JPEGMarkerReader

java.lang.Object
- net.sourceforge.jiu.codecs.jpeg.JPEGMarkerReader

```
public class JPEGMarkerReader
extends java.lang.Object
```
Static helper methods to read various JPEG bitstream headers from a DataInput source into objects of the appropriate data classes. Objects are then added to a JPEGData object.

Since:

0.14.0

Author:

Marco Schmidt

Constructor Summary

Constructors
Modifier Constructor and Description

private JPEGMarkerReader()
Private constructor to prevent instantiation.

Constructors
Modifier	Constructor and Description
`private`	`JPEGMarkerReader()` Private constructor to prevent instantiation.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`readHuffmanTables(java.io.DataInput in, JPEGData jpegData, int length)`
`static void`	`readQuantizationTables(java.io.DataInput in, JPEGData jpegData, int length)` Read quantization tables from a DQT marker.
`static void`	`readStartOfFrame(java.io.DataInput in, JPEGData jpegData, int marker, int length)`
`static void`	`readStartOfScan(java.io.DataInput in, JPEGData jpegData, int length)` Read an SOS (start of scan) marker.

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

Constructor Detail
- JPEGMarkerReader
```
private JPEGMarkerReader()
```
  Private constructor to prevent instantiation.

Method Detail

readHuffmanTables

public static void readHuffmanTables(java.io.DataInput in,
                                     JPEGData jpegData,
                                     int length)
                              throws InvalidFileStructureException,
                                     java.io.IOException

Throws:: InvalidFileStructureException; java.io.IOException

readQuantizationTables

public static void readQuantizationTables(java.io.DataInput in,
                                          JPEGData jpegData,
                                          int length)
                                   throws InvalidFileStructureException,
                                          java.io.IOException

Read quantization tables from a DQT marker. P&M 7.8.3, p. 118f.

Parameters:: jpegData - data object which will store the table(s); length - length of marker
Throws:: InvalidFileStructureException - if the DQT contains invalid data; java.io.IOException - on reading errors

readStartOfFrame

public static void readStartOfFrame(java.io.DataInput in,
                                    JPEGData jpegData,
                                    int marker,
                                    int length)
                             throws InvalidFileStructureException,
                                    java.io.IOException,
                                    UnsupportedTypeException

Throws:: InvalidFileStructureException; java.io.IOException; UnsupportedTypeException

readStartOfScan
```
public static void readStartOfScan(java.io.DataInput in,
                                   JPEGData jpegData,
                                   int length)
                            throws InvalidFileStructureException,
                                   java.io.IOException,
                                   UnsupportedTypeException
```
Read an SOS (start of scan) marker. P&M 7.6, p. 113.

Parameters:

in - source to read marker information from

jpegData - JPEGData object to update with information from the marker

length - size of marker in bytes

Throws:

InvalidFileStructureException - if encountered data does not follow the JPEG standard

java.io.IOException - on I/O errors

UnsupportedTypeException - if encountered data is valid but unsupported by this package

Class JPEGMarkerReader

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

JPEGMarkerReader

Method Detail

readHuffmanTables

readQuantizationTables

readStartOfFrame

readStartOfScan