-/* $Id: hash.c,v 1.2 1999/10/08 09:27:10 keithw Exp $ */
+/**
+ * \file hash.c
+ * Generic hash table.
+ *
+ * Used for display lists, texture objects, vertex/fragment programs,
+ * buffer objects, etc. The hash functions are thread-safe.
+ *
+ * \note key=0 is illegal.
+ *
+ * \author Brian Paul
+ */
/*
* Mesa 3-D graphics library
- * Version: 3.1
- *
- * Copyright (C) 1999 Brian Paul All Rights Reserved.
- *
+ *
+ * Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
+ *
* 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 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
- * BRIAN PAUL 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.
+ * 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.
*/
-
-
-
-
-#ifdef PC_HEADER
-#include "all.h"
-#else
-#ifndef XFree86Server
-#include <assert.h>
-#include <stdlib.h>
-#include <stdio.h>
-#else
-#include "GL/xf86glx.h"
-#endif
+#include "glheader.h"
+#include "imports.h"
#include "hash.h"
-#endif
-
+#include "util/hash_table.h"
-/*
- * Generic hash table. Only dependency is the GLuint datatype.
+/**
+ * Magic GLuint object name that gets stored outside of the struct hash_table.
*
- * This is used to implement display list and texture object lookup.
- * NOTE: key=0 is illegal.
+ * The hash table needs a particular pointer to be the marker for a key that
+ * was deleted from the table, along with NULL for the "never allocated in the
+ * table" marker. Legacy GL allows any GLuint to be used as a GL object name,
+ * and we use a 1:1 mapping from GLuints to key pointers, so we need to be
+ * able to track a GLuint that happens to match the deleted key outside of
+ * struct hash_table. We tell the hash table to use "1" as the deleted key
+ * value, so that we test the deleted-key-in-the-table path as best we can.
*/
+#define DELETED_KEY_VALUE 1
-
-#define TABLE_SIZE 1024
-
-struct HashEntry {
- GLuint Key;
- void *Data;
- struct HashEntry *Next;
+/**
+ * The hash table data structure.
+ */
+struct _mesa_HashTable {
+ struct hash_table *ht;
+ GLuint MaxKey; /**< highest key inserted so far */
+ mtx_t Mutex; /**< mutual exclusion lock */
+ mtx_t WalkMutex; /**< for _mesa_HashWalk() */
+ GLboolean InDeleteAll; /**< Debug check */
+ /** Value that would be in the table for DELETED_KEY_VALUE. */
+ void *deleted_key_data;
};
-struct HashTable {
- struct HashEntry *Table[TABLE_SIZE];
- GLuint MaxKey;
-};
+/** @{
+ * Mapping from our use of GLuint as both the key and the hash value to the
+ * hash_table.h API
+ *
+ * There exist many integer hash functions, designed to avoid collisions when
+ * the integers are spread across key space with some patterns. In GL, the
+ * pattern (in the case of glGen*()ed object IDs) is that the keys are unique
+ * contiguous integers starting from 1. Because of that, we just use the key
+ * as the hash value, to minimize the cost of the hash function. If objects
+ * are never deleted, we will never see a collision in the table, because the
+ * table resizes itself when it approaches full, and thus key % table_size ==
+ * key.
+ *
+ * The case where we could have collisions for genned objects would be
+ * something like: glGenBuffers(&a, 100); glDeleteBuffers(&a + 50, 50);
+ * glGenBuffers(&b, 100), because objects 1-50 and 101-200 are allocated at
+ * the end of that sequence, instead of 1-150. So far it doesn't appear to be
+ * a problem.
+ */
+static bool
+uint_key_compare(const void *a, const void *b)
+{
+ return a == b;
+}
+static uint32_t
+uint_hash(GLuint id)
+{
+ return id;
+}
+static uint32_t
+uint_key_hash(const void *key)
+{
+ return uint_hash((uintptr_t)key);
+}
-/*
- * Return pointer to a new, empty hash table.
