559 lines
20 KiB
C++
559 lines
20 KiB
C++
#include "./ebmlelement.h"
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#include "./ebmlid.h"
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#include "./matroskacontainer.h"
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#include "./matroskaid.h"
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#include "../mediafileinfo.h"
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#include "../exceptions.h"
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#include <c++utilities/conversion/types.h>
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#include <c++utilities/conversion/binaryconversion.h>
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#include <c++utilities/io/binaryreader.h>
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#include <c++utilities/io/binarywriter.h>
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#include <string>
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#include <sstream>
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#include <cstring>
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#include <memory>
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using namespace std;
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using namespace IoUtilities;
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using namespace ConversionUtilities;
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namespace Media {
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/*!
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* \class Media::EbmlElement
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* \brief The EbmlElement class helps to parse EBML files such as Matroska files.
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*/
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/*!
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* \brief Specifies the number of bytes to be skipped till a valid EBML element is found in the stream.
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*/
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uint64 EbmlElement::bytesToBeSkipped = 0x4000;
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/*!
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* \brief Constructs a new top level element with the specified \a container at the specified \a startOffset.
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*/
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EbmlElement::EbmlElement(MatroskaContainer &container, uint64 startOffset) :
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GenericFileElement<EbmlElement>(container, startOffset)
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{}
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/*!
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* \brief Constructs a new top level element with the specified \a container at the specified \a startOffset.
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*/
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EbmlElement::EbmlElement(MatroskaContainer &container, uint64 startOffset, uint64 maxSize) :
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GenericFileElement<EbmlElement>(container, startOffset, maxSize)
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{}
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/*!
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* \brief Constructs a new sub level element with the specified \a parent at the specified \a startOffset.
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*/
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EbmlElement::EbmlElement(EbmlElement &parent, uint64 startOffset) :
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GenericFileElement<EbmlElement>(parent, startOffset)
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{}
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/*!
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* \brief Returns the parsing context.
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*/
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string EbmlElement::parsingContext() const
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{
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return ("parsing header of EBML element " % idToString() % " at ") + startOffset();
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}
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/*!
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* \brief Parses the EBML element.
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*/
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void EbmlElement::internalParse()
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{
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invalidateStatus();
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static const string context("parsing EBML element header");
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for(uint64 skipped = 0; skipped < bytesToBeSkipped; ++m_startOffset, --m_maxSize, ++skipped) {
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// check whether max size is valid
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if(maxTotalSize() < 2) {
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addNotification(NotificationType::Critical, argsToString("The EBML element at ", startOffset(), " is truncated or does not exist."), context);
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throw TruncatedDataException();
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}
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stream().seekg(startOffset());
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// read ID
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char buf[maximumIdLengthSupported() > maximumSizeLengthSupported() ? maximumIdLengthSupported() : maximumSizeLengthSupported()] = {0};
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byte beg = static_cast<byte>(stream().peek()), mask = 0x80;
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m_idLength = 1;
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while(m_idLength <= maximumIdLengthSupported() && (beg & mask) == 0) {
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++m_idLength;
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mask >>= 1;
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}
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if(m_idLength > maximumIdLengthSupported()) {
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if(!skipped) {
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addNotification(NotificationType::Critical, argsToString("EBML ID length at ", startOffset(), " is not supported, trying to skip."), context);
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}
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continue; // try again
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}
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if(m_idLength > container().maxIdLength()) {
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if(!skipped) {
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addNotification(NotificationType::Critical, argsToString("EBML ID length at ", startOffset(), " is invalid, trying to skip."), context);
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}
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continue; // try again
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}
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reader().read(buf + (maximumIdLengthSupported() - m_idLength), m_idLength);
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m_id = BE::toUInt32(buf);
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// check whether this element is actually a sibling of one of its parents rather then a child
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// (might be the case if the parent's size is unknown and hence assumed to be the max file size)
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if(m_parent && m_parent->m_sizeUnknown) {
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// check at which level in the hierarchy the element is supposed to occour using its ID
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// (the only chance to find out whether the element belongs higher up in the hierarchy)
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const MatroskaElementLevel supposedLevel = matroskaIdLevel(m_id);
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const byte actualLevel = level();
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if(actualLevel > supposedLevel) {
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// the file belongs higher up in the hierarchy so find a better parent
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if(EbmlElement *betterParent = m_parent->parent(actualLevel - static_cast<byte>(supposedLevel))) {
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// recompute the parent size (assumption - which was rest of the available space - was wrong)
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m_parent->m_dataSize = m_startOffset - m_parent->m_startOffset - m_parent->headerSize();
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m_parent->m_sizeUnknown = false;
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// detatch from ...
