/*

* Copyright (c) 2010 Ixonos Plc.

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - Initial contribution

*

* Contributors:

* Ixonos Plc

*

* Description:

*

*/

/**************************************************************************

  l3sfb.cpp - Scalefactor band (sfb) implementations for layer III.

  Author(s): Juha Ojanpera

  Copyright (c) 1999-2004 by Nokia Research Center, Speech and Audio Systems.

  *************************************************************************/

/*-- Project Headers. --*/

#include "mp3tables.h"

#include "mpaud.h"

#include "mpheader.h"

/**************************************************************************

  External Objects Needed

  *************************************************************************/

/**************************************************************************

  Internal Objects

  *************************************************************************/

static const int16 *III_sfbOffsetLong(TMPEG_Header *header);

static const int16 *III_sfbOffsetShort(TMPEG_Header *header);

static const int16 *III_sfbWidthTblShort(int16 *sfb_offset, int16 *sfb_width);

/**************************************************************************

  Title        : III_SfbDataInit

  Purpose      : Initializes the sfb parameters.

  Usage        : III_SfbDataInit(sfbData, header)

  Input        : sfbData - sfb parameters

                 header  - mp3 header parameters

  Author(s)    : Juha Ojanpera

  *************************************************************************/

void

III_SfbDataInit(CIII_SfbData *sfbData, TMPEG_Header *header)

{

  COPY_MEMORY(sfbData->sfbOffsetLong, III_sfbOffsetLong(header),

              (MAX_LONG_SFB_BANDS + 1) * sizeof(int16));

  sfbData->sfbLong = sfbData->sfbOffsetLong;

  COPY_MEMORY(sfbData->sfbOffsetShort, III_sfbOffsetShort(header),

              (MAX_SHORT_SFB_BANDS + 1) * sizeof(int16));

  sfbData->sfbShort = sfbData->sfbOffsetShort;

  COPY_MEMORY(sfbData->sfbWidthShort, 

              III_sfbWidthTblShort(sfbData->sfbShort, sfbData->sfbWidthShort),

              (MAX_SHORT_SFB_BANDS + 1) * sizeof(int16));

  sfbData->sfbWidth = sfbData->sfbWidthShort;

  sfbData->bandLimit = MAX_MONO_SAMPLES;

}

/**************************************************************************

  Title        : III_BandLimit

  Purpose      : Saves the bandlimit value for Huffman decoding.

  Usage        : III_BandLimit(sfbData, decim_factor)

  Input        : sfbData  - sfb parameters

                 binLimit - number of spectral bins to be decoded from each channel

  Author(s)    : Juha Ojanpera

  *************************************************************************/

void

III_BandLimit(CIII_SfbData *sfbData, uint16 binLimit)

{

  sfbData->bandLimit = binLimit;

}

/**************************************************************************

  Title        : III_sfbOffsetLong

  Purpose      : Obtains the scalefactor table for long blocks.

  Usage        : y = III_sfbOffsetLong(header)

  Input        : header - mp3 header parameters

  Output       : y - scalefactor boundaries for long blocks

  Author(s)    : Juha Ojanpera

  *************************************************************************/

const int16 *

III_sfbOffsetLong(TMPEG_Header *header)

{

  int16 fidx, mp25idx = (int16) (6 * mp25version(header));

  fidx = (int16) (mp25idx + 3 * version(header) + sfreq(header));

  return (&sfBandIndex[fidx].l[0]);

}

/**************************************************************************

  Title        : III_sfbOffsetShort

  Purpose      : Obtains the scalefactor table for short blocks.

  Usage        : y = III_sfbOffsetShort(header)

  Input        : header - mp3 header parameters

  Output       : y - scalefactor boundaries for short blocks

  Author(s)    : Juha Ojanpera

  *************************************************************************/

const int16 *

III_sfbOffsetShort(TMPEG_Header *header)

{

  int16 mp25idx = (int16) (6 * mp25version(header));

  return (&sfBandIndex[mp25idx + 3 * version(header) + sfreq(header)].s[0]);

}

/**************************************************************************

  Title        : III_sfbWidthTblShort

  Purpose      : Obtains the scalefactor width table for short blocks.

  Usage        : y = III_sfbWidthTblShort(sfb_offset, sfb_width)

  Input        : sfb_offset - offset table of short blocks

                 sfb_width  - address of buffer to receive the sfb widths

  Output       : y - sfb width table for short blocks

  Author(s)    : Juha Ojanpera

  *************************************************************************/

const int16 *

III_sfbWidthTblShort(int16 *sfb_offset, int16 *sfb_width)

{

  for(int16 i = 0; i < MAX_SHORT_SFB_BANDS; i++)

    sfb_width[i] = (int16) (sfb_offset[i + 1] - sfb_offset[i]);

  return (sfb_width);

}