0,0 → 1,547 |
/** |
* \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 |
*/ |
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/* |
* Mesa 3-D graphics library |
* Version: 6.5.1 |
* |
* 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. |
*/ |
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#include "glheader.h" |
#include "imports.h" |
#include "glapi/glthread.h" |
#include "hash.h" |
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#define TABLE_SIZE 1023 /**< Size of lookup table/array */ |
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#define HASH_FUNC(K) ((K) % TABLE_SIZE) |
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/** |
* An entry in the hash table. |
*/ |
struct HashEntry { |
GLuint Key; /**< the entry's key */ |
void *Data; /**< the entry's data */ |
struct HashEntry *Next; /**< pointer to next entry */ |
}; |
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/** |
* The hash table data structure. |
*/ |
struct _mesa_HashTable { |
struct HashEntry *Table[TABLE_SIZE]; /**< the lookup table */ |
GLuint MaxKey; /**< highest key inserted so far */ |
_glthread_Mutex Mutex; /**< mutual exclusion lock */ |
_glthread_Mutex WalkMutex; /**< for _mesa_HashWalk() */ |
GLboolean InDeleteAll; /**< Debug check */ |
}; |
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/** |
* Create a new hash table. |
* |
* \return pointer to a new, empty hash table. |
*/ |
struct _mesa_HashTable * |
_mesa_NewHashTable(void) |
{ |
struct _mesa_HashTable *table = CALLOC_STRUCT(_mesa_HashTable); |
if (table) { |
_glthread_INIT_MUTEX(table->Mutex); |
_glthread_INIT_MUTEX(table->WalkMutex); |
} |
return table; |
} |
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/** |
* 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 |
_mesa_DeleteHashTable(struct _mesa_HashTable *table) |
{ |
GLuint pos; |
assert(table); |
for (pos = 0; pos < TABLE_SIZE; pos++) { |
struct HashEntry *entry = table->Table[pos]; |
while (entry) { |
struct HashEntry *next = entry->Next; |
if (entry->Data) { |
_mesa_problem(NULL, |
"In _mesa_DeleteHashTable, found non-freed data"); |
} |
free(entry); |
entry = next; |
} |
} |
_glthread_DESTROY_MUTEX(table->Mutex); |
_glthread_DESTROY_MUTEX(table->WalkMutex); |
free(table); |
} |
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/** |
* Lookup an entry in the hash table, without locking. |
* \sa _mesa_HashLookup |
*/ |
static INLINE void * |
_mesa_HashLookup_unlocked(struct _mesa_HashTable *table, GLuint key) |
{ |
GLuint pos; |
const struct HashEntry *entry; |
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assert(table); |
assert(key); |
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pos = HASH_FUNC(key); |
entry = table->Table[pos]; |
while (entry) { |
if (entry->Key == key) { |
return entry->Data; |
} |
entry = entry->Next; |
} |
return NULL; |
} |
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/** |
* 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); |
_glthread_LOCK_MUTEX(table->Mutex); |
res = _mesa_HashLookup_unlocked(table, key); |
_glthread_UNLOCK_MUTEX(table->Mutex); |
return res; |
} |
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/** |
* 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) |
{ |
/* search for existing entry with this key */ |
GLuint pos; |
struct HashEntry *entry; |
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assert(table); |
assert(key); |
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_glthread_LOCK_MUTEX(table->Mutex); |
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if (key > table->MaxKey) |
table->MaxKey = key; |
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pos = HASH_FUNC(key); |
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/* check if replacing an existing entry with same key */ |
for (entry = table->Table[pos]; entry; entry = entry->Next) { |
if (entry->Key == key) { |
/* replace entry's data */ |
#if 0 /* not sure this check is always valid */ |
if (entry->Data) { |
_mesa_problem(NULL, "Memory leak detected in _mesa_HashInsert"); |
} |
#endif |
entry->Data = data; |
_glthread_UNLOCK_MUTEX(table->Mutex); |
return; |
} |
} |
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/* alloc and insert new table entry */ |
entry = MALLOC_STRUCT(HashEntry); |
if (entry) { |
entry->Key = key; |
entry->Data = data; |
entry->Next = table->Table[pos]; |
table->Table[pos] = entry; |
} |
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_glthread_UNLOCK_MUTEX(table->Mutex); |
} |
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/** |
* Remove an entry from the hash table. |
* |
* \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) |
{ |
GLuint pos; |
struct HashEntry *entry, *prev; |
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assert(table); |
assert(key); |
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/* have to check this outside of mutex lock */ |
if (table->InDeleteAll) { |
_mesa_problem(NULL, "_mesa_HashRemove illegally called from " |
"_mesa_HashDeleteAll callback function"); |
return; |
} |
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_glthread_LOCK_MUTEX(table->Mutex); |
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pos = HASH_FUNC(key); |
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); |
_glthread_UNLOCK_MUTEX(table->Mutex); |
return; |
} |
prev = entry; |
entry = entry->Next; |
