PngChunk

Fields
Modifier and Type	Field and Description
`(package private) static int`	`CHUNK_IDAT`
`(package private) static int`	`CHUNK_IEND`
`(package private) static int`	`CHUNK_IHDR`
`(package private) static int`	`CHUNK_PLTE`
`(package private) static int`	`CHUNK_tRNS`
`(package private) static int`	`CHUNK_UNKNOWN`
`(package private) static int[]`	`CRC_TABLE`
`(package private) static int`	`DATA_OFFSET`
`(package private) int`	`length`
`(package private) static int`	`LENGTH_FIELD_LENGTH`
`(package private) static int`	`LENGTH_OFFSET`
`(package private) static int`	`MIN_LENGTH`
`(package private) byte[]`	`reference`
`(package private) static int`	`TYPE_FIELD_LENGTH`
`(package private) static byte[]`	`TYPE_IDAT`
`(package private) static byte[]`	`TYPE_IEND`
`(package private) static byte[]`	`TYPE_IHDR`
`(package private) static int`	`TYPE_OFFSET`
`(package private) static byte[]`	`TYPE_PLTE`
`(package private) static byte[]`	`TYPE_tRNS`

Constructors
Constructor and Description
`PngChunk(byte[] reference)` Construct a PngChunk using the reference bytes given.
`PngChunk(int dataLength)` Construct a PngChunk with the specified number of data bytes.

Methods
Modifier and Type	Method and Description
`(package private) boolean`	`checkCRC()` Compute the CRC value for the chunk's data.
`(package private) int`	`computeCRC()` Answer the CRC value of chunk's data.
`(package private) void`	`contributeToString(java.lang.StringBuffer buffer)` Provided so that subclasses can override and add data to the toString() call.
`(package private) int`	`getChunkType()`
`(package private) int`	`getCRC()` Get the CRC value for the chunk's data.
`(package private) byte[]`	`getData()` Get the chunk's data.
`(package private) int`	`getInt16(int offset)` Get the 16-bit integer from the reference byte array at the given offset.
`(package private) int`	`getInt32(int offset)` Get the 32-bit integer from the reference byte array at the given offset.
`(package private) int`	`getLength()` Get the length of the data component of this chunk.
`(package private) byte[]`	`getReference()` Get the PngChunk's reference byteArray;
`(package private) int`	`getSize()` Get the chunk's total size including the length, type, and crc fields.
`(package private) byte[]`	`getTypeBytes()` Get the chunk type.
`(package private) boolean`	`isCritical()`
`(package private) static PngChunk`	`readNextFromStream(LEDataInputStream stream)` Read the next PNG chunk from the input stream given.
`(package private) void`	`setCRC(int value)` Set the CRC value for the chunk's data.
`(package private) void`	`setData(byte[] data)` Set the chunk's data.
`(package private) void`	`setInt16(int offset, int value)` Set the 16-bit integer in the reference byte array at the given offset.
`(package private) void`	`setInt32(int offset, int value)` Set the 32-bit integer in the reference byte array at the given offset.
`(package private) void`	`setLength(int value)` Set the length of the data component of this chunk.
`(package private) void`	`setReference(byte[] reference)` Set the PngChunk's reference byteArray;
`(package private) void`	`setType(byte[] value)` Set the chunk type.
`java.lang.String`	`toString()` Returns a string containing a concise, human-readable description of the receiver.
`(package private) boolean`	`typeMatchesArray(byte[] array)`
`(package private) void`	`validate(PngFileReadState readState, PngIhdrChunk headerChunk)` Answer whether the chunk is a valid PNG chunk.

java.lang.Object
- org.eclipse.swt.internal.image.PngChunk

Direct Known Subclasses:

PngIdatChunk, PngIendChunk, PngIhdrChunk, PngPlteChunk, PngTrnsChunk
```
 class PngChunk
extends java.lang.Object
```
- Structure Diagram

Field Summary

Fields
Modifier and Type Field and Description

(package private) static int CHUNK_IDAT

(package private) static int CHUNK_IEND

(package private) static int CHUNK_IHDR

(package private) static int CHUNK_PLTE

(package private) static int CHUNK_tRNS

(package private) static int CHUNK_UNKNOWN

(package private) static int[] CRC_TABLE

(package private) static int DATA_OFFSET

(package private) int length

(package private) static int LENGTH_FIELD_LENGTH

(package private) static int LENGTH_OFFSET

(package private) static int MIN_LENGTH

(package private) byte[] reference

(package private) static int TYPE_FIELD_LENGTH

(package private) static byte[] TYPE_IDAT

(package private) static byte[] TYPE_IEND

(package private) static byte[] TYPE_IHDR

(package private) static int TYPE_OFFSET

(package private) static byte[] TYPE_PLTE

(package private) static byte[] TYPE_tRNS

Constructor Summary

Constructors
Constructor and Description

PngChunk(byte[] reference)
Construct a PngChunk using the reference bytes given.

