[igt-dev] [PATCH i-g-t v29 03/36] lib/igt_map: Adopt Mesa hash table

Jason Ekstrand jason at jlekstrand.net
Wed Mar 24 18:59:41 UTC 2021


On Wed, Mar 24, 2021 at 12:36 PM Zbigniew Kempczyński
<zbigniew.kempczynski at intel.com> wrote:
>
> From: Dominik Grzegorzek <dominik.grzegorzek at intel.com>

Is this still from Dominik?  Assuming it's a direct import of the Mesa
code, without ralloc,

Acked-by: Jason Ekstrand <jason at jlekstrand.net>

> The _search function has been changed to return a pointer to
> the stored data instead of the entry struct. The _search_entry function,
> which acts as the original search has been added. Additionally _remove function
> has an optional delete_function param, to make it more usable.
>
> For more information, see:
> http://cgit.freedesktop.org/~anholt/hash_table/tree/README
>
> Signed-off-by: Dominik Grzegorzek <dominik.grzegorzek at intel.com>
> Cc: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Jason Ekstrand <jason at jlekstrand.net>
> ---
>  .../igt-gpu-tools/igt-gpu-tools-docs.xml      |   1 +
>  lib/Makefile.sources                          |   2 +
>  lib/igt_map.c                                 | 502 ++++++++++++++++++
>  lib/igt_map.h                                 | 174 ++++++
>  lib/meson.build                               |   1 +
>  5 files changed, 680 insertions(+)
>  create mode 100644 lib/igt_map.c
>  create mode 100644 lib/igt_map.h
>
> diff --git a/docs/reference/igt-gpu-tools/igt-gpu-tools-docs.xml b/docs/reference/igt-gpu-tools/igt-gpu-tools-docs.xml
> index 9c9aa8f1d..bf5ac5428 100644
> --- a/docs/reference/igt-gpu-tools/igt-gpu-tools-docs.xml
> +++ b/docs/reference/igt-gpu-tools/igt-gpu-tools-docs.xml
> @@ -33,6 +33,7 @@
>      <xi:include href="xml/igt_kmod.xml"/>
>      <xi:include href="xml/igt_kms.xml"/>
>      <xi:include href="xml/igt_list.xml"/>
> +    <xi:include href="xml/igt_map.xml"/>
>      <xi:include href="xml/igt_pm.xml"/>
>      <xi:include href="xml/igt_primes.xml"/>
>      <xi:include href="xml/igt_rand.xml"/>
> diff --git a/lib/Makefile.sources b/lib/Makefile.sources
> index 4f6389f8a..84fd7b49c 100644
> --- a/lib/Makefile.sources
> +++ b/lib/Makefile.sources
> @@ -48,6 +48,8 @@ lib_source_list =             \
>         igt_infoframe.h         \
>         igt_list.c              \
>         igt_list.h              \
> +       igt_map.c               \
> +       igt_map.h               \
>         igt_matrix.c            \
>         igt_matrix.h            \
>         igt_params.c            \
> diff --git a/lib/igt_map.c b/lib/igt_map.c
> new file mode 100644
> index 000000000..da8713a18
> --- /dev/null
> +++ b/lib/igt_map.c
> @@ -0,0 +1,502 @@
> +/*
> + * Copyright © 2009, 2021 Intel Corporation
> + * Copyright © 1988-2004 Keith Packard and Bart Massey.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + * Except as contained in this notice, the names of the authors
> + * or their institutions shall not be used in advertising or
> + * otherwise to promote the sale, use or other dealings in this
> + * Software without prior written authorization from the
> + * authors.
