AudioSampleValue.h
Go to the documentation of this file.
/*
* steghide 0.5.1 - a steganography program
* Copyright (C) 1999-2003 Stefan Hetzl <shetzl@chello.at>
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#ifndef SH_AUDIOSAMPLEVALUE_H
#define SH_AUDIOSAMPLEVALUE_H
#include "CvrStgFile.h"
#include "SampleValue.h"
#include "common.h"
enum AUDIOSAMPLETYPE {
AuMuLaw,
AuPCM8,
AuPCM16,
AuPCM32
} ;
template<AUDIOSAMPLETYPE Type, class ValueType>
class AudioSampleValue : public SampleValue {
public:
AudioSampleValue (ValueType v) ;
ValueType getValue (void) const { return Value ; } ;
SampleValue* getNearestTargetSampleValue (EmbValue t) const ;
UWORD32 calcDistance (const SampleValue* s) const ;
std::string getName (void) const ;
private:
ValueType Value ;
static const ValueType MinValue ;
static const ValueType MaxValue ;
UWORD32 calcKey (ValueType v) const { return (v - MinValue) ; } ;
EmbValue calcEValue (ValueType v) const { return ((EmbValue) ((v - MinValue) % Globs.TheCvrStgFile->getEmbValueModulus())) ; } ;
} ;
template<AUDIOSAMPLETYPE Type, class ValueType>
AudioSampleValue<Type,ValueType>::AudioSampleValue (ValueType v)
: SampleValue(), Value(v)
{
Key = calcKey(v) ;
EValue = calcEValue(v) ;
}
template<AUDIOSAMPLETYPE Type, class ValueType>
UWORD32 AudioSampleValue<Type,ValueType>::calcDistance (const SampleValue* s) const
{
const AudioSampleValue<Type,ValueType>* sample = (const AudioSampleValue<Type,ValueType>*) s ;
/* If s is not a correct AudioSampleValue then we get into real trouble here.
But calcDistance is called very often, a dynamic_cast costs a lot of time and
it does not make sense to pass anything but a correct AudioSampleValue as s anyway. */
if (sample->Value > Value) {
return sample->Value - Value ;
}
else {
return Value - sample->Value ;
}
}
template<AUDIOSAMPLETYPE Type, class ValueType>
SampleValue* AudioSampleValue<Type,ValueType>::getNearestTargetSampleValue (EmbValue t) const
{
ValueType val_up = Value, val_down = Value, newval = 0 ;
bool found = false ;
do {
if (val_up < MaxValue) {
val_up++ ;
}
if (val_down > MinValue) {
val_down-- ;
}
if (calcEValue(val_up) == t && calcEValue(val_down) == t) {
if (RndSrc.getBool()) {
newval = val_up ;
}
else {
newval = val_down ;
}
found = true ;
}
else if (calcEValue(val_up) == t) {
newval = val_up ;
found = true ;
}
else if (calcEValue(val_down) == t) {
newval = val_down ;
found = true ;
}
} while (!found) ;
return ((SampleValue *) new AudioSampleValue<Type,ValueType> (newval)) ;
}
template<AUDIOSAMPLETYPE Type, class ValueType>
std::string AudioSampleValue<Type,ValueType>::getName (void) const
{
char buf[128] ;
sprintf (buf, "%ld", (long) Value) ;
return std::string (buf) ;
}
#endif // ndef SH_AUDIOSAMPLEVALUE_H
AudioSampleValue::AudioSampleValue
AudioSampleValue(ValueType v)
Definition: AudioSampleValue.h:69
AudioSampleValue::getNearestTargetSampleValue
SampleValue * getNearestTargetSampleValue(EmbValue t) const
Definition: AudioSampleValue.h:93
SampleValue::Key
UWORD32 Key
the key of this sample value - must be different for two different sample values - must be set in con...
Definition: SampleValue.h:137
CvrStgFile::getEmbValueModulus
EmbValue getEmbValueModulus(void) const
Definition: CvrStgFile.h:130
AudioSampleValue::getValue
ValueType getValue(void) const
Definition: AudioSampleValue.h:53
Globs
Globals Globs
Definition: Embedder.cc:41
AudioSampleValue::calcKey
UWORD32 calcKey(ValueType v) const
Definition: AudioSampleValue.h:64
SampleValue
the value of a sample in a CvrStgFile
Definition: SampleValue.h:61
AUDIOSAMPLETYPE
AUDIOSAMPLETYPE
Definition: AudioSampleValue.h:33
AudioSampleValue::MinValue
static const ValueType MinValue
Definition: AudioSampleValue.h:61
AudioSampleValue::getName
std::string getName(void) const
Definition: AudioSampleValue.h:129
AudioSampleValue::calcDistance
UWORD32 calcDistance(const SampleValue *s) const
Definition: AudioSampleValue.h:77
RandomSource::getBool
bool getBool(void)
Definition: RandomSource.cc:99
AudioSampleValue::calcEValue
EmbValue calcEValue(ValueType v) const
Definition: AudioSampleValue.h:65
SampleValue::EValue
EmbValue EValue
the bit that is embedded in this sample value - must be set in constructor of derived class ...
Definition: SampleValue.h:134
UWORD32
unsigned long UWORD32
Definition: common.h:45
AuMuLaw
au 8 Bit mu-law
Definition: AudioSampleValue.h:35
AudioSampleValue::MaxValue
static const ValueType MaxValue
Definition: AudioSampleValue.h:62
Globals::TheCvrStgFile
CvrStgFile * TheCvrStgFile
the cover-/stego- file that is operated on (set in CvrStgFile::CvrStgFile)
Definition: Globals.h:55
CvrStgFile.h
AudioSampleValue::Value
ValueType Value
Definition: AudioSampleValue.h:60
common.h
SampleValue.h
EmbValue
BYTE EmbValue
Definition: common.h:66
AuPCM32
au 32 Bit linear pcm
Definition: AudioSampleValue.h:41
RndSrc
RandomSource RndSrc
Definition: RandomSource.cc:31
AuPCM8
au 8 Bit linear pcm
Definition: AudioSampleValue.h:37
AudioSampleValue
a class representing an audio sample
Definition: AudioSampleValue.h:49
AuPCM16
au 16 Bit linear pcm
Definition: AudioSampleValue.h:39