vpx_mem/memory_manager/hmm_grow.c

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11
  12 /* This code is in the public domain.
  13 ** Version: 1.1  Author: Walt Karas
  14 */
  15
  16 #include "hmm_intrnl.h"
  17
  18 void U(grow_chunk)(U(descriptor) *desc, void *end, U(size_bau) n_baus)
  19 {
  20 #undef HEAD_PTR
  21 #define HEAD_PTR ((head_record *) end)
  22
  23     end = BAUS_BACKWARD(end, DUMMY_END_BLOCK_BAUS);
  24
  25 #ifdef HMM_AUDIT_FAIL
  26
  27     if (HEAD_PTR->block_size != 0)
  28         /* Chunk does not have valid dummy end block. */
  29         HMM_AUDIT_FAIL
  30
  31 #endif
  32
  33         /* Create a new block that absorbs the old dummy end block. */
  34         HEAD_PTR->block_size = n_baus;
  35
  36     /* Set up the new dummy end block. */
  37     {
  38         head_record *dummy = (head_record *) BAUS_FORWARD(end, n_baus);
  39         dummy->previous_block_size = n_baus;
  40         dummy->block_size = 0;
  41     }
  42
  43     /* Simply free the new block, allowing it to coalesce with any
  44     ** free block at that was the last block in the chunk prior to
  45     ** growth.
  46     */
  47     U(free)(desc, HEAD_TO_PTR_REC(end));
  48
  49 #undef HEAD_PTR
  50 }