> + *
> + * Authors:
> + *    Eric Anholt <eric at anholt.net>
> + *    Keith Packard <keithp at keithp.com>
> + */
> +
> +#include <assert.h>
> +#include <stdlib.h>
> +
> +#include "igt_map.h"
> +
> +#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
> +
> +/*
> + * From Knuth -- a good choice for hash/rehash values is p, p-2 where
> + * p and p-2 are both prime.  These tables are sized to have an extra 10%
> + * free to avoid exponential performance degradation as the hash table fills
> + */
> +
> +static const uint32_t deleted_key_value;
> +static const void *deleted_key = &deleted_key_value;
> +
> +static const struct {
> +       uint32_t max_entries, size, rehash;
> +} hash_sizes[] = {
> +       { 2,            5,              3         },
> +       { 4,            7,              5         },
> +       { 8,            13,             11        },
> +       { 16,           19,             17        },
> +       { 32,           43,             41        },
> +       { 64,           73,             71        },
> +       { 128,          151,            149       },
> +       { 256,          283,            281       },
> +       { 512,          571,            569       },
> +       { 1024,         1153,           1151      },
> +       { 2048,         2269,           2267      },
> +       { 4096,         4519,           4517      },
> +       { 8192,         9013,           9011      },
> +       { 16384,        18043,          18041     },
> +       { 32768,        36109,          36107     },
> +       { 65536,        72091,          72089     },
> +       { 131072,       144409,         144407    },
> +       { 262144,       288361,         288359    },
> +       { 524288,       576883,         576881    },
> +       { 1048576,      1153459,        1153457   },
> +       { 2097152,      2307163,        2307161   },
> +       { 4194304,      4613893,        4613891   },
> +       { 8388608,      9227641,        9227639   },
> +       { 16777216,     18455029,       18455027  },
> +       { 33554432,     36911011,       36911009  },
> +       { 67108864,     73819861,       73819859  },
> +       { 134217728,    147639589,      147639587 },
> +       { 268435456,    295279081,      295279079 },
> +       { 536870912,    590559793,      590559791 },
> +       { 1073741824,   1181116273,     1181116271},
> +       { 2147483648ul, 2362232233ul,   2362232231ul}
> +};
> +
> +static int
> +entry_is_free(const struct igt_map_entry *entry)
> +{
> +       return entry->key == NULL;
> +}
> +
> +static int
> +entry_is_deleted(const struct igt_map_entry *entry)
> +{
> +       return entry->key == deleted_key;
> +}
> +
> +static int
> +entry_is_present(const struct igt_map_entry *entry)
> +{
> +       return entry->key != NULL && entry->key != deleted_key;
> +}
> +
> +/**
> + * igt_map_create:
> + * @hash_function: function that maps key to 32b hash
> + * @key_equals_function: function that compares given hashes
> + *
> + * Function creates a map and initializes it with given @hash_function and
> + * @key_equals_function.
> + *
> + * Returns: pointer to just created map
> + */
> +struct igt_map *
> +igt_map_create(uint32_t (*hash_function)(const void *key),
> +              int (*key_equals_function)(const void *a, const void *b))
> +{
> +       struct igt_map *map;
> +
> +       map = malloc(sizeof(*map));
> +       if (map == NULL)
> +               return NULL;
> +
> +       map->size_index = 0;
> +       map->size = hash_sizes[map->size_index].size;
> +       map->rehash = hash_sizes[map->size_index].rehash;
> +       map->max_entries = hash_sizes[map->size_index].max_entries;
> +       map->hash_function = hash_function;
> +       map->key_equals_function = key_equals_function;
> +       map->table = calloc(map->size, sizeof(*map->table));
> +       map->entries = 0;
> +       map->deleted_entries = 0;
> +
> +       if (map->table == NULL) {
> +               free(map);
> +               return NULL;
> +       }
> +
> +       return map;
> +}
> +
> +/**
> + * igt_map_destroy:
> + * @map: igt_map pointer
> + * @delete_function: function that frees data in igt_map_entry
> + *
> + * Frees the given hash table. If @delete_function is passed, it gets called
> + * on each entry present before freeing.
> + */
> +void
> +igt_map_destroy(struct igt_map *map,
> +               void (*delete_function)(struct igt_map_entry *entry))
> +{
> +       if (!map)
> +               return;
> +
> +       if (delete_function) {
> +               struct igt_map_entry *entry;
> +
> +               igt_map_foreach(map, entry) {
> +                       delete_function(entry);
> +               }
> +       }
> +       free(map->table);
> +       free(map);
> +}
> +
> +/**
> + * igt_map_search:
> + * @map: igt_map pointer
> + * @key: pointer to searched key
> + *
> + * Finds a map entry's data with the given @key.
> + *
> + * Returns: data pointer if the entry was found, %NULL otherwise.
