JpegModule (JHOVE Validation Modules 1.16.5 API)

java.lang.Object
- ModuleBase
- - edu.harvard.hul.ois.jhove.module.JpegModule

```
public class JpegModule
extends ModuleBase
```
Module for identification and validation of JPEG files. General notes: There is no such thing as a "JPEG file format." There are several commonly used file formats which encapsulate JPEG data and conform to the JPEG stream format. There are also many formats which can encapsulate JPEG data within some larger wrapper; this module does not attempt to recognize them. Only JPEG file formats which are JPEG streams are treated here. A JPEG stream which isn't one of the known file formats will be regarded as well-formed, but not valid. To be valid, a file must conform to one of the following: JFIF, SPIFF, and JPEG/Exif. Other formats may be added in the future. This module uses the JPEG-L method of detecting a marker following a data stream, checking for a 0 high bit rather than an entire 0 byte. So long at no JPEG markers are defined with a value from 0 through 7F, this is valid for all JPEG files. * @author Gary McGath

Field Summary

Fields
Modifier and Type	Field and Description
`protected List<String>`	`_appSegsList`
`protected List<ArithConditioning>`	`_arithCondTables`
`protected int`	`_capability0`
`protected int`	`_capability1`
`protected Checksummer`	`_ckSummer`
`protected List<String>`	`_commentsList`
`protected Set`	`_compressSet`
`protected ChecksumInputStream`	`_cstream`
`protected DataInputStream`	`_dstream`
`protected boolean`	`_exifProfileOK`
`protected Property`	`_exifProp`
`protected List<boolean[]>`	`_expList`
`protected List<Property>`	`_imageList`
`protected Property`	`_imageProp`
`protected List<String>`	`_jpegExtsList`
`protected Property`	`_metadata`
`protected NisoImageMetadata`	`_niso`
`protected int`	`_numScans`
`protected int`	`_numSegments`
`protected List<Property>`	`_primaryImageList`
`protected List<Property>`	`_propList`
`protected List<QuantizationTable>`	`_quantTables`
`protected boolean`	`_reportedJFIF`
`protected boolean`	`_reportedSigMatch`
`protected int`	`_restartInterval`
`protected boolean`	`_seenExif`
`protected boolean`	`_seenJFIF`
`protected boolean`	`_seenJPEGL`
`protected boolean`	`_seenSOF`
`protected boolean`	`_seenSPIFF`
`protected SpiffDir`	`_spiffDir`
`protected List<SRS>`	`_srsList`
`protected Tiling`	`_tiling`
`protected int`	`_units`
`protected int`	`_xDensity`
`protected Property`	`_xmpProp`
`protected int`	`_yDensity`
`protected String`	`exifProfileName`
`protected String`	`jfifProfileName` PRIVATE INSTANCE FIELDS.
`protected String`	`jpeglProfileName`
`protected NumberFormat`	`minorFmt`
`protected String`	`spiffProfileName`

Constructor Summary

Constructors
Constructor and Description

JpegModule()
Instantiate a JpegModule object.

Constructors
Constructor and Description
`JpegModule()` Instantiate a `JpegModule` object.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected Property`	`buildCapProp(RepInfo info)`
`protected Property`	`buildExpandProp(RepInfo info)`
`protected Property`	`buildTilingProp(RepInfo info)`
`void`	`checkSignatures(File file, InputStream stream, RepInfo info)` Check if the digital object conforms to this Module's internal signature information.
`protected static boolean`	`equalArray(int[] a, int[] b)`
`protected void`	`extractExifNisoData(NisoImageMetadata exifData)`
`protected void`	`initNiso()` Initializes the constant portions of the niso metadata.
`protected void`	`initParse()` Initializes the state of the module for parsing.
`int`	`parse(InputStream stream, RepInfo info, int parseIndex)` Parse the content of a purported JPEG stream digital object and store the results in RepInfo.
`protected void`	`readAPP0(RepInfo info)`
`protected void`	`readAPP1(RepInfo info)`
`protected void`	`readAPP8(RepInfo info)`
`protected void`	`readComment(RepInfo info)`
`protected void`	`readDAC(RepInfo info)`
`protected void`	`readDHP(RepInfo info)`
`protected void`	`readDQT(RepInfo info)`
`protected void`	`readDRI(RepInfo info)`
`protected void`	`readDTI(RepInfo info)`
`protected void`	`readDTT(RepInfo info)`
`protected void`	`readEXP(RepInfo info)`
`protected boolean`	`readHeader(RepInfo info)`
`protected void`	`readJPEGExtension(int dbyt, RepInfo info)`
`protected void`	`readSOF(int dbyt, RepInfo info)`
`protected void`	`readSRS(RepInfo info)`
`long`	`readUnsignedInt(DataInputStream stream)` One-argument version of `readUnsignedInt`.
`int`	`readUnsignedShort(DataInputStream stream)` One-argument version of `readUnsignedShort`.
`protected void`	`readVer(RepInfo info)`
`protected Property`	`readXMP(byte[] buf)`
`protected void`	`reportAppExt(int dbyt, RepInfo info)`
`protected boolean`	`skipSegment(RepInfo info)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

