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+/*
+Bullet Continuous Collision Detection and Physics Library
+Copyright (c) 2003-2009 Erwin Coumans http://bulletphysics.org
+
+This software is provided 'as-is', without any express or implied warranty.
+In no event will the authors be held liable for any damages arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it freely,
+subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+*/
+
+
+#ifndef BT_HASH_MAP_H
+#define BT_HASH_MAP_H
+
+#include "btAlignedObjectArray.h"
+
+///very basic hashable string implementation, compatible with btHashMap
+struct btHashString
+{
+ const char* m_string;
+ unsigned int m_hash;
+
+ SIMD_FORCE_INLINE unsigned int getHash()const
+ {
+ return m_hash;
+ }
+
+ btHashString(const char* name)
+ :m_string(name)
+ {
+ /* magic numbers from http://www.isthe.com/chongo/tech/comp/fnv/ */
+ static const unsigned int InitialFNV = 2166136261u;
+ static const unsigned int FNVMultiple = 16777619u;
+
+ /* Fowler / Noll / Vo (FNV) Hash */
+ unsigned int hash = InitialFNV;
+
+ for(int i = 0; m_string[i]; i++)
+ {
+ hash = hash ^ (m_string[i]); /* xor the low 8 bits */
+ hash = hash * FNVMultiple; /* multiply by the magic number */
+ }
+ m_hash = hash;
+ }
+
+ int portableStringCompare(const char* src, const char* dst) const
+ {
+ int ret = 0 ;
+
+ while( ! (ret = *(const unsigned char *)src - *(const unsigned char *)dst) && *dst)
+ ++src, ++dst;
+
+ if ( ret < 0 )
+ ret = -1 ;
+ else if ( ret > 0 )
+ ret = 1 ;
+
+ return( ret );
+ }
+
+ bool equals(const btHashString& other) const
+ {
+ return (m_string == other.m_string) ||
+ (0==portableStringCompare(m_string,other.m_string));
+
+ }
+
+};
+
+const int BT_HASH_NULL=0xffffffff;
+
+
+class btHashInt
+{
+ int m_uid;
+public:
+
+ btHashInt()
+ {
+ }
+
+ btHashInt(int uid) :m_uid(uid)
+ {
+ }
+
+ int getUid1() const
+ {
+ return m_uid;
+ }
+
+ void setUid1(int uid)
+ {
+ m_uid = uid;
+ }
+
+ bool equals(const btHashInt& other) const
+ {
+ return getUid1() == other.getUid1();
+ }
+ //to our success
+ SIMD_FORCE_INLINE unsigned int getHash()const
+ {
+ unsigned int key = m_uid;
+ // Thomas Wang's hash
+ key += ~(key << 15); key ^= (key >> 10); key += (key << 3); key ^= (key >> 6); key += ~(key << 11); key ^= (key >> 16);
+
+ return key;
+ }
+};
+
+
+
+class btHashPtr
+{
+
+ union
+ {
+ const void* m_pointer;
+ unsigned int m_hashValues[2];
+ };
+
+public:
+
+ btHashPtr(const void* ptr)
+ :m_pointer(ptr)
+ {
+ }
+
+ const void* getPointer() const
+ {
+ return m_pointer;
+ }
+
+ bool equals(const btHashPtr& other) const
+ {
+ return getPointer() == other.getPointer();
+ }
+
+ //to our success
+ SIMD_FORCE_INLINE unsigned int getHash()const
+ {
+ const bool VOID_IS_8 = ((sizeof(void*)==8));
+
+ unsigned int key = VOID_IS_8? m_hashValues[0]+m_hashValues[1] : m_hashValues[0];
+ // Thomas Wang's hash
+ key += ~(key << 15); key ^= (key >> 10); key += (key << 3); key ^= (key >> 6); key += ~(key << 11); key ^= (key >> 16);
+ return key;
+ }
+
+
+};
+
+
+template <class Value>
+class btHashKeyPtr
+{
