ZipStream Module

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The ZipStream module is used to perform compression or decompression.

Syntax

IPWorksZip.Zipstream

Remarks

The ZipStream class provides a way to compress and decompress streamed data.

Data may be operated on in multiple ways as discussed below. The StreamFormat property specifies the algorithm to us. Possible values are:

• Deflate
• Zlib
• Gzip

CompressBlock and DecompressBlock

The CompressBlock and DecompressBlock methods operate on blocks (chunks) of data. The methods may be used to compress and decompress data as it becomes available.

Note that when using blocks of data the OutputData property is not applicable. Instead data is made available through the CompressedData and DecompressedData events.

If all data is available ahead of time CompressData and DecompressData may be called instead.

Compress Data

Set InputData to the current block to be compressed. Next call CompressBlock to compress the current block. Note that CompressBlock takes a LastBlock parameter. If the block of data is the final block to be compressed set this to True. For all other blocks set this to False.

During compression the CompressedData event will fire with the compressed data. Note that this event may not fire for every call to CompressBlock due to the way the compression algorithm operates. For example:

zipstream.InputDataB = MyDecompressedData; zipstream.CompressBlock(); Data is accumulated inside the CompressedData event: private static void Zipstream_OnCompressedData(object sender, ZipstreamCompressedDataEventArgs e) { DoSomethingWith(e.DataB); }

Note that OutputData is not applicable when compressing block data.

Decompress Data

Set InputData to the current block to be decompressed. Next call DecompressBlock to decompress the current block.

During decompression the DecompressedData event will fire with the decompressed data. Note that this event may not fire for every call to DecompressBlock due to the way the decompression algorithm operates. For example:

zipstream.InputDataB = MyCompressedData; zipstream.DecompressBlock(); Data is accumulated inside the DecompressedData event: private static void Zipstream_OnDecompressedData(object sender, ZipstreamDecompressedDataEventArgs e) { DoSomethingWith(e.DataB); }

Note that OutputData is not applicable when decompressing block data.

CompressData and DecompressData

The CompressData and DecompressData methods operate on the complete blob of data. The entire compressed or decompressed data must be set to InputData before calling either method.

To compress and decompress data in blocks (chunks) see CompressBlock and DecompressBlock.

Compress Data

Set InputData to the decompressed data. This should be the entire data to be compressed. Next call CompressData. After compression OutputData will hold the compressed data. For example:

zipstream.InputDataB = MyDecompressedData; zipstream.CompressData(); MyCompressedData = zipstream.OutputDataB;

In addition to OutputData, the compressed data may also be accumulated within the CompressedData event.

Decompress Data

Set InputData to the compressed data. This should be the entire data to be decompressed. Next call DecompressData. After decompression OutputData will hold the decompressed data. For example:

zipstream.InputDataB = MyCompressedData; zipstream.DecompressData(); MyDecompressedData = zipstream.OutputDataB;

In addition to OutputData, the compressed data may also be accumulated within the DecompressedData event.

Property List

The following is the full list of the properties of the module with short descriptions. Click on the links for further details.

Method List

The following is the full list of the methods of the module with short descriptions. Click on the links for further details.

Event List

The following is the full list of the events fired by the module with short descriptions. Click on the links for further details.

Config Settings

The following is a list of config settings for the module with short descriptions. Click on the links for further details.

CloseBaseStream Property (ZipStream Module)

Whether or not to close the underlying stream.

Syntax

• Swift
• Objective-C

public var closeBaseStream: Bool {
  get {...}
  set {...}
}

@property (nonatomic,readwrite,assign,getter=closeBaseStream,setter=setCloseBaseStream:) BOOL closeBaseStream;

- (BOOL)closeBaseStream;
- (void)setCloseBaseStream :(BOOL)newCloseBaseStream;

Default Value

True

Remarks

If true, streams created by GetCompressionStream and GetDecompressionStream will close their underlying streams when their Close method is invoked. If false, the underlying streams will remain open.

CompressionLevel Property (ZipStream Module)

The compression level to use.

Syntax

• Swift
• Objective-C

public var compressionLevel: Int32 {
  get {...}
  set {...}
}

@property (nonatomic,readwrite,assign,getter=compressionLevel,setter=setCompressionLevel:) int compressionLevel;

- (int)compressionLevel;
- (void)setCompressionLevel :(int)newCompressionLevel;

Default Value

4

Remarks

The compression level to use, from 1 to 6. Higher values will cause the component to compress better; lower values will cause the component to compress faster.