PngChunk(int dataLength)
Construct a PngChunk with the specified number of data bytes.

Method Summary

Methods
Modifier and Type Method and Description

(package private) boolean checkCRC()
Compute the CRC value for the chunk's data.

(package private) int computeCRC()
Answer the CRC value of chunk's data.

(package private) void contributeToString(java.lang.StringBuffer buffer)
Provided so that subclasses can override and add data to the toString() call.

(package private) int getChunkType()

(package private) int getCRC()
Get the CRC value for the chunk's data.

(package private) byte[] getData()
Get the chunk's data.

(package private) int getInt16(int offset)
Get the 16-bit integer from the reference byte array at the given offset.

(package private) int getInt32(int offset)
Get the 32-bit integer from the reference byte array at the given offset.

(package private) int getLength()
Get the length of the data component of this chunk.

(package private) byte[] getReference()
Get the PngChunk's reference byteArray;

(package private) int getSize()
Get the chunk's total size including the length, type, and crc fields.

(package private) byte[] getTypeBytes()
Get the chunk type.

(package private) boolean isCritical()

(package private) static PngChunk readNextFromStream(LEDataInputStream stream)
Read the next PNG chunk from the input stream given.

(package private) void setCRC(int value)
Set the CRC value for the chunk's data.

(package private) void setData(byte[] data)
Set the chunk's data.

(package private) void setInt16(int offset, int value)
Set the 16-bit integer in the reference byte array at the given offset.

(package private) void setInt32(int offset, int value)
Set the 32-bit integer in the reference byte array at the given offset.

(package private) void setLength(int value)
Set the length of the data component of this chunk.

(package private) void setReference(byte[] reference)
Set the PngChunk's reference byteArray;

(package private) void setType(byte[] value)
Set the chunk type.

java.lang.String toString()
Returns a string containing a concise, human-readable description of the receiver.

(package private) boolean typeMatchesArray(byte[] array)

(package private) void validate(PngFileReadState readState, PngIhdrChunk headerChunk)
Answer whether the chunk is a valid PNG chunk.