> + * Note that it may be modified by the user.
> + */
> +void *
> +igt_map_search(struct igt_map *map, const void *key)
> +{
> +       uint32_t hash = map->hash_function(key);
> +       struct igt_map_entry *entry;
> +
> +       entry = igt_map_search_pre_hashed(map, hash, key);
> +       return entry ? entry->data : NULL;
> +}
> +
> +/**
> + * igt_map_search_entry:
> + * @map: igt_map pointer
> + * @key: pointer to searched key
> + *
> + * Finds a map entry with the given @key.
> + *
> + * Returns: map entry or %NULL if no entry is found.
> + * Note that the data pointer may be modified by the user.
> + */
> +struct igt_map_entry *
> +igt_map_search_entry(struct igt_map *map, const void *key)
> +{
> +       uint32_t hash = map->hash_function(key);
> +
> +       return igt_map_search_pre_hashed(map, hash, key);
> +}
> +
> +/**
> + * igt_map_search_pre_hashed:
> + * @map: igt_map pointer
> + * @hash: hash of @key
> + * @key: pointer to searched key
> + *
> + * Finds a map entry with the given @key and @hash of that key.
> + *
> + * Returns: map entry or %NULL if no entry is found.
> + * Note that the data pointer may be modified by the user.
> + */
> +struct igt_map_entry *
> +igt_map_search_pre_hashed(struct igt_map *map, uint32_t hash,
> +                         const void *key)
> +{
> +       uint32_t start_hash_address = hash % map->size;
> +       uint32_t hash_address = start_hash_address;
> +
> +       do {
> +               uint32_t double_hash;
> +
> +               struct igt_map_entry *entry = map->table + hash_address;
> +
> +               if (entry_is_free(entry)) {
> +                       return NULL;
> +               } else if (entry_is_present(entry) && entry->hash == hash) {
> +                       if (map->key_equals_function(key, entry->key)) {
> +                               return entry;
> +                       }
> +               }
> +
> +               double_hash = 1 + hash % map->rehash;
> +
> +               hash_address = (hash_address + double_hash) % map->size;
> +       } while (hash_address != start_hash_address);
> +
> +       return NULL;
> +}
> +
> +static void
> +igt_map_rehash(struct igt_map *map, int new_size_index)
> +{
> +       struct igt_map old_map;
> +       struct igt_map_entry *table, *entry;
> +
> +       if (new_size_index >= ARRAY_SIZE(hash_sizes))
> +               return;
> +
> +       table = calloc(hash_sizes[new_size_index].size, sizeof(*map->table));
> +       if (table == NULL)
> +               return;
> +
> +       old_map = *map;
> +
> +       map->table = table;
> +       map->size_index = new_size_index;
> +       map->size = hash_sizes[map->size_index].size;
> +       map->rehash = hash_sizes[map->size_index].rehash;
> +       map->max_entries = hash_sizes[map->size_index].max_entries;
> +       map->entries = 0;
> +       map->deleted_entries = 0;
> +
> +       igt_map_foreach(&old_map, entry) {
> +               igt_map_insert_pre_hashed(map, entry->hash,
> +                                            entry->key, entry->data);
> +       }
> +
> +       free(old_map.table);
> +}
> +
> +/**
> + * igt_map_insert:
> + * @map: igt_map pointer
> + * @data: data to be store
> + * @key: pointer to searched key
> + *
> + * Inserts the @data indexed by given @key into the map. If the @map already
> + * contains an entry with the @key, it will be replaced. To avoid memory leaks,
> + * perform a search before inserting.
> + *
> + * Note that insertion may rearrange the table on a resize or rehash,
> + * so previously found hash entries are no longer valid after this function.
> + *
> + * Returns: pointer to just inserted entry
> + */
> +struct igt_map_entry *
> +igt_map_insert(struct igt_map *map, const void *key, void *data)
> +{
> +       uint32_t hash = map->hash_function(key);
> +
> +       /* Make sure nobody tries to add one of the magic values as a
> +        * key. If you need to do so, either do so in a wrapper, or
> +        * store keys with the magic values separately in the struct
> +        * igt_map.