+ int m_uid;
+public:
+
+ btHashKeyPtr(int uid) :m_uid(uid)
+ {
+ }
+
+ int getUid1() const
+ {
+ return m_uid;
+ }
+
+ bool equals(const btHashKeyPtr<Value>& other) const
+ {
+ return getUid1() == other.getUid1();
+ }
+
+ //to our success
+ SIMD_FORCE_INLINE unsigned int getHash()const
+ {
+ unsigned int key = m_uid;
+ // Thomas Wang's hash
+ key += ~(key << 15); key ^= (key >> 10); key += (key << 3); key ^= (key >> 6); key += ~(key << 11); key ^= (key >> 16);
+ return key;
+ }
+
+
+};
+
+
+template <class Value>
+class btHashKey
+{
+ int m_uid;
+public:
+
+ btHashKey(int uid) :m_uid(uid)
+ {
+ }
+
+ int getUid1() const
+ {
+ return m_uid;
+ }
+
+ bool equals(const btHashKey<Value>& other) const
+ {
+ return getUid1() == other.getUid1();
+ }
+ //to our success
+ SIMD_FORCE_INLINE unsigned int getHash()const
+ {
+ unsigned int key = m_uid;
+ // Thomas Wang's hash
+ key += ~(key << 15); key ^= (key >> 10); key += (key << 3); key ^= (key >> 6); key += ~(key << 11); key ^= (key >> 16);
+ return key;
+ }
+};
+
+
+///The btHashMap template class implements a generic and lightweight hashmap.
+///A basic sample of how to use btHashMap is located in Demos\BasicDemo\main.cpp
+template <class Key, class Value>
+class btHashMap
+{
+
+protected:
+ btAlignedObjectArray<int> m_hashTable;
+ btAlignedObjectArray<int> m_next;
+
+ btAlignedObjectArray<Value> m_valueArray;
+ btAlignedObjectArray<Key> m_keyArray;
+
+ void growTables(const Key& /*key*/)
+ {
+ int newCapacity = m_valueArray.capacity();
+
+ if (m_hashTable.size() < newCapacity)
+ {
+ //grow hashtable and next table
+ int curHashtableSize = m_hashTable.size();
+
+ m_hashTable.resize(newCapacity);
+ m_next.resize(newCapacity);
+
+ int i;
+
+ for (i= 0; i < newCapacity; ++i)
+ {
+ m_hashTable[i] = BT_HASH_NULL;
+ }
+ for (i = 0; i < newCapacity; ++i)
+ {
+ m_next[i] = BT_HASH_NULL;
+ }
+
+ for(i=0;i<curHashtableSize;i++)
+ {
+ //const Value& value = m_valueArray[i];
+ //const Key& key = m_keyArray[i];
+
+ int hashValue = m_keyArray[i].getHash() & (m_valueArray.capacity()-1); // New hash value with new mask
+ m_next[i] = m_hashTable[hashValue];
+ m_hashTable[hashValue] = i;
+ }
+
+
+ }
+ }
+
+ public:
+
+ void insert(const Key& key, const Value& value) {
+ int hash = key.getHash() & (m_valueArray.capacity()-1);
+
+ //replace value if the key is already there
+ int index = findIndex(key);
+ if (index != BT_HASH_NULL)
+ {
+ m_valueArray[index]=value;
+ return;
+ }
+
+ int count = m_valueArray.size();
+ int oldCapacity = m_valueArray.capacity();
+ m_valueArray.push_back(value);
+ m_keyArray.push_back(key);
+
+ int newCapacity = m_valueArray.capacity();
+ if (oldCapacity < newCapacity)
+ {
+ growTables(key);
+ //hash with new capacity
+ hash = key.getHash() & (m_valueArray.capacity()-1);
+ }
+ m_next[count] = m_hashTable[hash];
+ m_hashTable[hash] = count;
+ }
+
+ void remove(const Key& key) {
+
+ int hash = key.getHash() & (m_valueArray.capacity()-1);
+
+ int pairIndex = findIndex(key);
+
+ if (pairIndex ==BT_HASH_NULL)
+ {
+ return;
+ }
+
+ // Remove the pair from the hash table.
