--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Resources/Orthanc/Core/DicomFormat/DicomMap.cpp	Fri Mar 23 11:04:03 2018 +0100
@@ -0,0 +1,975 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2018 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * In addition, as a special exception, the copyright holders of this
+ * program give permission to link the code of its release with the
+ * OpenSSL project's "OpenSSL" library (or with modified versions of it
+ * that use the same license as the "OpenSSL" library), and distribute
+ * the linked executables. You must obey the GNU General Public License
+ * in all respects for all of the code used other than "OpenSSL". If you
+ * modify file(s) with this exception, you may extend this exception to
+ * your version of the file(s), but you are not obligated to do so. If
+ * you do not wish to do so, delete this exception statement from your
+ * version. If you delete this exception statement from all source files
+ * in the program, then also delete it here.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#include "../PrecompiledHeaders.h"
+#include "DicomMap.h"
+
+#include <stdio.h>
+#include <memory>
+
+#include "../Endianness.h"
+#include "../Logging.h"
+#include "../OrthancException.h"
+
+
+namespace Orthanc
+{
+  static DicomTag patientTags[] =
+  {
+    //DicomTag(0x0010, 0x1010), // PatientAge
+    //DicomTag(0x0010, 0x1040)  // PatientAddress
+    DicomTag(0x0010, 0x0010),   // PatientName
+    DicomTag(0x0010, 0x0030),   // PatientBirthDate
+    DicomTag(0x0010, 0x0040),   // PatientSex
+    DicomTag(0x0010, 0x1000),   // OtherPatientIDs
+    DICOM_TAG_PATIENT_ID
+  };
+
+  static DicomTag studyTags[] =
+  {
+    //DicomTag(0x0010, 0x1020), // PatientSize
+    //DicomTag(0x0010, 0x1030)  // PatientWeight
+    DICOM_TAG_STUDY_DATE,
+    DicomTag(0x0008, 0x0030),   // StudyTime
+    DicomTag(0x0020, 0x0010),   // StudyID
+    DICOM_TAG_STUDY_DESCRIPTION,
+    DICOM_TAG_ACCESSION_NUMBER,
+    DICOM_TAG_STUDY_INSTANCE_UID,
+    DICOM_TAG_REQUESTED_PROCEDURE_DESCRIPTION,   // New in db v6
+    DICOM_TAG_INSTITUTION_NAME,                  // New in db v6
+    DICOM_TAG_REQUESTING_PHYSICIAN,              // New in db v6
+    DICOM_TAG_REFERRING_PHYSICIAN_NAME           // New in db v6
+  };
+
+  static DicomTag seriesTags[] =
+  {
+    //DicomTag(0x0010, 0x1080), // MilitaryRank
+    DicomTag(0x0008, 0x0021),   // SeriesDate
+    DicomTag(0x0008, 0x0031),   // SeriesTime
+    DICOM_TAG_MODALITY,
+    DicomTag(0x0008, 0x0070),   // Manufacturer
+    DicomTag(0x0008, 0x1010),   // StationName
+    DICOM_TAG_SERIES_DESCRIPTION,
+    DicomTag(0x0018, 0x0015),   // BodyPartExamined
+    DicomTag(0x0018, 0x0024),   // SequenceName
+    DicomTag(0x0018, 0x1030),   // ProtocolName
+    DicomTag(0x0020, 0x0011),   // SeriesNumber
+    DICOM_TAG_CARDIAC_NUMBER_OF_IMAGES,
+    DICOM_TAG_IMAGES_IN_ACQUISITION,
+    DICOM_TAG_NUMBER_OF_TEMPORAL_POSITIONS,
+    DICOM_TAG_NUMBER_OF_SLICES,
+    DICOM_TAG_NUMBER_OF_TIME_SLICES,
+    DICOM_TAG_SERIES_INSTANCE_UID,
+    DICOM_TAG_IMAGE_ORIENTATION_PATIENT,                  // New in db v6
+    DICOM_TAG_SERIES_TYPE,                                // New in db v6
+    DICOM_TAG_OPERATOR_NAME,                              // New in db v6
+    DICOM_TAG_PERFORMED_PROCEDURE_STEP_DESCRIPTION,       // New in db v6
+    DICOM_TAG_ACQUISITION_DEVICE_PROCESSING_DESCRIPTION,  // New in db v6
+    DICOM_TAG_CONTRAST_BOLUS_AGENT                        // New in db v6
+  };
+
+  static DicomTag instanceTags[] =
+  {
+    DicomTag(0x0008, 0x0012),   // InstanceCreationDate
