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/*
* @(#) header.h 1.8, last edit: 25 Oct 1994 16:27:25
* @(#) Copyright (C) 1993, 1994 Tobias Bading (bading@cs.tu-berlin.de)
* @(#) Berlin University of Technology
*
* 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 program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef HEADER_H
#define HEADER_H
#include "all.h"
#include "ibitstream.h"
#include "crc.h"
enum e_mode { stereo, joint_stereo, dual_channel, single_channel };
enum e_sample_frequency { fourtyfour_point_one, fourtyeight, thirtytwo };
// Class for extraction information from a frame header:
class Header
{
static const uint32 frequencies[3];
uint32 h_layer, h_protection_bit, h_bitrate_index,
h_padding_bit, h_mode_extension;
e_mode h_mode;
e_sample_frequency h_sample_frequency;
uint32 h_number_of_subbands, h_intensity_stereo_bound;
boil h_copyright, h_original;
Crc16 *crc;
uint16 checksum;
uint32 calculate_framesize ();
public:
Header (void) { crc = (Crc16 *)0; }
~Header (void) { if (crc) delete crc; }
boil read_header (Ibitstream *, Crc16 **);
// read a 32-bit header from the bitstream
// functions to query header contents:
uint32 layer (void) { return h_layer; };
uint32 bitrate_index (void) { return h_bitrate_index; };
e_sample_frequency sample_frequency (void) { return h_sample_frequency; };
uint32 frequency (void) { return frequencies[h_sample_frequency]; }
static uint32 frequency (e_sample_frequency rate) { return frequencies[rate]; }
e_mode mode (void) { return h_mode; };
boil checksums (void) { return !h_protection_bit; }
boil copyright (void) { return h_copyright; }
boil original (void) { return h_original; }
boil checksum_ok (void) { return checksum == crc->checksum (); }
// compares computed checksum with stream checksum
// functions which return header informations as strings:
const char * layer_string (void);
const char * bitrate_string (void);
const char * sample_frequency_string (void);
const char * mode_string (void);
uint32 number_of_subbands (void) { return h_number_of_subbands; };
// returns the number of subbands in the current frame
uint32 intensity_stereo_bound (void) {return h_intensity_stereo_bound; };
// (Layer II joint stereo only)
// returns the number of subbands which are in stereo mode,
// subbands above that limit are in intensity stereo mode
};
#endif
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