> +        */
> +       assert(key != NULL);
> +
> +       return igt_map_insert_pre_hashed(map, hash, key, data);
> +}
> +
> +/**
> + * igt_map_insert_pre_hashed:
> + * @map: igt_map pointer
> + * @hash: hash of @key
> + * @data: data to be store
> + * @key: pointer to searched key
> + *
> + * Inserts the @data indexed by given @key and @hash of that @key into the map.
> + * If the @map already contains an entry with the @key, it will be replaced.
> + * To avoid memory leaks, perform a search before inserting.
> + *
> + * Note that insertion may rearrange the table on a resize or rehash,
> + * so previously found hash entries are no longer valid after this function.
> + *
> + * Returns: pointer to just inserted entry
> + */
> +struct igt_map_entry *
> +igt_map_insert_pre_hashed(struct igt_map *map, uint32_t hash,
> +                         const void *key, void *data)
> +{
> +       uint32_t start_hash_address, hash_address;
> +       struct igt_map_entry *available_entry = NULL;
> +
> +       if (map->entries >= map->max_entries) {
> +               igt_map_rehash(map, map->size_index + 1);
> +       } else if (map->deleted_entries + map->entries >= map->max_entries) {
> +               igt_map_rehash(map, map->size_index);
> +       }
> +
> +       start_hash_address = hash % map->size;
> +       hash_address = start_hash_address;
> +       do {
> +               struct igt_map_entry *entry = map->table + hash_address;
> +               uint32_t double_hash;
> +
> +               if (!entry_is_present(entry)) {
> +                       /* Stash the first available entry we find */
> +                       if (available_entry == NULL)
> +                               available_entry = entry;
> +                       if (entry_is_free(entry))
> +                               break;
> +               }
> +
> +               /* Implement replacement when another insert happens
> +                * with a matching key.  This is a relatively common
> +                * feature of hash tables, with the alternative
> +                * generally being "insert the new value as well, and
> +                * return it first when the key is searched for".
> +                *
> +                * Note that the hash table doesn't have a delete
> +                * callback.  If freeing of old data pointers is
> +                * required to avoid memory leaks, perform a search
> +                * before inserting.
> +                */
> +               if (!entry_is_deleted(entry) &&
> +                   entry->hash == hash &&
> +                   map->key_equals_function(key, entry->key)) {
> +                       entry->key = key;
> +                       entry->data = data;
> +                       return entry;
> +               }
> +
> +
> +               double_hash = 1 + hash % map->rehash;
> +
> +               hash_address = (hash_address + double_hash) % map->size;
> +       } while (hash_address != start_hash_address);
> +
> +       if (available_entry) {
> +               if (entry_is_deleted(available_entry))
> +                       map->deleted_entries--;
> +               available_entry->hash = hash;
> +               available_entry->key = key;
> +               available_entry->data = data;
> +               map->entries++;
> +               return available_entry;
> +       }
> +
> +       /* We could hit here if a required resize failed. An unchecked-malloc
> +        * application could ignore this result.
> +        */
> +       return NULL;
> +}
> +
> +/**
> + * igt_map_remove:
> + * @map: igt_map pointer
> + * @key: pointer to searched key
> + * @delete_function: function that frees data in igt_map_entry
> + *
> + * Function searches for an entry with a given @key, and removes it from
> + * the map. If @delete_function is passed, it will be called on removed entry.
> + *
> + * If the caller has previously found a struct igt_map_entry pointer,
> + * (from calling igt_map_search() or remembering it from igt_map_insert()),
> + * then igt_map_remove_entry() can be called instead to avoid an extra search.
> + */
> +void
> +igt_map_remove(struct igt_map *map, const void *key,
> +               void (*delete_function)(struct igt_map_entry *entry))
> +{
> +       struct igt_map_entry *entry;
> +
> +       entry = igt_map_search_entry(map, key);
> +       if (delete_function)
> +               delete_function(entry);
> +
> +       igt_map_remove_entry(map, entry);
> +}
> +
> +/**
> + * igt_map_remove_entry:
> + * @map: igt_map pointer
> + * @entry: pointer to map entry
> + *
> + * Function deletes the given hash entry.
> + *
> + * Note that deletion doesn't otherwise modify the table, so an iteration over
> + * the map deleting entries is safe.
