Program: gdcm
Module: $RCSfile: gdcmDocument.cxx,v $
Language: C++
- Date: $Date: 2005/01/12 11:33:39 $
- Version: $Revision: 1.182 $
+ Date: $Date: 2005/01/12 15:22:23 $
+ Version: $Revision: 1.183 $
Copyright (c) CREATIS (Centre de Recherche et d'Applications en Traitement de
l'Image). All rights reserved. See Doc/License.txt or
long lgt = Fp->tellg();
Fp->seekg( 0, std::ios::beg);
+
CheckSwap();
long beg = Fp->tellg();
lgt -= beg;
/// lines state that the corresponding tag contents are in fact
/// the ones of a BinEntry.
/// In order to fix things "Quick and Dirty" the dictionnary was
- /// altered on PURPOUS but now contains a WRONG value.
+ /// altered on PURPOSE but now contains a WRONG value.
/// In order to fix things and restore the dictionary to its
/// correct value, one needs to decided of the semantics by deciding
/// wether the following tags are either:
if ( ! Global::GetVR()->IsVROfBinaryRepresentable(vr) )
{
////// Neither ValEntry NOR BinEntry: should mean UNKOWN VR
- gdcmVerboseMacro( "Neither Valentry, nor BinEntry."
+ gdcmVerboseMacro( std::hex << newDocEntry->GetGroup()
+ << "|" << newDocEntry->GetElement()
+ << " : Neither Valentry, nor BinEntry."
"Probably unknown VR.");
}
newSeqEntry->SetDepthLevel( 1 );
newSeqEntry->SetKey( newSeqEntry->GetKey() );
}
- // But when "set" is allready a SQItem, we are building a nested
+ // But when "set" is already a SQItem, we are building a nested
// sequence, and hence the depth level of the new SeqEntry
// we are building, is one level deeper:
if (SQItem *parentSQItem = dynamic_cast< SQItem* > ( set ) )
// Length is encoded on 2 bytes.
length16 = ReadInt16();
+
+ // FIXME : This heuristic supposes that the first group following
+ // group 0002 *has* and element 0000.
+ // BUT ... Element 0000 is optionnal :-(
+
+
+ // Fixed using : HandleOutOfGroup0002()
+ // (first hereafter strategy ...)
// We can tell the current file is encoded in big endian (like
// Data/US-RGB-8-epicard) when we find the "Transfer Syntax" tag
// ones with zero as element number) has to be of 4 (0x0004). When we
// encounter 1024 (0x0400) chances are the encoding changed and we
// found a group with big endian encoding.
+ //---> Unfortunately, element 0000 is optional.
+ //---> This will not work when missing!
// We shall use this second strategy. In order to make sure that we
// can interpret the presence of an apparently big endian encoded
// length of a "Group Length" without committing a big mistake, we
// endian encoding". When this is the case, chances are we have got our
// hands on a big endian encoded file: we switch the swap code to
// big endian and proceed...
- if ( element == 0x0000 && length16 == 0x0400 )
- {
- std::string ts = GetTransferSyntax();
- if ( Global::GetTS()->GetSpecialTransferSyntax(ts)
- != TS::ExplicitVRBigEndian )
- {
- throw FormatError( "Document::FindDocEntryLength()",
- " not explicit VR." );
- return;
- }
- length16 = 4;
- SwitchByteSwapCode();
+
+ //
+ // if ( element == 0x0000 && length16 == 0x0400 )
+ // {
+ // std::string ts = GetTransferSyntax();
+ // if ( Global::GetTS()->GetSpecialTransferSyntax(ts)
+ // != TS::ExplicitVRBigEndian )
+ // {
+ // throw FormatError( "Document::FindDocEntryLength()",
+ // " not explicit VR." );
+ // return;
+ // }
+ // length16 = 4;
+ // SwitchByteSwapCode();
// Restore the unproperly loaded values i.e. the group, the element
// and the dictionary entry depending on them.
- uint16_t correctGroup = SwapShort( entry->GetGroup() );
- uint16_t correctElem = SwapShort( entry->GetElement() );
- DictEntry *newTag = GetDictEntry( correctGroup, correctElem );
- if ( !newTag )
- {
+// uint16_t correctGroup = SwapShort( entry->GetGroup() );
+// uint16_t correctElem = SwapShort( entry->GetElement() );
+// DictEntry *newTag = GetDictEntry( correctGroup, correctElem ); if ( !newTag )
+// {
// This correct tag is not in the dictionary. Create a new one.
- newTag = NewVirtualDictEntry(correctGroup, correctElem);
- }
+// newTag = NewVirtualDictEntry(correctGroup, correctElem);
+// }
// FIXME this can create a memory leaks on the old entry that be
// left unreferenced.
- entry->SetDictEntry( newTag );
- }
-
- // Heuristic: well, some files are really ill-formed.