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

- Field Detail
  - reference
```
byte[] reference
```
  - LENGTH_OFFSET
```
static final int LENGTH_OFFSET
```
    See Also:
    Constant Field Values
  - TYPE_OFFSET
```
static final int TYPE_OFFSET
```
    See Also:
    Constant Field Values
  - DATA_OFFSET
```
static final int DATA_OFFSET
```
    See Also:
    Constant Field Values
  - TYPE_FIELD_LENGTH
```
static final int TYPE_FIELD_LENGTH
```
    See Also:
    Constant Field Values
  - LENGTH_FIELD_LENGTH
```
static final int LENGTH_FIELD_LENGTH
```
    See Also:
    Constant Field Values
  - MIN_LENGTH
```
static final int MIN_LENGTH
```
    See Also:
    Constant Field Values
  - CHUNK_UNKNOWN
```
static final int CHUNK_UNKNOWN
```
    See Also:
    Constant Field Values
  - CHUNK_IHDR
```
static final int CHUNK_IHDR
```
    See Also:
    Constant Field Values
  - CHUNK_PLTE
```
static final int CHUNK_PLTE
```
    See Also:
    Constant Field Values
  - CHUNK_IDAT
```
static final int CHUNK_IDAT
```
    See Also:
    Constant Field Values
  - CHUNK_IEND
```
static final int CHUNK_IEND
```
    See Also:
    Constant Field Values
  - CHUNK_tRNS
```
static final int CHUNK_tRNS
```
    See Also:
    Constant Field Values
  - TYPE_IHDR
```
static final byte[] TYPE_IHDR
```
  - TYPE_PLTE
```
static final byte[] TYPE_PLTE
```
  - TYPE_IDAT
```
static final byte[] TYPE_IDAT
```
  - TYPE_IEND
```
static final byte[] TYPE_IEND
```
  - TYPE_tRNS
```
static final byte[] TYPE_tRNS
```
  - CRC_TABLE
```
static final int[] CRC_TABLE
```
  - length
```
int length
```
- Constructor Detail
  - PngChunk
```
PngChunk(byte[] reference)
```
    Construct a PngChunk using the reference bytes given.
  - PngChunk
```
PngChunk(int dataLength)
```
    Construct a PngChunk with the specified number of data bytes.
- Method Detail
  - getReference
```
byte[] getReference()
```
    Get the PngChunk's reference byteArray;
  - setReference
```
void setReference(byte[] reference)
```
    Set the PngChunk's reference byteArray;
  - getInt16
```
int getInt16(int offset)
```
    Get the 16-bit integer from the reference byte array at the given offset.
  - setInt16
```
void setInt16(int offset,
            int value)
```
    Set the 16-bit integer in the reference byte array at the given offset.
  - getInt32
```
int getInt32(int offset)
```
    Get the 32-bit integer from the reference byte array at the given offset.
  - setInt32
```
void setInt32(int offset,
            int value)
```
    Set the 32-bit integer in the reference byte array at the given offset.
  - getLength
```
int getLength()
```
    Get the length of the data component of this chunk. This is not the length of the entire chunk.
  - setLength
```
void setLength(int value)
```
    Set the length of the data component of this chunk. This is not the length of the entire chunk.
  - getTypeBytes
```
byte[] getTypeBytes()
```
    Get the chunk type. This is a four byte value. Each byte should be an ASCII character. The first byte is upper case if the chunk is critical. The second byte is upper case if the chunk is publicly defined. The third byte must be upper case. The fourth byte is upper case if the chunk is unsafe to copy. Public chunk types are defined by the PNG Development Group.
  - setType
```
void setType(byte[] value)
```
    Set the chunk type. This is a four byte value. Each byte should be an ASCII character. The first byte is upper case if the chunk is critical. The second byte is upper case if the chunk is publicly defined. The third byte must be upper case. The fourth byte is upper case if the chunk is unsafe to copy. Public chunk types are defined by the PNG Development Group.
  - getData
```
byte[] getData()
```
    Get the chunk's data.
  - setData
```
void setData(byte[] data)
```
    Set the chunk's data. This method has two side-effects. 1. It will set the length field to be the length of the data array given. 2. It will set the CRC field to the computed CRC value of the data array given.
  - getCRC
```
int getCRC()
```
    Get the CRC value for the chunk's data. Ensure that the length field has a good value before making this call.
  - setCRC
```
void setCRC(int value)
```
    Set the CRC value for the chunk's data. Ensure that the length field has a good value before making this call.
  - getSize
```
int getSize()
```
    Get the chunk's total size including the length, type, and crc fields.
  - checkCRC
```
boolean checkCRC()
```
    Compute the CRC value for the chunk's data. Answer whether this value matches the value stored in the chunk.
  - computeCRC
```
int computeCRC()
```
    Answer the CRC value of chunk's data.
  - typeMatchesArray
```
boolean typeMatchesArray(byte[] array)
```
  - isCritical
```
boolean isCritical()
```
  - getChunkType
```
int getChunkType()
```
  - readNextFromStream
```
static PngChunk readNextFromStream(LEDataInputStream stream)
```
    Read the next PNG chunk from the input stream given. If unable to read a chunk, return null.
  - validate
```
void validate(PngFileReadState readState,
            PngIhdrChunk headerChunk)
```
    Answer whether the chunk is a valid PNG chunk.
  - contributeToString
```
void contributeToString(java.lang.StringBuffer buffer)
```
    Provided so that subclasses can override and add data to the toString() call.
  - toString
```
public java.lang.String toString()
```
    Returns a string containing a concise, human-readable description of the receiver.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    a string representation of the event

Class PngChunk

Structure Diagram

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

reference

LENGTH_OFFSET

TYPE_OFFSET

DATA_OFFSET

TYPE_FIELD_LENGTH

LENGTH_FIELD_LENGTH

MIN_LENGTH

CHUNK_UNKNOWN

CHUNK_IHDR

CHUNK_PLTE

CHUNK_IDAT

CHUNK_IEND

CHUNK_tRNS

TYPE_IHDR

TYPE_PLTE

TYPE_IDAT

TYPE_IEND

TYPE_tRNS

CRC_TABLE

length

Constructor Detail

PngChunk

PngChunk

Method Detail

getReference

setReference

getInt16

setInt16

getInt32

setInt32

getLength

setLength

getTypeBytes

setType

getData

setData

getCRC

setCRC

getSize

checkCRC

computeCRC

typeMatchesArray

isCritical

getChunkType

readNextFromStream

validate

contributeToString

toString