long MPEG_File::previousFrameOffset(long position)
{
// TODO: This will miss syncs spanning buffer read boundaries.
while(int(position - BufferSize()) > int(BufferSize()))
{
position -= BufferSize();
Seek(position);
SjByteVector buffer = ReadBlock(BufferSize());
// If the amount of data is smaller than an MPEG header (4 bytes) there's no
// chance of this being valid.
if(buffer.size() < 4)
{
return -1;
}
for(int i = buffer.size() - 2; i >= 0; i--)
{
if((unsigned char)(buffer[i]) == 0xff && secondSynchByte(buffer[i + 1]))
{
return position + i;
}
}
}
return -1;
}
void ID3v2_PopularimeterFrame::parseFields(const SjByteVector& data)
{
m_email.Empty();
m_rating255 = 0;
m_counter = 0;
int offset, pos = 0, size = (int)data.size();
offset = data.find(textDelimiter(SJ_LATIN1), pos);
if( offset < pos ) {
return;
}
m_email = data.mid(pos, offset - pos).toString(SJ_LATIN1);
pos = offset + 1;
if(pos < size)
{
m_rating255 = (int)(data[pos]);
pos++;
if(pos < size)
{
m_counter = data.mid(pos, 4).toUInt();
}
}
}
SjByteVector ID3v2_Frame::render() const
{
SjByteVector fieldData = renderFields();
m_header->setFrameSize(fieldData.size());
SjByteVector headerData = m_header->render();
return headerData + fieldData;
}
SjByteVector ID3v2_Tag::render()
{
// We need to render the "tag data" first so that we have to correct size to
// render in the tag's header. The "tag data" -- everything that is included
// in ID3v2::Header::tagSize() -- includes the extended header, frames and
// padding, but does not include the tag's header or footer.
SjByteVector tagData;
// TODO: Render the extended header.
// Loop through the frames rendering them and adding them to the tagData.
//for(FrameList::Iterator it = d->frameList.begin(); it != d->frameList.end(); it++)
for ( ID3v2_FrameList::Node *node = m_frameList.GetFirst(); node; node = node->GetNext() )
{
ID3v2_Frame* it = node->GetData();
if(!it->header()->tagAlterPreservation())
tagData.append(it->render());
}
// Compute the amount of padding, and append that to tagData.
SjUint paddingSize = 0;
SjUint originalSize = m_header.tagSize();
if(tagData.size() < originalSize)
paddingSize = originalSize - tagData.size();
else
paddingSize = 1024;
tagData.append(SjByteVector(paddingSize, char(0)));
// Set the tag size.
m_header.setTagSize(tagData.size());
// TODO: This should eventually include d->footer->render().
return m_header.render() + tagData;
}
long MPEG_File::nextFrameOffset(long position)
{
// TODO: This will miss syncs spanning buffer read boundaries.
SjByteVector buffer = ReadBlock(BufferSize());
while(buffer.size() > 0)
{
Seek(position);
SjByteVector buffer = ReadBlock(BufferSize());
for(SjUint i = 0; i < buffer.size(); i++)
{
if((unsigned char)(buffer[i]) == 0xff && secondSynchByte(buffer[i + 1]))
{
return position + i;
}
}
position += BufferSize();
}
return -1;
}
void APE_Tag::parse(const SjByteVector &data)
{
SjUint pos = 0;
// 11 bytes is the minimum size for an APE item
for(SjUint i = 0; i < m_footer.itemCount() && pos <= data.size() - 11; i++)
{
APE_Item item;
item.parse(data.mid(pos));
setItem(item.key().Upper(), item);
pos += item.size();
}
}
void ID3v2_AttachedPictureFrame::parseFields(const SjByteVector &data)
{
if(data.size() < 5) {
wxLogDebug(wxT("A picture frame must contain at least 5 bytes."));
return;
}
int pos = 0, offset;
// read text encoding
m_textEncoding = (SjStringType)(data[pos]);
pos += 1;
if( header()->version() <= 2 )
{
// read image format (3 characters), valid for ID3V2_2_1 or older
m_mimeType = data.mid(pos, 3).toString(SJ_LATIN1);
pos += 3;
}
else
{
// read mime type (null-terminated), valid for newer specs
offset = data.find(textDelimiter(SJ_LATIN1), pos);
if(offset < pos)
return;
m_mimeType = data.mid(pos, offset - pos).toString(SJ_LATIN1);
pos = offset + 1;
}
// read type
m_type = (ID3v2_AttachedPictureType)(data[pos]);
pos += 1;
// read description
offset = data.find(textDelimiter(m_textEncoding), pos);
if(offset < pos)
return;
m_description = data.mid(pos, offset - pos).toString(m_textEncoding);
