src/glu/sgi/libnurbs/internals/bufpool.h

   1 /*
   2  * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
   3  * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice including the dates of first publication and
  13  * either this permission notice or a reference to
  14  * http://oss.sgi.com/projects/FreeB/
  15  * shall be included in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  21  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
  22  * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24  *
  25  * Except as contained in this notice, the name of Silicon Graphics, Inc.
  26  * shall not be used in advertising or otherwise to promote the sale, use or
  27  * other dealings in this Software without prior written authorization from
  28  * Silicon Graphics, Inc.
  29  */
  30
  31 /*
  32  * bufpool.h
  33  *
  34  * $Date: 2006/03/29 18:46:46 $ $Revision: 1.3 $
  35  * $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libnurbs/internals/bufpool.h,v 1.3 2006/03/29 18:46:46 brianp Exp $
  36  */
  37
  38 #ifndef __glubufpool_h_
  39 #define __glubufpool_h_
  40
  41 #include "gluos.h"
  42 #include "myassert.h"
  43 #include "mystdlib.h"
  44
  45 #define NBLOCKS 32
  46
  47 class Buffer {
  48         friend class    Pool;
  49         Buffer  *       next;           /* next buffer on free list     */
  50 };
  51
  52 class Pool {
  53 public:
  54                         Pool( int, int, const char * );
  55                         ~Pool( void );
  56     inline void*        new_buffer( void );
  57     inline void         free_buffer( void * );
  58     void                clear( void );
  59
  60 private:
  61     void                grow( void );
  62
  63 protected:
  64     Buffer              *freelist;              /* linked list of free buffers */
  65     char                *blocklist[NBLOCKS];    /* blocks of malloced memory */
  66     int                 nextblock;              /* next free block index */
  67     char                *curblock;              /* last malloced block */
  68     int                 buffersize;             /* bytes per buffer */
  69     int                 nextsize;               /* size of next block of memory */
  70     int                 nextfree;               /* byte offset past next free buffer */
  71     int                 initsize;
  72     enum Magic { is_allocated = 0xf3a1, is_free = 0xf1a2 };
  73     const char          *name;                  /* name of the pool */
  74     Magic               magic;                  /* marker for valid pool */
  75 };
  76
  77 /*-----------------------------------------------------------------------------
  78  * Pool::free_buffer - return a buffer to a pool
  79  *-----------------------------------------------------------------------------
  80  */
  81
  82 inline void
  83 Pool::free_buffer( void *b )
  84 {
  85     assert( (this != 0) && (magic == is_allocated) );
  86
  87     /* add buffer to singly connected free list */
  88
  89     ((Buffer *) b)->next = freelist;
  90     freelist = (Buffer *) b;
  91 }
  92
  93
  94 /*-----------------------------------------------------------------------------
  95  * Pool::new_buffer - allocate a buffer from a pool
  96  *-----------------------------------------------------------------------------
  97  */
  98
  99 inline void *
 100 Pool::new_buffer( void )
 101 {
 102     void *buffer;
 103
 104     assert( (this != 0) && (magic == is_allocated) );
 105
 106     /* find free buffer */
 107
 108     if( freelist ) {
 109         buffer = (void *) freelist;
 110         freelist = freelist->next;
 111     } else {
 112         if( ! nextfree )
 113             grow( );
 114         nextfree -= buffersize;;
 115         buffer = (void *) (curblock + nextfree);
 116     }
 117     return buffer;
 118 }
 119
 120 class PooledObj {
 121 public:
 122     inline void *       operator new( size_t, Pool & );
 123     inline void *       operator new( size_t, void *);
 124     inline void *       operator new( size_t s)
 125                                 { return ::new char[s]; }
 126     inline void         operator delete( void * ) { assert( 0 ); }
 127     inline void         operator delete( void *, Pool & ) { assert( 0 ); }
 128     inline void         deleteMe( Pool & );
 129 };
 130
 131 inline void *
 132 PooledObj::operator new( size_t, Pool& pool )
 133 {
 134     return pool.new_buffer();
 135 }
 136
 137 inline void
 138 PooledObj::deleteMe( Pool& pool )
 139 {
 140     pool.free_buffer( (void *) this );
 141 }
 142
 143 #endif /* __glubufpool_h_ */