00001 /* 00002 * The Apache Software License, Version 1.1 00003 * 00004 * 00005 * Copyright (c) 2000 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 template<class ObjectType> 00074 class ReusableArenaAllocator : public ArenaAllocator<ObjectType, 00075 ReusableArenaBlock<ObjectType> > 00076 { 00077 public: 00078 00079 typedef ReusableArenaBlock<ObjectType> ReusableArenaBlockType; 00080 00081 typedef typename ReusableArenaBlockType::size_type size_type; 00082 00083 typedef ArenaAllocator<ObjectType, 00084 ReusableArenaBlockType> BaseClassType; 00085 00086 // $$$ ToDo: This typedef is here because of a bug in gcc. 00087 #if defined (XALAN_NO_NAMESPACES) 00088 typedef vector<ReusableArenaBlockType*> ArenaBlockListType; 00089 #else 00090 typedef std::vector<ReusableArenaBlockType*> ArenaBlockListType; 00091 #endif 00092 00093 /* 00094 * Construct an instance that will allocate blocks of the specified size. 00095 * 00096 * @param theBlockSize The block size. 00097 */ 00098 ReusableArenaAllocator(size_type theBlockSize) : 00099 BaseClassType(theBlockSize), 00100 m_lastBlockReferenced(0) 00101 { 00102 } 00103 00104 virtual 00105 ~ReusableArenaAllocator() 00106 { 00107 } 00108 00109 /* 00110 * Destroy the object, and free the block for re-use. 00111 * 00112 * @param theObject the address of the object. 00113 * @return true if the object was deleted, false if not. 00114 */ 00115 bool 00116 destroyObject(ObjectType* theObject) 00117 { 00118 bool fSucess = false; 00119 00120 // Check this, just in case... 00121 if (m_lastBlockReferenced != 0 && m_lastBlockReferenced->ownsObject(theObject) == true) 00122 { 00123 m_lastBlockReferenced->destroyObject(theObject); 00124 00125 fSucess = true; 00126 } 00127 else 00128 { 00129 // Note that this-> is required by template lookup rules. 00130 const typename ArenaBlockListType::reverse_iterator theEnd = this->m_blocks.rend(); 00131 00132 typename ArenaBlockListType::reverse_iterator i = this->m_blocks.rbegin(); 00133 00134 while(i != theEnd) 00135 { 00136 if ((*i)->ownsObject(theObject) == true) 00137 { 00138 m_lastBlockReferenced = *i; 00139 00140 m_lastBlockReferenced->destroyObject(theObject); 00141 00142 fSucess = true; 00143 00144 break; 00145 } 00146 else 00147 { 00148 ++i; 00149 } 00150 } 00151 } 00152 00153 return fSucess; 00154 } 00155 00156 /* 00157 * Allocate a block of the appropriate size for an 00158 * object. Call commitAllocation() when after 00159 * the object is successfully constructed. You _must_ 00160 * commit an allocation before performing any other 00161 * operation on the allocator. 00162 * 00163 * @return A pointer to a block of memory 00164 */ 00165 virtual ObjectType* 00166 allocateBlock() 00167 { 00168 if (m_lastBlockReferenced == 0 || 00169 m_lastBlockReferenced->blockAvailable() == false) 00170 { 00171 // Search back for a block with some space available... 00172 const typename ArenaBlockListType::reverse_iterator theEnd = this->m_blocks.rend(); 00173 00174 // Note that this-> is required by template lookup rules. 00175 typename ArenaBlockListType::reverse_iterator i = this->m_blocks.rbegin(); 00176 00177 while(i != theEnd) 00178 { 00179 assert(*i != 0); 00180 00181 if (*i != m_lastBlockReferenced && (*i)->blockAvailable() == true) 00182 { 00183 // Ahh, found one with free space. 00184 m_lastBlockReferenced = *i; 00185 00186 break; 00187 } 00188 else 00189 { 00190 ++i; 00191 } 00192 } 00193 00194 if (i == theEnd) 00195 { 00196 // No blocks have free space available, so create a new block, and 00197 // push it on the list. 00198 // Note that this-> is required by template lookup rules. 00199 m_lastBlockReferenced = new ReusableArenaBlockType(this->m_blockSize); 00200 00201 this->m_blocks.push_back(m_lastBlockReferenced); 00202 } 00203 } 00204 assert(m_lastBlockReferenced != 0 && m_lastBlockReferenced->blockAvailable() == true); 00205 00206 return m_lastBlockReferenced->allocateBlock(); 00207 } 00208 00209 /* 00210 * Commits the allocation of the previous 00211 * allocateBlock() call. 00212 * 00213 * @param theObject A pointer to a block of memory 00214 */ 00215 virtual void 00216 commitAllocation(ObjectType* theObject) 00217 { 00218 // Note that this-> is required by template lookup rules. 00219 assert(this->m_blocks.size() != 0 && m_lastBlockReferenced != 0 && m_lastBlockReferenced->ownsBlock(theObject) == true); 00220 00221 m_lastBlockReferenced->commitAllocation(theObject); 00222 assert(m_lastBlockReferenced->ownsObject(theObject) == true); 00223 } 00224 00225 virtual void 00226 reset() 00227 { 00228 m_lastBlockReferenced = 0; 00229 00230 BaseClassType::reset(); 00231 } 00232 00233 virtual bool 00234 ownsObject(const ObjectType* theObject) const 00235 { 00236 bool fResult = false; 00237 00238 // If no block has ever been referenced, then we haven't allocated 00239 // any objects. 00240 if (m_lastBlockReferenced != 0) 00241 { 00242 // Check the last referenced block first. 00243 fResult = m_lastBlockReferenced->ownsObject(theObject); 00244 00245 if (fResult == false) 00246 { 00247 fResult = BaseClassType::ownsObject(theObject); 00248 } 00249 } 00250 00251 return fResult; 00252 } 00253 00254 private: 00255 00256 // Not defined... 00257 ReusableArenaAllocator(const ReusableArenaAllocator<ObjectType>&); 00258 00259 ReusableArenaAllocator<ObjectType>& 00260 operator=(const ReusableArenaAllocator<ObjectType>&); 00261 00262 // Data members... 00263 ReusableArenaBlockType* m_lastBlockReferenced; 00264 }; 00265 00266 00267 00268 #endif // !defined(REUSABLEARENAALLOCATOR_INCLUDE_GUARD_1357924680)
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