-/* $Id: hash.c,v 1.13 2002/09/16 17:55:36 brianp 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: 4.1
+ * Version: 6.3
*
- * Copyright (C) 1999-2002 Brian Paul All Rights Reserved.
+ * Copyright (C) 1999-2005 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"),
*/
-#ifdef PC_HEADER
-#include "all.h"
-#else
#include "glheader.h"
+#include "imports.h"
#include "glthread.h"
#include "hash.h"
-#include "context.h"
-#include "mem.h"
-#endif
-
-
-/**
- * \file hash.c
- * \brief Generic hash table. Used for display lists and texture objects.
- * The hash functions are thread-safe.
- * \author Brian Paul
- * \note key=0 is illegal
- */
#define TABLE_SIZE 1023 /**< Size of lookup table/array */
/**
- * An entry in the hash table. This struct is private to this file.
+ * An entry in the hash table.
+ *
+ * This struct is private to this file.
*/
struct HashEntry {
GLuint Key; /**< the entry's key */
};
/**
- * The hashtable data structure. This is an opaque types (it's not
- * defined in the .h file).
+ * The hash table data structure.
+ *
+ * This is an opaque types (it's not defined in hash.h file).
*/
struct _mesa_HashTable {
struct HashEntry *Table[TABLE_SIZE]; /**< the lookup table */
};
-
/**
* Create a new hash table.
+ *
* \return pointer to a new, empty hash table.
*/
-struct _mesa_HashTable *_mesa_NewHashTable(void)
+struct _mesa_HashTable *
+_mesa_NewHashTable(void)
{
struct _mesa_HashTable *table = CALLOC_STRUCT(_mesa_HashTable);
if (table) {
/**
* Delete a hash table.
- * \param table - the hash table to delete
+ * 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 _mesa_DeleteHashTable(struct _mesa_HashTable *table)
+void
+_mesa_DeleteHashTable(struct _mesa_HashTable *table)
{
GLuint i;
assert(table);
- for (i=0;i<TABLE_SIZE;i++) {
+ for (i = 0; i < TABLE_SIZE; i++) {
struct HashEntry *entry = table->Table[i];
while (entry) {
struct HashEntry *next = entry->Next;
entry = next;
}
}
+ _glthread_DESTROY_MUTEX(table->Mutex);
FREE(table);
}
/**
* Lookup an entry in the hash table.
- * \param table - the hash table
- * \param key - the key
+ *
+ * \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(const struct _mesa_HashTable *table, GLuint key)
+void *
+_mesa_HashLookup(const struct _mesa_HashTable *table, GLuint key)
{
GLuint pos;
const struct HashEntry *entry;
/**
- * Insert 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
+ * 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)
+void
+_mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data)
{
/* search for existing entry with this key */
GLuint pos;
/**
* Remove an entry from the hash table.
- * \param table - the hash table
- * \param 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 _mesa_HashRemove(struct _mesa_HashTable *table, GLuint key)
+void
+_mesa_HashRemove(struct _mesa_HashTable *table, GLuint key)
{
GLuint pos;
struct HashEntry *entry, *prev;
/**
* Get the key of the "first" entry in the hash table.
+ *
* This is used in the course of deleting all display lists when
* a context is destroyed.
- * \param table - the hash table
+ *
+ * \param table the hash table
+ *
* \return key for the "first" entry in the hash table.
+ *
+ * While holding the lock, walks through all table positions until finding
+ * the first entry of the first non-empty one.
*/
-GLuint _mesa_HashFirstEntry(struct _mesa_HashTable *table)
+GLuint
+_mesa_HashFirstEntry(struct _mesa_HashTable *table)
{
GLuint pos;
assert(table);
}
+/**
+ * Given a hash table key, return the next key. This is used to walk
+ * over all entries in the table. Note that the keys returned during
+ * walking won't be in any particular order.
+ * \return next hash key or 0 if end of table.