} |
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_glthread_UNLOCK_MUTEX(table->Mutex); |
} |
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/** |
* 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) |
*/ |
void |
_mesa_HashDeleteAll(struct _mesa_HashTable *table, |
void (*callback)(GLuint key, void *data, void *userData), |
void *userData) |
{ |
GLuint pos; |
ASSERT(table); |
ASSERT(callback); |
_glthread_LOCK_MUTEX(table->Mutex); |
table->InDeleteAll = GL_TRUE; |
for (pos = 0; pos < TABLE_SIZE; pos++) { |
struct HashEntry *entry, *next; |
for (entry = table->Table[pos]; entry; entry = next) { |
callback(entry->Key, entry->Data, userData); |
next = entry->Next; |
free(entry); |
} |
table->Table[pos] = NULL; |
} |
table->InDeleteAll = GL_FALSE; |
_glthread_UNLOCK_MUTEX(table->Mutex); |
} |
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/** |
* 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 |
_mesa_HashWalk(const struct _mesa_HashTable *table, |
void (*callback)(GLuint key, void *data, void *userData), |
void *userData) |
{ |
/* cast-away const */ |
struct _mesa_HashTable *table2 = (struct _mesa_HashTable *) table; |
GLuint pos; |
ASSERT(table); |
ASSERT(callback); |
_glthread_LOCK_MUTEX(table2->WalkMutex); |
for (pos = 0; pos < TABLE_SIZE; pos++) { |
struct HashEntry *entry, *next; |
for (entry = table->Table[pos]; entry; entry = next) { |
/* save 'next' pointer now in case the callback deletes the entry */ |
next = entry->Next; |
callback(entry->Key, entry->Data, userData); |
} |
} |
_glthread_UNLOCK_MUTEX(table2->WalkMutex); |
} |
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/** |
* Return the key of 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. |
* |
* \param table the hash table |
* \return key for the "first" entry in the hash table. |
*/ |
GLuint |
_mesa_HashFirstEntry(struct _mesa_HashTable *table) |
{ |
GLuint pos; |
assert(table); |
_glthread_LOCK_MUTEX(table->Mutex); |
for (pos = 0; pos < TABLE_SIZE; pos++) { |
if (table->Table[pos]) { |
_glthread_UNLOCK_MUTEX(table->Mutex); |
return table->Table[pos]->Key; |
} |
} |
_glthread_UNLOCK_MUTEX(table->Mutex); |
return 0; |
} |
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/** |
* 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; |
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assert(table); |
assert(key); |
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/* Find the entry with given key */ |
pos = HASH_FUNC(key); |
for (entry = table->Table[pos]; entry ; entry = entry->Next) { |
if (entry->Key == key) { |
break; |
} |
} |
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if (!entry) { |
/* the given key was not found, so we can't find the next entry */ |
return 0; |
} |
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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; |
} |
} |
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/** |
* Dump contents of hash table for debugging. |
* |
* \param table the hash table. |
*/ |
void |
_mesa_HashPrint(const struct _mesa_HashTable *table) |
{ |
GLuint pos; |
assert(table); |
for (pos = 0; pos < TABLE_SIZE; pos++) { |
const struct HashEntry *entry = table->Table[pos]; |
while (entry) { |
_mesa_debug(NULL, "%u %p\n", entry->Key, entry->Data); |
entry = entry->Next; |
} |
} |
} |
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/** |
* 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) |
{ |
const GLuint maxKey = ~((GLuint) 0); |
_glthread_LOCK_MUTEX(table->Mutex); |
if (maxKey - numKeys > table->MaxKey) { |
/* the quick solution */ |
_glthread_UNLOCK_MUTEX(table->Mutex); |
return table->MaxKey + 1; |
} |
else { |
/* the slow solution */ |
GLuint freeCount = 0; |
GLuint freeStart = 1; |
GLuint 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; |
} |
else { |
/* this key not in use, check if we've found enough */ |
freeCount++; |
if (freeCount == numKeys) { |
_glthread_UNLOCK_MUTEX(table->Mutex); |
return freeStart; |
} |
} |
} |
/* cannot allocate a block of numKeys consecutive keys */ |
_glthread_UNLOCK_MUTEX(table->Mutex); |
return 0; |
} |
} |
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#if 0 /* debug only */ |
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/** |
* 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; |
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/* 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); |
} |
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/* 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); |
} |
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_mesa_DeleteHashTable(t); |
} |
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void |
_mesa_test_hash_functions(void) |
{ |
int a, b, c; |
struct _mesa_HashTable *t; |
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t = _mesa_NewHashTable(); |
_mesa_HashInsert(t, 501, &a); |
_mesa_HashInsert(t, 10, &c); |
_mesa_HashInsert(t, 0xfffffff8, &b); |
/*_mesa_HashPrint(t);*/ |
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assert(_mesa_HashLookup(t,501)); |
assert(!_mesa_HashLookup(t,1313)); |
assert(_mesa_HashFindFreeKeyBlock(t, 100)); |
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_mesa_DeleteHashTable(t); |
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test_hash_walking(); |
} |
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#endif |