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if(m_parent->firstChild() == this) {
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// ... parent
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m_parent->m_firstChild.release();
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m_parent->m_firstChild = move(m_nextSibling);
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} else {
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// ... previous sibling
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for(EbmlElement *sibling = m_parent->firstChild(); sibling; sibling = sibling->nextSibling()) {
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if(sibling->nextSibling() == this) {
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sibling->m_nextSibling.release();
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sibling->m_nextSibling = move(m_nextSibling);
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break;
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}
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}
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}
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// insert as child of better parent
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if(EbmlElement *previousSibling = betterParent->lastChild()) {
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previousSibling->m_nextSibling.reset(this);
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} else {
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betterParent->m_firstChild.reset(this);
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}
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// update own reference to parent
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m_parent = betterParent;
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}
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}
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}
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// read size
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beg = static_cast<byte>(stream().peek()), mask = 0x80;
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m_sizeLength = 1;
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if((m_sizeUnknown = (beg == 0xFF))) {
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// this indicates that the element size is unknown
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// -> just assume the element takes the maximum available size
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m_dataSize = maxTotalSize() - headerSize();
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} else {
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while(m_sizeLength <= maximumSizeLengthSupported() && (beg & mask) == 0) {
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++m_sizeLength;
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mask >>= 1;
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}
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if(m_sizeLength > maximumSizeLengthSupported()) {
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if(!skipped) {
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addNotification(NotificationType::Critical, "EBML size length is not supported.", parsingContext());
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}
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continue; // try again
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}
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if(m_sizeLength > container().maxSizeLength()) {
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if(!skipped) {
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addNotification(NotificationType::Critical, "EBML size length is invalid.", parsingContext());
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}
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continue; // try again
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}
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// read size into buffer
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memset(buf, 0, sizeof(DataSizeType)); // reset buffer
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reader().read(buf + (maximumSizeLengthSupported() - m_sizeLength), m_sizeLength);
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// xor the first byte in buffer which has been read from the file with mask
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*(buf + (maximumSizeLengthSupported() - m_sizeLength)) ^= mask;
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m_dataSize = ConversionUtilities::BE::toUInt64(buf);
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// check if element is truncated
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if(totalSize() > maxTotalSize()) {
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if(m_idLength + m_sizeLength > maxTotalSize()) { // header truncated
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if(!skipped) {
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addNotification(NotificationType::Critical, "EBML header seems to be truncated.", parsingContext());
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}
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continue; // try again
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} else { // data truncated
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addNotification(NotificationType::Warning, "Data of EBML element seems to be truncated; unable to parse siblings of that element.", parsingContext());
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m_dataSize = maxTotalSize() - m_idLength - m_sizeLength; // using max size instead
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}
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}
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}
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// check if there's a first child
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const uint64 firstChildOffset = this->firstChildOffset();
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if(firstChildOffset && firstChildOffset < totalSize()) {
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m_firstChild.reset(new EbmlElement(static_cast<EbmlElement &>(*this), startOffset() + firstChildOffset));
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} else {
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m_firstChild.reset();
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}
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// check if there's a sibling
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if(totalSize() < maxTotalSize()) {
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if(parent()) {
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m_nextSibling.reset(new EbmlElement(*(parent()), startOffset() + totalSize()));
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} else {
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m_nextSibling.reset(new EbmlElement(container(), startOffset() + totalSize(), maxTotalSize() - totalSize()));
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}
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} else {
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m_nextSibling.reset();
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}
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// no critical errors occured
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// -> add a warning if bytes have been skipped
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if(skipped) {
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addNotification(NotificationType::Warning, argsToString(skipped, " bytes have been skipped"), parsingContext());
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}
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// -> don't need another try, return here
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return;
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}
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// critical errors occured and skipping some bytes wasn't successful
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throw InvalidDataException();
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}
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/*!
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* \brief Reads the content of the element as string.
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*/
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std::string EbmlElement::readString()
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{
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stream().seekg(dataOffset());
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return reader().readString(dataSize());
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}
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/*!
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* \brief Reads the content of the element as unsigned integer.
