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
18int U(resize)(U(descriptor) *desc, void *mem, U(size_aau) n) {
19  U(size_aau) i;
20  head_record *next_head_ptr;
21  head_record *head_ptr = PTR_REC_TO_HEAD(mem);
22
23  /* Flag. */
24  int next_block_free;
25
26  /* Convert n from desired block size in AAUs to BAUs. */
27  n += HEAD_AAUS;
28  n = DIV_ROUND_UP(n, HMM_BLOCK_ALIGN_UNIT);
29
30  if (n < MIN_BLOCK_BAUS)
31    n = MIN_BLOCK_BAUS;
32
33#ifdef HMM_AUDIT_FAIL
34
35  AUDIT_BLOCK(head_ptr)
36
37  if (!IS_BLOCK_ALLOCATED(head_ptr))
38    HMM_AUDIT_FAIL
39
40    if (desc->avl_tree_root)
41      AUDIT_BLOCK(PTR_REC_TO_HEAD(desc->avl_tree_root))
42
43#endif
44
45      i = head_ptr->block_size;
46
47  next_head_ptr =
48    (head_record *) BAUS_FORWARD(head_ptr, head_ptr->block_size);
49
50  next_block_free =
51    (next_head_ptr == desc->last_freed) ||
52    !IS_BLOCK_ALLOCATED(next_head_ptr);
53
54  if (next_block_free)
55    /* Block can expand into next free block. */
56    i += BLOCK_BAUS(next_head_ptr);
57
58  if (n > i)
59    /* Not enough room for block to expand. */
60    return(-1);
61
62  if (next_block_free) {
63#ifdef HMM_AUDIT_FAIL
64    AUDIT_BLOCK(next_head_ptr)
65#endif
66
67    if (next_head_ptr == desc->last_freed)
68      desc->last_freed = 0;
69    else
70      U(out_of_free_collection)(desc, next_head_ptr);
71
72    next_head_ptr =
73      (head_record *) BAUS_FORWARD(head_ptr, (U(size_bau)) i);
74  }
75
76  /* Set i to number of "extra" BAUs. */
77  i -= n;
78
79  if (i < MIN_BLOCK_BAUS)
80    /* Not enough extra BAUs to be a block on their own, so just keep them
81    ** in the block being resized.
82    */
83  {
84    n += i;
85    i = n;
86  } else {
87    /* There are enough "leftover" BAUs in the next block to
88    ** form a remainder block. */
89
90    head_record *rem_head_ptr;
91
92    rem_head_ptr = (head_record *) BAUS_FORWARD(head_ptr, n);
93
94    rem_head_ptr->previous_block_size = (U(size_bau)) n;
95    rem_head_ptr->block_size = (U(size_bau)) i;
96
97    if (desc->last_freed) {
98#ifdef HMM_AUDIT_FAIL
99      AUDIT_BLOCK(desc->last_freed)
100#endif
101
102      U(into_free_collection)(desc, (head_record *)(desc->last_freed));
103
104      desc->last_freed = 0;
105    }
106
107    desc->last_freed = rem_head_ptr;
108  }
109
110  head_ptr->block_size = (U(size_bau)) n;
111  next_head_ptr->previous_block_size = (U(size_bau)) i;
112
113  return(0);
114}
115