFunctions TWO_STR_FNS = {
.hash = ht_string_hash_callback,
.equal = ht_string_equal_callback,
.destroy_key = counting_free,
.destroy_value = counting_free,
.user_data = &allocation_count,
};
const HTAllocator ALLOCATOR = {
.malloc = counting_malloc,
.free = counting_free,
.user_data = &allocation_count,
};
const HTTableFunctions INT_FNS = {
.hash = ht_intptr_hash_callback,
.equal = ht_intptr_equal_callback,
.destroy_key = NULL,
.destroy_value = NULL,
.user_data = NULL,
};
#define malloc(s) counting_malloc((s), &allocation_count)
#define free(p) counting_free((p), &allocation_count)
#define strdup(s) counting_strdup((s), &allocation_count)
HTTable *t = ht_new(&ONE_STR_FNS, &ALLOCATOR, NULL);
assert(ht_count(t) == 0);
assert(ht_insert(t, strdup("str1"), HT_STUFF(1)));
assert(ht_has(t, "str1"));
assert(ht_count(t) == 1);
assert(ht_get(t, "str1") == HT_STUFF(1));
assert(ht_insert(t, strdup("str2"), HT_STUFF(2)));
assert(ht_count(t) == 2);
assert(ht_get(t, "str2") == HT_STUFF(2));
assert(ht_has(t, "str1"));
assert(ht_has(t, "str2"));
assert(!ht_has(t, "str3"));
assert(ht_get(t, "str3") == NULL);
assert(ht_remove(t, "str2"));
assert(ht_count(t) == 1);
assert(ht_remove(t, "str2"));
assert(!ht_has(t, "str2"));
assert(ht_get(t, "str2") == NULL);
assert(ht_count(t) == 1);
ht_free(t);
t = ht_new(&ONE_STR_FNS, &ALLOCATOR, NULL);
HTTable *t2 = ht_new(&ONE_STR_FNS, &ALLOCATOR, NULL);
assert(ht_insert(t, strdup("1"), HT_STUFF(1)));
assert(ht_insert(t, strdup("2"), HT_STUFF(2)));
assert(ht_insert(t2, strdup("2"), HT_STUFF(4)));
assert(ht_insert(t2, strdup("3"), HT_STUFF(3)));
assert(ht_count(t) == 2);
assert(ht_count(t2) == 2);
assert(ht_steal_from(t, t2));
assert(ht_count(t) == 3);
assert(ht_count(t2) == 0);
assert(ht_get(t, "1") == HT_STUFF(1));
assert(ht_get(t, "2") == HT_STUFF(4));
assert(ht_get(t, "3") == HT_STUFF(3));
void *found_key;
assert(ht_steal(t, "2", &found_key, NULL));
assert(strcmp(found_key, "2") == 0);
free(found_key);
void *found_value;
assert(ht_steal(t, "1", NULL, &found_value));
assert(found_value == HT_STUFF(1));
assert(ht_steal(t, "3", &found_key, &found_value));
assert(strcmp(found_key, "3") == 0);
assert(found_value == HT_STUFF(3));
free(found_key);
ht_free(t);
ht_free(t2);
t = ht_new(&INT_FNS, &ALLOCATOR, NULL);
assert(ht_count(t) == 0);
for (size_t i = 0; i < 500; ++i) {
assert(ht_insert(t, HT_STUFF(i), HT_STUFF(-i)));
assert(ht_count(t) == i + 1);
assert(ht_has(t, HT_STUFF(i)));
assert(ht_get(t, HT_STUFF(i)) == HT_STUFF(-i));
assert(!ht_has(t, HT_STUFF(i + 1)));
}
for (size_t i = 0; i < 500; ++i) {
assert(ht_has(t, HT_STUFF(i)));
}
for (size_t i = 0; i < 500; ++i) {
assert(ht_remove(t, HT_STUFF(i)));
assert(ht_count(t) == 499 - i);
assert(!ht_has(t, HT_STUFF(i)));
