00001 /* 00002 * The Apache Software License, Version 1.1 00003 * 00004 * 00005 * Copyright (c) 2000-2002 The Apache Software Foundation. All rights 00006 * reserved. 00007 * 00008 * Redistribution and use in source and binary forms, with or without 00009 * modification, are permitted provided that the following conditions 00010 * are met: 00011 * 00012 * 1. Redistributions of source code must retain the above copyright 00013 * notice, this list of conditions and the following disclaimer. 00014 * 00015 * 2. Redistributions in binary form must reproduce the above copyright 00016 * notice, this list of conditions and the following disclaimer in 00017 * the documentation and/or other materials provided with the 00018 * distribution. 00019 * 00020 * 3. The end-user documentation included with the redistribution, 00021 * if any, must include the following acknowledgment: 00022 * "This product includes software developed by the 00023 * Apache Software Foundation (http://www.apache.org/)." 00024 * Alternately, this acknowledgment may appear in the software itself, 00025 * if and wherever such third-party acknowledgments normally appear. 00026 * 00027 * 4. The names "Xalan" and "Apache Software Foundation" must 00028 * not be used to endorse or promote products derived from this 00029 * software without prior written permission. For written 00030 * permission, please contact apache@apache.org. 00031 * 00032 * 5. Products derived from this software may not be called "Apache", 00033 * nor may "Apache" appear in their name, without prior written 00034 * permission of the Apache Software Foundation. 00035 * 00036 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 00037 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 00038 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 00039 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 00040 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 00041 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 00042 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 00043 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 00044 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 00045 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 00046 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00047 * SUCH DAMAGE. 00048 * ==================================================================== 00049 * 00050 * This software consists of voluntary contributions made by many 00051 * individuals on behalf of the Apache Software Foundation and was 00052 * originally based on software copyright (c) 1999, International 00053 * Business Machines, Inc., http://www.ibm.com. For more 00054 * information on the Apache Software Foundation, please see 00055 * <http://www.apache.org/>. 00056 */ 00057 00058 #if !defined(REUSABLEARENAALLOCATOR_INCLUDE_GUARD_1357924680) 00059 #define REUSABLEARENAALLOCATOR_INCLUDE_GUARD_1357924680 00060 00061 00062 00063 #include <algorithm> 00064 #include <vector> 00065 00066 00067 00068 #include "ReusableArenaBlock.hpp" 00069 #include "ArenaAllocator.hpp" 00070 00071 00072 00073 XALAN_CPP_NAMESPACE_BEGIN 00074 00075 00076 00077 template<class ObjectType> 00078 class ReusableArenaAllocator : public ArenaAllocator<ObjectType, 00079 ReusableArenaBlock<ObjectType> > 00080 { 00081 public: 00082 00083 typedef ReusableArenaBlock<ObjectType> ReusableArenaBlockType; 00084 00085 typedef typename ReusableArenaBlockType::size_type size_type; 00086 00087 typedef ArenaAllocator<ObjectType, 00088 ReusableArenaBlockType> BaseClassType; 00089 00090 #if defined (XALAN_NO_STD_NAMESPACE) 00091 typedef vector<ReusableArenaBlockType*> ArenaBlockListType; 00092 #else 00093 typedef std::vector<ReusableArenaBlockType*> ArenaBlockListType; 00094 #endif 00095 00096 /* 00097 * Construct an instance that will allocate blocks of the specified size. 00098 * 00099 * @param theBlockSize The block size. 00100 */ 00101 ReusableArenaAllocator(size_type theBlockSize) : 00102 BaseClassType(theBlockSize), 00103 m_lastBlockReferenced(0) 00104 { 00105 } 00106 00107 virtual 00108 ~ReusableArenaAllocator() 00109 { 00110 } 00111 00112 /* 00113 * Destroy the object, and free the block for re-use. 00114 * 00115 * @param theObject the address of the object. 