+    DicomTag(0x0008, 0x0013),   // InstanceCreationTime
+    DicomTag(0x0020, 0x0012),   // AcquisitionNumber
+    DICOM_TAG_IMAGE_INDEX,
+    DICOM_TAG_INSTANCE_NUMBER,
+    DICOM_TAG_NUMBER_OF_FRAMES,
+    DICOM_TAG_TEMPORAL_POSITION_IDENTIFIER,
+    DICOM_TAG_SOP_INSTANCE_UID,
+    DICOM_TAG_IMAGE_POSITION_PATIENT,    // New in db v6
+    DICOM_TAG_IMAGE_COMMENTS             // New in db v6
+  };
+
+
+  void DicomMap::LoadMainDicomTags(const DicomTag*& tags,
+                                   size_t& size,
+                                   ResourceType level)
+  {
+    switch (level)
+    {
+      case ResourceType_Patient:
+        tags = patientTags;
+        size = sizeof(patientTags) / sizeof(DicomTag);
+        break;
+
+      case ResourceType_Study:
+        tags = studyTags;
+        size = sizeof(studyTags) / sizeof(DicomTag);
+        break;
+
+      case ResourceType_Series:
+        tags = seriesTags;
+        size = sizeof(seriesTags) / sizeof(DicomTag);
+        break;
+
+      case ResourceType_Instance:
+        tags = instanceTags;
+        size = sizeof(instanceTags) / sizeof(DicomTag);
+        break;
+
+      default:
+        throw OrthancException(ErrorCode_ParameterOutOfRange);
+    }
+  }
+
+
+  void DicomMap::SetValue(uint16_t group, 
+                          uint16_t element, 
+                          DicomValue* value)
+  {
+    DicomTag tag(group, element);
+    Map::iterator it = map_.find(tag);
+
+    if (it != map_.end())
+    {
+      delete it->second;
+      it->second = value;
+    }
+    else
+    {
+      map_.insert(std::make_pair(tag, value));
+    }
+  }
+
+  void DicomMap::SetValue(DicomTag tag, 
+                          DicomValue* value)
+  {
+    SetValue(tag.GetGroup(), tag.GetElement(), value);
+  }
+
+
+
+
+  void DicomMap::Clear()
+  {
+    for (Map::iterator it = map_.begin(); it != map_.end(); ++it)
+    {
+      delete it->second;
+    }
+
+    map_.clear();
+  }
+
+
+  void DicomMap::ExtractTags(DicomMap& result,
+                             const DicomTag* tags,
+                             size_t count) const
+  {
+    result.Clear();
+
+    for (unsigned int i = 0; i < count; i++)
+    {
+      Map::const_iterator it = map_.find(tags[i]);
+      if (it != map_.end())
+      {
+        result.SetValue(it->first, it->second->Clone());
+      }
+    }
+  }
+
+
+  void DicomMap::ExtractPatientInformation(DicomMap& result) const
+  {
+    ExtractTags(result, patientTags, sizeof(patientTags) / sizeof(DicomTag));
+  }
+
+  void DicomMap::ExtractStudyInformation(DicomMap& result) const
+  {
+    ExtractTags(result, studyTags, sizeof(studyTags) / sizeof(DicomTag));
+  }
+
+  void DicomMap::ExtractSeriesInformation(DicomMap& result) const
+  {
+    ExtractTags(result, seriesTags, sizeof(seriesTags) / sizeof(DicomTag));
+  }
+
+  void DicomMap::ExtractInstanceInformation(DicomMap& result) const
+  {
+    ExtractTags(result, instanceTags, sizeof(instanceTags) / sizeof(DicomTag));
+  }
+
+
+
+  DicomMap* DicomMap::Clone() const
+  {
+    std::auto_ptr<DicomMap> result(new DicomMap);
+
+    for (Map::const_iterator it = map_.begin(); it != map_.end(); ++it)
+    {
+      result->map_.insert(std::make_pair(it->first, it->second->Clone()));
+    }
+
+    return result.release();
+  }
+
+
+  void DicomMap::Assign(const DicomMap& other)
+  {
+    Clear();
+
+    for (Map::const_iterator it = other.map_.begin(); it != other.map_.end(); ++it)
+    {
+      map_.insert(std::make_pair(it->first, it->second->Clone()));
+    }
+  }
+
+
+  const DicomValue& DicomMap::GetValue(const DicomTag& tag) const
+  {
+    const DicomValue* value = TestAndGetValue(tag);
+