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*
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* Reads up to 8 bytes. If the element stores more data the
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* additional bytes are ignored.
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*/
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uint64 EbmlElement::readUInteger()
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{
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char buff[sizeof(uint64)] = {0};
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int i = static_cast<int>(sizeof(buff)) - dataSize();
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if(i < 0) {
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i = 0;
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}
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stream().seekg(dataOffset(), ios_base::beg);
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stream().read(buff + i, sizeof(buff) - i);
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return BE::toUInt64(buff);
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}
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/*!
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* \brief Reads the content of the element as float.
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* \remarks Reads exactly 4 or 8 bytes. If the element stores more or less data zero is returned.
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*/
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float64 EbmlElement::readFloat()
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{
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stream().seekg(dataOffset());
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switch(dataSize()) {
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case sizeof(float32):
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return reader().readFloat32BE();
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case sizeof(float64):
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return reader().readFloat64BE();
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default:
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return 0.0;
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}
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}
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/*!
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* \brief Returns the length of the specified \a id in byte.
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* \throws Throws InvalidDataException() if \a id can not be represented.
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*/
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byte EbmlElement::calculateIdLength(GenericFileElement::IdentifierType id)
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{
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if(id <= 0xFF) {
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return 1;
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} else if(id <= 0x7FFF) {
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return 2;
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} else if(id <= 0x3FFFFF) {
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return 3;
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} else if(id <= 0x1FFFFFFF) {
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return 4;
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} else {
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throw InvalidDataException();
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}
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}
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/*!
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* \brief Returns the length of the size denotation for the specified \a size in byte.
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* \throws Throws InvalidDataException() if \a size can not be represented.
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*/
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byte EbmlElement::calculateSizeDenotationLength(uint64 size)
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{
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if(size < 126) {
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return 1;
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} else if(size <= 16382ul) {
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return 2;
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} else if(size <= 2097150ul) {
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return 3;
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} else if(size <= 268435454ul) {
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return 4;
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} else if(size <= 34359738366ul) {
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return 5;
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} else if(size <= 4398046511102ul) {
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return 6;
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} else if(size <= 562949953421310ul) {
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return 7;
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} else if(size <= 72057594037927934ul) {
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return 8;
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} else {
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throw InvalidDataException();
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}
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}
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/*!
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* \brief Stores the specified \a id in the specified buffer
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* which must be at least 8 bytes long.
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* \returns Returns the number of bytes written to \a buff.
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* \throws Throws InvalidDataException() if \a id can not be represented.
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*/
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byte EbmlElement::makeId(GenericFileElement::IdentifierType id, char *buff)
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{
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if(id <= 0xFF) {
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*buff = static_cast<byte>(id);
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return 1;
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} else if(id <= 0x7FFF) {
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BE::getBytes(static_cast<uint16>(id), buff);
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return 2;
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} else if(id <= 0x3FFFFF) {
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BE::getBytes(static_cast<uint32>(id << 0x8), buff);
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return 3;
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} else if(id <= 0x1FFFFFFF) {
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BE::getBytes(static_cast<uint32>(id), buff);
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return 4;
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} else {
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throw InvalidDataException();
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}
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}
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/*!
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* \brief Makes the size denotation for the specified \a size and stores it to \a buff.
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* \param size Specifies the size to be denoted.
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* \param buff Specifies the buffer to store the denotation. Must be at least 8 bytes long.
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* \returns Returns the number of bytes written to \a buff.
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* \throws Throws InvalidDataException() if \a size can not be represented.
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*/
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byte EbmlElement::makeSizeDenotation(uint64 size, char *buff)
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{
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if(size < 126) {
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*buff = static_cast<byte>(size | 0x80);
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return 1;
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} else if(size <= 16382ul) {
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BE::getBytes(static_cast<uint16>(size | 0x4000), buff);
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return 2;
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} else if(size <= 2097150ul) {
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BE::getBytes(static_cast<uint32>((size | 0x200000) << 0x08), buff);
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return 3;
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} else if(size <= 268435454ul) {
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BE::getBytes(static_cast<uint32>(size | 0x10000000), buff);
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return 4;
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} else if(size <= 34359738366ul) {
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BE::getBytes(static_cast<uint64>((size | 0x800000000) << 0x18), buff);
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return 5;
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} else if(size <= 4398046511102ul) {
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BE::getBytes(static_cast<uint64>((size | 0x40000000000) << 0x10), buff);
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return 6;
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} else if(size <= 562949953421310ul) {
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BE::getBytes(static_cast<uint64>((size | 0x2000000000000) << 0x08), buff);
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return 7;
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} else if(size <= 72057594037927934ul) {
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BE::getBytes(static_cast<uint64>(size | 0x100000000000000), buff);
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return 8;
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}
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throw InvalidDataException();
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}
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/*!