assert(ht_get(t, HT_STUFF(i)) == 0);
if (i < 499) {
assert(ht_has(t, HT_STUFF(i + 1)));
}
}
ht_free(t);
t = ht_new(&TWO_STR_FNS, &ALLOCATOR, NULL);
char *STRS_COPY1[100];
char *STRS_COPY2[100];
char *STRS_COPY3[100];
const size_t MAX_STR_LEN = sizeof("str100");
for (size_t i = 0; i < 100; ++i) {
STRS_COPY1[i] = malloc(MAX_STR_LEN);
snprintf(STRS_COPY1[i], MAX_STR_LEN, "str%zu", i + 1);
STRS_COPY2[i] = strdup(STRS_COPY1[i]);
STRS_COPY3[i] = strdup(STRS_COPY1[i]);
assert(ht_insert(t, STRS_COPY1[i], STRS_COPY2[i]));
}
assert(ht_count(t) == 100);
for (size_t i = 0; i < 100; ++i) {
void *found_key;
assert(ht_get_extended(t, STRS_COPY3[i], &found_key) == STRS_COPY2[i]);
assert(found_key == STRS_COPY1[i]);
}
t2 = ht_copy(t, counting_strdup, counting_strdup, &allocation_count);
assert(ht_count(t) == 100);
assert(ht_count(t2) == 100);
assert(ht_equal(t, t2));
for (size_t i = 0; i < 100; ++i) {
assert(ht_remove(t, STRS_COPY3[i]));
if (i < 5) {
assert(!ht_equal(t, t2));
}
}
assert(ht_count(t) == 0);
assert(ht_count(t2) == 100);
assert(!ht_equal(t, t2));
ht_free(t);
assert(ht_count(t2) == 100);
for (size_t i = 0; i < 100; ++i) {
void *found_key;
assert(ht_has_extended(t2, STRS_COPY3[i], &found_key));
assert(STRS_COPY3[i] != found_key);
}
void **keys1, **keys2;
void **values1, **values2;
assert((keys1 = ht_get_keys(t2)));
assert((values1 = ht_get_values(t2)));
assert(ht_get_keys_and_values(t2, &keys2, &values2));
for (size_t i = 0; i < 100; ++i) {
char *index_str = (char *) keys1[i] + sizeof("str") - 1;
int num = atoi(index_str) - 1;
assert(strcmp(keys1[i], keys2[i]) == 0);
assert(strcmp(keys1[i], STRS_COPY3[num]) == 0);
assert(strcmp(values1[i], values1[i]) == 0);
assert(strcmp(values1[i], STRS_COPY3[num]) == 0);
}
free(keys1);
free(keys2);
free(values1);
free(values2);
struct count_and_strs cas = {
.strs = STRS_COPY3,
.count = 0,
};
ht_foreach(t2, foreach_test_callback, &cas);
assert(cas.count == 50);
assert(ht_count(t2) == 100);
bool flag = NULL;
assert(ht_foreach_remove(t2, foreach_remove_test_callback, &flag));
assert(ht_count(t2) == 50);
struct alloc_count_and_flag acaf = {
.flag = false,
.count = &allocation_count,
};
assert(ht_foreach_steal(t2, foreach_steal_test_callback, &acaf));
assert(ht_count(t2) == 25);
t = ht_copy(t2, counting_strdup, counting_strdup, &allocation_count);
assert(ht_clear(t2));
assert(ht_count(t2) == 0);
ht_free(t2);
for (size_t i = 0; i < 100; ++i) {
free(STRS_COPY3[i]);
}
assert(ht_count(t) == 25);
void **keys, **values;
ht_steal_all(t, &keys, &values);
assert(ht_count(t) == 0);
for (size_t i = 0; i < 25; ++i) {
assert(strcmp(keys[i], values[i]) == 0);
assert(keys[i] != values[i]);
free(keys[i]);
free(values[i]);
}
free(keys);
free(values);
ht_free(t);
assert(allocation_count == 0);
return 0;
}