+    if (value)
+    {
+      return *value;
+    }
+    else
+    {
+      throw OrthancException(ErrorCode_InexistentTag);
+    }
+  }
+
+
+  const DicomValue* DicomMap::TestAndGetValue(const DicomTag& tag) const
+  {
+    Map::const_iterator it = map_.find(tag);
+
+    if (it == map_.end())
+    {
+      return NULL;
+    }
+    else
+    {
+      return it->second;
+    }
+  }
+
+
+  void DicomMap::Remove(const DicomTag& tag) 
+  {
+    Map::iterator it = map_.find(tag);
+    if (it != map_.end())
+    {
+      delete it->second;
+      map_.erase(it);
+    }
+  }
+
+
+  static void SetupFindTemplate(DicomMap& result,
+                                const DicomTag* tags,
+                                size_t count) 
+  {
+    result.Clear();
+
+    for (size_t i = 0; i < count; i++)
+    {
+      result.SetValue(tags[i], "", false);
+    }
+  }
+
+  void DicomMap::SetupFindPatientTemplate(DicomMap& result)
+  {
+    SetupFindTemplate(result, patientTags, sizeof(patientTags) / sizeof(DicomTag));
+  }
+
+  void DicomMap::SetupFindStudyTemplate(DicomMap& result)
+  {
+    SetupFindTemplate(result, studyTags, sizeof(studyTags) / sizeof(DicomTag));
+    result.SetValue(DICOM_TAG_ACCESSION_NUMBER, "", false);
+    result.SetValue(DICOM_TAG_PATIENT_ID, "", false);
+
+    // These main DICOM tags are only indirectly related to the
+    // General Study Module, remove them
+    result.Remove(DICOM_TAG_INSTITUTION_NAME);
+    result.Remove(DICOM_TAG_REQUESTING_PHYSICIAN);
+    result.Remove(DICOM_TAG_REQUESTED_PROCEDURE_DESCRIPTION);
+  }
+
+  void DicomMap::SetupFindSeriesTemplate(DicomMap& result)
+  {
+    SetupFindTemplate(result, seriesTags, sizeof(seriesTags) / sizeof(DicomTag));
+    result.SetValue(DICOM_TAG_ACCESSION_NUMBER, "", false);
+    result.SetValue(DICOM_TAG_PATIENT_ID, "", false);
+    result.SetValue(DICOM_TAG_STUDY_INSTANCE_UID, "", false);
+
+    // These tags are considered as "main" by Orthanc, but are not in the Series module
+    result.Remove(DicomTag(0x0008, 0x0070));  // Manufacturer
+    result.Remove(DicomTag(0x0008, 0x1010));  // Station name
+    result.Remove(DicomTag(0x0018, 0x0024));  // Sequence name
+    result.Remove(DICOM_TAG_CARDIAC_NUMBER_OF_IMAGES);
+    result.Remove(DICOM_TAG_IMAGES_IN_ACQUISITION);
+    result.Remove(DICOM_TAG_NUMBER_OF_SLICES);
+    result.Remove(DICOM_TAG_NUMBER_OF_TEMPORAL_POSITIONS);
+    result.Remove(DICOM_TAG_NUMBER_OF_TIME_SLICES);
+    result.Remove(DICOM_TAG_IMAGE_ORIENTATION_PATIENT);
+    result.Remove(DICOM_TAG_SERIES_TYPE);
+    result.Remove(DICOM_TAG_ACQUISITION_DEVICE_PROCESSING_DESCRIPTION);
+    result.Remove(DICOM_TAG_CONTRAST_BOLUS_AGENT);
+  }
+
+  void DicomMap::SetupFindInstanceTemplate(DicomMap& result)
+  {
+    SetupFindTemplate(result, instanceTags, sizeof(instanceTags) / sizeof(DicomTag));
+    result.SetValue(DICOM_TAG_ACCESSION_NUMBER, "", false);
+    result.SetValue(DICOM_TAG_PATIENT_ID, "", false);
+    result.SetValue(DICOM_TAG_STUDY_INSTANCE_UID, "", false);
+    result.SetValue(DICOM_TAG_SERIES_INSTANCE_UID, "", false);
+  }
+
+
+  void DicomMap::CopyTagIfExists(const DicomMap& source,
+                                 const DicomTag& tag)
+  {
+    if (source.HasTag(tag))
+    {
+      SetValue(tag, source.GetValue(tag));
+    }
+  }
+
+
+  bool DicomMap::IsMainDicomTag(const DicomTag& tag, ResourceType level)
+  {
+    DicomTag *tags = NULL;
+    size_t size;
+
+    switch (level)
+    {
+      case ResourceType_Patient:
+        tags = patientTags;
+        size = sizeof(patientTags) / sizeof(DicomTag);
+        break;
+
+      case ResourceType_Study:
+        tags = studyTags;
