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# /home/coin/SVN-release/Bcps-0.91.0/CoinUtils/src/CoinAlloc.hpp

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    00001 // Copyright (C) 2007, International Business Machines
    00002 // Corporation and others.  All Rights Reserved.
    00003
    00004 #ifndef CoinAlloc_hpp
    00005 #define CoinAlloc_hpp
    00006
    00007 #include "CoinUtilsConfig.h"
    00008 #include <cstdlib>
    00009
    00010 #if !defined(COINUTILS_MEMPOOL_MAXPOOLED)
    00011 #  define COINUTILS_MEMPOOL_MAXPOOLED -1
    00012 #endif
    00013
    00014 #if (COINUTILS_MEMPOOL_MAXPOOLED >= 0)
    00015
    00016 #ifdef HAVE_STDLIB_H
    00017 #include <stdlib.h>
    00018 #endif
    00019
    00020 #ifndef COINUTILS_MEMPOOL_ALIGNMENT
    00021 #define COINUTILS_MEMPOOL_ALIGNMENT 16
    00022 #endif
    00023
    00024 /* Note:
    00025    This memory pool implementation assumes that sizeof(size_t) and
    00026    sizeof(void*) are both <= COINUTILS_MEMPOOL_ALIGNMENT.
    00027    Choosing an alignment of 4 will cause segfault on 64-bit platforms and may
    00028    lead to bad performance on 32-bit platforms. So 8 is a mnimum recommended
    00029    alignment. Probably 16 does not waste too much space either and may be even
    00030    better for performance. One must play with it.
    00031 */
    00032
    00033 //#############################################################################
    00034
    00035 #if (COINUTILS_MEMPOOL_ALIGNMENT == 16)
    00036 static const std::size_t CoinAllocPtrShift = 4;
    00037 static const std::size_t CoinAllocRoundMask = ~((std::size_t)15);
    00038 #elif (COINUTILS_MEMPOOL_ALIGNMENT == 8)
    00039 static const std::size_t CoinAllocPtrShift = 3;
    00040 static const std::size_t CoinAllocRoundMask = ~((std::size_t)7);
    00041 #else
    00042 #error "COINUTILS_MEMPOOL_ALIGNMENT must be defined as 8 or 16 (or this code needs to be changed :-)"
    00043 #endif
    00044
    00045 //#############################################################################
    00046
    00047 #ifndef COIN_MEMPOOL_SAVE_BLOCKHEADS
    00048 #  define COIN_MEMPOOL_SAVE_BLOCKHEADS 0
    00049 #endif
    00050
    00051 //#############################################################################
    00052
    00053 class CoinMempool
    00054 {
    00055 private:
    00056 #if (COIN_MEMPOOL_SAVE_BLOCKHEADS == 1)
    00057    char** block_heads;
    00058    std::size_t block_num;
    00059    std::size_t max_block_num;
    00060 #endif
    00061 #if defined(COINUTILS_PTHREADS) && (COINUTILS_PTHREAD == 1)
    00062   pthread_mutex_t mutex_;
    00063 #endif
    00064   int last_block_size_;
    00065   char* first_free_;
    00066   const std::size_t entry_size_;
    00067
    00068 private:
    00069   CoinMempool(const CoinMempool&);
    00070   CoinMempool& operator=(const CoinMempool&);
    00071
    00072 private:
    00073   char* allocate_new_block();
    00074   inline void lock_mutex() {
    00075 #if defined(COINUTILS_PTHREADS) && (COINUTILS_PTHREAD == 1)
    00076     pthread_mutex_lock(&mutex_);
    00077 #endif
    00078   }
    00079   inline void unlock_mutex() {
    00080 #if defined(COINUTILS_PTHREADS) && (COINUTILS_PTHREAD == 1)
    00081     pthread_mutex_unlock(&mutex_);
    00082 #endif
    00083   }
    00084
    00085 public:
    00086   CoinMempool(std::size_t size = 0);
    00087   ~CoinMempool();
    00088
    00089   char* alloc();
    00090   inline void dealloc(char *p)
    00091   {
    00092     char** pp = (char**)p;
    00093     lock_mutex();
    00094     *pp = first_free_;
    00095     first_free_ = p;
    00096     unlock_mutex();
    00097   }
    00098 };
    00099
    00100 //#############################################################################
    00101
    00114 class CoinAlloc
    00115 {
    00116 private:
    00117   CoinMempool* pool_;
    00118   int maxpooled_;
    00119 public:
    00120   CoinAlloc();
    00121   ~CoinAlloc() {}
    00122
    00123   inline void* alloc(const std::size_t n)
    00124   {
    00125     if (maxpooled_ <= 0) {
    00126       return std::malloc(n);
    00127     }
    00128     char *p = NULL;
    00129     const std::size_t to_alloc =
    00130       ((n+COINUTILS_MEMPOOL_ALIGNMENT-1) & CoinAllocRoundMask) +
    00131       COINUTILS_MEMPOOL_ALIGNMENT;
    00132     CoinMempool* pool = NULL;
    00133     if (maxpooled_ > 0 && to_alloc >= (size_t)maxpooled_) {
    00134       p = static_cast<char*>(std::malloc(to_alloc));
    00135       if (p == NULL) throw std::bad_alloc();
    00136     } else {
    00137       pool = pool_ + (to_alloc >> CoinAllocPtrShift);
    00138       p = pool->alloc();
    00139     }
    00140     *((CoinMempool**)p) = pool;
    00141     return static_cast<void*>(p+COINUTILS_MEMPOOL_ALIGNMENT);
    00142   }
    00143
    00144   inline void dealloc(void* p)
    00145   {
    00146     if (maxpooled_ <= 0) {
    00147       std::free(p);
    00148       return;
    00149     }
    00150     if (p) {
    00151       char* base = static_cast<char*>(p)-COINUTILS_MEMPOOL_ALIGNMENT;
    00152       CoinMempool* pool = *((CoinMempool**)base);
    00153       if (!pool) {
    00154         std::free(base);
    00155       } else {
    00156         pool->dealloc(base);
    00157       }
    00158     }
    00159   }
    00160 };
    00161
    00162 extern CoinAlloc CoinAllocator;
    00163
    00164 //#############################################################################
    00165
    00166 #if defined(COINUTILS_MEMPOOL_OVERRIDE_NEW) && (COINUTILS_MEMPOOL_OVERRIDE_NEW == 1)
    00167 void* operator new(std::size_t size) throw (std::bad_alloc);
    00168 void* operator new[](std::size_t) throw (std::bad_alloc);
    00169 void operator delete(void*) throw();
    00170 void operator delete[](void*) throw();
    00171 void* operator new(std::size_t, const std::nothrow_t&) throw();
    00172 void* operator new[](std::size_t, const std::nothrow_t&) throw();
    00173 void operator delete(void*, const std::nothrow_t&) throw();
    00174 void operator delete[](void*, const std::nothrow_t&) throw();
    00175 #endif
    00176
    00177 #endif /*(COINUTILS_MEMPOOL_MAXPOOLED >= 0)*/
    00178 #endif