When GetCompressionStream is invoked the stream will be created with the specified compression level. After a stream has been created it is independent of the control, and changing CompressionLevel will have no effect on existing streams.

InputData Property (ZipStream Module)

Specifies the data to compress or decompress.

Syntax

• Swift
• Objective-C

public var inputData: String {
  get {...}
  set {...}
}

public var inputDataB: Data {
  get {...}
  set {...}
}

@property (nonatomic,readwrite,assign,getter=inputData,setter=setInputData:) NSString* inputData;

- (NSString*)inputData;
- (void)setInputData :(NSString*)newInputData;

@property (nonatomic,readwrite,assign,getter=inputDataB,setter=setInputDataB:) NSData* inputDataB;

- (NSData*)inputDataB;
- (void)setInputDataB :(NSData*)newInputData;

Default Value

""

Remarks

This property specifies the data to compress or decompress.

When decompressing this should be set to the compressed data before calling DecompressData or DecompressBlock.

When compressing this should be set to the decompressed data before calling CompressData or CompressBlock.

OutputData Property (ZipStream Module)

The output data after compression or decompression.

Syntax

• Swift
• Objective-C

public var outputData: String {
  get {...}
}

public var outputDataB: Data {
  get {...}
}

@property (nonatomic,readonly,assign,getter=outputData) NSString* outputData;

- (NSString*)outputData;

@property (nonatomic,readonly,assign,getter=outputDataB) NSData* outputDataB;

- (NSData*)outputDataB;

Default Value

""

Remarks

This property holds the compressed or decompressed data after CompressData or DecompressData is called.

This property is not applicable when calling CompressBlock or DecompressBlock.

This property is read-only.

StreamFormat Property (ZipStream Module)

The stream format to use.

Syntax

• Swift
• Objective-C

public var streamFormat: ZipstreamStreamFormats {
  get {...}
  set {...}
}

public enum ZipstreamStreamFormats: Int32 {
  case sfDeflate = 0
  case sfZlib = 1
  case sfGzip = 2
}

@property (nonatomic,readwrite,assign,getter=streamFormat,setter=setStreamFormat:) int streamFormat;

- (int)streamFormat;
- (void)setStreamFormat :(int)newStreamFormat;

Default Value

0

Remarks

The stream format to use, by default Deflate.

All three stream formats use the Deflate algorithm specified in RFC 1951, which is the same algorithm used by Zip. The Zlib stream format adds a two-byte header and an Adler-32 checksum; the Gzip format adds a longer header and a CRC checksum, and is identical to the Gzip file format.

Caution: The terms zlib and deflate are sometimes used interchangeably (which is technically incorrect).

CompressBlock Method (ZipStream Module)

Compresses a block of data.

Syntax

• Swift
• Objective-C

public func compressBlock(lastBlock: Bool) throws -> Void

- (void)compressBlock:(BOOL)lastBlock;

Remarks

This method compresses the block of data specified by InputData.

The CompressBlock and DecompressBlock methods operate on blocks (chunks) of data. The methods may be used to compress and decompress data as it becomes available.

Note that when using blocks of data the OutputData property is not applicable. Instead data is made available through the CompressedData and DecompressedData events.

If all data is available ahead of time CompressData and DecompressData may be called instead.

Compress Data

Set InputData to the current block to be compressed. Next call CompressBlock to compress the current block. Note that CompressBlock takes a LastBlock parameter. If the block of data is the final block to be compressed set this to True. For all other blocks set this to False.

During compression the CompressedData event will fire with the compressed data. Note that this event may not fire for every call to CompressBlock due to the way the compression algorithm operates. For example:

zipstream.InputDataB = MyDecompressedData; zipstream.CompressBlock(); Data is accumulated inside the CompressedData event: private static void Zipstream_OnCompressedData(object sender, ZipstreamCompressedDataEventArgs e) { DoSomethingWith(e.DataB); }

Note that OutputData is not applicable when compressing block data.

Decompress Data

Set InputData to the current block to be decompressed. Next call DecompressBlock to decompress the current block.

During decompression the DecompressedData event will fire with the decompressed data. Note that this event may not fire for every call to DecompressBlock due to the way the decompression algorithm operates. For example:

zipstream.InputDataB = MyCompressedData; zipstream.DecompressBlock(); Data is accumulated inside the DecompressedData event: private static void Zipstream_OnDecompressedData(object sender, ZipstreamDecompressedDataEventArgs e) { DoSomethingWith(e.DataB); }

Note that OutputData is not applicable when decompressing block data.

