PNGChunk (JHOVE - JSTOR/Harvard Object Validation Environment 1.16.0 API)

java.lang.Object
- com.mcgath.jhove.module.png.PNGChunk

Direct Known Subclasses:

BkgdChunk, ChrmChunk, GamaChunk, GeneralTextChunk, HistChunk, IccpChunk, IdatChunk, IendChunk, IhdrChunk, PhysChunk, PlteChunk, SbitChunk, SpltChunk, SrgbChunk, TimeChunk, TrnsChunk, UnknownChunk
```
public abstract class PNGChunk
extends Object
```

Field Summary

Fields
Modifier and Type	Field and Description
`protected DataInputStream`	`_dstream` The invoking module's input stream
`protected PngModule`	`_module` The invoking module
`protected NisoImageMetadata`	`_nisoMetadata`
`protected List<Property>`	`_propList`
`protected boolean`	`ancillary`
`protected static int`	`bKGD_HEAD_SIG`
`protected static int`	`cHRM_HEAD_SIG`
`protected char[]`	`chunkData`
`protected int`	`chunkType`
`protected CRC32`	`crc`
`protected boolean`	`duplicateAllowed`
`protected static int`	`gAMA_HEAD_SIG`
`protected static int`	`hIST_HEAD_SIG`
`protected static int`	`iCCP_HEAD_SIG`
`protected static int`	`IDAT_HEAD_SIG`
`protected static int`	`IEND_HEAD_SIG`
`protected static int`	`IHDR_HEAD_SIG`
`protected static int`	`iTXt_HEAD_SIG`
`protected long`	`length`
`protected static int`	`pHYs_HEAD_SIG`
`protected static int`	`PLTE_HEAD_SIG`
`protected static int`	`sBIT_HEAD_SIG`
`protected static int`	`sPLT_HEAD_SIG`
`protected static int`	`sRGB_HEAD_SIG`
`protected static int`	`tEXt_HEAD_SIG`
`protected static int`	`tIME_HEAD_SIG`
`protected static int`	`tRNS_HEAD_SIG`
`protected static int`	`zTXt_HEAD_SIG`

Constructor Summary

Constructors
Constructor and Description

PNGChunk()

Constructors
Constructor and Description
`PNGChunk()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`String`	`chunkTypeString()`
`char[]`	`getChunkData()`
`int`	`getChunkType()`
`long`	`getCRC()`
`long`	`getLength()`
`static PNGChunk`	`makePNGChunk(long length, int sig)` Construct a PNGChunk object of the appropriate subtype based on the chunk type.
`void`	`processChunk(RepInfo info)` Process a chunk.
`void`	`processChunkCommon(RepInfo info)` Common code to call at the start of every processChunk method.
`long`	`readCRC()` Read the CRC itself.
`int`	`readUnsignedByte()` Read a single byte and update the CRC
`long`	`readUnsignedInt()` Read a 4-byte unsigned integer and update the CRC
`int`	`readUnsignedShort()` Read a 2-byte unsigned integer and update the CRC
`void`	`setInputStream(DataInputStream dstrm)` Give the chunk a reference to the data stream.
`void`	`setModule(PngModule mdl)` Give the chunk a reference to the PNG module.
`void`	`setNisoMetadata(NisoImageMetadata nmd)` Hand the chunk the NISO metadata object if it needs to put information into it.
`void`	`setPropertyList(List<Property> lst)` Hand the main property list to the chunk
`void`	`skipBytes(int count)` Skip over all the bytes, updating the CRC

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

- Field Detail
  - length
```
protected long length
```
  - chunkType
```
protected int chunkType
```
  - chunkData
```
protected char[] chunkData
```
  - crc
```
protected CRC32 crc
```
  - ancillary
```
protected boolean ancillary
```
  - duplicateAllowed
```
protected boolean duplicateAllowed
```
  - _nisoMetadata
```
protected NisoImageMetadata _nisoMetadata
```
  - _module
```
protected PngModule _module
```
    The invoking module
  - _dstream
```
protected DataInputStream _dstream
```
    The invoking module's input stream
  - _propList
```
protected List<Property> _propList
```
  - IHDR_HEAD_SIG
```
protected static final int IHDR_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - PLTE_HEAD_SIG
```
protected static final int PLTE_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - IDAT_HEAD_SIG
```
protected static final int IDAT_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - IEND_HEAD_SIG
```
protected static final int IEND_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - cHRM_HEAD_SIG
```
protected static final int cHRM_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - gAMA_HEAD_SIG
```
protected static final int gAMA_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - iCCP_HEAD_SIG
```
protected static final int iCCP_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - sBIT_HEAD_SIG
```
protected static final int sBIT_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - sRGB_HEAD_SIG
```
protected static final int sRGB_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - tEXt_HEAD_SIG
```
protected static final int tEXt_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - zTXt_HEAD_SIG
```
protected static final int zTXt_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - iTXt_HEAD_SIG
```
protected static final int iTXt_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - bKGD_HEAD_SIG
```
protected static final int bKGD_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - hIST_HEAD_SIG
```
protected static final int hIST_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - pHYs_HEAD_SIG
```
protected static final int pHYs_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - sPLT_HEAD_SIG
```
protected static final int sPLT_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - tIME_HEAD_SIG
```
protected static final int tIME_HEAD_SIG
```
    See Also:
    
