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-rw-r--r--mesalib/src/mesa/main/hash_table.c440
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diff --git a/mesalib/src/mesa/main/hash_table.c b/mesalib/src/mesa/main/hash_table.c
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-/*
- * Copyright © 2009,2012 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@anholt.net>
- * Keith Packard <keithp@keithp.com>
- */
-
-/**
- * Implements an open-addressing, linear-reprobing hash table.
- *
- * For more information, see:
- *
- * http://cgit.freedesktop.org/~anholt/hash_table/tree/README
- */
-
-#include <stdlib.h>
-#include <string.h>
-
-#include "main/hash_table.h"
-#include "main/macros.h"
-#include "ralloc.h"
-
-static const uint32_t deleted_key_value;
-
-/**
- * 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 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 hash_entry *entry)
-{
- return entry->key == NULL;
-}
-
-static int
-entry_is_deleted(const struct hash_table *ht, struct hash_entry *entry)
-{
- return entry->key == ht->deleted_key;
-}
-
-static int
-entry_is_present(const struct hash_table *ht, struct hash_entry *entry)
-{
- return entry->key != NULL && entry->key != ht->deleted_key;
-}
-
-struct hash_table *
-_mesa_hash_table_create(void *mem_ctx,
- bool (*key_equals_function)(const void *a,
- const void *b))
-{
- struct hash_table *ht;
-
- ht = ralloc(mem_ctx, struct hash_table);
- if (ht == NULL)
- return NULL;
-
- ht->size_index = 0;
- ht->size = hash_sizes[ht->size_index].size;
- ht->rehash = hash_sizes[ht->size_index].rehash;
- ht->max_entries = hash_sizes[ht->size_index].max_entries;
- ht->key_equals_function = key_equals_function;
- ht->table = rzalloc_array(ht, struct hash_entry, ht->size);
- ht->entries = 0;
- ht->deleted_entries = 0;
- ht->deleted_key = &deleted_key_value;
-
- if (ht->table == NULL) {
- ralloc_free(ht);
- return NULL;
- }
-
- return ht;
-}
-
-/**
- * Frees the given hash table.
- *
- * If delete_function is passed, it gets called on each entry present before
- * freeing.
- */
-void
-_mesa_hash_table_destroy(struct hash_table *ht,
- void (*delete_function)(struct hash_entry *entry))
-{
- if (!ht)
- return;
-
- if (delete_function) {
- struct hash_entry *entry;
-
- hash_table_foreach(ht, entry) {
- delete_function(entry);
- }
- }
- ralloc_free(ht);
-}
-
-/** Sets the value of the key pointer used for deleted entries in the table.
- *
- * The assumption is that usually keys are actual pointers, so we use a
- * default value of a pointer to an arbitrary piece of storage in the library.
- * But in some cases a consumer wants to store some other sort of value in the
- * table, like a uint32_t, in which case that pointer may conflict with one of
- * their valid keys. This lets that user select a safe value.
- *
- * This must be called before any keys are actually deleted from the table.
- */
-void
-_mesa_hash_table_set_deleted_key(struct hash_table *ht, const void *deleted_key)
-{
- ht->deleted_key = deleted_key;
-}
-
-/**
- * Finds a hash table entry with the given key and hash of that key.
- *
- * Returns NULL if no entry is found. Note that the data pointer may be
- * modified by the user.
- */
-struct hash_entry *
-_mesa_hash_table_search(struct hash_table *ht, uint32_t hash,
- const void *key)
-{
- uint32_t start_hash_address = hash % ht->size;
- uint32_t hash_address = start_hash_address;
-
- do {
- uint32_t double_hash;
-
- struct hash_entry *entry = ht->table + hash_address;
-
- if (entry_is_free(entry)) {
- return NULL;
- } else if (entry_is_present(ht, entry) && entry->hash == hash) {
- if (ht->key_equals_function(key, entry->key)) {
- return entry;
- }
- }
-
- double_hash = 1 + hash % ht->rehash;
-
- hash_address = (hash_address + double_hash) % ht->size;
- } while (hash_address != start_hash_address);
-
- return NULL;
-}
-
-static void
-_mesa_hash_table_rehash(struct hash_table *ht, int new_size_index)
-{
- struct hash_table old_ht;
- struct hash_entry *table, *entry;
-
- if (new_size_index >= ARRAY_SIZE(hash_sizes))
- return;
-
- table = rzalloc_array(ht, struct hash_entry,
- hash_sizes[new_size_index].size);
- if (table == NULL)
- return;
-
- old_ht = *ht;
-
- ht->table = table;
- ht->size_index = new_size_index;
- ht->size = hash_sizes[ht->size_index].size;
- ht->rehash = hash_sizes[ht->size_index].rehash;
- ht->max_entries = hash_sizes[ht->size_index].max_entries;
- ht->entries = 0;
- ht->deleted_entries = 0;
-
- hash_table_foreach(&old_ht, entry) {
- _mesa_hash_table_insert(ht, entry->hash,
- entry->key, entry->data);
- }
-
- ralloc_free(old_ht.table);
-}
-
-/**
- * Inserts the key with the given hash into the table.