jfifProfileName
```
protected String jfifProfileName
```
PRIVATE INSTANCE FIELDS.

spiffProfileName
```
protected String spiffProfileName
```

exifProfileName
```
protected String exifProfileName
```

jpeglProfileName
```
protected String jpeglProfileName
```

minorFmt
```
protected NumberFormat minorFmt
```

_ckSummer
```
protected Checksummer _ckSummer
```

_cstream
```
protected ChecksumInputStream _cstream
```

_dstream
```
protected DataInputStream _dstream
```

_metadata
```
protected Property _metadata
```

_imageProp
```
protected Property _imageProp
```

_exifProp
```
protected Property _exifProp
```

_xmpProp
```
protected Property _xmpProp
```

_niso
```
protected NisoImageMetadata _niso
```

_propList
```
protected List<Property> _propList
```

_imageList
```
protected List<Property> _imageList
```

_tiling
```
protected Tiling _tiling
```

_quantTables

protected List<QuantizationTable> _quantTables

_arithCondTables

protected List<ArithConditioning> _arithCondTables

_srsList
```
protected List<SRS> _srsList
```

_primaryImageList

protected List<Property> _primaryImageList

_numSegments
```
protected int _numSegments
```

_numScans
```
protected int _numScans
```

_restartInterval
```
protected int _restartInterval
```

_seenJFIF
```
protected boolean _seenJFIF
```

_seenSPIFF
```
protected boolean _seenSPIFF
```

_seenJPEGL
```
protected boolean _seenJPEGL
```

_reportedSigMatch
```
protected boolean _reportedSigMatch
```

_spiffDir
```
protected SpiffDir _spiffDir
```

_seenExif
```
protected boolean _seenExif
```

_exifProfileOK
```
protected boolean _exifProfileOK
```

_reportedJFIF
```
protected boolean _reportedJFIF
```

_seenSOF
```
protected boolean _seenSOF
```

_commentsList
```
protected List<String> _commentsList
```

_jpegExtsList
```
protected List<String> _jpegExtsList
```

_appSegsList
```
protected List<String> _appSegsList
```

_expList
```
protected List<boolean[]> _expList
```

_compressSet
```
protected Set _compressSet
```

_capability0
```
protected int _capability0
```

_capability1
```
protected int _capability1
```

_units
```
protected int _units
```

_xDensity
```
protected int _xDensity
```

_yDensity
```
protected int _yDensity
```

Constructor Detail
- JpegModule
```
public JpegModule()
```
  Instantiate a JpegModule object.

Method Detail

checkSignatures
```
public void checkSignatures(File file,
                            InputStream stream,
                            RepInfo info)
                     throws IOException
```
Check if the digital object conforms to this Module's internal signature information.

Parameters:

file - A RandomAccessFile, positioned at its beginning, which is generated from the object to be parsed

stream - An InputStream, positioned at its beginning, which is generated from the object to be parsed

info - A fresh RepInfo object which will be modified to reflect the results of the test

Throws:

IOException

parse
```
public int parse(InputStream stream,
                 RepInfo info,
                 int parseIndex)
          throws IOException
```
Parse the content of a purported JPEG stream digital object and store the results in RepInfo. This function uses the JPEG-L method of detecting a marker following a data stream, checking for a 0 high bit rather than an entire 0 byte. So long at no JPEG markers are defined with a value from 0 through 7F, this is valid for all JPEG files.

