[gdcm.git] / dcmlib.h

// gdcmlib Intro:  
// * gdcmlib is a library dedicated to reading and writing dicom files.
// * LGPL for the license
// * lightweigth as opposed to CTN or DCMTK wich come bundled which try
//   to implement the full DICOM standard (networking...). gdcmlib concentrates
//   on reading and 
// * Formats: this lib should be able to read ACR-NEMA v1 and v2, Dicom v3 (as
//   stated in part10). [cf dcmtk/dcmdata/docs/datadict.txt]
// * Targeted plateforms: Un*xes and Win32/VC++6.0

#include <string>
#include <stddef.h>    // For size_t

// The requirement for the hash table (or map) that we shall use:
// 1/ First, next, last (iterators)
// 2/ should be sortable (i.e. sorted by TagKey). This condition
//    shall be droped since the Win32/VC++ implementation doesn't look
//    a sorted one. Pffff....
// 3/ Make sure we can setup some default size value, which should be
//    around 4500 entries which is the average dictionary size (said JPR)
#include <map>

// Tag based hash tables.
// We shall use as keys the strings (as the C++ type) obtained by
// concatenating the group value and the element value (both of type
// unsigned 16 bit integers in Dicom) expressed in hexadecimal.
// Example: consider the tag given as (group, element) = (0x0010, 0x0010).
// Then the corresponding TagKey shall be the string 00100010 (or maybe
// 0x00100x0010, we need some checks here).
typedef string TagKey;
typedef map<TagKey, char*> TagHT;

// Dummy declaration for the time being
typedef int guint16;    // We shall need glib.h !

class DictEntry {
private:
////// QUESTION: it is not sure that we need to store the group and
//////           and the element within a DictEntry. What is the point
//////           of storing the equivalent of a TagKey within the information
//////           accessed through that TagKey !?
        guint16 group;          // e.g. 0x0010
        guint16 element;        // e.g. 0x0010
        string  name;           // e.g. "Patient_Name"
        string  ValRep; // Value Representation i.e. some clue about the nature
                                                        // of the data represented e.g. "FD" short for
                                                        // "Floating Point Double"
        // DCMTK has many fields for handling a DictEntry (see below). What are the
        // relevant ones for gdcmlib ?
        //      struct DBI_SimpleEntry {
        //         Uint16 group;
        //         Uint16 element;
        //         Uint16 upperGroup;
        //         Uint16 upperElement;
        //         DcmEVR evr;
        //         const char* tagName;
        //         int vmMin;
        //         int vmMax;
        //         const char* standardVersion;
        //         DcmDictRangeRestriction groupRestriction;
        //         DcmDictRangeRestriction elementRestriction;
        //       };
public:
        DictEntry();
        DictEntry(guint16 group, guint16 element, string  name, string  VR);
};

// A single DICOM dictionary i.e. a container for a collection of dictionary
// entries. There should be a single public dictionary (THE dictionary of
// the actual DICOM v3) but as many shadow dictionaries as imagers 
// combined with all software versions...
class Dict {
        string name;
        string filename;
        TagHT entries;
public:
        Dict();
        Dict(string filename);  // Read Dict from disk
        int AppendEntry(DictEntry* NewEntry);
};

// Container for managing a set of loaded dictionaries. Sharing dictionaries
// should avoid :
// * reloading an allready loaded dictionary.
// * having many in memory representations of the same dictionary.
typedef int DictId;
class DictSet {
private:
        map<DictId, Dict*> dicts;
        int AppendDict(Dict* NewDict);
public:
        DictSet();              // Default constructor loads THE DICOM v3 dictionary
        int LoadDictFromFile(string filename);
///// QUESTION: the following function might not be thread safe !? Maybe
/////           we need some mutex here, to avoid concurent creation of
/////           the same dictionary !?!?!
        int LoadDictFromName(string filename);
        int LoadAllDictFromDirectory(string directorynanme);
        string* GetAllDictNames();
        Dict* GetDict(string DictName);
};

// The dicom header of a Dicom file contains a set of such ELement VALUES
// (when successfuly parsed against a given Dicom dictionary)
class ElValue {
        DictEntry entry;
        string  value;
};

// Container for a set of succefully parsed ElValues.
typedef map<TagKey, char*> TagHT;
class ElValSet {
        // We need both accesses with a TagKey and the Dicentry.Name
////// QUESTION: this leads to a double storage of a single ElValue
        map<TagKey, ElValue> tagHt;
        map<srting, ElValue> NameHt;
public:
        int Add(ElValue);
};