- *
- * Note that insertion may rearrange the table on a resize or rehash,
- * so previously found hash_entries are no longer valid after this function.
- */
-struct hash_entry *
-_mesa_hash_table_insert(struct hash_table *ht, uint32_t hash,
- const void *key, void *data)
-{
- uint32_t start_hash_address, hash_address;
-
- if (ht->entries >= ht->max_entries) {
- _mesa_hash_table_rehash(ht, ht->size_index + 1);
- } else if (ht->deleted_entries + ht->entries >= ht->max_entries) {
- _mesa_hash_table_rehash(ht, ht->size_index);
- }
-
- start_hash_address = hash % ht->size;
- hash_address = start_hash_address;
- do {
- struct hash_entry *entry = ht->table + hash_address;
- uint32_t double_hash;
-
- if (!entry_is_present(ht, entry)) {
- if (entry_is_deleted(ht, entry))
- ht->deleted_entries--;
- entry->hash = hash;
- entry->key = key;
- entry->data = data;
- ht->entries++;
- return entry;
- }
-
- /* 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->hash == hash &&
- ht->key_equals_function(key, entry->key)) {
- entry->key = key;
- entry->data = data;
- return entry;
- }
-
-
- double_hash = 1 + hash % ht->rehash;
-
- hash_address = (hash_address + double_hash) % ht->size;
- } while (hash_address != start_hash_address);
-
- /* We could hit here if a required resize failed. An unchecked-malloc
- * application could ignore this result.
- */
- return NULL;
-}
-
-/**
- * This function deletes the given hash table entry.
- *
- * Note that deletion doesn't otherwise modify the table, so an iteration over
- * the table deleting entries is safe.
- */
-void
-_mesa_hash_table_remove(struct hash_table *ht,
- struct hash_entry *entry)
-{
- if (!entry)
- return;
-
- entry->key = ht->deleted_key;
- ht->entries--;
- ht->deleted_entries++;
-}
-
-/**
- * This function is an iterator over the hash table.
- *
- * Pass in NULL for the first entry, as in the start of a for loop. Note that
- * an iteration over the table is O(table_size) not O(entries).
- */
-struct hash_entry *
-_mesa_hash_table_next_entry(struct hash_table *ht,
- struct hash_entry *entry)
-{
- if (entry == NULL)
- entry = ht->table;
- else
- entry = entry + 1;
-
- for (; entry != ht->table + ht->size; entry++) {
- if (entry_is_present(ht, entry)) {
- return entry;
- }
- }
-
- return NULL;
-}
-
-/**
- * Returns a random entry from the hash table.
- *
- * 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.
- */
-struct hash_entry *
-_mesa_hash_table_random_entry(struct hash_table *ht,
- bool (*predicate)(struct hash_entry *entry))
-{
- struct hash_entry *entry;
- uint32_t i = rand() % ht->size;
-
- if (ht->entries == 0)
- return NULL;
-
- for (entry = ht->table + i; entry != ht->table + ht->size; entry++) {
- if (entry_is_present(ht, entry) &&
- (!predicate || predicate(entry))) {
- return entry;
- }
- }
-
- for (entry = ht->table; entry != ht->table + i; entry++) {
- if (entry_is_present(ht, entry) &&
- (!predicate || predicate(entry))) {
- return entry;
- }
- }
-
- return NULL;
-}
-
-
-/**
- * Quick FNV-1 hash implementation based on:
- * http://www.isthe.com/chongo/tech/comp/fnv/
- *
- * FNV-1 is not be the best hash out there -- Jenkins's lookup3 is supposed to
- * be quite good, and it probably beats FNV. But FNV has the advantage that
- * it involves almost no code. For an improvement on both, see Paul
- * Hsieh's http://www.azillionmonkeys.com/qed/hash.html
- */
-uint32_t
-_mesa_hash_data(const void *data, size_t size)
-{
- uint32_t hash = 2166136261ul;
- const uint8_t *bytes = data;
-
- while (size-- != 0) {
- hash ^= *bytes;
- hash = hash * 0x01000193;
- bytes++;
- }
-
- return hash;
-}
-
-/** FNV-1 string hash implementation */
-uint32_t
-_mesa_hash_string(const char *key)
-{
- uint32_t hash = 2166136261ul;
-
- while (*key != 0) {
- hash ^= *key;
- hash = hash * 0x01000193;
- key++;
- }
-
- return hash;
-}
-
-/**
- * String compare function for use as the comparison callback in
- * _mesa_hash_table_create().
- */
-bool
-_mesa_key_string_equal(const void *a, const void *b)
-{
- return strcmp(a, b) == 0;
-}
-
-bool
-_mesa_key_pointer_equal(const void *a, const void *b)
-{
- return a == b;
-}
generated by cgit v1.2.3 (git 2.25.1) at 2025-01-15 15:44:35 +0000