+static void *
+uint_key(GLuint id)
+{
+ return (void *)(uintptr_t) id;
+}
+/** @} */
+
+/**
+ * Create a new hash table.
+ *
+ * \return pointer to a new, empty hash table.
*/
-struct HashTable *NewHashTable(void)
+struct _mesa_HashTable *
+_mesa_NewHashTable(void)
{
- return (struct HashTable *) calloc(sizeof (struct HashTable), 1);
+ struct _mesa_HashTable *table = CALLOC_STRUCT(_mesa_HashTable);
+
+ if (table) {
+ table->ht = _mesa_hash_table_create(NULL, uint_key_hash,
+ uint_key_compare);
+ if (table->ht == NULL) {
+ free(table);
+ _mesa_error_no_memory(__func__);
+ return NULL;
+ }
+
+ _mesa_hash_table_set_deleted_key(table->ht, uint_key(DELETED_KEY_VALUE));
+ mtx_init(&table->Mutex, mtx_plain);
+ mtx_init(&table->WalkMutex, mtx_plain);
+ }
+ else {
+ _mesa_error_no_memory(__func__);
+ }
+
+ return table;
}
-/*
+/**
* Delete a hash table.
+ * Frees each entry on the hash table and then the hash table structure itself.
+ * Note that the caller should have already traversed the table and deleted
+ * the objects in the table (i.e. We don't free the entries' data pointer).
+ *
+ * \param table the hash table to delete.
*/
-void DeleteHashTable(struct HashTable *table)
+void
+_mesa_DeleteHashTable(struct _mesa_HashTable *table)
{
- GLuint i;
assert(table);
- for (i=0;i<TABLE_SIZE;i++) {
- struct HashEntry *entry = table->Table[i];
- while (entry) {
- struct HashEntry *next = entry->Next;
- free(entry);
- entry = next;
- }
+
+ if (_mesa_hash_table_next_entry(table->ht, NULL) != NULL) {
+ _mesa_problem(NULL, "In _mesa_DeleteHashTable, found non-freed data");
}
+
+ _mesa_hash_table_destroy(table->ht, NULL);
+
+ mtx_destroy(&table->Mutex);
+ mtx_destroy(&table->WalkMutex);
free(table);
}
-/*
- * Lookup an entry in the hash table.
- * Input: table - the hash table
- * key - the key
- * Return: user data pointer or NULL if key not in table
+/**
+ * Lookup an entry in the hash table, without locking.
+ * \sa _mesa_HashLookup
*/
-void *HashLookup(const struct HashTable *table, GLuint key)
+static inline void *
+_mesa_HashLookup_unlocked(struct _mesa_HashTable *table, GLuint key)
{
- GLuint pos;
- const struct HashEntry *entry;
+ const struct hash_entry *entry;
assert(table);
assert(key);
- pos = key & (TABLE_SIZE-1);
- entry = table->Table[pos];
- while (entry) {
- if (entry->Key == key) {
- return entry->Data;
- }
- entry = entry->Next;
- }
- return NULL;
+ if (key == DELETED_KEY_VALUE)
+ return table->deleted_key_data;
+
+ entry = _mesa_hash_table_search(table->ht, uint_key(key));
+ if (!entry)
+ return NULL;
+
+ return entry->data;
}
+/**
+ * Lookup an entry in the hash table.
+ *
+ * \param table the hash table.
+ * \param key the key.
+ *
+ * \return pointer to user's data or NULL if key not in table
+ */
+void *
+_mesa_HashLookup(struct _mesa_HashTable *table, GLuint key)
+{
+ void *res;
+ assert(table);
+ mtx_lock(&table->Mutex);
+ res = _mesa_HashLookup_unlocked(table, key);
+ mtx_unlock(&table->Mutex);
+ return res;
+}
+
-/*
- * Insert into the hash table. If an entry with this key already exists
- * we'll replace the existing entry.