+        size = sizeof(studyTags) / sizeof(DicomTag);
+        break;
+
+      case ResourceType_Series:
+        tags = seriesTags;
+        size = sizeof(seriesTags) / sizeof(DicomTag);
+        break;
+
+      case ResourceType_Instance:
+        tags = instanceTags;
+        size = sizeof(instanceTags) / sizeof(DicomTag);
+        break;
+
+      default:
+        throw OrthancException(ErrorCode_ParameterOutOfRange);
+    }
+
+    for (size_t i = 0; i < size; i++)
+    {
+      if (tags[i] == tag)
+      {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  bool DicomMap::IsMainDicomTag(const DicomTag& tag)
+  {
+    return (IsMainDicomTag(tag, ResourceType_Patient) ||
+            IsMainDicomTag(tag, ResourceType_Study) ||
+            IsMainDicomTag(tag, ResourceType_Series) ||
+            IsMainDicomTag(tag, ResourceType_Instance));
+  }
+
+
+  void DicomMap::GetMainDicomTagsInternal(std::set<DicomTag>& result, ResourceType level)
+  {
+    DicomTag *tags = NULL;
+    size_t size;
+
+    switch (level)
+    {
+      case ResourceType_Patient:
+        tags = patientTags;
+        size = sizeof(patientTags) / sizeof(DicomTag);
+        break;
+
+      case ResourceType_Study:
+        tags = studyTags;
+        size = sizeof(studyTags) / sizeof(DicomTag);
+        break;
+
+      case ResourceType_Series:
+        tags = seriesTags;
+        size = sizeof(seriesTags) / sizeof(DicomTag);
+        break;
+
+      case ResourceType_Instance:
+        tags = instanceTags;
+        size = sizeof(instanceTags) / sizeof(DicomTag);
+        break;
+
+      default:
+        throw OrthancException(ErrorCode_ParameterOutOfRange);
+    }
+
+    for (size_t i = 0; i < size; i++)
+    {
+      result.insert(tags[i]);
+    }
+  }
+
+
+  void DicomMap::GetMainDicomTags(std::set<DicomTag>& result, ResourceType level)
+  {
+    result.clear();
+    GetMainDicomTagsInternal(result, level);
+  }
+
+
+  void DicomMap::GetMainDicomTags(std::set<DicomTag>& result)
+  {
+    result.clear();
+    GetMainDicomTagsInternal(result, ResourceType_Patient);
+    GetMainDicomTagsInternal(result, ResourceType_Study);
+    GetMainDicomTagsInternal(result, ResourceType_Series);
+    GetMainDicomTagsInternal(result, ResourceType_Instance);
+  }
+
+
+  void DicomMap::GetTags(std::set<DicomTag>& tags) const
+  {
+    tags.clear();
+
+    for (Map::const_iterator it = map_.begin();
+         it != map_.end(); ++it)
+    {
+      tags.insert(it->first);
+    }
+  }
+
+
+  static uint16_t ReadUnsignedInteger16(const char* dicom)
+  {
+    return le16toh(*reinterpret_cast<const uint16_t*>(dicom));
+  }
+
+
+  static uint32_t ReadUnsignedInteger32(const char* dicom)
+  {
+    return le32toh(*reinterpret_cast<const uint32_t*>(dicom));
+  }
+
+
+  static bool ValidateTag(const ValueRepresentation& vr,
+                          const std::string& value)
+  {
+    switch (vr)
+    {
+      case ValueRepresentation_ApplicationEntity:
+        return value.size() <= 16;
+
+      case ValueRepresentation_AgeString:
+        return (value.size() == 4 &&
+                isdigit(value[0]) &&
+                isdigit(value[1]) &&
+                isdigit(value[2]) &&
+                (value[3] == 'D' || value[3] == 'W' || value[3] == 'M' || value[3] == 'Y'));
+
+      case ValueRepresentation_AttributeTag:
+        return value.size() == 4;
+
+      case ValueRepresentation_CodeString:
+        return value.size() <= 16;
+
+      case ValueRepresentation_Date:
+        return value.size() <= 18;
+
+      case ValueRepresentation_DecimalString:
+        return value.size() <= 16;
+
+      case ValueRepresentation_DateTime:
