Provide a new API for DcmItem to delete a private attribute

Extend DcmItem with findAndDeletePrivateElement to allow user to delete a private tag directly (reservation number is computed internally).
DCMTK · Feb 8, 2022 · abb31ee · abb31ee
1 parent aca0e8e
commit abb31ee
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diff --git a/dcmdata/include/dcmtk/dcmdata/dcitem.h b/dcmdata/include/dcmtk/dcmdata/dcitem.h
@@ -1043,6 +1043,19 @@ class DCMTK_DCMDATA_EXPORT DcmItem
                                      const OFBool allOccurrences = OFFalse,
                                      const OFBool searchIntoSub = OFFalse);
 
+    /** find private element, remove it from the dataset and free the associated memory.
+     *  Applicable to all DICOM value representations (VR).
+     *  @param tag DICOM tag specifying the private attribute to be searched for
+     *  @param allOccurrences flag indicating whether to delete all occurrences of the
+     *    attribute tag or the first one only (implies 'searchIntoSub' to be true)
+     *  @param searchIntoSub flag indicating whether to search into sequences or not
+     *  @return EC_Normal upon success, an error code otherwise.
+     */
+    OFCondition findAndDeletePrivateElement(const DcmTag &tag,
+                                            const OFBool allOccurrences = OFFalse,
+                                            const OFBool searchIntoSub = OFFalse);
+
+
     /** looks up the given sequence in the current dataset and deletes the given item.
      *  Applicable to the following VRs: SQ, (pixelSQ).
      *  @param seqTagKey DICOM tag specifying the sequence attribute to be searched for

diff --git a/dcmdata/libsrc/dcitem.cc b/dcmdata/libsrc/dcitem.cc
@@ -3202,6 +3202,46 @@ OFCondition DcmItem::findAndDeleteElement(const DcmTagKey &tagKey,
     return status;
 }
 
+OFCondition DcmItem::findAndDeletePrivateElement(const DcmTag &privTag,
+                                                 const OFBool allOccurrences,
+                                                 const OFBool searchIntoSub)
+{
+    OFCondition status = EC_TagNotFound;
+    DcmStack stack;
+    DcmObject *object = NULL;
+    OFBool intoSub = OFTrue;
+    /* make sure private tag */
+    if( !privTag.isPrivate() || privTag.getPrivateCreator() == NULL || privTag.getElement() >= 0x1000)
+      return status;
+    DcmTagKey curTag;
+    /* iterate over all elements */
+    while (nextObject(stack, intoSub).good())
+    {
+        /* get element */
+        object = stack.top();
+        curTag = object->getTag();
+        if (curTag.getGroup() == privTag.getGroup() && (curTag.getElement() > 0 && curTag.getElement() <= 0xff)) {
+          DcmElement *elem;
+          elem = OFstatic_cast(DcmElement *, stack.top());
+          OFString value;
+          if (elem->getOFStringArray(value).good()) {
+            if (value.compare(privTag.getPrivateCreator()) == 0) {
+              const Uint16 actualElement = OFstatic_cast(
+                  Uint16, (curTag.getElement() << 8) | privTag.getElement());
+              const DcmTagKey tagKey(curTag.getGroup(), actualElement);
+              status = findAndDeleteElement(tagKey, allOccurrences, searchIntoSub);
+              /* delete only the first element? */
+              if (!allOccurrences)
+                  break;
+            }
+          }
+        }
+        intoSub = searchIntoSub || allOccurrences;
+    }
+    return status;
+}
+
+
 
 OFCondition DcmItem::findAndDeleteSequenceItem(const DcmTagKey &seqTagKey,
                                                const signed long itemNum)

diff --git a/dcmdata/tests/tests.cc b/dcmdata/tests/tests.cc
@@ -95,6 +95,7 @@ OFTEST_REGISTER(dcmdata_sequenceInsert);
 OFTEST_REGISTER(dcmdata_pixelSequenceInsert);
 OFTEST_REGISTER(dcmdata_findAndGetSequenceItem);
 OFTEST_REGISTER(dcmdata_findAndGetUint16Array);
+OFTEST_REGISTER(dcmdata_findAndDeletePrivateElement);
 OFTEST_REGISTER(dcmdata_parser_missingDelimitationItems);
 OFTEST_REGISTER(dcmdata_parser_missingSequenceDelimitationItem_1);
 OFTEST_REGISTER(dcmdata_parser_missingSequenceDelimitationItem_2);

diff --git a/dcmdata/tests/titem.cc b/dcmdata/tests/titem.cc
@@ -26,6 +26,7 @@
 #include "dcmtk/dcmdata/dcitem.h"
 #include "dcmtk/dcmdata/dcvrat.h"
 #include "dcmtk/dcmdata/dcvrus.h"
+#include "dcmtk/dcmdata/dcvrlo.h"
 #include "dcmtk/dcmdata/dcdeftag.h"
 
 
@@ -48,3 +49,26 @@ OFTEST(dcmdata_findAndGetUint16Array)
     OFCHECK(item.findAndGetUint16Array(DCM_FrameIncrementPointer, uintVals, &numUints).good());
     OFCHECK_EQUAL(numUints, 2);
 }
+
+OFTEST(dcmdata_findAndDeletePrivateElement)
+{
+    DcmItem item;
+    const DcmTag privTag(0x0009,0x0042,"PRIVATE CREATOR");
+    /* create data elements with values */
+    const Uint16 reservationElem = 0x0070;
+    /* reservation */
+    const DcmTagKey reservationTag(privTag.getGroup(), reservationElem);
+    DcmLongString loValue( reservationTag );
+    loValue.putString(privTag.getPrivateCreator());
+    item.insert(new DcmLongString(loValue));
+
+    /* actual private element */
+    const DcmTagKey privTagKey( privTag.getGroup(), (reservationElem << 8) | privTag.getElement());
+    DcmUnsignedShort usValue(privTagKey);
+    usValue.putString("1");
+    item.insert(new DcmUnsignedShort(usValue));
+    OFCHECK(item.tagExists (privTagKey));
+    /* remove it */
+    item.findAndDeletePrivateElement(privTag);
+    OFCHECK(!item.tagExists (privTagKey));
+}