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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2010 Yoshihisa Uchida
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "adpcm_seek.h"
#include "codeclib.h"
/*
* The helper functions in order to seek for the adpcm codec
* which does not include the header each the data block.
*/
#define MAX_STORE_COUNT 1000
static struct adpcm_data seek_table[MAX_STORE_COUNT];
static int seek_count;
static int cur_count;
static int max_ratio;
static int cur_ratio;
void init_seek_table(uint32_t max_count)
{
int i = 0;
for ( ; i < MAX_STORE_COUNT; i++)
{
seek_table[i].is_valid = false;
}
seek_count = max_count / MAX_STORE_COUNT + 1;
max_ratio = max_count / seek_count + 1;
cur_count = 0;
cur_ratio = -1;
}
void add_adpcm_data(struct adpcm_data *data)
{
if (--cur_count <= 0)
{
cur_count = seek_count;
if (++cur_ratio >= max_ratio)
cur_ratio = max_ratio - 1;
if (!seek_table[cur_ratio].is_valid)
{
seek_table[cur_ratio].pcmdata[0] = data->pcmdata[0];
seek_table[cur_ratio].pcmdata[1] = data->pcmdata[1];
seek_table[cur_ratio].step[0] = data->step[0];
seek_table[cur_ratio].step[1] = data->step[1];
seek_table[cur_ratio].is_valid = true;
}
}
}
uint32_t seek(uint32_t count, struct adpcm_data *seek_data,
uint8_t *(*read_buffer)(size_t *realsize),
int (*decode)(const uint8_t *inbuf, size_t inbufsize))
{
int new_ratio = count / seek_count;
if (new_ratio >= max_ratio)
new_ratio = max_ratio - 1;
if (!seek_table[new_ratio].is_valid)
{
uint8_t *buffer;
size_t n;
do
{
buffer = read_buffer(&n);
if (n == 0)
break;
decode(buffer, n);
} while (cur_ratio < new_ratio);
}
seek_data->pcmdata[0] = seek_table[new_ratio].pcmdata[0];
seek_data->pcmdata[1] = seek_table[new_ratio].pcmdata[1];
seek_data->step[0] = seek_table[new_ratio].step[0];
seek_data->step[1] = seek_table[new_ratio].step[1];
cur_ratio = new_ratio;
cur_count = seek_count;
return cur_ratio * seek_count;
}
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