> + */
> +void
> +igt_map_remove_entry(struct igt_map *map, struct igt_map_entry *entry)
> +{
> +       if (!entry)
> +               return;
> +
> +       entry->key = deleted_key;
> +       map->entries--;
> +       map->deleted_entries++;
> +}
> +
> +/**
> + * igt_map_next_entry:
> + * @map: igt_map pointer
> + * @entry: pointer to map entry, %NULL for the first map entry
> + *
> + * This function is an iterator over the hash table.
> + * Note that an iteration over the table is O(table_size) not O(entries).
> + *
> + * Returns: pointer to the next entry
> + */
> +struct igt_map_entry *
> +igt_map_next_entry(struct igt_map *map, struct igt_map_entry *entry)
> +{
> +       if (entry == NULL)
> +               entry = map->table;
> +       else
> +               entry = entry + 1;
> +
> +       for (; entry != map->table + map->size; entry++) {
> +               if (entry_is_present(entry)) {
> +                       return entry;
> +               }
> +       }
> +
> +       return NULL;
> +}
> +
> +/**
> + * igt_map_random_entry:
> + * @map: igt_map pointer
> + * @predicate: filtering entries function
> + *
> + * Functions returns random entry from the map. This may be useful in
> + * implementing random replacement (as opposed to just removing everything)
> + * in caches based on this hash table implementation. @predicate may be used to
> + * filter entries, or may be set to %NULL for no filtering.
> + *
> + * Returns: pointer to the randomly chosen map entry
> + */
> +struct igt_map_entry *
> +igt_map_random_entry(struct igt_map *map,
> +                    int (*predicate)(struct igt_map_entry *entry))
> +{
> +       struct igt_map_entry *entry;
> +       uint32_t i = random() % map->size;
> +
> +       if (map->entries == 0)
> +               return NULL;
> +
> +       for (entry = map->table + i; entry != map->table + map->size; entry++) {
> +               if (entry_is_present(entry) &&
> +                   (!predicate || predicate(entry))) {
> +                       return entry;
> +               }
> +       }
> +
> +       for (entry = map->table; entry != map->table + i; entry++) {
> +               if (entry_is_present(entry) &&
> +                   (!predicate || predicate(entry))) {
> +                       return entry;
> +               }
> +       }
> +
> +       return NULL;
> +}
> diff --git a/lib/igt_map.h b/lib/igt_map.h
> new file mode 100644
> index 000000000..cadcd6e35
> --- /dev/null
> +++ b/lib/igt_map.h
> @@ -0,0 +1,174 @@
> +/*
> + * Copyright © 2009,2021 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + * Authors:
> + *    Eric Anholt <eric at anholt.net>
> + *
> + */
> +
> +#ifndef IGT_MAP_H
> +#define IGT_MAP_H
> +
> +#include <inttypes.h>
> +
> +/**
> + * SECTION:igt_map
> + * @short_description: a linear-reprobing hashmap implementation
> + * @title: IGT Map
> + * @include: igt_map.h
> + *
> + * Implements an open-addressing, linear-reprobing hash table.
