PPMdCompressionSettings
Inheritance: java.lang.Object, com.aspose.zip.CompressionSettings
public class PPMdCompressionSettings extends CompressionSettings
Settings for PPMd compression method.
PPMd is a data compression algorithm developed by Dmitry Shkarin. This algorithm is based on predictive phrase matching on multiple order contexts.
Constructors
| Constructor | Description |
|---|---|
| PPMdCompressionSettings(int modelOrder, int suballocatorSize) | Initializes a new instance of the PPMdCompressionSettings class. |
| PPMdCompressionSettings() | Initializes a new instance of the PPMdCompressionSettings class with default model order and sub-allocator size. |
Methods
| Method | Description |
|---|---|
| getModelOrder() | Gets the order of the model. |
| getSuballocatorSize() | Gets the sub-allocator size in MB. |
PPMdCompressionSettings(int modelOrder, int suballocatorSize)
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:
| Parameter | Type | Description |
|---|---|---|
| modelOrder | int | Order of the model. |
Bigger model orders almost surely results in better compression and surely more memory and CPU usage. | | suballocatorSize | int | 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. |
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");
}
Default model order is 8 and sub-allocator size is 50MB.
getModelOrder()
public final int getModelOrder()
Gets the order of the model.
Returns: int - the order of the model
getSuballocatorSize()
public final int getSuballocatorSize()
Gets the sub-allocator size in MB.
Returns: int - the sub-allocator size in MB