hmm_grow.c revision 1b362b15af34006e6a11974088a46d42b903418e 
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
18void 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}
51