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tagparser
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check cluster offset / padding

This commit is contained in:
Martchus 2015-11-11 11:52:32 +01:00
parent 054e404858
commit a2673127fa
1 changed files with 76 additions and 23 deletions
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99
matroska/matroskacontainer.cpp
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@ -694,11 +694,12 @@ void MatroskaContainer::internalMakeFile()
{
invalidateStatus();
static const string context("making Matroska container");
updateStatus("Calculating element sizes ...");
if(!isHeaderParsed()) {
addNotification(NotificationType::Critical, "The header has not been parsed yet.", context);
throw InvalidDataException();
}
EbmlElement *level0Element = firstElement();
EbmlElement *level0Element = firstElement(), *level1Element, *level2Element;
if(!level0Element) {
addNotification(NotificationType::Critical, "No EBML elements could be found.", context);
throw InvalidDataException();
@ -741,15 +742,59 @@ void MatroskaContainer::internalMakeFile()
}
}
uint64 attachmentsSize = attachedFileElementsSize ? 4 + EbmlElement::calculateSizeDenotationLength(attachedFileElementsSize) + attachedFileElementsSize : 0;
// check the number of segments to be written
// check:
// - the number of segments to be written
// - current media data / first cluster offset
// - current padding
// - whether there are tags or attachments in additional segments
// to determine whether a rewrite is required
unsigned int lastSegmentIndex = static_cast<unsigned int>(-1);
bool firstClusterFound = false;
uint64 currentFirstClusterOffset = 0;
uint64 currentPadding = 0;
bool rewriteRequired = false;
for(; level0Element; level0Element = level0Element->nextSibling()) {
level0Element->parse();
if(level0Element->id() == MatroskaIds::Segment) {
++lastSegmentIndex;
switch(level0Element->id()) {
case EbmlIds::Void:
if(!firstClusterFound) {
currentPadding += level0Element->totalSize();
}
break;
case MatroskaIds::Segment:
// check the additional segment for tags and attachments
if(++lastSegmentIndex && !rewriteRequired) {
for(level1Element = level0Element->firstChild(); level1Element; level1Element = level1Element->nextSibling()) {
level1Element->parse();
if(level1Element->id() == MatroskaIds::Attachments || level1Element->id() == MatroskaIds::Tags) {
rewriteRequired = true;
break;
}
}
}
// check the segment for the first "Cluster"-element (if not found yet)
if(!firstClusterFound) {
for(level1Element = level0Element->firstChild(); level1Element; level1Element = level1Element->nextSibling()) {
level1Element->parse();
switch(level1Element->id()) {
case EbmlIds::Void:
currentPadding += level1Element->totalSize();
break;
case MatroskaIds::Cluster:
currentFirstClusterOffset = level1Element->startOffset();
firstClusterFound = true;
break;
}
}
}
break;
}
}
if(!rewriteRequired) {
rewriteRequired = currentPadding <= fileInfo().maxPadding() && currentPadding >= fileInfo().minPadding();
}
// prepare rewriting the file
//TODO: do backup stuff only when rewrite is really required
updateStatus("Preparing for rewriting Matroska/EBML file ...");
fileInfo().close(); // ensure the file is close before renaming it
string backupPath;
@ -778,27 +823,14 @@ void MatroskaContainer::internalMakeFile()
byte sizeLength; // size length used to make size denotations
char buff[8]; // buffer used to make size denotations
// calculate EBML header size
updateStatus("Writing EBML header ...");
elementSize = 2 * 7; // sub element ID sizes
uint64 ebmlHeaderSize = 2 * 7; // sub element ID sizes
for(auto headerValue : initializer_list<uint64>{m_version, m_readVersion, m_maxIdLength, m_maxSizeLength, m_doctypeVersion, m_doctypeReadVersion}) {
elementSize += sizeLength = EbmlElement::calculateUIntegerLength(headerValue);
elementSize += EbmlElement::calculateSizeDenotationLength(sizeLength);
ebmlHeaderSize += sizeLength = EbmlElement::calculateUIntegerLength(headerValue);
ebmlHeaderSize += EbmlElement::calculateSizeDenotationLength(sizeLength);
}
elementSize += m_doctype.size();
elementSize += EbmlElement::calculateSizeDenotationLength(m_doctype.size());
// write EBML header
outputWriter.writeUInt32BE(EbmlIds::Header);
sizeLength = EbmlElement::makeSizeDenotation(elementSize, buff);
outputStream.write(buff, sizeLength);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::Version, m_version);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::ReadVersion, m_readVersion);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::MaxIdLength, m_maxIdLength);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::MaxSizeLength, m_maxSizeLength);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::DocType, m_doctype);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::DocTypeVersion, m_doctypeVersion);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::DocTypeReadVersion, m_doctypeReadVersion);
// write segments
EbmlElement *level1Element, *level2Element;
ebmlHeaderSize += m_doctype.size();
ebmlHeaderSize += EbmlElement::calculateSizeDenotationLength(m_doctype.size());
// prepare writing segments
uint64 segmentInfoElementDataSize;
MatroskaSeekInfo seekInfo;
MatroskaCuePositionUpdater cuesUpdater;
@ -985,6 +1017,24 @@ void MatroskaContainer::internalMakeFile()
}
}
}
// start the actual writing
if(!segmentIndex) {
// nothing written so far (just prepared)
// -> decided whether it is necessary to rewrite the entire file
// TODO
// write EBML header (before writing the first segment)
updateStatus("Writing EBML header ...");
outputWriter.writeUInt32BE(EbmlIds::Header);
sizeLength = EbmlElement::makeSizeDenotation(ebmlHeaderSize, buff);
outputStream.write(buff, sizeLength);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::Version, m_version);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::ReadVersion, m_readVersion);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::MaxIdLength, m_maxIdLength);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::MaxSizeLength, m_maxSizeLength);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::DocType, m_doctype);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::DocTypeVersion, m_doctypeVersion);
EbmlElement::makeSimpleElement(outputStream, EbmlIds::DocTypeReadVersion, m_doctypeReadVersion);
}
// write "Segment"-element actually
updateStatus("Writing segment header ...");
outputWriter.writeUInt32BE(MatroskaIds::Segment);
@ -1139,7 +1189,10 @@ void MatroskaContainer::internalMakeFile()
level0Element->copyEntirely(outputStream);
}
}
} catch(OperationAbortedException &) {
throw;
} catch(Failure &) {
// any failures here are caused because the original faile could not be parsed correctly (except OperationAbortedException which is handled above)
addNotifications(cuesUpdater);
addNotification(NotificationType::Critical, "Unable to parse content in top-level element at " + numberToString(level0Element->startOffset()) + " of original file.", context);
throw;