Fix reading partial objects #27
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…a info Use case: * DcmFileFormat::readUntilTag() (called from DcmFileFormat::read()) tries to read DcmMetaInfo which is partially available in input stream * DcmMetaInfo::read() returns EC_StreamNotifyClient * DcmFileFormat::readUntilTag() does not check the returned condition and tries to use DcmMetaInfo (by calling lookForXfer()) even though the object is not completely read. By using it, DcmFileFormat changes meta info's current elemetnt to have index -1. * next time DcmFileFormat::readUntilTag() is called, it tries to finish reading last incomplete object. Having its current index set to -1 that leads to a crash Fix: * check returned condition from DcmMetaInfo::read() and exit early if it is bad
Use case: * DcmMetaInfo::read() is called to read object which is partially available in input stream * Transfer syntax is detected from the preamble and is stored in member variable Xfer * On the second call to DcmMetaInfo::read() the stored transfer syntax is overwritten with the value of the input transfer syntax (typically EXS_Unknown). This time preamble is already read and is not used to detect transfer syntax. If input parameter is equal to EXS_Unknown current transfer syntax is maintained in local vairable newxfer will also be EXS_Unknown. Calling readGroupLength() with EXS_Unknown will return condition EC_IllegalCall and that is the be also the returned value of DcmMetaInfo::read() Fix: * do not overwrite store transfer syntax in Xfer if object's transfer has started * use stored transfer syntax on consecutive calls
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Thank you. We've added this issue to out to-do list so it doesn't get lost. |
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This PR fixes reading DcmFileFormat when object is only partially available in input stream.