- * Input: table - the hash table
- * key - the key (not zero)
- * data - pointer to user data
+/**
+ * Lookup an entry in the hash table without locking the mutex.
+ *
+ * The hash table mutex must be locked manually by calling
+ * _mesa_HashLockMutex() before calling this function.
+ *
+ * \param table the hash table.
+ * \param key the key.
+ *
+ * \return pointer to user's data or NULL if key not in table
+ */
+void *
+_mesa_HashLookupLocked(struct _mesa_HashTable *table, GLuint key)
+{
+ return _mesa_HashLookup_unlocked(table, key);
+}
+
+
+/**
+ * Lock the hash table mutex.
+ *
+ * This function should be used when multiple objects need
+ * to be looked up in the hash table, to avoid having to lock
+ * and unlock the mutex each time.
+ *
+ * \param table the hash table.
*/
-void HashInsert(struct HashTable *table, GLuint key, void *data)
+void
+_mesa_HashLockMutex(struct _mesa_HashTable *table)
+{
+ assert(table);
+ mtx_lock(&table->Mutex);
+}
+
+
+/**
+ * Unlock the hash table mutex.
+ *
+ * \param table the hash table.
+ */
+void
+_mesa_HashUnlockMutex(struct _mesa_HashTable *table)
+{
+ assert(table);
+ mtx_unlock(&table->Mutex);
+}
+
+
+static inline void
+_mesa_HashInsert_unlocked(struct _mesa_HashTable *table, GLuint key, void *data)
{
- /* search for existing entry with this key */
- GLuint pos;
- struct HashEntry *entry;
+ uint32_t hash = uint_hash(key);
+ struct hash_entry *entry;
assert(table);
assert(key);
if (key > table->MaxKey)
table->MaxKey = key;
- pos = key & (TABLE_SIZE-1);
- entry = table->Table[pos];
- while (entry) {
- if (entry->Key == key) {
- /* replace entry's data */
- entry->Data = data;
- return;
+ if (key == DELETED_KEY_VALUE) {
+ table->deleted_key_data = data;
+ } else {
+ entry = _mesa_hash_table_search_pre_hashed(table->ht, hash, uint_key(key));
+ if (entry) {
+ entry->data = data;
+ } else {
+ _mesa_hash_table_insert_pre_hashed(table->ht, hash, uint_key(key), data);
}
- entry = entry->Next;
}
+}
+
- /* alloc and insert new table entry */
- entry = (struct HashEntry *) calloc(sizeof(struct HashEntry), 1);
- entry->Key = key;
- entry->Data = data;
- entry->Next = table->Table[pos];
- table->Table[pos] = entry;
+/**
+ * Insert a key/pointer pair into the hash table without locking the mutex.
+ * If an entry with this key already exists we'll replace the existing entry.
+ *
+ * The hash table mutex must be locked manually by calling
+ * _mesa_HashLockMutex() before calling this function.
+ *
+ * \param table the hash table.
+ * \param key the key (not zero).
+ * \param data pointer to user data.
+ */
+void
+_mesa_HashInsertLocked(struct _mesa_HashTable *table, GLuint key, void *data)
+{
+ _mesa_HashInsert_unlocked(table, key, data);
}
+/**
+ * Insert a key/pointer pair into the hash table.
+ * If an entry with this key already exists we'll replace the existing entry.
+ *
+ * \param table the hash table.
+ * \param key the key (not zero).
+ * \param data pointer to user data.
+ */
+void
+_mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data)
+{
+ assert(table);
+ mtx_lock(&table->Mutex);
+ _mesa_HashInsert_unlocked(table, key, data);
+ mtx_unlock(&table->Mutex);
+}
-/*
+
+/**
* Remove an entry from the hash table.
- * Input: table - the hash table
- * key - key of entry to remove
+ *
+ * \param table the hash table.
+ * \param key key of entry to remove.
+ *
+ * While holding the hash table's lock, searches the entry with the matching
+ * key and unlinks it.