+        return value.size() <= 54;
+
+      case ValueRepresentation_FloatingPointSingle:
+        return value.size() == 4;
+
+      case ValueRepresentation_FloatingPointDouble:
+        return value.size() == 8;
+
+      case ValueRepresentation_IntegerString:
+        return value.size() <= 12;
+
+      case ValueRepresentation_LongString:
+        return value.size() <= 64;
+
+      case ValueRepresentation_LongText:
+        return value.size() <= 10240;
+
+      case ValueRepresentation_OtherByte:
+        return true;
+      
+      case ValueRepresentation_OtherDouble:
+        return value.size() <= (static_cast<uint64_t>(1) << 32) - 8;
+
+      case ValueRepresentation_OtherFloat:
+        return value.size() <= (static_cast<uint64_t>(1) << 32) - 4;
+
+      case ValueRepresentation_OtherLong:
+        return true;
+
+      case ValueRepresentation_OtherWord:
+        return true;
+
+      case ValueRepresentation_PersonName:
+        return true;
+
+      case ValueRepresentation_ShortString:
+        return value.size() <= 16;
+
+      case ValueRepresentation_SignedLong:
+        return value.size() == 4;
+
+      case ValueRepresentation_Sequence:
+        return true;
+
+      case ValueRepresentation_SignedShort:
+        return value.size() == 2;
+
+      case ValueRepresentation_ShortText:
+        return value.size() <= 1024;
+
+      case ValueRepresentation_Time:
+        return value.size() <= 28;
+
+      case ValueRepresentation_UnlimitedCharacters:
+        return value.size() <= (static_cast<uint64_t>(1) << 32) - 2;
+
+      case ValueRepresentation_UniqueIdentifier:
+        return value.size() <= 64;
+
+      case ValueRepresentation_UnsignedLong:
+        return value.size() == 4;
+
+      case ValueRepresentation_Unknown:
+        return true;
+
+      case ValueRepresentation_UniversalResource:
+        return value.size() <= (static_cast<uint64_t>(1) << 32) - 2;
+
+      case ValueRepresentation_UnsignedShort:
+        return value.size() == 2;
+
+      case ValueRepresentation_UnlimitedText:
+        return value.size() <= (static_cast<uint64_t>(1) << 32) - 2;
+
+      default:
+        // Assume unsupported tags are OK
+        return true;
+    }
+  }
+
+
+  static void RemoveTagPadding(std::string& value,
+                               const ValueRepresentation& vr)
+  {
+    /**
+     * Remove padding from character strings, if need be. For the time
+     * being, only the UI VR is supported.
+     * http://dicom.nema.org/medical/dicom/current/output/chtml/part05/sect_6.2.html
+     **/
+
+    switch (vr)
+    {
+      case ValueRepresentation_UniqueIdentifier:
+      {
+        /**
+         * "Values with a VR of UI shall be padded with a single
+         * trailing NULL (00H) character when necessary to achieve even
+         * length."
+         **/
+
+        if (!value.empty() &&
+            value[value.size() - 1] == '\0')
+        {
+          value.resize(value.size() - 1);
+        }
+
+        break;
+      }
+
+      /**
+       * TODO implement other VR
+       **/
+
+      default:
+        // No padding is applicable to this VR
+        break;
+    }
+  }
+
+
+  static bool ReadNextTag(DicomTag& tag,
+                          ValueRepresentation& vr,
+                          std::string& value,
+                          const char* dicom,
+                          size_t size,
+                          size_t& position)
+  {
+    /**
+     * http://dicom.nema.org/medical/dicom/current/output/chtml/part05/chapter_7.html#sect_7.1.2
+     * This function reads a data element with Explicit VR encoded using Little-Endian.
