+
+/**
+ * \brief Assuming the internal file pointer \ref Document::Fp
+ * is placed at the beginning of a tag check whether this
+ * tag is (TestGroup, TestElement).
+ * \warning On success the internal file pointer \ref Document::Fp
+ * is modified to point after the tag.
+ * On failure (i.e. when the tag wasn't the expected tag
+ * (TestGroup, TestElement) the internal file pointer
+ * \ref Document::Fp is restored to it's original position.
+ * @param testGroup The expected group of the tag.
+ * @param testElement The expected Element of the tag.
+ * @return True on success, false otherwise.
+ */
+bool File::ReadTag(uint16_t testGroup, uint16_t testElement)
+{
+ long positionOnEntry = Fp->tellg();
+ long currentPosition = Fp->tellg(); // On debugging purposes
+
+ // Read the Item Tag group and element, and make
+ // sure they are what we expected:
+ uint16_t itemTagGroup;
+ uint16_t itemTagElement;
+ try
+ {
+ itemTagGroup = ReadInt16();
+ itemTagElement = ReadInt16();
+ }
+ catch ( FormatError e )
+ {
+ //std::cerr << e << std::endl;
+ return false;
+ }
+ if ( itemTagGroup != testGroup || itemTagElement != testElement )
+ {
+ gdcmWarningMacro( "Wrong Item Tag found:"
+ << " We should have found tag ("
+ << std::hex << testGroup << "," << testElement << ")" << std::endl
+ << " but instead we encountered tag ("
+ << std::hex << itemTagGroup << "," << itemTagElement << ")"
+ << " at address: " << " 0x(" << (unsigned int)currentPosition << ")"
+ ) ;
+ Fp->seekg(positionOnEntry, std::ios::beg);
+
+ return false;
+ }
+ return true;
+}
+
+/**
+ * \brief Assuming the internal file pointer \ref Document::Fp
+ * is placed at the beginning of a tag (TestGroup, TestElement),
+ * read the length associated to the Tag.
+ * \warning On success the internal file pointer \ref Document::Fp
+ * is modified to point after the tag and it's length.
+ * On failure (i.e. when the tag wasn't the expected tag
+ * (TestGroup, TestElement) the internal file pointer
+ * \ref Document::Fp is restored to it's original position.
+ * @param testGroup The expected group of the tag.
+ * @param testElement The expected Element of the tag.
+ * @return On success returns the length associated to the tag. On failure
+ * returns 0.
+ */
+uint32_t File::ReadTagLength(uint16_t testGroup, uint16_t testElement)
+{
+
+ if ( !ReadTag(testGroup, testElement) )
+ {
+ return 0;
+ }
+
+ //// Then read the associated Item Length
+ long currentPosition = Fp->tellg();
+ uint32_t itemLength = ReadInt32();
+ {
+ gdcmWarningMacro( "Basic Item Length is: "
+ << itemLength << std::endl
+ << " at address: " << std::hex << (unsigned int)currentPosition);
+ }
+ return itemLength;
+}
+
+/**
+ * \brief When parsing the Pixel Data of an encapsulated file, read
+ * the basic offset table (when present, and BTW dump it).
+ */
+void File::ReadAndSkipEncapsulatedBasicOffsetTable()
+{
+ //// Read the Basic Offset Table Item Tag length...
+ uint32_t itemLength = ReadTagLength(0xfffe, 0xe000);
+
+ // When present, read the basic offset table itself.
+ // Notes: - since the presence of this basic offset table is optional
+ // we can't rely on it for the implementation, and we will simply
+ // trash it's content (when present).
+ // - still, when present, we could add some further checks on the
+ // lengths, but we won't bother with such fuses for the time being.
+ if ( itemLength != 0 )
+ {
+ char *basicOffsetTableItemValue = new char[itemLength + 1];
+ Fp->read(basicOffsetTableItemValue, itemLength);
+
+#ifdef GDCM_DEBUG
+ for (unsigned int i=0; i < itemLength; i += 4 )
+ {
+ uint32_t individualLength = str2num( &basicOffsetTableItemValue[i],
+ uint32_t);
+ gdcmWarningMacro( "Read one length: " <<
+ std::hex << individualLength );
+ }
+#endif //GDCM_DEBUG
+
+ delete[] basicOffsetTableItemValue;
+ }
+}
+
+//-----------------------------------------------------------------------------
+// Print
+
+//-----------------------------------------------------------------------------
+} // end namespace gdcm