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* \brief Makes the size denotation for the specified \a size and stores it to \a buff.
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* \param size Specifies the size to be denoted.
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* \param buff Specifies the buffer to store the denotation. Must be at least 8 bytes long.
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* \param minBytes Specifies the minimum number of bytes to use. Might be use allow subsequent element growth.
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* \returns Returns the number of bytes written to \a buff. Always in the range of \a minBytes and 8.
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* \throws Throws InvalidDataException() if \a size can not be represented.
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*/
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byte EbmlElement::makeSizeDenotation(uint64 size, char *buff, byte minBytes)
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{
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if(minBytes <= 1 && size < 126) {
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*buff = static_cast<byte>(size | 0x80);
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return 1;
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} else if(minBytes <= 2 && size <= 16382ul) {
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BE::getBytes(static_cast<uint16>(size | 0x4000), buff);
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return 2;
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} else if(minBytes <= 3 && size <= 2097150ul) {
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BE::getBytes(static_cast<uint32>((size | 0x200000) << 0x08), buff);
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return 3;
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} else if(minBytes <= 4 && size <= 268435454ul) {
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BE::getBytes(static_cast<uint32>(size | 0x10000000), buff);
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return 4;
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} else if(minBytes <= 5 && size <= 34359738366ul) {
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BE::getBytes(static_cast<uint64>((size | 0x800000000) << 0x18), buff);
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return 5;
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} else if(minBytes <= 6 && size <= 4398046511102ul) {
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BE::getBytes(static_cast<uint64>((size | 0x40000000000) << 0x10), buff);
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return 6;
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} else if(minBytes <= 7 && size <= 562949953421310ul) {
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BE::getBytes(static_cast<uint64>((size | 0x2000000000000) << 0x08), buff);
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return 7;
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} else if(minBytes <= 8 && size <= 72057594037927934ul) {
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BE::getBytes(static_cast<uint64>(size | 0x100000000000000), buff);
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return 8;
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}
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throw InvalidDataException();
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}
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/*!
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* \brief Returns the length of the specified unsigned \a integer in byte.
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* \throws Throws InvalidDataException() if \a integer can not be represented.
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*/
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byte EbmlElement::calculateUIntegerLength(uint64 integer)
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{
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if(integer <= 0xFFul) {
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return 1;
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} else if(integer <= 0xFFFFul) {
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return 2;
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} else if(integer <= 0xFFFFFFul) {
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return 3;
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} else if(integer <= 0xFFFFFFFFul) {
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return 4;
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} else if(integer <= 0xFFFFFFFFFFul) {
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return 5;
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} else if(integer <= 0xFFFFFFFFFFFFul) {
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return 6;
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} else if(integer <= 0xFFFFFFFFFFFFFFul) {
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return 7;
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} else {
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return 8;
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}
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}
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/*!
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* \brief Writes \a value to \a buff.
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* \returns Returns the number of bytes written to \a buff.
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*/
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byte EbmlElement::makeUInteger(uint64 value, char *buff)
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{
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if(value <= 0xFFul) {
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*buff = static_cast<char>(value);
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return 1;
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} else if(value <= 0xFFFFul) {
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BE::getBytes(static_cast<uint16>(value), buff);
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return 2;
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} else if(value <= 0xFFFFFFul) {
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BE::getBytes(static_cast<uint32>(value << 0x08), buff);
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return 3;
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} else if(value <= 0xFFFFFFFFul) {
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BE::getBytes(static_cast<uint32>(value), buff);
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return 4;
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} else if(value <= 0xFFFFFFFFFFul) {
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BE::getBytes(static_cast<uint64>(value << 0x18), buff);
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return 5;
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} else if(value <= 0xFFFFFFFFFFFFul) {
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BE::getBytes(static_cast<uint64>(value << 0x10), buff);
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return 6;
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} else if(value <= 0xFFFFFFFFFFFFFFul) {
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BE::getBytes(static_cast<uint64>(value << 0x08), buff);
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return 7;
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} else {
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BE::getBytes(static_cast<uint64>(value), buff);
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return 8;
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}
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}
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/*!
