- sw = 0;
- dbg.Verbose(1, "gdcmHeader::CheckSwap:",
- "HostByteOrder = NetworkByteOrder");
- }
-
- // Position the file position indicator at first tag (i.e.
- // after the file preamble and the "DICM" string).
- rewind(fp);
- fseek (fp, 132L, SEEK_SET);
- return;
- } // End of DicomV3
-
- // Alas, this is not a DicomV3 file and whatever happens there is no file
- // preamble. We can reset the file position indicator to where the data
- // is (i.e. the beginning of the file).
- dbg.Verbose(1, "gdcmHeader::CheckSwap:", "not a DICOM Version3 file");
- rewind(fp);
-
- // Our next best chance would be to be considering a 'clean' ACR/NEMA file.
- // By clean we mean that the length of the first tag is written down.
- // If this is the case and since the length of the first group HAS to be
- // four (bytes), then determining the proper swap code is straightforward.
-
- entCur = deb + 4;
- // We assume the array of char we are considering contains the binary
- // representation of a 32 bits integer. Hence the following dirty
- // trick :
- s = *((guint32 *)(entCur));
-
- switch (s) {
- case 0x00040000 :
- sw = 3412;
- filetype = ACR;
- return;
- case 0x04000000 :
- sw = 4321;
- filetype = ACR;
- return;
- case 0x00000400 :
- sw = 2143;
- filetype = ACR;
- return;
- case 0x00000004 :
- sw = 0;
- filetype = ACR;
- return;
- default :
- dbg.Verbose(0, "gdcmHeader::CheckSwap:",
- "ACR/NEMA unfound swap info (time to raise bets)");
- }
-
- // We are out of luck. It is not a DicomV3 nor a 'clean' ACR/NEMA file.
- // It is time for despaired wild guesses. So, let's assume this file
- // happens to be 'dirty' ACR/NEMA, i.e. the length of the group is
- // not present. Then the only info we have is the net2host one.
- filetype = Unknown;
- if (! net2host )
- sw = 0;
- else
- sw = 4321;
- return;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief
- */
-void gdcmHeader::SwitchSwapToBigEndian(void) {
- dbg.Verbose(1, "gdcmHeader::SwitchSwapToBigEndian",
- "Switching to BigEndian mode.");
- if ( sw == 0 ) {
- sw = 4321;
- return;
- }
- if ( sw == 4321 ) {
- sw = 0;
- return;
- }
- if ( sw == 3412 ) {
- sw = 2143;
- return;
- }
- if ( sw == 2143 )
- sw = 3412;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief Find the value representation of the current tag.
- * @param ElVal
- */
-void gdcmHeader::FindVR( gdcmElValue *ElVal) {
- if (filetype != ExplicitVR)
- return;
-
- char VR[3];
- string vr;
- int lgrLue;
- char msg[100]; // for sprintf. Sorry
-
- long PositionOnEntry = ftell(fp);
- // Warning: we believe this is explicit VR (Value Representation) because
- // we used a heuristic that found "UL" in the first tag. Alas this
- // doesn't guarantee that all the tags will be in explicit VR. In some
- // cases (see e-film filtered files) one finds implicit VR tags mixed
- // within an explicit VR file. Hence we make sure the present tag
- // is in explicit VR and try to fix things if it happens not to be
- // the case.
- bool RealExplicit = true;
-
- lgrLue=fread (&VR, (size_t)2,(size_t)1, fp);
- VR[2]=0;
- vr = string(VR);
-
- // Assume we are reading a falsely explicit VR file i.e. we reached
- // a tag where we expect reading a VR but are in fact we read the
- // first to bytes of the length. Then we will interogate (through find)
- // the dicom_vr dictionary with oddities like "\004\0" which crashes
- // both GCC and VC++ implementations of the STL map. Hence when the
- // expected VR read happens to be non-ascii characters we consider
- // we hit falsely explicit VR tag.
-
- if ( (!isalpha(VR[0])) && (!isalpha(VR[1])) )
- RealExplicit = false;
-
- // CLEANME searching the dicom_vr at each occurence is expensive.
- // PostPone this test in an optional integrity check at the end
- // of parsing or only in debug mode.
- if ( RealExplicit && !dicom_vr->Count(vr) )
- RealExplicit= false;
-
- if ( RealExplicit ) {
- if ( ElVal->IsVrUnknown() ) {
- // When not a dictionary entry, we can safely overwrite the vr.
- ElVal->SetVR(vr);
- return;
- }
- if ( ElVal->GetVR() == vr ) {
- // The vr we just read and the dictionary agree. Nothing to do.
- return;
- }
- // The vr present in the file and the dictionary disagree. We assume
- // the file writer knew best and use the vr of the file. Since it would
- // be unwise to overwrite the vr of a dictionary (since it would
- // compromise it's next user), we need to clone the actual DictEntry
- // and change the vr for the read one.
- gdcmDictEntry* NewTag = new gdcmDictEntry(ElVal->GetGroup(),
- ElVal->GetElement(),
- vr,
- "FIXME",
- ElVal->GetName());
- ElVal->SetDictEntry(NewTag);
- return;
- }
-
- // We thought this was explicit VR, but we end up with an
- // implicit VR tag. Let's backtrack.