+     **/
+
+    if (position + 6 > size)
+    {
+      return false;
+    }
+
+    tag = DicomTag(ReadUnsignedInteger16(dicom + position),
+                   ReadUnsignedInteger16(dicom + position + 2));
+
+    vr = StringToValueRepresentation(std::string(dicom + position + 4, 2), true);
+    if (vr == ValueRepresentation_NotSupported)
+    {
+      return false;
+    }
+
+    if (vr == ValueRepresentation_OtherByte ||
+        vr == ValueRepresentation_OtherDouble ||
+        vr == ValueRepresentation_OtherFloat ||
+        vr == ValueRepresentation_OtherLong ||
+        vr == ValueRepresentation_OtherWord ||
+        vr == ValueRepresentation_Sequence ||
+        vr == ValueRepresentation_UnlimitedCharacters ||
+        vr == ValueRepresentation_UniversalResource ||
+        vr == ValueRepresentation_UnlimitedText ||
+        vr == ValueRepresentation_Unknown)    // Note that "UN" should never appear in the Meta Information
+    {
+      if (position + 12 > size)
+      {
+        return false;
+      }
+
+      uint32_t length = ReadUnsignedInteger32(dicom + position + 8);
+
+      if (position + 12 + length > size)
+      {
+        return false;
+      }
+
+      value.assign(dicom + position + 12, length);
+      position += (12 + length);
+    }
+    else
+    {
+      if (position + 8 > size)
+      {
+        return false;
+      }
+
+      uint16_t length = ReadUnsignedInteger16(dicom + position + 6);
+
+      if (position + 8 + length > size)
+      {
+        return false;
+      }
+
+      value.assign(dicom + position + 8, length);
+      position += (8 + length);
+    }
+
+    if (!ValidateTag(vr, value))
+    {
+      return false;
+    }
+
+    RemoveTagPadding(value, vr);
+
+    return true;
+  }
+
+
+  bool DicomMap::ParseDicomMetaInformation(DicomMap& result,
+                                           const char* dicom,
+                                           size_t size)
+  {
+    /**
+     * http://dicom.nema.org/medical/dicom/current/output/chtml/part10/chapter_7.html
+     * According to Table 7.1-1, besides the "DICM" DICOM prefix, the
+     * file preamble (i.e. dicom[0..127]) should not be taken into
+     * account to determine whether the file is or is not a DICOM file.
+     **/
+
+    if (size < 132 ||
+        dicom[128] != 'D' ||
+        dicom[129] != 'I' ||
+        dicom[130] != 'C' ||
+        dicom[131] != 'M')
+    {
+      return false;
+    }
+
+
+    /**
+     * The DICOM File Meta Information must be encoded using the
+     * Explicit VR Little Endian Transfer Syntax
+     * (UID=1.2.840.10008.1.2.1).
+     **/
+
+    result.Clear();
+
+    // First, we read the "File Meta Information Group Length" tag
+    // (0002,0000) to know where to stop reading the meta header
+    size_t position = 132;
+
+    DicomTag tag(0x0000, 0x0000);  // Dummy initialization
+    ValueRepresentation vr;
+    std::string value;
+    if (!ReadNextTag(tag, vr, value, dicom, size, position) ||
+        tag.GetGroup() != 0x0002 ||
+        tag.GetElement() != 0x0000 ||
+        vr != ValueRepresentation_UnsignedLong ||
+        value.size() != 4)
+    {
+      return false;
+    }
+
+    size_t stopPosition = position + ReadUnsignedInteger32(value.c_str());
+    if (stopPosition > size)
+    {
+      return false;
+    }
+
+    while (position < stopPosition)
+    {
+      if (ReadNextTag(tag, vr, value, dicom, size, position))
+      {
+        result.SetValue(tag, value, IsBinaryValueRepresentation(vr));
+      }
+      else
+      {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+
+  static std::string ValueAsString(const DicomMap& summary,
+                                   const DicomTag& tag)
+  {
+    const DicomValue& value = summary.GetValue(tag);
+    if (value.IsNull())
+    {
+      return "(null)";
+    }
+    else