+ */
+GLuint
+_mesa_HashNextEntry(const struct _mesa_HashTable *table, GLuint key)
+{
+ const struct HashEntry *entry;
+ GLuint pos;
+
+ assert(table);
+ assert(key);
+
+ /* Find the entry with given key */
+ pos = key & (TABLE_SIZE - 1);
+ entry = table->Table[pos];
+ while (entry) {
+ if (entry->Key == key) {
+ break;
+ }
+ entry = entry->Next;
+ }
+
+ if (!entry) {
+ /* the key was not found, we can't find next entry */
+ return 0;
+ }
+
+ if (entry->Next) {
+ /* return next in linked list */
+ return entry->Next->Key;
+ }
+ else {
+ /* look for next non-empty table slot */
+ pos++;
+ while (pos < TABLE_SIZE) {
+ if (table->Table[pos]) {
+ return table->Table[pos]->Key;
+ }
+ pos++;
+ }
+ return 0;
+ }
+}
+
/**
* Dump contents of hash table for debugging.
- * \param table - the hash table
+ *
+ * \param table the hash table.
*/
-void _mesa_HashPrint(const struct _mesa_HashTable *table)
+void
+_mesa_HashPrint(const struct _mesa_HashTable *table)
{
GLuint i;
assert(table);
/**
- * Find a block of 'numKeys' 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
+ * 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 _mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys)
+GLuint
+_mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys)
{
GLuint maxKey = ~((GLuint) 0);
_glthread_LOCK_MUTEX(table->Mutex);
}
+/**
+ * Test walking over all the entries in a hash table.
+ */
+static void
+test_hash_walking(void)
+{
+ struct _mesa_HashTable *t = _mesa_NewHashTable();
+ const GLuint limit = 50000;
+ GLuint i;
+
+ /* create some entries */
+ for (i = 0; i < limit; i++) {
+ GLuint dummy;
+ GLuint k = (rand() % (limit * 10)) + 1;
+ while (_mesa_HashLookup(t, k)) {
+ /* id already in use, try another */
+ k = (rand() % (limit * 10)) + 1;
+ }
+ _mesa_HashInsert(t, k, &dummy);
+ }
-#ifdef HASH_TEST_HARNESS
-int main(int argc, char *argv[])
+ /* walk over all entries */
+ {
+ GLuint k = _mesa_HashFirstEntry(t);
+ GLuint count = 0;
+ while (k) {
+ GLuint knext = _mesa_HashNextEntry(t, k);
+ assert(knext != k);
+ _mesa_HashRemove(t, k);
+ count++;
+ k = knext;
+ }
+ assert(count == limit);
+ k = _mesa_HashFirstEntry(t);
+ assert(k==0);
+ }
+
+ _mesa_DeleteHashTable(t);
+}
+
+
+void
+_mesa_test_hash_functions(void)
{
int a, b, c;
- struct HashTable *t;
-
- _mesa_printf("&a = %p\n", &a);
- _mesa_printf("&b = %p\n", &b);
+ struct _mesa_HashTable *t;
t = _mesa_NewHashTable();
_mesa_HashInsert(t, 501, &a);
_mesa_HashInsert(t, 10, &c);
_mesa_HashInsert(t, 0xfffffff8, &b);
- _mesa_HashPrint(t);
+ /*_mesa_HashPrint(t);*/
- _mesa_printf("Find 501: %p\n", _mesa_HashLookup(t,501));
- _mesa_printf("Find 1313: %p\n", _mesa_HashLookup(t,1313));
- _mesa_printf("Find block of 100: %d\n", _mesa_HashFindFreeKeyBlock(t, 100));
+ assert(_mesa_HashLookup(t,501));
+ assert(!_mesa_HashLookup(t,1313));
+ assert(_mesa_HashFindFreeKeyBlock(t, 100));
_mesa_DeleteHashTable(t);
- return 0;
+ test_hash_walking();
}
-#endif
projects / mesa.git / blobdiff