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// The authors have released ID3Lib as Public Domain (PD) and claim no copyright,
// patent or other intellectual property protection in this work. This means that
// it may be modified, redistributed and used in commercial and non-commercial
// software and hardware without restrictions. ID3Lib is distributed on an "AS IS"
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
//
// The ID3Lib authors encourage improvements and optimisations to be sent to the
// ID3Lib coordinator, currently Dirk Mahoney (dirk@id3.org). Approved
// submissions may be altered, and will be included and released under these terms.
//
// Mon Nov 23 18:34:01 1998
#include <string.h>
#include <memory.h>
#include "id3_tag.h"
#include "id3_misc_support.h"
#include "zlib.h"
luint ID3_Frame::Render ( uchar *buffer )
{
luint bytesUsed = 0;
if ( buffer )
{
ID3_FrameHeader header;
ID3_FrameDef *info;
luint flags;
luint extras = 0;
bool didCompress = false;
header.SetVersion ( version, revision );
bytesUsed += header.Size();
// here is where we include things like
// grouping IDs and crypto IDs
if ( strlen ( encryptionID ) )
{
buffer[ bytesUsed ] = encryptionID[ 0 ];
bytesUsed++, extras++;
}
if ( strlen ( groupingID ) )
{
buffer[ bytesUsed ] = groupingID[ 0 ];
bytesUsed++, extras++;
}
// this call is to tell the string fields
// what they should be rendered/parsed as
// (ASCII or Unicode)
UpdateStringTypes();
for ( luint i = 0; i < numFields; i++ )
{
fields[ i ]->SetVersion ( version, revision );
bytesUsed += fields[ i ]->Render ( &buffer[ bytesUsed ] );
}
// if we can compress frames individually and we
// have been asked to compress the frames
if ( compression && version >= 3 )
{
luint newFrameSize;
uchar *newTemp;
bytesUsed -= header.Size();
newFrameSize = bytesUsed + ( bytesUsed / 10 ) + 12;
if ( newTemp = new uchar[ newFrameSize ] )
{
if ( compress ( newTemp, &newFrameSize, &buffer[ header.Size() + extras ], bytesUsed - extras ) == Z_OK )
{
// if the compression actually saves space
if ( ( newFrameSize + sizeof ( luint ) ) < bytesUsed )
{
luint posn;
int i;
posn = header.Size();
extras += sizeof ( luint );
memcpy ( &buffer[ posn + sizeof ( luint ) ], newTemp, newFrameSize );
for ( i = 0; i < sizeof ( luint ); i++ )
buffer[ posn + i ] = (uchar) ( ( bytesUsed >> ( ( sizeof ( luint ) - i - 1 ) * 8 ) ) & 0xFF );
bytesUsed = newFrameSize + sizeof ( luint );
didCompress = true;
}
}
else
ID3_THROW ( ID3E_zlibError );
bytesUsed += header.Size();
delete[] newTemp;
}
else
ID3_THROW ( ID3E_NoMemory );
}
// perform any encryption here
if ( strlen ( encryptionID ) )
{
}
// determine which flags need to be set
if ( info = ID3_FindFrameDef ( frameID ) )
{
flags = 0;
if ( info->tagDiscard )
flags |= ID3FL_TAGALTER;
if ( info->fileDiscard )
flags |= ID3FL_FILEALTER;
if ( didCompress )
flags |= ID3FL_COMPRESSION;
if ( strlen ( encryptionID ) )
flags |= ID3FL_ENCRYPTION;
if ( strlen ( groupingID ) )
flags |= ID3FL_GROUPING;
}
else
ID3_THROW ( ID3E_InvalidFrameID );
header.SetFrameID ( frameID );
header.SetFlags ( flags );
header.SetDataSize ( bytesUsed - header.Size() );
header.Render ( buffer );
hasChanged = false;
}
else
ID3_THROW ( ID3E_NoBuffer );
return bytesUsed;
}
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