pos = offset + 1;
// read image data
m_data = data.mid(pos);
}
SjByteVector APE_Tag::render() const
{
SjByteVector data;
SjUint itemCount = 0;
{
SjHashIterator iterator;
APE_Item* item;
wxString key;
while( (item=(APE_Item*)m_itemListMap.Iterate(iterator, key)) )
{
data.append(item->render());
itemCount++;
}
}
m_footer.setItemCount(itemCount);
m_footer.setTagSize(data.size()+APE_FOOTER_SIZE);
m_footer.setHeaderPresent(true);
return m_footer.renderHeader() + data + m_footer.renderFooter();
}
void APE_Item::parse(const SjByteVector &data)
{
// 11 bytes is the minimum size for an APE item
if(data.size() < 11)
{
wxLogDebug(wxT("APE::Item::parse() -- no data in item"));
return;
}
SjUint valueLength = data.mid(0, 4).toUInt(false);
SjUint flags = data.mid(4, 4).toUInt(false);
m_key = data.mid(8).toString(SJ_UTF8); // data.mid(8) contains more than just the string -- but SjBytevector only converts up to the first null-byte at (***)
m_binary = data.mid(8 + m_key.size() + 1, valueLength);
setReadOnly(flags & 1);
setType((APE_ItemType)((flags >> 1) & 3));
if(int(m_type) < 2)
{
m_stringList = m_binary.splitToStrings((unsigned char)'\0', SJ_UTF8);
}
}
void ID3v2_CommentsFrame::parseFields(const SjByteVector &data)
{
if(data.size() < 5) {
wxLogDebug(wxT("A comment frame must contain at least 5 bytes."));
return;
}
m_textEncoding = (SjStringType)(data[0]);
m_language = data.mid(1, 3);
int byteAlign = (m_textEncoding == SJ_LATIN1 || m_textEncoding == SJ_UTF8) ? 1 : 2;
//ByteVectorList l = ByteVectorList::split(data.mid(4), textDelimiter(d->textEncoding), byteAlign, 2);
SjArrayByteVector l = data.mid(4).splitToArray(textDelimiter(m_textEncoding), byteAlign, 2);
if(l.GetCount() == 2) {
/*d->description = String(l.front(), d->textEncoding);
d->text = String(l.back(), d->textEncoding);
*/
m_description = l.Item(0).toString(m_textEncoding);
m_text = l.Item(1).toString(m_textEncoding);
}
}
SjByteVector APE_Item::render() const
{
SjByteVector data;
SjUint flags = ((m_readOnly) ? 1 : 0) | (m_type << 1);
SjByteVector value;
if(isEmpty())
return data;
if(m_type != APE_ItemBinary)
{
int i, iCount = m_stringList.GetCount();
if( iCount>0 )
{
value.appendString(m_stringList.Item(0), SJ_UTF8);
for( i = 1; i < iCount; i++ )
{
value.append((unsigned char)'\0');
value.appendString(m_stringList.Item(i), SJ_UTF8);
}
}
// there should be no need to set back m_binary
}
else
{
value.append(m_binary);
}
data.append(SjByteVector::fromUint(value.size(), false));
data.append(SjByteVector::fromUint(flags, false));
data.appendString(m_key, SJ_UTF8);
data.append(SjByteVector((unsigned char)'\0'));
data.append(value);
return data;
}
void APE_Footer::parse(const SjByteVector &data)
{
if( data.size() < APE_FOOTER_SIZE )
{
return;
}
// The first eight bytes, data[0..7], are the File Identifier, "APETAGEX".
// Read the version number
m_version = data.mid(8, 4).toUInt(false);
// Read the tag size
m_tagSize = data.mid(12, 4).toUInt(false);
// Read the item count
m_itemCount = data.mid(16, 4).toUInt(false);
// Read the flags
unsigned long flags = (unsigned long)data.mid(20, 4).toUInt(false);
m_headerPresent = (flags & (1<<31))!=0;
m_footerPresent = !((flags & (1<<30))!=0);
m_isHeader = (flags & (1<<29))!=0;
}
long MPEG_File::findID3v2()
{
// This method is based on the contents of Tagger_File::find(), but because
// of some subtlteies -- specifically the need to look for the bit pattern of
// an MPEG sync, it has been modified for use here.
if( IsValid()
&& ID3v2_Header::fileIdentifier().size() <= BufferSize() )
{
// The position in the file that the current buffer starts at.
long bufferOffset = 0;
SjByteVector buffer;
// These variables are used to keep track of a partial match that happens at
// the end of a buffer.
int previousPartialMatch = -1;
bool previousPartialSynchMatch = false;
// Save the location of the current read pointer. We will restore the
// position using seek() before all returns.
long originalPosition = Tell();
// Start the search at the beginning of the file.
