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# include "mpeg4descriptor.h"
# include "mp4container.h"
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# include "mp4ids.h"
# include <c++utilities/io/binaryreader.h>
# include <c++utilities/conversion/stringconversion.h>
using namespace std ;
using namespace ConversionUtilities ;
namespace Media {
/*!
* \ class Media : : Mpeg4Descriptor
* \ brief The Mpeg4Descriptor class helps to parse MPEG - 4 descriptors .
*/
/*!
* \ brief Constructs a new top level descriptor with the specified \ a container at the specified \ a startOffset
* and with the specified \ a maxSize .
*/
Mpeg4Descriptor : : Mpeg4Descriptor ( containerType & container , uint64 startOffset , uint64 maxSize ) :
GenericFileElement < Mpeg4Descriptor > ( container , startOffset , maxSize )
{ }
/*!
* \ brief Constructs a new sub level descriptor with the specified \ a parent at the specified \ a startOffset .
*/
Mpeg4Descriptor : : Mpeg4Descriptor ( implementationType & parent , uint64 startOffset ) :
GenericFileElement < Mpeg4Descriptor > ( parent , startOffset )
{ }
/*!
* \ brief Returns the parsing context .
*/
string Mpeg4Descriptor : : parsingContext ( ) const
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{
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return " parsing " + idToString ( ) + " descriptor at " + numberToString ( startOffset ( ) ) ;
}
/*!
* \ brief Converts the specified atom \ a ID to a printable string .
*/
std : : string Mpeg4Descriptor : : idToString ( ) const
{
return " 0x " + ConversionUtilities : : numberToString ( id ( ) , 16 ) ;
}
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/*!
* \ brief Parses the MPEG - 4 descriptor .
* \ remarks Does not detect the first child .
*/
void Mpeg4Descriptor : : internalParse ( )
{
invalidateStatus ( ) ;
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if ( maxTotalSize ( ) < minimumElementSize ( ) ) {
addNotification ( NotificationType : : Critical , " Descriptor is smaller then 2 byte and hence invalid. The maximum size within the encloding element is " + numberToString ( maxTotalSize ( ) ) + " . " , " parsing MPEG-4 descriptor " ) ;
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throw TruncatedDataException ( ) ;
}
stream ( ) . seekg ( startOffset ( ) ) ;
// read ID
m_idLength = m_sizeLength = 1 ;
m_id = reader ( ) . readByte ( ) ;
// read data size
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byte tmp = reader ( ) . readByte ( ) ;
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m_dataSize = tmp & 0x7F ;
while ( tmp & 0x80 ) {
m_dataSize = ( m_dataSize < < 7 ) | ( ( tmp = reader ( ) . readByte ( ) ) & 0x7F ) ;
+ + m_sizeLength ;
}
// check whether the denoted data size exceeds the available data size
if ( maxTotalSize ( ) < totalSize ( ) ) {
addNotification ( NotificationType : : Warning , " The descriptor seems to be truncated; unable to parse siblings of that " , parsingContext ( ) ) ;
m_dataSize = maxTotalSize ( ) ; // using max size instead
}
m_firstChild . reset ( ) ;
implementationType * sibling = nullptr ;
if ( totalSize ( ) < maxTotalSize ( ) ) {
if ( parent ( ) ) {
sibling = new implementationType ( * ( parent ( ) ) , startOffset ( ) + totalSize ( ) ) ;
} else {
sibling = new implementationType ( container ( ) , startOffset ( ) + totalSize ( ) , maxTotalSize ( ) - totalSize ( ) ) ;
}
}
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m_nextSibling . reset ( sibling ) ;
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}
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}