Package com.aspose.zip

Class PPMdCompressionSettings

java.lang.Object

com.aspose.zip.CompressionSettings

com.aspose.zip.PPMdCompressionSettings

public class PPMdCompressionSettings
extends CompressionSettings

Settings for PPMd compression within a ZIP archive.

PPMd is a data compression algorithm developed by Dmitry Shkarin. This algorithm is based on predictive phrase matching on multiple order contexts.

Constructor Summary

Constructors

Constructor	Description
PPMdCompressionSettings()	Initializes a new instance of the PPMdCompressionSettings class with default model order and sub-allocator size.
PPMdCompressionSettings(int modelOrder, int suballocatorSize)	Initializes a new instance of the PPMdCompressionSettings class.

Method Summary

Modifier and Type	Method	Description
int	getModelOrder()	Gets the order of the model.
int	getSuballocatorSize()	Gets the sub-allocator size in MB.

Methods inherited from class com.aspose.zip.CompressionSettings

getBzip2, getDeflate, getEnhancedDeflate, getLzma, getPPMd, getStore, getXz, getZstd

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PPMdCompressionSettings

public PPMdCompressionSettings(int modelOrder,
                               int suballocatorSize)

Initializes a new instance of the PPMdCompressionSettings class.

     try (Archive archive = new Archive(new ArchiveEntrySettings(new PPMdCompressionSettings(4, 10)))) {
         archive.createEntry("data.bin", "data.bin");
         archive.save("zipFile.zip");
     }
 

Parameters:

modelOrder - Order of the model.

Bigger model orders almost surely results in better compression and surely more memory and CPU usage.

suballocatorSize - Memory size in MB suballocator may consume.

The PPMd algorithm might need a lot of memory, especially when used on large files and/or used with large model order. If ppmd needs more memory than you give it, the compression will be worse.

Throws:

com.aspose.ms.System.ArgumentOutOfRangeException - modelOrder is not between 2 and 16, or suballocatorSize is not between 1 and 256.

PPMdCompressionSettings

public PPMdCompressionSettings()

Initializes a new instance of the PPMdCompressionSettings class with default model order and sub-allocator size.

     try (Archive archive = new Archive(new ArchiveEntrySettings(new PPMdCompressionSettings()))) {
         archive.createEntry("data.bin", "data.bin");
         archive.save("zipFile.zip");
     }
 

The default model order is 8, and the sub-allocator size is 50MB.

Method Detail

getModelOrder

public final int getModelOrder()

Gets the order of the model.

Returns:

the order of the model

getSuballocatorSize

public final int getSuballocatorSize()

Gets the sub-allocator size in MB.

Returns:

the sub-allocator size in MB