Seek(0);
// This loop is the crux of the find method. There are three cases that we
// want to account for:
// (1) The previously searched buffer contained a partial match of the search
// pattern and we want to see if the next one starts with the remainder of
// that pattern.
//
// (2) The search pattern is wholly contained within the current buffer.
//
// (3) The current buffer ends with a partial match of the pattern. We will
// note this for use in the next itteration, where we will check for the rest
// of the pattern.
for(buffer = ReadBlock(BufferSize()); buffer.size() > 0; buffer = ReadBlock(BufferSize()))
{
// (1) previous partial match
if(previousPartialSynchMatch && secondSynchByte(buffer[0]))
{
return -1;
}
if(previousPartialMatch >= 0 && int(BufferSize()) > previousPartialMatch)
{
const int patternOffset = (BufferSize() - previousPartialMatch);
if(buffer.containsAt(ID3v2_Header::fileIdentifier(), 0, patternOffset))
{
Seek(originalPosition);
return bufferOffset - BufferSize() + previousPartialMatch;
}
}
// (2) pattern contained in current buffer
long location = buffer.find(ID3v2_Header::fileIdentifier());
if(location >= 0)
{
Seek(originalPosition);
return bufferOffset + location;
}
int firstSynchByte = buffer.find(/*(char)*/((unsigned char)(255)));
// Here we have to loop because there could be several of the first
// (11111111) byte, and we want to check all such instances until we find
// a full match (11111111 111) or hit the end of the buffer.
while(firstSynchByte >= 0)
{
// if this *is not* at the end of the buffer
if(firstSynchByte < int(buffer.size()) - 1)
{
if(secondSynchByte(buffer[firstSynchByte + 1]))
{
// We've found the frame synch pattern.
Seek(originalPosition);
return -1;
}
else
{
// We found 11111111 at the end of the current buffer indicating a
// partial match of the synch pattern. The find() below should
// return -1 and break out of the loop.
previousPartialSynchMatch = true;
}
}
// Check in the rest of the buffer.
firstSynchByte = buffer.find(/*char*/((unsigned char)(255)), firstSynchByte + 1);
}
// (3) partial match
previousPartialMatch = buffer.endsWithPartialMatch(ID3v2_Header::fileIdentifier());
bufferOffset += BufferSize();
} // for()
// Since we hit the end of the file, reset the status before continuing.
Clear();
Seek(originalPosition);
}
return -1;
}
void ID3v2_Tag::parse(const SjByteVector &data)
{
SjUint frameDataPosition = 0;
SjUint frameDataLength = data.size();
// check for extended header
if(m_header.extendedHeader()) {
if(!m_extendedHeader)
m_extendedHeader = new ID3v2_ExtendedHeader;
m_extendedHeader->setData(data);
if(m_extendedHeader->size() <= data.size()) {
frameDataPosition += m_extendedHeader->size();
frameDataLength -= m_extendedHeader->size();
}
}
// check for footer -- we don't actually need to parse it, as it *must*
// contain the same data as the header, but we do need to account for its
// size.
if(m_header.footerPresent() && ID3v2_Footer::size() <= frameDataLength)
frameDataLength -= ID3v2_Footer::size();
// parse frames
// Make sure that there is at least enough room in the remaining frame data for
// a frame header.
while(frameDataPosition < frameDataLength - ID3v2_Frame::headerSize(m_header.majorVersion())) {
// If the next data is position is 0, assume that we've hit the padding
// portion of the frame data.
if(data.at(frameDataPosition) == 0) {
if(m_header.footerPresent())
wxLogDebug(wxT("Padding *and* a footer found. This is not allowed by the spec."));
m_paddingSize = frameDataLength - frameDataPosition;
return;
}
ID3v2_Frame *frame = m_factory->createFrame(data.mid(frameDataPosition),
m_header.majorVersion());
if(!frame)
return;
// get the next frame position
frameDataPosition += frame->size() + ID3v2_Frame::headerSize(m_header.majorVersion());
// add the frame if it has a size of at least 1 byte (smaller frames are not allowed
// by the specification, but they're returned from createFrame() to allow seeking to the
// next frame).