-
- sprintf(msg,"Falsely explicit vr file (%04x,%04x)\n", ElVal->GetGroup(),ElVal->GetElement());
- dbg.Verbose(1, "gdcmHeader::FindVR: ",msg);
-
- fseek(fp, PositionOnEntry, SEEK_SET);
- // When this element is known in the dictionary we shall use, e.g. for
- // the semantics (see the usage of IsAnInteger), the vr proposed by the
- // dictionary entry. Still we have to flag the element as implicit since
- // we know now our assumption on expliciteness is not furfilled.
- // avoid .
- if ( ElVal->IsVrUnknown() )
- ElVal->SetVR("Implicit");
- ElVal->SetImplicitVr();
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief Determines if the Transfer Syntax was already encountered
- * and if it corresponds to a ImplicitVRLittleEndian one.
- *
- * @return True when ImplicitVRLittleEndian found. False in all other cases.
- */
-bool gdcmHeader::IsImplicitVRLittleEndianTransferSyntax(void) {
- gdcmElValue* Element = PubElValSet.GetElementByNumber(0x0002, 0x0010);
- if ( !Element )
- return false;
- LoadElementValueSafe(Element);
- string Transfer = Element->GetValue();
- if ( Transfer == "1.2.840.10008.1.2" )
- return true;
- return false;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief Determines if the Transfer Syntax was already encountered
- * and if it corresponds to a ExplicitVRLittleEndian one.
- *
- * @return True when ExplicitVRLittleEndian found. False in all other cases.
- */
-bool gdcmHeader::IsExplicitVRLittleEndianTransferSyntax(void) {
- gdcmElValue* Element = PubElValSet.GetElementByNumber(0x0002, 0x0010);
- if ( !Element )
- return false;
- LoadElementValueSafe(Element);
- string Transfer = Element->GetValue();
- if ( Transfer == "1.2.840.10008.1.2.1" )
- return true;
- return false;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief Determines if the Transfer Syntax was already encountered
- * and if it corresponds to a DeflatedExplicitVRLittleEndian one.
- *
- * @return True when DeflatedExplicitVRLittleEndian found. False in all other cases.
- */
-bool gdcmHeader::IsDeflatedExplicitVRLittleEndianTransferSyntax(void) {
- gdcmElValue* Element = PubElValSet.GetElementByNumber(0x0002, 0x0010);
- if ( !Element )
- return false;
- LoadElementValueSafe(Element);
- string Transfer = Element->GetValue();
- if ( Transfer == "1.2.840.10008.1.2.1.99" )
- return true;
- return false;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief Determines if the Transfer Syntax was already encountered
- * and if it corresponds to a Explicit VR Big Endian one.
- *
- * @return True when big endian found. False in all other cases.
- */
-bool gdcmHeader::IsExplicitVRBigEndianTransferSyntax(void) {
- gdcmElValue* Element = PubElValSet.GetElementByNumber(0x0002, 0x0010);
- if ( !Element )
- return false;
- LoadElementValueSafe(Element);
- string Transfer = Element->GetValue();
- if ( Transfer == "1.2.840.10008.1.2.2" ) //1.2.2 ??? A verifier !
- return true;
- return false;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief Determines if the Transfer Syntax was already encountered
- * and if it corresponds to a JPEGBaseLineProcess1 one.
- *
- * @return True when JPEGBaseLineProcess1found. False in all other cases.
- */
-bool gdcmHeader::IsJPEGBaseLineProcess1TransferSyntax(void) {
- gdcmElValue* Element = PubElValSet.GetElementByNumber(0x0002, 0x0010);
- if ( !Element )
- return false;
- LoadElementValueSafe(Element);
- string Transfer = Element->GetValue();
- if ( Transfer == "1.2.840.10008.1.2.4.50" )
- return true;
- return false;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief
- *
- * @return
- */
-bool gdcmHeader::IsJPEGLossless(void) {
- gdcmElValue* Element = PubElValSet.GetElementByNumber(0x0002, 0x0010);
- // faire qq chose d'intelligent a la place de ça
- if ( !Element )
- return false;
- LoadElementValueSafe(Element);
- const char * Transfert = Element->GetValue().c_str();
- if ( memcmp(Transfert+strlen(Transfert)-2 ,"70",2)==0) return true;
- if ( memcmp(Transfert+strlen(Transfert)-2 ,"55",2)==0) return true;
- return false;
-}
-
-
-/**
- * \ingroup gdcmHeader
- * \brief Determines if the Transfer Syntax was already encountered
- * and if it corresponds to a JPEGExtendedProcess2-4 one.
- *
- * @return True when JPEGExtendedProcess2-4 found. False in all other cases.
- */
-bool gdcmHeader::IsJPEGExtendedProcess2_4TransferSyntax(void) {
- gdcmElValue* Element = PubElValSet.GetElementByNumber(0x0002, 0x0010);
- if ( !Element )
- return false;
- LoadElementValueSafe(Element);
- string Transfer = Element->GetValue();
- if ( Transfer == "1.2.840.10008.1.2.4.51" )
- return true;
- return false;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief Determines if the Transfer Syntax was already encountered
- * and if it corresponds to a JPEGExtendeProcess3-5 one.
