* \file hash.c
* Generic hash table.
*
- * Used for display lists and texture objects. The hash functions are
- * thread-safe.
+ * Used for display lists, texture objects, vertex/fragment programs,
+ * buffer objects, etc. The hash functions are thread-safe.
*
* \note key=0 is illegal.
*
/*
* 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"),
#include "imports.h"
#include "glthread.h"
#include "hash.h"
-#include "context.h"
#define TABLE_SIZE 1023 /**< Size of lookup table/array */
};
-
/**
* 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;
* \param key the key.
*
* \return pointer to user's data or NULL if key not in table
- *
- * Walks through the hash entry until finding the matching key.
*/
-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.
- *
+ * 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.
- *
- * While holding the hash table's lock, walk through the hash entry list replacing the data if a
- * matching key is found, or inserts a new table entry otherwise.
*/
-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;
* 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;
* 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.
*/
-void _mesa_HashPrint(const struct _mesa_HashTable *table)
+void
+_mesa_HashPrint(const struct _mesa_HashTable *table)
{
GLuint i;
assert(table);
* 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);
+ }
+
+ /* 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);
+ }
-#ifdef HASH_TEST_HARNESS
-int main(int argc, char *argv[])
+ _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
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