// modification by me
if(frame->size() <= 0) {
delete frame;
}
else {
addFrame(frame);
}
}
}
void ID3v2_FrameHeader::setData(const SjByteVector &data, SjUint version)
{
// this was ID3v2_FrameHeaderPrivate
m_isOkay = FALSE;
m_frameSize = 0;
m_version = 4;
m_tagAlterPreservation = false;
m_fileAlterPreservation = false;
m_readOnly = false;
m_groupingIdentity = false;
m_compression = false;
m_encryption = false;
m_unsyncronisation = false;
m_dataLengthIndicator = false;
// /ID3v2_FrameHeaderPrivate
m_version = version;
switch(version) {
case 0:
case 1:
case 2:
{
// ID3v2.2
if(data.size() < 3) {
wxLogDebug(wxT("You must at least specify a frame ID."));
return;
}
// Set the frame ID -- the first three bytes
m_frameID = data.mid(0, 3);
// If the full header information was not passed in, do not continue to the
// steps to parse the frame size and flags.
if(data.size() < 6) {
return;
}
m_frameSize = data.mid(3, 3).toUInt();
break;
}
case 3:
{
// ID3v2.3 - see http://www.id3.org/id3v2.3.0.html#sec3.3
if(data.size() < 4) {
wxLogDebug(wxT("You must at least specify a frame ID."));
return;
}
// Set the frame ID -- the first four bytes
m_frameID = data.mid(0, 4);
// If the full header information was not passed in, do not continue to the
// steps to parse the frame size and flags.
if(data.size() < 10) {
return;
}
// Set the size -- the frame size is the four bytes starting at byte four in
// the frame header (structure 4)
m_frameSize = data.mid(4, 4).toUInt();
{ // read the first byte of flags
/*std::bitset<8> flags(data[8]);
d->tagAlterPreservation = flags[7]; // (structure 3.3.1.a)
d->fileAlterPreservation = flags[6]; // (structure 3.3.1.b)
d->readOnly = flags[5]; // (structure 3.3.1.c)*/
unsigned char flags = data[8];
m_tagAlterPreservation = (flags & (1<<7)) != 0;
m_fileAlterPreservation = (flags & (1<<6)) != 0;
m_readOnly = (flags & (1<<5)) != 0;
}
{ // read the second byte of flags
/*std::bitset<8> flags(data[9]);
d->compression = flags[7]; // (structure 3.3.1.i)
d->encryption = flags[6]; // (structure 3.3.1.j)
d->groupingIdentity = flags[5]; // (structure 3.3.1.k)*/
unsigned char flags = data[9];
m_compression = (flags & (1<<7)) != 0;
m_encryption = (flags & (1<<6)) != 0;
m_groupingIdentity = (flags & (1<<5)) != 0;
}
break;
}
case 4:
default:
{
// ID3v2.4
if(data.size() < 4) {
wxLogDebug(wxT("You must at least specify a frame ID."));
return;
}
// Set the frame ID -- the first four bytes
m_frameID = data.mid(0, 4);
// If the full header information was not passed in, do not continue to the
// steps to parse the frame size and flags.