00116 * @return true if the object was deleted, false if not. 00117 */ 00118 bool 00119 destroyObject(ObjectType* theObject) 00120 { 00121 bool fSuccess = false; 00122 00123 // Check this, just in case... 00124 if (m_lastBlockReferenced != 0 && m_lastBlockReferenced->ownsObject(theObject) == true) 00125 { 00126 m_lastBlockReferenced->destroyObject(theObject); 00127 00128 fSuccess = true; 00129 } 00130 else 00131 { 00132 // Note that this-> is required by template lookup rules. 00133 const typename ArenaBlockListType::reverse_iterator theEnd = this->m_blocks.rend(); 00134 00135 typename ArenaBlockListType::reverse_iterator i = this->m_blocks.rbegin(); 00136 00137 while(i != theEnd) 00138 { 00139 if ((*i)->ownsObject(theObject) == true) 00140 { 00141 m_lastBlockReferenced = *i; 00142 00143 m_lastBlockReferenced->destroyObject(theObject); 00144 00145 fSuccess = true; 00146 00147 break; 00148 } 00149 else 00150 { 00151 ++i; 00152 } 00153 } 00154 } 00155 00156 return fSuccess; 00157 } 00158 00159 /* 00160 * Allocate a block of the appropriate size for an 00161 * object. Call commitAllocation() when after 00162 * the object is successfully constructed. You _must_ 00163 * commit an allocation before performing any other 00164 * operation on the allocator. 00165 * 00166 * @return A pointer to a block of memory 00167 */ 00168 virtual ObjectType* 00169 allocateBlock() 00170 { 00171 if (m_lastBlockReferenced == 0 || 00172 m_lastBlockReferenced->blockAvailable() == false) 00173 { 00174 // Search back for a block with some space available... 00175 const typename ArenaBlockListType::reverse_iterator theEnd = this->m_blocks.rend(); 00176 00177 // Note that this-> is required by template lookup rules. 00178 typename ArenaBlockListType::reverse_iterator i = this->m_blocks.rbegin(); 00179 00180 while(i != theEnd) 00181 { 00182 assert(*i != 0); 00183 00184 if (*i != m_lastBlockReferenced && (*i)->blockAvailable() == true) 00185 { 00186 // Ahh, found one with free space. 00187 m_lastBlockReferenced = *i; 00188 00189 break; 00190 } 00191 else 00192 { 00193 ++i; 00194 } 00195 } 00196 00197 if (i == theEnd) 00198 { 00199 // No blocks have free space available, so create a new block, and 00200 // push it on the list. 00201 // Note that this-> is required by template lookup rules. 00202 m_lastBlockReferenced = new ReusableArenaBlockType(this->m_blockSize); 00203 00204 this->m_blocks.push_back(m_lastBlockReferenced); 00205 } 00206 } 00207 assert(m_lastBlockReferenced != 0 && m_lastBlockReferenced->blockAvailable() == true); 00208 00209 return m_lastBlockReferenced->allocateBlock(); 00210 } 00211 00212 /* 00213 * Commits the allocation of the previous 00214 * allocateBlock() call. 00215 * 00216 * @param theObject A pointer to a block of memory 00217 */ 00218 virtual void 00219 commitAllocation(ObjectType* theObject) 00220 { 00221 // Note that this-> is required by template lookup rules. 00222 assert(this->m_blocks.empty() == false && m_lastBlockReferenced != 0 && m_lastBlockReferenced->ownsBlock(theObject) == true); 00223 00224 m_lastBlockReferenced->commitAllocation(theObject); 00225 assert(m_lastBlockReferenced->ownsObject(theObject) == true); 00226 } 00227 00228 virtual void 00229 reset() 00230 { 00231 m_lastBlockReferenced = 0; 00232 00233 BaseClassType::reset(); 00234 } 00235 00236 virtual bool 00237 ownsObject(const ObjectType* theObject) const 00238 { 00239 bool fResult = false; 00240 00241 // If no block has ever been referenced, then we haven't allocated 00242 // any objects. 00243 if (m_lastBlockReferenced != 0) 00244 { 00245 // Check the last referenced block first. 00246 fResult = m_lastBlockReferenced->ownsObject(theObject); 00247 00248 if (fResult == false) 00249 { 00250 fResult = BaseClassType::ownsObject(theObject); 00251 } 00252 } 00253 00254 return fResult; 00255 } 00256 00257 private: 00258 00259 // Not defined... 00260 ReusableArenaAllocator(const ReusableArenaAllocator<ObjectType>&); 00261 00262 ReusableArenaAllocator<ObjectType>& 00263 operator=(const ReusableArenaAllocator<ObjectType>&); 00264 00265 // Data members... 00266 ReusableArenaBlockType* m_lastBlockReferenced; 00267 }; 00268 00269 00270 00271 XALAN_CPP_NAMESPACE_END 00272 00273 00274 00275 #endif // !defined(REUSABLEARENAALLOCATOR_INCLUDE_GUARD_1357924680)
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