+ int index = m_hashTable[hash];
+ btAssert(index != BT_HASH_NULL);
+
+ int previous = BT_HASH_NULL;
+ while (index != pairIndex)
+ {
+ previous = index;
+ index = m_next[index];
+ }
+
+ if (previous != BT_HASH_NULL)
+ {
+ btAssert(m_next[previous] == pairIndex);
+ m_next[previous] = m_next[pairIndex];
+ }
+ else
+ {
+ m_hashTable[hash] = m_next[pairIndex];
+ }
+
+ // We now move the last pair into spot of the
+ // pair being removed. We need to fix the hash
+ // table indices to support the move.
+
+ int lastPairIndex = m_valueArray.size() - 1;
+
+ // If the removed pair is the last pair, we are done.
+ if (lastPairIndex == pairIndex)
+ {
+ m_valueArray.pop_back();
+ m_keyArray.pop_back();
+ return;
+ }
+
+ // Remove the last pair from the hash table.
+ int lastHash = m_keyArray[lastPairIndex].getHash() & (m_valueArray.capacity()-1);
+
+ index = m_hashTable[lastHash];
+ btAssert(index != BT_HASH_NULL);
+
+ previous = BT_HASH_NULL;
+ while (index != lastPairIndex)
+ {
+ previous = index;
+ index = m_next[index];
+ }
+
+ if (previous != BT_HASH_NULL)
+ {
+ btAssert(m_next[previous] == lastPairIndex);
+ m_next[previous] = m_next[lastPairIndex];
+ }
+ else
+ {
+ m_hashTable[lastHash] = m_next[lastPairIndex];
+ }
+
+ // Copy the last pair into the remove pair's spot.
+ m_valueArray[pairIndex] = m_valueArray[lastPairIndex];
+ m_keyArray[pairIndex] = m_keyArray[lastPairIndex];
+
+ // Insert the last pair into the hash table
+ m_next[pairIndex] = m_hashTable[lastHash];
+ m_hashTable[lastHash] = pairIndex;
+
+ m_valueArray.pop_back();
+ m_keyArray.pop_back();
+
+ }
+
+
+ int size() const
+ {
+ return m_valueArray.size();
+ }
+
+ const Value* getAtIndex(int index) const
+ {
+ btAssert(index < m_valueArray.size());
+ btAssert(index>=0);
+ if (index>=0 && index < m_valueArray.size())
+ {
+ return &m_valueArray[index];
+ }
+ return 0;
+ }
+
+ Value* getAtIndex(int index)
+ {
+ btAssert(index < m_valueArray.size());
+ btAssert(index>=0);
+ if (index>=0 && index < m_valueArray.size())
+ {
+ return &m_valueArray[index];
+ }
+ return 0;
+ }
+
+ Key getKeyAtIndex(int index)
+ {
+ btAssert(index < m_keyArray.size());
+ btAssert(index>=0);
+ return m_keyArray[index];
+ }
+
+ const Key getKeyAtIndex(int index) const
+ {
+ btAssert(index < m_keyArray.size());
+ btAssert(index>=0);
+ return m_keyArray[index];
+ }
+
+
+ Value* operator[](const Key& key) {
+ return find(key);
+ }
+
+ const Value* operator[](const Key& key) const {
+ return find(key);
+ }
+
+ const Value* find(const Key& key) const
+ {
+ int index = findIndex(key);
+ if (index == BT_HASH_NULL)
+ {
+ return NULL;
+ }
+ return &m_valueArray[index];
+ }
+
+ Value* find(const Key& key)
+ {
+ int index = findIndex(key);
+ if (index == BT_HASH_NULL)
+ {
+ return NULL;
+ }
+ return &m_valueArray[index];
+ }
+
+
+ int findIndex(const Key& key) const
+ {
+ unsigned int hash = key.getHash() & (m_valueArray.capacity()-1);
+
+ if (hash >= (unsigned int)m_hashTable.size())
+ {
+ return BT_HASH_NULL;
+ }
+
+ int index = m_hashTable[hash];
+ while ((index != BT_HASH_NULL) && key.equals(m_keyArray[index]) == false)
+ {
+ index = m_next[index];
+ }
+ return index;
+ }
+
+ void clear()
+ {
+ m_hashTable.clear();
+ m_next.clear();
+ m_valueArray.clear();
+ m_keyArray.clear();
+ }
+
+};
+
+#endif //BT_HASH_MAP_H