if(data.size() < 10) {
return;
}
// Set the size -- the frame size is the four bytes starting at byte four in
// the frame header (structure 4)
m_frameSize = ID3v2_SynchDataToUInt(data.mid(4, 4));
{ // read the first byte of flags
/*std::bitset<8> flags(data[8]);
d->tagAlterPreservation = flags[6]; // (structure 4.1.1.a)
d->fileAlterPreservation = flags[5]; // (structure 4.1.1.b)
d->readOnly = flags[4]; // (structure 4.1.1.c)*/
unsigned char flags = data[8];
m_tagAlterPreservation = (flags & (1<<6)) != 0;
m_fileAlterPreservation = (flags & (1<<5)) != 0;
m_readOnly = (flags & (1<<4)) != 0;
}
{ // read the second byte of flags
/*std::bitset<8> flags(data[9]);
d->groupingIdentity = flags[6]; // (structure 4.1.2.h)
d->compression = flags[3]; // (structure 4.1.2.k)
d->encryption = flags[2]; // (structure 4.1.2.m)
d->unsyncronisation = flags[1]; // (structure 4.1.2.n)
d->dataLengthIndicator = flags[0]; // (structure 4.1.2.p)*/
unsigned char flags = data[9];
m_groupingIdentity = (flags & (1<<6)) != 0;
m_compression = (flags & (1<<3)) != 0;
m_encryption = (flags & (1<<2)) != 0;
m_unsyncronisation = (flags & (1<<1)) != 0;
m_dataLengthIndicator = (flags & (1<<0)) != 0;
}
break;
}
}
m_isOkay = TRUE;
}
void MPEG_Header::parse(const SjByteVector &data)
{
// see http://www.mp3-tech.org/programmer/frame_header.html
m_isValid = false;
m_version = MPEG_Version1;
m_layer = 0;
m_protectionEnabled = false;
m_sampleRate = 0;
m_isPadded = false;
m_channelMode = MPEG_Stereo;
m_isCopyrighted = false;
m_isOriginal = false;
m_emphasis = 0;
m_frameLength = 0;
// check for the size and for the first synch byte
if(data.size() < 4 || (unsigned char)(data[0]) != 0xff)
{
wxLogDebug(wxT("MPEG::Header::parse() -- First byte did not mactch MPEG synch."));
return;
}
unsigned long flags = data.toUInt();
// Check for the second byte's part of the MPEG synch
if( !(flags&(1<<23)) || !(flags&(1<<22)) || !(flags&(1<<21)) )
{
wxLogDebug(wxT("MPEG::Header::parse() -- Second byte did not mactch MPEG synch."));
return;
}
// Set the MPEG version
if( !(flags&(1<<20)) && !(flags&(1<<19)) )
{
m_version = MPEG_Version2_5;
}
else if( (flags&(1<<20)) && !(flags&(1<<19)) )
{
m_version = MPEG_Version2;
}
else if( (flags&(1<<20)) && (flags&(1<<19)) )
{
m_version = MPEG_Version1;
}
// Set the MPEG layer
if( !(flags&(1<<18)) && (flags&(1<<17)) )
{
m_layer = 3;
}
else if( (flags&(1<<18)) && !(flags&(1<<17)) )
{
m_layer = 2;
}
else if( (flags&(1<<18)) && (flags&(1<<17)) )
{
m_layer = 1;
}
// set protection flags
m_protectionEnabled = !(flags&(1<<16));
// Set the bitrate
static const int bitrates[2][3][16] =
{
{ // Version 1
{ 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, 0 }, // layer 1
{ 0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 0 }, // layer 2
{ 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 0 } // layer 3
},
{ // Version 2 or 2.5
{ 0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0 }, // layer 1
{ 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0 }, // layer 2
{ 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0 } // layer 3
}
};
const int versionIndex = m_version == MPEG_Version1 ? 0 : 1;
const int layerIndex = m_layer > 0 ? m_layer - 1 : 0;
// The bitrate index is encoded as the first 4 bits of the 3rd byte,
// i.e. 1111xxxx
int i = (unsigned char)(data[2]) >> 4;
m_bitrate = bitrates[versionIndex][layerIndex][i];
// Set the sample rate
static const int sampleRates[3][4] =
{
{ 44100, 48000, 32000, 0 }, // Version 1
{ 22050, 24000, 16000, 0 }, // Version 2
{ 11025, 12000, 8000, 0 } // Version 2.5
};
// The sample rate index is encoded as two bits in the 3nd byte, i.e. xxxx11xx
i = (unsigned char)(data[2]) >> 2 & 0x03;
m_sampleRate = sampleRates[m_version][i];
if(m_sampleRate == 0)
{
wxLogDebug(wxT("MPEG::Header::parse() -- Invalid sample rate."));
return;
}
// The channel mode is encoded as a 2 bit value at the end of the 3nd byte,
// i.e. xxxxxx11 - stimmt nicht! s. http://www.mp3-tech.org/programmer/frame_header.html
m_channelMode = (MPEG_HeaderChannelMode)((flags&0xC0) >> 6);
// TODO: Add mode extension for completeness
m_isCopyrighted = (flags&(1<<3)) != 0;
m_isOriginal = (flags&(1<<2)) != 0;
m_emphasis = (unsigned char)flags&3;
// Calculate the frame length
if( m_layer == 1 )
{
m_frameLength = 24000 * 2 * m_bitrate / m_sampleRate + int(m_isPadded);
}
else
{
m_frameLength = 72000 * m_bitrate / m_sampleRate + int(m_isPadded);
}
// Now that we're done parsing, set this to be a valid header
m_isValid = true;
}