- *
- * @return True when JPEGExtendedProcess3-5 found. False in all other cases.
- */
-bool gdcmHeader::IsJPEGExtendedProcess3_5TransferSyntax(void) {
- gdcmElValue* Element = PubElValSet.GetElementByNumber(0x0002, 0x0010);
- if ( !Element )
- return false;
- LoadElementValueSafe(Element);
- string Transfer = Element->GetValue();
- if ( Transfer == "1.2.840.10008.1.2.4.52" )
- return true;
- return false;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief Determines if the Transfer Syntax was already encountered
- * and if it corresponds to a JPEGSpectralSelectionProcess6-8 one.
- *
- * @return True when JPEGSpectralSelectionProcess6-8 found. False in all
- * other cases.
- */
-bool gdcmHeader::IsJPEGSpectralSelectionProcess6_8TransferSyntax(void) {
- gdcmElValue* Element = PubElValSet.GetElementByNumber(0x0002, 0x0010);
- if ( !Element )
- return false;
- LoadElementValueSafe(Element);
- string Transfer = Element->GetValue();
- if ( Transfer == "1.2.840.10008.1.2.4.53" )
- return true;
- return false;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief Predicate for dicom version 3 file.
- * @return True when the file is a dicom version 3.
- */
-bool gdcmHeader::IsDicomV3(void) {
- if ( (filetype == ExplicitVR)
- || (filetype == ImplicitVR) )
- return true;
- return false;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief When the length of an element value is obviously wrong (because
- * the parser went Jabberwocky) one can hope improving things by
- * applying this heuristic.
- */
-void gdcmHeader::FixFoundLength(gdcmElValue * ElVal, guint32 FoundLength) {
- if ( FoundLength == 0xffffffff)
- FoundLength = 0;
- ElVal->SetLength(FoundLength);
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief
- *
- * @return
- */
- guint32 gdcmHeader::FindLengthOB(void) {
- // See PS 3.5-2001, section A.4 p. 49 on encapsulation of encoded pixel data.
- guint16 g;
- guint16 n;
- long PositionOnEntry = ftell(fp);
- bool FoundSequenceDelimiter = false;
- guint32 TotalLength = 0;
- guint32 ItemLength;
-
- while ( ! FoundSequenceDelimiter) {
- g = ReadInt16();
- n = ReadInt16();
-
- long l = ftell(fp);
-
- if (errno == 1)
- return 0;
- TotalLength += 4; // We even have to decount the group and element
-
- if ( g != 0xfffe && g!=0xb00c ) /*for bogus header */ {
- char msg[100]; // for sprintf. Sorry
- sprintf(msg,"wrong group (%04x) for an item sequence (%04x,%04x)\n",g, g,n);
- dbg.Verbose(1, "gdcmHeader::FindLengthOB: ",msg);
- long l = ftell(fp);
- errno = 1;
- return 0;
- }
- if ( n == 0xe0dd || ( g==0xb00c && n==0x0eb6 ) ) /* for bogus header */
- FoundSequenceDelimiter = true;
- else if ( n != 0xe000 ){
- char msg[100]; // for sprintf. Sorry
- sprintf(msg,"wrong element (%04x) for an item sequence (%04x,%04x)\n",n, g,n);
- dbg.Verbose(1, "gdcmHeader::FindLengthOB: ",msg);
- errno = 1;
- return 0;
- }
- ItemLength = ReadInt32();
- TotalLength += ItemLength + 4; // We add 4 bytes since we just read
- // the ItemLength with ReadInt32
-
- SkipBytes(ItemLength);
- }
- fseek(fp, PositionOnEntry, SEEK_SET);
- return TotalLength;
-}
-
-/**
- * \ingroup gdcmHeader
- * \brief
- *
- * @return
- */
- void gdcmHeader::FindLength (gdcmElValue * ElVal) {
- guint16 element = ElVal->GetElement();
- guint16 group = ElVal->GetGroup();
- string vr = ElVal->GetVR();
- guint16 length16;
- if( (element == 0x0010) && (group == 0x7fe0) ) {
- dbg.SetDebug(0);
- dbg.Verbose(2, "gdcmHeader::FindLength: ",
- "on est sur 7fe0 0010");
- }
-
- if ( (filetype == ExplicitVR) && ! ElVal->IsImplicitVr() ) {
- if ( (vr=="OB") || (vr=="OW") || (vr=="SQ") || (vr=="UN") ) {
-
- // The following reserved two bytes (see PS 3.5-2001, section
- // 7.1.2 Data element structure with explicit vr p27) must be
- // skipped before proceeding on reading the length on 4 bytes.
- fseek(fp, 2L, SEEK_CUR);
-
- guint32 length32 = ReadInt32();
- if ( (vr == "OB") && (length32 == 0xffffffff) ) {
- ElVal->SetLength(FindLengthOB());
- return;
- }
- FixFoundLength(ElVal, length32);
- return;
- }