-/* $Id: hash.c,v 1.15 2002/12/12 13:03:15 keithw Exp $ */
+/**
+ * \file hash.c
+ * Generic hash table.
+ *
+ * Used for display lists and texture objects. The hash functions are
+ * thread-safe.
+ *
+ * \note key=0 is illegal.
+ *
+ * \author Brian Paul
+ */
/*
* Mesa 3-D graphics library
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
+
#include "glheader.h"
#include "imports.h"
#include "glthread.h"
#include "context.h"
-/**
- * \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)
/**
* Delete a hash table.
- * \param table - the hash table to delete
+ *
+ * \param table the hash table to delete.
+ *
+ * Frees each entry on the hash table and then the hash table structure itself.
*/
void _mesa_DeleteHashTable(struct _mesa_HashTable *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
+ *
+ * Walks through the hash entry until finding the matching key.
*/
void *_mesa_HashLookup(const struct _mesa_HashTable *table, GLuint key)
{
/**
- * 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 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)
{
/**
* 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)
{
/**
* 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)
{
/**
* 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)
{
/**
- * 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)
{