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comparison OrthancFramework/Sources/DicomFormat/DicomStreamReader.h @ 4220:92a21efa5c96

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reorganization of DicomStreamReader
author Sebastien Jodogne <s.jodogne@gmail.com>
date Wed, 30 Sep 2020 15:33:47 +0200
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children e4c0218b6b23
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4219:b8ed2852a35d 4220:92a21efa5c96
1 /**
2 * Orthanc - A Lightweight, RESTful DICOM Store
3 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
4 * Department, University Hospital of Liege, Belgium
5 * Copyright (C) 2017-2020 Osimis S.A., Belgium
6 *
7 * This program is free software: you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public License
9 * as published by the Free Software Foundation, either version 3 of
10 * the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this program. If not, see
19 * <http://www.gnu.org/licenses/>.
20 **/
21
22
23 #pragma once
24
25 #include "DicomTag.h"
26 #include "StreamBlockReader.h"
27
28 namespace Orthanc
29 {
30 /**
31 * This class parses a stream containing a DICOM instance. It does
32 * *not* support the visit of sequences (it only works at the first
33 * level of the hierarchy), and as a consequence, it doesn't give
34 * access to the pixel data of compressed transfer syntaxes.
35 **/
36 class DicomStreamReader : public boost::noncopyable
37 {
38 public:
39 class IVisitor : public boost::noncopyable
40 {
41 public:
42 virtual ~IVisitor()
43 {
44 }
45
46 // The data from this function will always be Little Endian (as
47 // specified by the DICOM standard)
48 virtual void VisitMetaHeaderTag(const DicomTag& tag,
49 const ValueRepresentation& vr,
50 const std::string& value) = 0;
51
52 virtual void VisitTransferSyntax(DicomTransferSyntax transferSyntax) = 0;
53
54 // Return "false" to stop processing
55 virtual bool VisitDatasetTag(const DicomTag& tag,
56 const ValueRepresentation& vr,
57 const std::string& value,
58 bool isLittleEndian) = 0;
59 };
60
61 private:
62 enum State
63 {
64 State_Preamble,
65 State_MetaHeader,
66 State_DatasetTag,
67 State_SequenceExplicitLength,
68 State_SequenceExplicitValue,
69 State_DatasetExplicitLength,
70 State_DatasetValue,
71 State_Done
72 };
73
74 StreamBlockReader reader_;
75 State state_;
76 DicomTransferSyntax transferSyntax_;
77 DicomTag previousTag_;
78 DicomTag danglingTag_; // Root-level tag
79 ValueRepresentation danglingVR_;
80 unsigned int sequenceDepth_;
81
82 bool IsLittleEndian() const;
83
84 void HandlePreamble(IVisitor& visitor,
85 const std::string& block);
86
87 void HandleMetaHeader(IVisitor& visitor,
88 const std::string& block);
89
90 void HandleDatasetTag(const std::string& block,
91 const DicomTag& untilTag);
92
93 void HandleDatasetExplicitLength(uint32_t length);
94
95 void HandleDatasetExplicitLength(const std::string& block);
96
97 void HandleSequenceExplicitLength(const std::string& block);
98
99 void HandleSequenceExplicitValue();
100
101 void HandleDatasetValue(IVisitor& visitor,
102 const std::string& block);
103
104 public:
105 DicomStreamReader(std::istream& stream);
106
107 /**
108 * Consume all the available bytes from the input stream, until
109 * end-of-stream is reached or the current tag is ">= untilTag".
110 * This method can be invoked several times, as more bytes are
111 * available from the input stream. To check if the DICOM stream
112 * is fully parsed until the goal tag, call "IsDone()".
113 **/
114 void Consume(IVisitor& visitor,
115 const DicomTag& untilTag);
116
117 void Consume(IVisitor& visitor);
118
119 bool IsDone() const
120 {
121 return (state_ == State_Done);
122 }
123
124 uint64_t GetProcessedBytes() const
125 {
126 return reader_.GetProcessedBytes();
127 }
128 };
129 }