    Constant Field Values
  - tRNS_HEAD_SIG
```
protected static final int tRNS_HEAD_SIG
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - PNGChunk
```
public PNGChunk()
```
- Method Detail
  - makePNGChunk
```
public static PNGChunk makePNGChunk(long length,
                                    int sig)
```
    Construct a PNGChunk object of the appropriate subtype based on the chunk type.
  - setNisoMetadata
```
public void setNisoMetadata(NisoImageMetadata nmd)
```
    Hand the chunk the NISO metadata object if it needs to put information into it.
  - setPropertyList
```
public void setPropertyList(List<Property> lst)
```
    Hand the main property list to the chunk
  - setModule
```
public void setModule(PngModule mdl)
```
    Give the chunk a reference to the PNG module.
  - setInputStream
```
public void setInputStream(DataInputStream dstrm)
```
    Give the chunk a reference to the data stream.
  - getLength
```
public long getLength()
```
  - getChunkType
```
public int getChunkType()
```
  - getChunkData
```
public char[] getChunkData()
```
  - getCRC
```
public long getCRC()
```
  - processChunk
```
public void processChunk(RepInfo info)
                  throws Exception
```
    Process a chunk. When this is called, the input stream needs to have read the type and length and be positioned at the start of the data. The default behavior is to eat the chunk. This should be the behavior only for UnknownChunk when we're done.
    
    Throws:
    
    Exception
  - processChunkCommon
```
public void processChunkCommon(RepInfo info)
                        throws PNGException
```
    Common code to call at the start of every processChunk method.
    
    Throws:
    
    PNGException
  - readUnsignedInt
```
public long readUnsignedInt()
                     throws IOException
```
    Read a 4-byte unsigned integer and update the CRC
    
    Throws:
    
    IOException
  - readUnsignedShort
```
public int readUnsignedShort()
                      throws IOException
```
    Read a 2-byte unsigned integer and update the CRC
    
    Throws:
    
    IOException
  - readUnsignedByte
```
public int readUnsignedByte()
                     throws IOException
```
    Read a single byte and update the CRC
    
    Throws:
    
    IOException
  - skipBytes
```
public void skipBytes(int count)
               throws IOException
```
    Skip over all the bytes, updating the CRC
    
    Throws:
    
    IOException
  - readCRC
```
public long readCRC()
             throws IOException
```
    Read the CRC itself. Naturally, this doesn't update the CRC.
    
    Throws:
    
    IOException
  - chunkTypeString
```
public String chunkTypeString()
```

Class PNGChunk

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

length

chunkType

chunkData

crc

ancillary

duplicateAllowed

_nisoMetadata

_module

_dstream

_propList

IHDR_HEAD_SIG

PLTE_HEAD_SIG

IDAT_HEAD_SIG

IEND_HEAD_SIG

cHRM_HEAD_SIG

gAMA_HEAD_SIG

iCCP_HEAD_SIG

sBIT_HEAD_SIG

sRGB_HEAD_SIG

tEXt_HEAD_SIG

zTXt_HEAD_SIG

iTXt_HEAD_SIG

bKGD_HEAD_SIG

hIST_HEAD_SIG

pHYs_HEAD_SIG

sPLT_HEAD_SIG

tIME_HEAD_SIG

tRNS_HEAD_SIG

Constructor Detail

PNGChunk

Method Detail

makePNGChunk

setNisoMetadata

setPropertyList

setModule

setInputStream

getLength

getChunkType

getChunkData

getCRC

processChunk

processChunkCommon

readUnsignedInt

readUnsignedShort

readUnsignedByte

skipBytes

readCRC

chunkTypeString