// The typical usage of objects of this class is to classify a set of
// dicom files according to header information e.g. to create a file hierachy
// reflecting the Patient/Study/Serie informations, or extracting a given
// SerieId. Accesing the content (image[s] or volume[s]) is beyond the
// functionality of this class (see dmcFile below).
// Notes:
// * the gdcmHeader::Set*Tag* family members cannot be defined as protected
//   (Swig limitations for as Has_a dependency between gdcmFile and gdcmHeader)
class gdcmHeader {
private:
        static DictSet* Dicts;  // Global dictionary container
        Dict* RefPubDict;                       // Public Dictionary
        Dict* RefShaDict;                       // Shadow Dictionary (optional)
        int swapcode;
        ElValSet PubElVals;             // Element Values parsed with Public Dictionary
        ElValSet ShaElVals;             // Element Values parsed with Shadow Dictionary
protected:
///// QUESTION: Maybe Print is a better name than write !?
        int write(ostream&);   
///// QUESTION: Maybe anonymize should be a friend function !?!?
/////           See below for an example of how anonymize might be implemented.
        int anonymize(ostream&);
public:
        gdcmHeader();
        gdcmHeader(string filename);
        ~gdcmHeader();

        int SetPubDict(string filename);
        // When some proprietary shadow groups are disclosed, whe can set
        // up an additional specific dictionary to access extra information.
        int SetShaDict(string filename);

        // Retrieve all potentially available tag [tag = (group, element)] names
        // from the standard (or public) dictionary (hence static). Typical usage:
        // enable the user of a GUI based interface to select his favorite fields
        // for sorting or selection.
        string* GetPubTagNames();
        // Get the element values themselves:
        string GetPubElValByName(string TagName);
        string GetPubElValByNumber(guint16 group, guint16 element);
        // Get the element value representation: (VR) might be needed by caller
        // to convert the string typed content to caller's native type (think
        // of C/C++ vs Python).
        string GetPubElValRepByName(string TagName);
        string GetPubElValRepByNumber(guint16 group, guint16 element);
          
        // Same thing with the shadow :
        string* GetShaTagNames(); 
        string GetShaElValByName(string TagName);
        string GetShaElValByNumber(guint16 group, guint16 element);
        string GetShaElValRepByName(string TagName);
        string GetShaElValRepByNumber(guint16 group, guint16 element);

        // Wrappers of the above (both public and shadow) to avoid bugging the
        // caller with knowing if ElVal is from the public or shadow dictionary.
        string GetElValByName(string TagName);
        string GetElValByNumber(guint16 group, guint16 element);
        string GetElValRepByName(string TagName);
        string GetElValRepByNumber(guint16 group, guint16 element);

        int SetPubElValByName(string content, string TagName);
        int SetPubElValByNumber(string content, guint16 group, guint16 element);
        int SetShaElValByName(string content, string ShadowTagName);
        int SetShaElValByNumber(string content, guint16 group, guint16 element);

        int GetSwapCode();
};

// In addition to Dicom header exploration, this class is designed
// for accessing the image/volume content. One can also use it to
// write Dicom files.
////// QUESTION: this looks still like an open question wether the
//////           relationship between a gdcmFile and gdcmHeader is of
//////           type IS_A or HAS_A !
class gdcmFile: gdcmHeader
{
private:
        void* Data;
        int Parsed;                             // weather allready parsed
        string OrigFileName;    // To avoid file overwrite
public:
        // Constructor dedicated to writing a new DICOMV3 part10 compliant
        // file (see SetFileName, SetDcmTag and Write)
        gdcmFile();
        // Opens (in read only and when possible) an existing file and checks
        // for DICOM compliance. Returns NULL on failure.
        // Note: the in-memory representation of all available tags found in
        //    the DICOM header is post-poned to first header information access.
        //    This avoid a double parsing of public part of the header when
        //    one sets an a posteriori shadow dictionary (efficiency can be
        //    seen a a side effect).
        gdcmFile(string filename);
        // For promotion (performs a deepcopy of pointed header object)
        gdcmFile(gdcmHeader* header);
        ~gdcmFile();

        // On writing purposes. When instance was created through
        // gdcmFile(string filename) then the filename argument MUST be different
        // from the constructor's one (no overwriting aloud).
        int SetFileName(string filename);

        // Allocates necessary memory, copies the data (image[s]/volume[s]) to
        // newly allocated zone and return a pointer to it:
        void * GetImageData();
        // Returns size (in bytes) of required memory to contain data
        // represented in this file.
        size_t GetImageDataSize();
        // Copies (at most MaxSize bytes) of data to caller's memory space.
        // Returns an error code on failure (if MaxSize is not big enough)
        int PutImageDataHere(void* destination, size_t MaxSize );
        // Allocates ExpectedSize bytes of memory at this->Data and copies the
        // pointed data to it.
        int SetImageData(void * Data, size_t ExpectedSize);
        // Push to disk.
        int Write();
};

//class gdcmSerie : gdcmFile;
//class gdcmMultiFrame : gdcmFile;

//
//Examples:
// * gdcmFile WriteDicom;
//   WriteDicom.SetFileName("MyDicomFile.dcm");
//      string * AllTags = gdcmHeader.GetDcmTagNames();
//   WriteDicom.SetDcmTag(AllTags[5], "253");
//   WriteDicom.SetDcmTag("Patient Name", "bozo");
//   WriteDicom.SetDcmTag("Patient Name", "bozo");
//      WriteDicom.SetImageData(Image);
//   WriteDicom.Write();
//
//
//   Anonymize(ostream& output) {
//   a = gdcmFile("toto1");
//   a.SetPubValueByName("Patient Name", "");
//   a.SetPubValueByName("Date", "");
//   a.SetPubValueByName("Study Date", "");
//   a.write(output);
//   }