src/gromacs/selection/mempool.cpp

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  35 /*! \internal \file
  36  * \brief
  37  * Implements functions in mempool.h.
  38  *
  39  * \author Teemu Murtola <teemu.murtola@gmail.com>
  40  * \ingroup module_selection
  41  */
  42 #include "gmxpre.h"
  43
  44 #include "mempool.h"
  45
  46 #include <stdlib.h>
  47
  48 #include <new>
  49
  50 #include "gromacs/selection/indexutil.h"
  51 #include "gromacs/utility/exceptions.h"
  52 #include "gromacs/utility/gmxassert.h"
  53 #include "gromacs/utility/smalloc.h"
  54
  55 //! Alignment in bytes for all returned blocks.
  56 #define ALIGN_STEP 8
  57
  58 /*! \internal \brief
  59  * Describes a single block allocated from the memory pool.
  60  */
  61 typedef struct gmx_sel_mempool_block_t
  62 {
  63     //! Pointer to the start of the block (as returned to the user).
  64     void                       *ptr;
  65     //! Size of the block, including padding required to align next block.
  66     size_t                      size;
  67 } gmx_sel_mempool_block_t;
  68
  69 /*! \internal \brief
  70  * Describes a memory pool.
  71  */
  72 struct gmx_sel_mempool_t
  73 {
  74     //! Number of bytes currently allocated from the pool.
  75     size_t                      currsize;
  76     //! Number of bytes free in the pool, or 0 if \a buffer is NULL.
  77     size_t                      freesize;
  78     //! Memory area allocated for the pool, or NULL if not yet reserved.
  79     char                       *buffer;
  80     //! Pointer to the first free byte (aligned at ::ALIGN_STEP) in \a buffer.
  81     char                       *freeptr;
  82     //! Number of blocks allocated from the pool.
  83     int                         nblocks;
  84     //! Array describing the allocated blocks.
  85     gmx_sel_mempool_block_t    *blockstack;
  86     //! Number of elements allocated for the \a blockstack array.
  87     int                         blockstack_nalloc;
  88     /*! \brief
  89      * Maximum number of bytes that have been reserved from the pool
  90      * simultaneously.
  91      */
  92     size_t                      maxsize;
  93 };
  94
  95 gmx_sel_mempool_t *
  96 _gmx_sel_mempool_create()
  97 {
  98     gmx_sel_mempool_t *mp;
  99
 100     snew(mp, 1);
 101     mp->currsize          = 0;
 102     mp->freesize          = 0;
 103     mp->buffer            = NULL;
 104     mp->freeptr           = NULL;
 105     mp->nblocks           = 0;
 106     mp->blockstack        = NULL;
 107     mp->blockstack_nalloc = 0;
 108     mp->maxsize           = 0;
 109     return mp;
 110 }
 111
 112 void
 113 _gmx_sel_mempool_destroy(gmx_sel_mempool_t *mp)
 114 {
 115     if (!mp->buffer)
 116     {
 117         int  i;
 118
 119         for (i = 0; i < mp->nblocks; ++i)
 120         {
 121             sfree(mp->blockstack[i].ptr);
 122         }
 123     }
 124     sfree(mp->buffer);
 125     sfree(mp->blockstack);
 126     sfree(mp);
 127 }
 128
 129 void *
 130 _gmx_sel_mempool_alloc(gmx_sel_mempool_t *mp, size_t size)
 131 {
 132     void   *ptr = NULL;
 133     size_t  size_walign;
 134
 135     size_walign = ((size + ALIGN_STEP - 1) / ALIGN_STEP) * ALIGN_STEP;
 136     if (mp->buffer)
 137     {
 138         if (mp->freesize < size)
 139         {
 140             GMX_THROW(gmx::InternalError("Out of memory pool memory"));
 141         }
 142         ptr           = mp->freeptr;
 143         mp->freeptr  += size_walign;
 144         mp->freesize -= size_walign;
 145         mp->currsize += size_walign;
 146     }
 147     else
 148     {
 149         ptr = malloc(size);
 150         if (!ptr)
 151         {
 152             throw std::bad_alloc();
 153         }
 154         mp->currsize += size_walign;
 155         if (mp->currsize > mp->maxsize)
 156         {
 157             mp->maxsize = mp->currsize;
 158         }
 159     }
 160
 161     if (mp->nblocks >= mp->blockstack_nalloc)
 162     {
 163         mp->blockstack_nalloc = mp->nblocks + 10;
 164         srenew(mp->blockstack, mp->blockstack_nalloc);
 165     }
 166     mp->blockstack[mp->nblocks].ptr  = ptr;
 167     mp->blockstack[mp->nblocks].size = size_walign;
 168     mp->nblocks++;
 169
 170     return ptr;
 171 }
 172
 173 void
 174 _gmx_sel_mempool_free(gmx_sel_mempool_t *mp, void *ptr)
 175 {
 176     int size;
 177
 178     if (ptr == NULL)
 179     {
 180         return;
 181     }
 182     GMX_RELEASE_ASSERT(mp->nblocks > 0 && mp->blockstack[mp->nblocks - 1].ptr == ptr,
 183                        "Invalid order of memory pool free calls");
 184     mp->nblocks--;
 185     size          = mp->blockstack[mp->nblocks].size;
 186     mp->currsize -= size;
 187     if (mp->buffer)
 188     {
 189         mp->freeptr   = (char *)ptr;
 190         mp->freesize += size;
 191     }
 192     else
 193     {
 194         sfree(ptr);
 195     }
 196 }
 197
 198 void
 199 _gmx_sel_mempool_reserve(gmx_sel_mempool_t *mp, size_t size)
 200 {
 201     GMX_RELEASE_ASSERT(mp->nblocks == 0,
 202                        "Cannot reserve memory pool when there is something allocated");
 203     GMX_RELEASE_ASSERT(!mp->buffer, "Cannot reserve memory pool twice");
 204     if (size == 0)
 205     {
 206         size = mp->maxsize;
 207     }
 208     mp->buffer = (char *)malloc(size);
 209     if (!mp->buffer)
 210     {
 211         throw std::bad_alloc();
 212     }
 213     mp->freesize = size;
 214     mp->freeptr  = mp->buffer;
 215 }
 216
 217 void
 218 _gmx_sel_mempool_alloc_group(gmx_sel_mempool_t *mp, gmx_ana_index_t *g,
 219                              int isize)
 220 {
 221     void *ptr = _gmx_sel_mempool_alloc(mp, sizeof(*g->index)*isize);
 222     g->index = static_cast<int *>(ptr);
 223 }
 224
 225 void
 226 _gmx_sel_mempool_free_group(gmx_sel_mempool_t *mp, gmx_ana_index_t *g)
 227 {
 228     _gmx_sel_mempool_free(mp, g->index);
 229     g->index = NULL;
 230 }