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* \brief Writes \a value to \a buff.
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* \returns Returns the number of bytes written to \a buff.
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* \param value Specifies the value to be written.
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* \param buff Specifies the buffer to write to.
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* \param minBytes Specifies the minimum number of bytes to use.
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*/
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byte EbmlElement::makeUInteger(uint64 value, char *buff, byte minBytes)
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{
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if(minBytes <= 1 && value <= 0xFFul) {
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*buff = static_cast<char>(value);
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return 1;
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} else if(minBytes <= 2 && value <= 0xFFFFul) {
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BE::getBytes(static_cast<uint16>(value), buff);
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return 2;
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} else if(minBytes <= 3 && value <= 0xFFFFFFul) {
|
|
BE::getBytes(static_cast<uint32>(value << 0x08), buff);
|
|
return 3;
|
|
} else if(minBytes <= 4 && value <= 0xFFFFFFFFul) {
|
|
BE::getBytes(static_cast<uint32>(value), buff);
|
|
return 4;
|
|
} else if(minBytes <= 5 && value <= 0xFFFFFFFFFFul) {
|
|
BE::getBytes(static_cast<uint64>(value << 0x18), buff);
|
|
return 5;
|
|
} else if(minBytes <= 6 && value <= 0xFFFFFFFFFFFFul) {
|
|
BE::getBytes(static_cast<uint64>(value << 0x10), buff);
|
|
return 6;
|
|
} else if(minBytes <= 7 && value <= 0xFFFFFFFFFFFFFFul) {
|
|
BE::getBytes(static_cast<uint64>(value << 0x08), buff);
|
|
return 7;
|
|
} else {
|
|
BE::getBytes(static_cast<uint64>(value), buff);
|
|
return 8;
|
|
}
|
|
}
|
|
|
|
/*!
|
|
* \brief Makes a simple EBML element.
|
|
* \param stream Specifies the stream to write the data to.
|
|
* \param id Specifies the element ID.
|
|
* \param content Specifies the value of the element as unsigned integer.
|
|
*/
|
|
void EbmlElement::makeSimpleElement(ostream &stream, IdentifierType id, uint64 content)
|
|
{
|
|
char buff1[8];
|
|
char buff2[8];
|
|
byte sizeLength = EbmlElement::makeId(id, buff1);
|
|
stream.write(buff1, sizeLength);
|
|
byte elementSize = EbmlElement::makeUInteger(content, buff2);
|
|
sizeLength = EbmlElement::makeSizeDenotation(elementSize, buff1);
|
|
stream.write(buff1, sizeLength);
|
|
stream.write(buff2, elementSize);
|
|
}
|
|
|
|
/*!
|
|
* \brief Makes a simple EBML element.
|
|
* \param stream Specifies the stream to write the data to.
|
|
* \param id Specifies the element ID.
|
|
* \param content Specifies the value of the element as string.
|
|
*/
|
|
void EbmlElement::makeSimpleElement(std::ostream &stream, GenericFileElement::IdentifierType id, const std::string &content)
|
|
{
|
|
char buff1[8];
|
|
byte sizeLength = EbmlElement::makeId(id, buff1);
|
|
stream.write(buff1, sizeLength);
|
|
sizeLength = EbmlElement::makeSizeDenotation(content.size(), buff1);
|
|
stream.write(buff1, sizeLength);
|
|
stream.write(content.c_str(), content.size());
|
|
}
|
|
|
|
/*!
|
|
* \brief Makes a simple EBML element.
|
|
* \param stream Specifies the stream to write the data to.
|
|
* \param id Specifies the element ID.
|
|
* \param data Specifies the data of the element.
|
|
* \param dataSize Specifies the size of \a data.
|
|
*/
|
|
void EbmlElement::makeSimpleElement(ostream &stream, GenericFileElement::IdentifierType id, const char *data, std::size_t dataSize)
|
|
{
|
|
char buff1[8];
|
|
byte sizeLength = EbmlElement::makeId(id, buff1);
|
|
stream.write(buff1, sizeLength);
|
|
sizeLength = EbmlElement::makeSizeDenotation(dataSize, buff1);
|
|
stream.write(buff1, sizeLength);
|
|
stream.write(data, dataSize);
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|