+// entry->SetDictEntry( newTag );
+// }
+
+
+ // 0xffff means that we deal with 'No Length' Sequence
+ // or 'No Length' SQItem
if ( length16 == 0xffff)
- {
- // 0xffff means that we deal with 'Unknown Length' Sequence
+ {
length16 = 0;
}
FixDocEntryFoundLength( entry, (uint32_t)length16 );
net2host = false;
}
- // The easiest case is the one of a DICOM header, since it possesses a
- // file preamble where it suffice to look for the string "DICM".
+ // The easiest case is the one of a 'true' DICOM header, we just have
+ // to look for the string "DICM" inside the file preamble.
Fp->read(deb, 256);
char *entCur = deb + 128;
if( memcmp(entCur, "DICM", (size_t)4) == 0 )
{
- gdcmVerboseMacro( "Looks like DICOM Version3" );
+ gdcmVerboseMacro( "Looks like DICOM Version3 (preamble + DCM)" );
- // Next, determine the value representation (VR). Let's skip to the
- // first element (0002, 0000) and check there if we find "UL"
- // - or "OB" if the 1st one is (0002,0001) -,
+ // Group 0002 should always be VR, and the first element 0000
+ // Let's be carefull (so many wrong hedaers ...)
+ // and determine the value representation (VR) :
+ // Let's skip to the first element (0002,0000) and check there if we find
+ // "UL" - or "OB" if the 1st one is (0002,0001) -,
// in which case we (almost) know it is explicit VR.
// WARNING: if it happens to be implicit VR then what we will read
// is the length of the group. If this ascii representation of this
// length happens to be "UL" then we shall believe it is explicit VR.
- // FIXME: in order to fix the above warning, we could read the next
- // element value (or a couple of elements values) in order to make
- // sure we are not commiting a big mistake.
// We need to skip :
// * the 128 bytes of File Preamble (often padded with zeroes),
// * the 4 bytes of "DICM" string,
// i.e. a total of 136 bytes.
entCur = deb + 136;
- // FIXME : FIXME:
- // Sometimes (see : gdcmData/icone.dcm) group 0x0002 *is* Explicit VR,
- // but elem 0002,0010 (Transfer Syntax) tells us the file is
- // *Implicit* VR. -and it is !-
+ // group 0x0002 *is always* Explicit VR Sometimes ,
+ // even elem 0002,0010 (Transfer Syntax) tells us the file is
+ // *Implicit* VR (see former 'gdcmData/icone.dcm')
if( memcmp(entCur, "UL", (size_t)2) == 0 ||
memcmp(entCur, "OB", (size_t)2) == 0 ||
memcmp(entCur, "UI", (size_t)2) == 0 ||
memcmp(entCur, "CS", (size_t)2) == 0 ) // CS, to remove later
- // when Write DCM *adds*
+ // when Write DCM *adds*
// FIXME
// Use Document::dicom_vr to test all the possibilities
// instead of just checking for UL, OB and UI !? group 0000
{
Filetype = ExplicitVR;
- gdcmVerboseMacro( "Explicit Value Representation");
+ gdcmVerboseMacro( "Group 0002 : Explicit Value Representation");
}
else
{
Filetype = ImplicitVR;
- gdcmVerboseMacro( "Not an explicit Value Representation");
+ gdcmVerboseMacro( "Group 0002 :Not an explicit Value Representation;"
+ << "Looks like a bugged Header!");
}
if ( net2host )
gdcmVerboseMacro( "HostByteOrder = NetworkByteOrder");
}
- // Position the file position indicator at first tag (i.e.
- // after the file preamble and the "DICM" string).
+ // Position the file position indicator at first tag
+ // (i.e. after the file preamble and the "DICM" string).
Fp->seekg(0, std::ios::beg);
Fp->seekg ( 132L, std::ios::beg);
return true;
*/
void Document::SwitchByteSwapCode()
{
- gdcmVerboseMacro( "Switching Byte Swap code.");
+ gdcmVerboseMacro( "Switching Byte Swap code from "<< SwapCode);
if ( SwapCode == 1234 )
{
SwapCode = 4321;
// we just came out of group 0002
// if Transfer syntax is Big Endian we have to change CheckSwap
- std::string ts = GetTransferSyntaxName();
+ std::string ts = GetTransferSyntax();
if ( !Global::GetTS()->IsTransferSyntax(ts) )
{
gdcmVerboseMacro("True DICOM File, with NO Tansfer Syntax: " << ts );
//'Implicit VR Transfer Syntax (GE Private)
if ( Global::GetTS()->GetSpecialTransferSyntax(ts) == TS::ExplicitVRBigEndian )
{
- gdcmVerboseMacro("Tansfer Syntax = Explicit VR - Big Endian");
+ gdcmVerboseMacro("Transfer Syntax Name = ["
+ << GetTransferSyntaxName() << "]" );
SwitchByteSwapCode();
}
}
// Sometimes file contains groups of tags with reversed endianess.
HandleBrokenEndian(group, elem);
-// In 'true DICOM' files Group 0002 is allways little endian
+// In 'true DICOM' files Group 0002 is always little endian
if ( HasDCMPreamble )
HandleOutOfGroup0002(group);
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