> + *
> + * For more information, see:
> + * http://cgit.freedesktop.org/~anholt/hash_table/tree/README
> + *
> + * Example usage:
> + *
> + *|[<!-- language="C" -->
> + * #define GOLDEN_RATIO_PRIME_32 0x9e370001UL
> + *
> + * static inline uint32_t hash_identifier(const void *val)
> + * {
> + *     uint32_t hash = *(uint32_t *) val;
> + *
> + *     hash = hash * GOLDEN_RATIO_PRIME_32;
> + *     return hash;
> + * }
> + *
> + * static int equal_identifiers(const void *a, const void *b)
> + * {
> + *     uint32_t *key1 = (uint32_t *) a, *key2 = (uint32_t *) b;
> + *
> + *     return *key1 == *key2;
> + * }
> + *
> + * static void free_func(struct igt_map_entry *entry)
> + * {
> + *     free(entry->data);
> + * }
> + *
> + * struct igt_map *map;
> + *
> + * struct record {
> + *      int foo;
> + *      uint32_t unique_identifier;
> + * };
> + *
> + * struct record *r1, r2, *record;
> + * struct igt_map_entry *entry;
> + *
> + * r1 = malloc(sizeof(struct record));
> + * map = igt_map_create(hash_identifier, equal_identifiers);
> + * igt_map_insert(map, &r1->unique_identifier, r1);
> + * igt_map_insert(map, &r2.unique_identifier, &r2);
> + *
> + * igt_map_foreach(map, entry) {
> + *     record = entry->data;
> + *     printf("key: %u, foo: %d\n", *(uint32_t *) entry->key, record->foo);
> + * }
> + *
> + * record = igt_map_search(map, &r1->unique_identifier);
> + * entry = igt_map_search_entry(map, &r2.unique_identifier);
> + *
> + * igt_map_remove(map, &r1->unique_identifier, free_func);
> + * igt_map_remove_entry(map, entry);
> + *
> + *  igt_map_destroy(map, NULL);
> + * ]|
> + */
> +
> +struct igt_map_entry {
> +       uint32_t hash;
> +       const void *key;
> +       void *data;
> +};
> +
> +struct igt_map {
> +       struct igt_map_entry *table;
> +       uint32_t (*hash_function)(const void *key);
> +       int (*key_equals_function)(const void *a, const void *b);
> +       uint32_t size;
> +       uint32_t rehash;
> +       uint32_t max_entries;
> +       uint32_t size_index;
> +       uint32_t entries;
> +       uint32_t deleted_entries;
> +};
> +
> +struct igt_map *
> +igt_map_create(uint32_t (*hash_function)(const void *key),
> +              int (*key_equals_function)(const void *a, const void *b));
> +void
> +igt_map_destroy(struct igt_map *map,
> +               void (*delete_function)(struct igt_map_entry *entry));
> +
> +struct igt_map_entry *
> +igt_map_insert(struct igt_map *map, const void *key, void *data);
> +
> +void *
> +igt_map_search(struct igt_map *map, const void *key);
> +
> +struct igt_map_entry *
> +igt_map_search_entry(struct igt_map *map, const void *key);
> +
> +void
> +igt_map_remove(struct igt_map *map, const void *key,
> +              void (*delete_function)(struct igt_map_entry *entry));
> +
> +void
> +igt_map_remove_entry(struct igt_map *map, struct igt_map_entry *entry);
> +
> +struct igt_map_entry *
> +igt_map_next_entry(struct igt_map *map, struct igt_map_entry *entry);
> +
> +struct igt_map_entry *
> +igt_map_random_entry(struct igt_map *map,
> +                    int (*predicate)(struct igt_map_entry *entry));
> +/**
> + * igt_map_foreach
> + * @map: igt_map pointer
> + * @entry: igt_map_entry pointer
> + *
> + * Macro is a loop, which iterates through each map entry. Inside a
> + * loop block current element is accessible by the @entry pointer.
> + *
> + * This foreach function is safe against deletion (which just replaces
> + * an entry's data with the deleted marker), but not against insertion
> + * (which may rehash the table, making entry a dangling pointer).
> + */
> +#define igt_map_foreach(map, entry)                            \
> +       for (entry = igt_map_next_entry(map, NULL);             \
> +            entry != NULL;                                     \
> +            entry = igt_map_next_entry(map, entry))
> +
> +/* Alternate interfaces to reduce repeated calls to hash function. */
> +struct igt_map_entry *
> +igt_map_search_pre_hashed(struct igt_map *map,
> +                            uint32_t hash,
> +                            const void *key);
> +
> +struct igt_map_entry *
> +igt_map_insert_pre_hashed(struct igt_map *map,
> +                            uint32_t hash,
> +                            const void *key, void *data);
> +
> +#endif
> diff --git a/lib/meson.build b/lib/meson.build
> index 672b42062..7254faeac 100644
> --- a/lib/meson.build
> +++ b/lib/meson.build
> @@ -61,6 +61,7 @@ lib_sources = [
>         'igt_core.c',
>         'igt_draw.c',
>         'igt_list.c',
> +       'igt_map.c',
>         'igt_pm.c',
>         'igt_dummyload.c',
>         'uwildmat/uwildmat.c',
> --
> 2.26.0
>


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