+    {
+      return value.GetContent();
+    }
+  }
+
+
+  void DicomMap::LogMissingTagsForStore() const
+  {
+    std::string s, t;
+
+    if (HasTag(DICOM_TAG_PATIENT_ID))
+    {
+      if (t.size() > 0)
+        t += ", ";
+      t += "PatientID=" + ValueAsString(*this, DICOM_TAG_PATIENT_ID);
+    }
+    else
+    {
+      if (s.size() > 0)
+        s += ", ";
+      s += "PatientID";
+    }
+
+    if (HasTag(DICOM_TAG_STUDY_INSTANCE_UID))
+    {
+      if (t.size() > 0)
+        t += ", ";
+      t += "StudyInstanceUID=" + ValueAsString(*this, DICOM_TAG_STUDY_INSTANCE_UID);
+    }
+    else
+    {
+      if (s.size() > 0)
+        s += ", ";
+      s += "StudyInstanceUID";
+    }
+
+    if (HasTag(DICOM_TAG_SERIES_INSTANCE_UID))
+    {
+      if (t.size() > 0)
+        t += ", ";
+      t += "SeriesInstanceUID=" + ValueAsString(*this, DICOM_TAG_SERIES_INSTANCE_UID);
+    }
+    else
+    {
+      if (s.size() > 0)
+        s += ", ";
+      s += "SeriesInstanceUID";
+    }
+
+    if (HasTag(DICOM_TAG_SOP_INSTANCE_UID))
+    {
+      if (t.size() > 0)
+        t += ", ";
+      t += "SOPInstanceUID=" + ValueAsString(*this, DICOM_TAG_SOP_INSTANCE_UID);
+    }
+    else
+    {
+      if (s.size() > 0)
+        s += ", ";
+      s += "SOPInstanceUID";
+    }
+
+    if (t.size() == 0)
+    {
+      LOG(ERROR) << "Store has failed because all the required tags (" << s << ") are missing (is it a DICOMDIR file?)";
+    }
+    else
+    {
+      LOG(ERROR) << "Store has failed because required tags (" << s << ") are missing for the following instance: " << t;
+    }
+  }
+
+
+  bool DicomMap::CopyToString(std::string& result,
+                              const DicomTag& tag,
+                              bool allowBinary) const
+  {
+    const DicomValue* value = TestAndGetValue(tag);
+
+    if (value == NULL)
+    {
+      return false;
+    }
+    else
+    {
+      return value->CopyToString(result, allowBinary);
+    }
+  }
+    
+  bool DicomMap::ParseInteger32(int32_t& result,
+                                const DicomTag& tag) const
+  {
+    const DicomValue* value = TestAndGetValue(tag);
+
+    if (value == NULL)
+    {
+      return false;
+    }
+    else
+    {
+      return value->ParseInteger32(result);
+    }
+  }
+
+  bool DicomMap::ParseInteger64(int64_t& result,
+                                const DicomTag& tag) const
+  {
+    const DicomValue* value = TestAndGetValue(tag);
+
+    if (value == NULL)
+    {
+      return false;
+    }
+    else
+    {
+      return value->ParseInteger64(result);
+    }
+  }
+
+  bool DicomMap::ParseUnsignedInteger32(uint32_t& result,
+                                        const DicomTag& tag) const
+  {
+    const DicomValue* value = TestAndGetValue(tag);
+
+    if (value == NULL)
+    {
+      return false;
+    }
+    else
+    {
+      return value->ParseUnsignedInteger32(result);
+    }
+  }
+
+  bool DicomMap::ParseUnsignedInteger64(uint64_t& result,
+                                        const DicomTag& tag) const
+  {
+    const DicomValue* value = TestAndGetValue(tag);
+
+    if (value == NULL)
+    {
+      return false;
+    }
+    else
+    {
+      return value->ParseUnsignedInteger64(result);
+    }
+  }
+
+  bool DicomMap::ParseFloat(float& result,
+                            const DicomTag& tag) const
+  {
+    const DicomValue* value = TestAndGetValue(tag);
+
+    if (value == NULL)
+    {
+      return false;
+    }
+    else
+    {
+      return value->ParseFloat(result);
+    }
+  }
+
+  bool DicomMap::ParseDouble(double& result,
+                             const DicomTag& tag) const
+  {
+    const DicomValue* value = TestAndGetValue(tag);
+
+    if (value == NULL)
+    {
+      return false;
+    }
+    else
+    {
+      return value->ParseDouble(result);
+    }
+  }
+}