thirdparty/scummvm
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The hashmap uses the memorypool for allocating/deallocating its Nodes

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(It is faster and it saves approximately 70kB the DS or other small devices will appreciate having)

svn-id: r31321
This commit is contained in:
Bertrand Augereau 2008-03-30 06:02:34 +00:00
parent 411a588850
commit a84d1ea78b
2 changed files with 38 additions and 6 deletions
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36
common/hashmap.h
View file

@ -58,6 +58,12 @@
#include "common/str.h" #include "common/str.h"
#include "common/util.h" #include "common/util.h"
#define USE_HASHMAP_MEMORY_POOL
#ifdef USE_HASHMAP_MEMORY_POOL
#include "common/memorypool.h"
#include <new>
#endif
namespace Common { namespace Common {
// The table sizes ideally are primes. We use a helper function to find // The table sizes ideally are primes. We use a helper function to find
@ -70,6 +76,7 @@ uint nextTableSize(uint x);
// hash table that is too small). // hash table that is too small).
//#define DEBUG_HASH_COLLISIONS //#define DEBUG_HASH_COLLISIONS
/** /**
* HashMap<Key,Val> maps objects of type Key to objects of type Val. * HashMap<Key,Val> maps objects of type Key to objects of type Val.
* For each used Key type, we need an "uint hashit(Key,uint)" function * For each used Key type, we need an "uint hashit(Key,uint)" function
@ -98,13 +105,28 @@ public:
Node(const Key &key) : _key(key), _value() {} Node(const Key &key) : _key(key), _value() {}
}; };
#ifdef USE_HASHMAP_MEMORY_POOL
MemoryPool _nodePool;
Node *allocNode(const Key& key) { Node *allocNode(const Key& key) {
void* mem = _nodePool.malloc();
return new (mem) Node(key);
}
void freeNode(Node* node) {
node->~Node();
_nodePool.free(node);
}
#else
Node* allocNode(const Key& key) {
return new Node(key); return new Node(key);
} }
void freeNode(Node *node) { void freeNode(Node *node) {
delete node; delete node;
} }
#endif
Node **_arr; // hashtable of size arrsize. Node **_arr; // hashtable of size arrsize.
uint _arrsize, _nele; uint _arrsize, _nele;
@ -328,8 +350,11 @@ public:
* Base constructor, creates an empty hashmap. * Base constructor, creates an empty hashmap.
*/ */
template <class Key, class Val, class HashFunc, class EqualFunc> template <class Key, class Val, class HashFunc, class EqualFunc>
HashMap<Key, Val, HashFunc, EqualFunc>::HashMap() HashMap<Key, Val, HashFunc, EqualFunc>::HashMap() :
: _defaultVal() { #ifdef USE_HASHMAP_MEMORY_POOL
_nodePool(sizeof(Node)),
#endif
_defaultVal() {
_arrsize = nextTableSize(0); _arrsize = nextTableSize(0);
_arr = new Node *[_arrsize]; _arr = new Node *[_arrsize];
assert(_arr != NULL); assert(_arr != NULL);
@ -349,8 +374,11 @@ HashMap<Key, Val, HashFunc, EqualFunc>::HashMap()
* to heap buffers for the internal storage. * to heap buffers for the internal storage.
*/ */
template <class Key, class Val, class HashFunc, class EqualFunc> template <class Key, class Val, class HashFunc, class EqualFunc>
HashMap<Key, Val, HashFunc, EqualFunc>::HashMap(const HM_t& map) HashMap<Key, Val, HashFunc, EqualFunc>::HashMap(const HM_t& map) :
: _defaultVal() { #ifdef USE_HASHMAP_MEMORY_POOL
_nodePool(sizeof(Node)),
#endif
_defaultVal() {
assign(map); assign(map);
} }

8
common/memorypool.cpp
View file

@ -33,7 +33,7 @@ MemoryPool::MemoryPool(size_t chunkSize) {
MemoryPool::~MemoryPool() { MemoryPool::~MemoryPool() {
for(size_t i=0; i<_pages.size(); ++i) for(size_t i=0; i<_pages.size(); ++i)
free(_pages[i]); ::free(_pages[i]);
} }
void* MemoryPool::malloc() { void* MemoryPool::malloc() {
@ -83,12 +83,16 @@ void MemoryPool::freeUnusedPages() {
iterator = *(void**)iterator; iterator = *(void**)iterator;
} }
size_t freedPagesCount = 0;
for(size_t i=0; i<_pages.size(); ++i) { for(size_t i=0; i<_pages.size(); ++i) {
if(numberOfFreeChunksPerPage[i] == CHUNK_PAGE_SIZE) { if(numberOfFreeChunksPerPage[i] == CHUNK_PAGE_SIZE) {
free(_pages[i]); ::free(_pages[i]);
_pages[i] = NULL; // TODO : Remove NULL values _pages[i] = NULL; // TODO : Remove NULL values
++freedPagesCount;
} }
} }
printf("%d freed pages\n", freedPagesCount);
} }
} }