/* * * Copyright (C) 1994-2016, OFFIS e.V. * All rights reserved. See COPYRIGHT file for details. * * This software and supporting documentation were developed by * * OFFIS e.V. * R&D Division Health * Escherweg 2 * D-26121 Oldenburg, Germany * * * Module: dcmdata * * Author: Gerd Ehlers, Andreas Barth * * Purpose: Interface of class DcmMetaInfo * */ #ifndef DCMETINF_H #define DCMETINF_H #include "dcmtk/config/osconfig.h" /* make sure OS specific configuration is included first */ #include "dcmtk/dcmdata/dcitem.h" /// magic string identifying DICOM files #define DCM_Magic "DICM" /// length of magic string identifying DICOM files #define DCM_MagicLen 4 /// length of DICOM file preamble, in bytes #define DCM_PreambleLen 128 /// transfer syntax used for encoding DICOM meta-headers #define META_HEADER_DEFAULT_TRANSFERSYNTAX EXS_LittleEndianExplicit /** a class representing the DICOM file meta information header */ class DCMTK_DCMDATA_EXPORT DcmMetaInfo : public DcmItem { public: /** default constructor */ DcmMetaInfo(); /** copy constructor * @param old item to be copied */ DcmMetaInfo(const DcmMetaInfo &old); /** assignment operator. * @param obj the metainfo to be copied */ DcmMetaInfo &operator=(const DcmMetaInfo &obj); /** destructor */ virtual ~DcmMetaInfo(); /** clone method * @return deep copy of this object */ virtual DcmObject *clone() const { return new DcmMetaInfo(*this); } /** Virtual object copying. This method can be used for DcmObject * and derived classes to get a deep copy of an object. Internally * the assignment operator is called if the given DcmObject parameter * is of the same type as "this" object instance. If not, an error * is returned. This function permits copying an object by value * in a virtual way which therefore is different to just calling the * assignment operator of DcmElement which could result in slicing * the object. * @param rhs - [in] The instance to copy from. Has to be of the same * class type as "this" object * @return EC_Normal if copying was successful, error otherwise */ virtual OFCondition copyFrom(const DcmObject& rhs); /** get type identifier * @return type identifier of this class (EVR_item) */ virtual DcmEVR ident() const; /** remove all elements with an invalid group number, i.e. everything but 0x0002 */ virtual void removeInvalidGroups(); /** return the transfer syntax in which this dataset was originally read. * @return transfer syntax in which this dataset was originally read, EXS_Unknown if the dataset was created in memory */ E_TransferSyntax getOriginalXfer() const; /** print meta information header to a stream * @param out output stream * @param flags optional flag used to customize the output (see DCMTypes::PF_xxx) * @param level current level of nested items. Used for indentation. * @param pixelFileName not used * @param pixelCounter not used */ virtual void print(STD_NAMESPACE ostream&out, const size_t flags = 0, const int level = 0, const char *pixelFileName = NULL, size_t *pixelCounter = NULL); /** initialize the transfer state of this object. This method must be called * before this object is written to a stream or read (parsed) from a stream. */ virtual void transferInit(); /** finalize the transfer state of this object. This method must be called * when reading/writing this object from/to a stream has been completed. */ virtual void transferEnd(); /** calculate the length of this DICOM element when encoded with the * given transfer syntax and the given encoding type for sequences. * For elements, the length includes the length of the tag, length field, * VR field and the value itself, for items and sequences it returns * the length of the complete item or sequence including delimitation tags * if applicable. Never returns undefined length. * @param xfer transfer syntax for length calculation * @param enctype sequence encoding type for length calculation * @return length of DICOM element */ virtual Uint32 calcElementLength(const E_TransferSyntax xfer, const E_EncodingType enctype); /** read object from a stream. * @param inStream DICOM input stream * @param xfer transfer syntax to use when parsing. EXS_Unknown will * lead to reading the preamble (if any) and parsing * metaheader using detected transfer syntax, usually * Explicit VR Little Endian. * @param glenc handling of group length parameters * @param maxReadLength attribute values larger than this value are skipped * while parsing and read later upon first access if the stream type supports * this. * @return EC_Normal if successful, an error code otherwise */ virtual OFCondition read(DcmInputStream &inStream, const E_TransferSyntax xfer = EXS_Unknown, const E_GrpLenEncoding glenc = EGL_noChange, const Uint32 maxReadLength = DCM_MaxReadLength); /** write meta information header to a stream * @param outStream DICOM output stream * @param oxfer output transfer syntax * @param enctype encoding types (undefined or explicit length) * @param wcache pointer to write cache object, may be NULL * @return status, EC_Normal if successful, an error code otherwise */ virtual OFCondition write(DcmOutputStream &outStream, const E_TransferSyntax oxfer, const E_EncodingType enctype, DcmWriteCache *wcache); /** write object in XML format * @param out output stream to which the XML document is written * @param flags optional flag used to customize the output (see DCMTypes::XF_xxx) * @return status, EC_Normal if successful, an error code otherwise */ virtual OFCondition writeXML(STD_NAMESPACE ostream &out, const size_t flags = 0); /** load object from a DICOM file. If the file preamble is missing, an error is returned. * @param fileName name of the file to load (may contain wide chars if support enabled). * Since there are various constructors for the OFFilename class, a "char *", "OFString" * or "wchar_t *" can also be passed directly to this parameter. * @param readXfer transfer syntax used to read the data (auto detection if EXS_Unknown) * @param groupLength flag, specifying how to handle the group length tags * @param maxReadLength maximum number of bytes to be read for an element value. * Element values with a larger size are not loaded until their value is retrieved * (with getXXX()) or loadAllDataIntoMemory() is called. * @return status, EC_Normal if successful, an error code otherwise */ virtual OFCondition loadFile(const OFFilename &fileName, const E_TransferSyntax readXfer = EXS_Unknown, const E_GrpLenEncoding groupLength = EGL_noChange, const Uint32 maxReadLength = DCM_MaxReadLength); private: /// initialize the preamble buffer with 128 zero bytes followed by "DICM" void setPreamble(); /** check if the next 132 bytes in the input stream are a preamble * followed by the DICOM "magic word" DICM. If so, try to determine * the transfer syntax of the meta-header and return in parameter * newxfer. If not, reset stream to start position. * @param inStream input stream, should be at start position * @param newxfer as input parameter contains the expected transfer syntax, * as output parameter returns the real transfer syntax of the * meta-header as determined heuristically * @return true if meta-header found and read, false otherwise */ OFBool checkAndReadPreamble(DcmInputStream &inStream, E_TransferSyntax &newxfer); // out /** peeks into the input stream and checks whether the next element * is group 0002, i.e. belongs to the meta-header * @return true if next element is part of meta-header, false otherwise */ OFBool nextTagIsMeta(DcmInputStream &inStream); /** read meta-header group length element which is important because * it tells us where to switch from meta-header transfer syntax to * dataset transfer syntax. Insert element into dataset * @param inStream input stream * @param xfer transfer syntax of meta-header * @param xtag attribute tag for group length * @param glenc handling of group length encoding element in dataset * @param headerLen output parameter; length of meta-header as encoded in group length element * @param bytesRead output parameter; number of bytes read when reading group length (for counting the remaining number of meta-header bytes) * @param maxReadLength max read length for elements * @return EC_Normal if successful, an error code otherwise */ OFCondition readGroupLength(DcmInputStream &inStream, // inout const E_TransferSyntax xfer, // in const DcmTagKey &xtag, // in const E_GrpLenEncoding glenc, // in Uint32 &headerLen, // out Uint32 &bytesRead, // out const Uint32 maxReadLength = DCM_MaxReadLength); // in /// buffer for 132 byte DICOM file preamble char filePreamble[DCM_PreambleLen + DCM_MagicLen]; /// true if the preamble was read from stream OFBool preambleUsed; /// transfer state of the preamble E_TransferState fPreambleTransferState; /// transfer syntax in which the meta-header was read E_TransferSyntax Xfer; }; #endif // DCMETINF_H