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

   1 /*
   2 ** License Applicability. Except to the extent portions of this file are
   3 ** made subject to an alternative license as permitted in the SGI Free
   4 ** Software License B, Version 1.1 (the "License"), the contents of this
   5 ** file are subject only to the provisions of the License. You may not use
   6 ** this file except in compliance with the License. You may obtain a copy
   7 ** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
   8 ** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
   9 **
  10 ** http://oss.sgi.com/projects/FreeB
  11 **
  12 ** Note that, as provided in the License, the Software is distributed on an
  13 ** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
  14 ** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
  15 ** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
  16 ** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
  17 **
  18 ** Original Code. The Original Code is: OpenGL Sample Implementation,
  19 ** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
  20 ** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
  21 ** Copyright in any portions created by third parties is as indicated
  22 ** elsewhere herein. All Rights Reserved.
  23 **
  24 ** Additional Notice Provisions: The application programming interfaces
  25 ** established by SGI in conjunction with the Original Code are The
  26 ** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
  27 ** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
  28 ** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
  29 ** Window System(R) (Version 1.3), released October 19, 1998. This software
  30 ** was created using the OpenGL(R) version 1.2.1 Sample Implementation
  31 ** published by SGI, but has not been independently verified as being
  32 ** compliant with the OpenGL(R) version 1.2.1 Specification.
  33 */
  34
  35 /*
  36  * bufpool.h
  37  *
  38  */
  39
  40 #ifndef __glubufpool_h_
  41 #define __glubufpool_h_
  42
  43 #include "gluos.h"
  44 #include "myassert.h"
  45 #include "mystdlib.h"
  46
  47 #define NBLOCKS 32
  48
  49 class Buffer {
  50         friend class    Pool;
  51         Buffer  *       next;           /* next buffer on free list     */
  52 };
  53
  54 class Pool {
  55 public:
  56                         Pool( int, int, char * );
  57                         ~Pool( void );
  58     inline void*        new_buffer( void );
  59     inline void         free_buffer( void * );
  60     void                clear( void );
  61
  62 private:
  63     void                grow( void );
  64
  65 protected:
  66     Buffer              *freelist;              /* linked list of free buffers */
  67     char                *blocklist[NBLOCKS];    /* blocks of malloced memory */
  68     int                 nextblock;              /* next free block index */
  69     char                *curblock;              /* last malloced block */
  70     int                 buffersize;             /* bytes per buffer */
  71     int                 nextsize;               /* size of next block of memory */
  72     int                 nextfree;               /* byte offset past next free buffer */
  73     int                 initsize;
  74     enum Magic { is_allocated = 0xf3a1, is_free = 0xf1a2 };
  75     char                *name;                  /* name of the pool */
  76     Magic               magic;                  /* marker for valid pool */
  77 };
  78
  79 /*-----------------------------------------------------------------------------
  80  * Pool::free_buffer - return a buffer to a pool
  81  *-----------------------------------------------------------------------------
  82  */
  83
  84 inline void
  85 Pool::free_buffer( void *b )
  86 {
  87     assert( (this != 0) && (magic == is_allocated) );
  88
  89     /* add buffer to singly connected free list */
  90
  91     ((Buffer *) b)->next = freelist;
  92     freelist = (Buffer *) b;
  93 }
  94
  95
  96 /*-----------------------------------------------------------------------------
  97  * Pool::new_buffer - allocate a buffer from a pool
  98  *-----------------------------------------------------------------------------
  99  */
 100
 101 inline void *
 102 Pool::new_buffer( void )
 103 {
 104     void *buffer;
 105
 106     assert( (this != 0) && (magic == is_allocated) );
 107
 108     /* find free buffer */
 109
 110     if( freelist ) {
 111         buffer = (void *) freelist;
 112         freelist = freelist->next;
 113     } else {
 114         if( ! nextfree )
 115             grow( );
 116         nextfree -= buffersize;;
 117         buffer = (void *) (curblock + nextfree);
 118     }
 119     return buffer;
 120 }
 121
 122 class PooledObj {
 123 public:
 124     inline void *       operator new( size_t, Pool & );
 125     inline void *       operator new( size_t, void *);
 126     inline void *       operator new( size_t s)
 127                                 { return ::new char[s]; }
 128     inline void         operator delete( void * ) { assert( 0 ); }
 129     inline void         operator delete( void *, Pool & ) { assert( 0 ); }
 130     inline void         deleteMe( Pool & );
 131 };
 132
 133 inline void *
 134 PooledObj::operator new( size_t, Pool& pool )
 135 {
 136     return pool.new_buffer();
 137 }
 138
 139 inline void
 140 PooledObj::deleteMe( Pool& pool )
 141 {
 142     pool.free_buffer( (void *) this );
 143 }
 144
 145 #endif /* __glubufpool_h_ */