*/
-void HashRemove(struct HashTable *table, GLuint key)
+static inline void
+_mesa_HashRemove_unlocked(struct _mesa_HashTable *table, GLuint key)
{
- GLuint pos;
- struct HashEntry *entry, *prev;
+ struct hash_entry *entry;
assert(table);
assert(key);
- pos = key & (TABLE_SIZE-1);
- prev = NULL;
- entry = table->Table[pos];
- while (entry) {
- if (entry->Key == key) {
- /* found it! */
- if (prev) {
- prev->Next = entry->Next;
- }
- else {
- table->Table[pos] = entry->Next;
- }
- free(entry);
- return;
- }
- prev = entry;
- entry = entry->Next;
+ /* have to check this outside of mutex lock */
+ if (table->InDeleteAll) {
+ _mesa_problem(NULL, "_mesa_HashRemove illegally called from "
+ "_mesa_HashDeleteAll callback function");
+ return;
+ }
+
+ if (key == DELETED_KEY_VALUE) {
+ table->deleted_key_data = NULL;
+ } else {
+ entry = _mesa_hash_table_search(table->ht, uint_key(key));
+ _mesa_hash_table_remove(table->ht, entry);
}
}
+void
+_mesa_HashRemoveLocked(struct _mesa_HashTable *table, GLuint key)
+{
+ _mesa_HashRemove_unlocked(table, key);
+}
-/*
- * Return the key of the "first" entry in the hash table.
- * By calling this function until zero is returned we can get
- * the keys of all entries in the table.
+void
+_mesa_HashRemove(struct _mesa_HashTable *table, GLuint key)
+{
+ mtx_lock(&table->Mutex);
+ _mesa_HashRemove_unlocked(table, key);
+ mtx_unlock(&table->Mutex);
+}
+
+/**
+ * Delete all entries in a hash table, but don't delete the table itself.
+ * Invoke the given callback function for each table entry.
+ *
+ * \param table the hash table to delete
+ * \param callback the callback function
+ * \param userData arbitrary pointer to pass along to the callback
+ * (this is typically a struct gl_context pointer)
*/
-GLuint HashFirstEntry(const struct HashTable *table)
+void
+_mesa_HashDeleteAll(struct _mesa_HashTable *table,
+ void (*callback)(GLuint key, void *data, void *userData),
+ void *userData)
{
- GLuint pos;
+ struct hash_entry *entry;
+
assert(table);
- for (pos=0; pos < TABLE_SIZE; pos++) {
- if (table->Table[pos])
- return table->Table[pos]->Key;
+ assert(callback);
+ mtx_lock(&table->Mutex);
+ table->InDeleteAll = GL_TRUE;
+ hash_table_foreach(table->ht, entry) {
+ callback((uintptr_t)entry->key, entry->data, userData);
+ _mesa_hash_table_remove(table->ht, entry);
+ }
+ if (table->deleted_key_data) {
+ callback(DELETED_KEY_VALUE, table->deleted_key_data, userData);
+ table->deleted_key_data = NULL;
}
- return 0;
+ table->InDeleteAll = GL_FALSE;
+ mtx_unlock(&table->Mutex);
}
-
-/*
- * Dump contents of hash table for debugging.
+/**
+ * Walk over all entries in a hash table, calling callback function for each.
+ * Note: we use a separate mutex in this function to avoid a recursive
+ * locking deadlock (in case the callback calls _mesa_HashRemove()) and to
+ * prevent multiple threads/contexts from getting tangled up.
+ * A lock-less version of this function could be used when the table will
+ * not be modified.
