vpx/vpx_mem/memory_manager/hmm_resize.c
John Koleszar c2140b8af1 Use WebM in copyright notice for consistency
Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.

Fixes issue #97.

Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba
2010-09-09 10:01:21 -04:00

120 lines
2.9 KiB
C

/*
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/* This code is in the public domain.
** Version: 1.1 Author: Walt Karas
*/
#include "hmm_intrnl.h"
int U(resize)(U(descriptor) *desc, void *mem, U(size_aau) n)
{
U(size_aau) i;
head_record *next_head_ptr;
head_record *head_ptr = PTR_REC_TO_HEAD(mem);
/* Flag. */
int next_block_free;
/* Convert n from desired block size in AAUs to BAUs. */
n += HEAD_AAUS;
n = DIV_ROUND_UP(n, HMM_BLOCK_ALIGN_UNIT);
if (n < MIN_BLOCK_BAUS)
n = MIN_BLOCK_BAUS;
#ifdef HMM_AUDIT_FAIL
AUDIT_BLOCK(head_ptr)
if (!IS_BLOCK_ALLOCATED(head_ptr))
HMM_AUDIT_FAIL
if (desc->avl_tree_root)
AUDIT_BLOCK(PTR_REC_TO_HEAD(desc->avl_tree_root))
#endif
i = head_ptr->block_size;
next_head_ptr =
(head_record *) BAUS_FORWARD(head_ptr, head_ptr->block_size);
next_block_free =
(next_head_ptr == desc->last_freed) ||
!IS_BLOCK_ALLOCATED(next_head_ptr);
if (next_block_free)
/* Block can expand into next free block. */
i += BLOCK_BAUS(next_head_ptr);
if (n > i)
/* Not enough room for block to expand. */
return(-1);
if (next_block_free)
{
#ifdef HMM_AUDIT_FAIL
AUDIT_BLOCK(next_head_ptr)
#endif
if (next_head_ptr == desc->last_freed)
desc->last_freed = 0;
else
U(out_of_free_collection)(desc, next_head_ptr);
next_head_ptr =
(head_record *) BAUS_FORWARD(head_ptr, (U(size_bau)) i);
}
/* Set i to number of "extra" BAUs. */
i -= n;
if (i < MIN_BLOCK_BAUS)
/* Not enough extra BAUs to be a block on their own, so just keep them
** in the block being resized.
*/
{
n += i;
i = n;
}
else
{
/* There are enough "leftover" BAUs in the next block to
** form a remainder block. */
head_record *rem_head_ptr;
rem_head_ptr = (head_record *) BAUS_FORWARD(head_ptr, n);
rem_head_ptr->previous_block_size = (U(size_bau)) n;
rem_head_ptr->block_size = (U(size_bau)) i;
if (desc->last_freed)
{
#ifdef HMM_AUDIT_FAIL
AUDIT_BLOCK(desc->last_freed)
#endif
U(into_free_collection)(desc, (head_record *)(desc->last_freed));
desc->last_freed = 0;
}
desc->last_freed = rem_head_ptr;
}
head_ptr->block_size = (U(size_bau)) n;
next_head_ptr->previous_block_size = (U(size_bau)) i;
return(0);
}