Parameters:

stream - An InputStream, positioned at its beginning, which is generated from the object to be parsed

info - A fresh RepInfo object which will be modified to reflect the results of the parsing

parseIndex - Must be 0 in first call to parse. If parse returns a nonzero value, it must be called again with parseIndex equal to that return value.

Throws:

IOException

readUnsignedShort
```
public int readUnsignedShort(DataInputStream stream)
                      throws IOException
```
One-argument version of readUnsignedShort. JPEG is always big-endian, so readUnsignedShort can unambiguously drop its endian argument.

Throws:

IOException

readUnsignedInt
```
public long readUnsignedInt(DataInputStream stream)
                     throws IOException
```
One-argument version of readUnsignedInt. JPEG is always big-endian, so readUnsignedInt can unambiguously drop its endian argument.

Throws:

IOException

initParse
```
protected void initParse()
```
Initializes the state of the module for parsing.

initNiso
```
protected void initNiso()
```
Initializes the constant portions of the niso metadata.

readHeader

protected boolean readHeader(RepInfo info)

readAPP0

protected void readAPP0(RepInfo info)
                 throws IOException

Throws:: IOException

readAPP1

protected void readAPP1(RepInfo info)
                 throws IOException

Throws:: IOException

readAPP8

protected void readAPP8(RepInfo info)
                 throws IOException

Throws:: IOException

readVer

protected void readVer(RepInfo info)
                throws IOException

Throws:: IOException

readDTI

protected void readDTI(RepInfo info)
                throws IOException

Throws:: IOException

readDTT

protected void readDTT(RepInfo info)
                throws IOException

Throws:: IOException

readSRS

protected void readSRS(RepInfo info)
                throws IOException

Throws:: IOException

reportAppExt

protected void reportAppExt(int dbyt,
                            RepInfo info)

readSOF

protected void readSOF(int dbyt,
                       RepInfo info)
                throws IOException

Throws:: IOException

readDHP

protected void readDHP(RepInfo info)
                throws IOException

Throws:: IOException

readEXP

protected void readEXP(RepInfo info)
                throws IOException

Throws:: IOException

readDRI

protected void readDRI(RepInfo info)
                throws IOException

Throws:: IOException

readDQT

protected void readDQT(RepInfo info)
                throws IOException

Throws:: IOException

readDAC

protected void readDAC(RepInfo info)
                throws IOException

Throws:: IOException

readJPEGExtension

protected void readJPEGExtension(int dbyt,
                                 RepInfo info)
                          throws IOException

Throws:: IOException

readComment

protected void readComment(RepInfo info)
                    throws IOException

Throws:: IOException

buildCapProp

protected Property buildCapProp(RepInfo info)

buildTilingProp

protected Property buildTilingProp(RepInfo info)

buildExpandProp

protected Property buildExpandProp(RepInfo info)

readXMP

protected Property readXMP(byte[] buf)

extractExifNisoData

protected void extractExifNisoData(NisoImageMetadata exifData)

skipSegment

protected boolean skipSegment(RepInfo info)
                       throws IOException

Throws:: IOException

equalArray

protected static boolean equalArray(int[] a,
                                    int[] b)

Class JpegModule

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

jfifProfileName

spiffProfileName

exifProfileName

jpeglProfileName

minorFmt

_ckSummer

_cstream

_dstream

_metadata

_imageProp

_exifProp

_xmpProp

_niso

_propList

_imageList

_tiling

_quantTables

_arithCondTables

_srsList

_primaryImageList

_numSegments

_numScans

_restartInterval

_seenJFIF

_seenSPIFF

_seenJPEGL

_reportedSigMatch

_spiffDir

_seenExif

_exifProfileOK

_reportedJFIF

_seenSOF

_commentsList

_jpegExtsList

_appSegsList

_expList

_compressSet

_capability0

_capability1

_units

_xDensity

_yDensity

Constructor Detail

JpegModule

Method Detail

checkSignatures

parse

readUnsignedShort

readUnsignedInt

initParse

initNiso

readHeader

readAPP0

readAPP1

readAPP8

readVer

readDTI

readDTT

readSRS

reportAppExt

readSOF

readDHP

readEXP

readDRI

readDQT

readDAC

readJPEGExtension

readComment

buildCapProp

buildTilingProp

buildExpandProp

readXMP

extractExifNisoData

skipSegment