+ * \param table the hash table to walk
+ * \param callback the callback function
+ * \param userData arbitrary pointer to pass along to the callback
+ * (this is typically a struct gl_context pointer)
*/
-void HashPrint(const struct HashTable *table)
+void
+_mesa_HashWalk(const struct _mesa_HashTable *table,
+ void (*callback)(GLuint key, void *data, void *userData),
+ void *userData)
{
- GLuint i;
+ /* cast-away const */
+ struct _mesa_HashTable *table2 = (struct _mesa_HashTable *) table;
+ struct hash_entry *entry;
+
assert(table);
- for (i=0;i<TABLE_SIZE;i++) {
- const struct HashEntry *entry = table->Table[i];
- while (entry) {
- printf("%u %p\n", entry->Key, entry->Data);
- entry = entry->Next;
- }
+ assert(callback);
+ mtx_lock(&table2->WalkMutex);
+ hash_table_foreach(table->ht, entry) {
+ callback((uintptr_t)entry->key, entry->data, userData);
}
+ if (table->deleted_key_data)
+ callback(DELETED_KEY_VALUE, table->deleted_key_data, userData);
+ mtx_unlock(&table2->WalkMutex);
}
+static void
+debug_print_entry(GLuint key, void *data, void *userData)
+{
+ _mesa_debug(NULL, "%u %p\n", key, data);
+}
+
+/**
+ * Dump contents of hash table for debugging.
+ *
+ * \param table the hash table.
+ */
+void
+_mesa_HashPrint(const struct _mesa_HashTable *table)
+{
+ if (table->deleted_key_data)
+ debug_print_entry(DELETED_KEY_VALUE, table->deleted_key_data, NULL);
+ _mesa_HashWalk(table, debug_print_entry, NULL);
+}
-/*
- * Find a block of 'numKeys' adjacent unused hash keys.
- * Input: table - the hash table
- * numKeys - number of keys needed
- * Return: startint key of free block or 0 if failure
+/**
+ * Find a block of adjacent unused hash keys.
+ *
+ * \param table the hash table.
+ * \param numKeys number of keys needed.
+ *
+ * \return Starting key of free block or 0 if failure.
+ *
+ * If there are enough free keys between the maximum key existing in the table
+ * (_mesa_HashTable::MaxKey) and the maximum key possible, then simply return
+ * the adjacent key. Otherwise do a full search for a free key block in the
+ * allowable key range.
*/
-GLuint HashFindFreeKeyBlock(const struct HashTable *table, GLuint numKeys)
+GLuint
+_mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys)
{
- GLuint maxKey = ~((GLuint) 0);
+ const GLuint maxKey = ~((GLuint) 0) - 1;
if (maxKey - numKeys > table->MaxKey) {
/* the quick solution */
return table->MaxKey + 1;
else {
/* the slow solution */
GLuint freeCount = 0;
- GLuint freeStart = 0;
+ GLuint freeStart = 1;
GLuint key;
- for (key=0; key!=maxKey; key++) {
- if (HashLookup(table, key)) {
+ for (key = 1; key != maxKey; key++) {
+ if (_mesa_HashLookup_unlocked(table, key)) {
/* darn, this key is already in use */
freeCount = 0;
freeStart = key+1;
}
-
-#ifdef HASH_TEST_HARNESS
-int main(int argc, char *argv[])
+/**
+ * Return the number of entries in the hash table.
+ */
+GLuint
+_mesa_HashNumEntries(const struct _mesa_HashTable *table)
{
- int a, b, c;
- struct HashTable *t;
-
- printf("&a = %p\n", &a);
- printf("&b = %p\n", &b);
-
- t = NewHashTable();
- HashInsert(t, 501, &a);
- HashInsert(t, 10, &c);
- HashInsert(t, 0xfffffff8, &b);
- HashPrint(t);
- printf("Find 501: %p\n", HashLookup(t,501));
- printf("Find 1313: %p\n", HashLookup(t,1313));
- printf("Find block of 100: %d\n", HashFindFreeKeyBlock(t, 100));
- DeleteHashTable(t);
-
- return 0;
+ GLuint count = 0;
+
+ if (table->deleted_key_data)
+ count++;
+
+ count += _mesa_hash_table_num_entries(table->ht);
+
+ return count;
}
-#endif