CompressData Method (ZipStream Module)

Compresses the specified data.

Syntax

• Swift
• Objective-C

public func compressData() throws -> Void

- (void)compressData;

Remarks

This method compresses the data specified by InputData. After calling this method OutputData holds the compressed data.

The CompressData and DecompressData methods operate on the complete blob of data. The entire compressed or decompressed data must be set to InputData before calling either method.

To compress and decompress data in blocks (chunks) see CompressBlock and DecompressBlock.

Compress Data

Set InputData to the decompressed data. This should be the entire data to be compressed. Next call CompressData. After compression OutputData will hold the compressed data. For example:

zipstream.InputDataB = MyDecompressedData; zipstream.CompressData(); MyCompressedData = zipstream.OutputDataB;

In addition to OutputData, the compressed data may also be accumulated within the CompressedData event.

Decompress Data

Set InputData to the compressed data. This should be the entire data to be decompressed. Next call DecompressData. After decompression OutputData will hold the decompressed data. For example:

zipstream.InputDataB = MyCompressedData; zipstream.DecompressData(); MyDecompressedData = zipstream.OutputDataB;

In addition to OutputData, the compressed data may also be accumulated within the DecompressedData event.

Config Method (ZipStream Module)

Sets or retrieves a configuration setting.

Syntax

• Swift
• Objective-C

public func config(configurationString: String) throws -> String

- (NSString*)config:(NSString*)configurationString;

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

DecompressBlock Method (ZipStream Module)

Decompresses a block of data.

Syntax

• Swift
• Objective-C

public func decompressBlock() throws -> Void

- (void)decompressBlock;

Remarks

This method decompresses the block of data specified by InputData.

The CompressBlock and DecompressBlock methods operate on blocks (chunks) of data. The methods may be used to compress and decompress data as it becomes available.

Note that when using blocks of data the OutputData property is not applicable. Instead data is made available through the CompressedData and DecompressedData events.

If all data is available ahead of time CompressData and DecompressData may be called instead.

Compress Data

Set InputData to the current block to be compressed. Next call CompressBlock to compress the current block. Note that CompressBlock takes a LastBlock parameter. If the block of data is the final block to be compressed set this to True. For all other blocks set this to False.

During compression the CompressedData event will fire with the compressed data. Note that this event may not fire for every call to CompressBlock due to the way the compression algorithm operates. For example:

zipstream.InputDataB = MyDecompressedData; zipstream.CompressBlock(); Data is accumulated inside the CompressedData event: private static void Zipstream_OnCompressedData(object sender, ZipstreamCompressedDataEventArgs e) { DoSomethingWith(e.DataB); }

Note that OutputData is not applicable when compressing block data.

Decompress Data

Set InputData to the current block to be decompressed. Next call DecompressBlock to decompress the current block.

During decompression the DecompressedData event will fire with the decompressed data. Note that this event may not fire for every call to DecompressBlock due to the way the decompression algorithm operates. For example:

zipstream.InputDataB = MyCompressedData; zipstream.DecompressBlock(); Data is accumulated inside the DecompressedData event: private static void Zipstream_OnDecompressedData(object sender, ZipstreamDecompressedDataEventArgs e) { DoSomethingWith(e.DataB); }

Note that OutputData is not applicable when decompressing block data.

DecompressData Method (ZipStream Module)

Decompresses the specified data.

Syntax

• Swift
• Objective-C

public func decompressData() throws -> Void

- (void)decompressData;

Remarks

This method decompresses the data specified by InputData. After calling this method OutputData holds the decompressed data.

The CompressData and DecompressData methods operate on the complete blob of data. The entire compressed or decompressed data must be set to InputData before calling either method.

To compress and decompress data in blocks (chunks) see CompressBlock and DecompressBlock.

Compress Data

Set InputData to the decompressed data. This should be the entire data to be compressed. Next call CompressData. After compression OutputData will hold the compressed data. For example:

zipstream.InputDataB = MyDecompressedData; zipstream.CompressData(); MyCompressedData = zipstream.OutputDataB;

In addition to OutputData, the compressed data may also be accumulated within the CompressedData event.

Decompress Data

Set InputData to the compressed data. This should be the entire data to be decompressed. Next call DecompressData. After decompression OutputData will hold the decompressed data. For example:

zipstream.InputDataB = MyCompressedData; zipstream.DecompressData(); MyDecompressedData = zipstream.OutputDataB;

In addition to OutputData, the compressed data may also be accumulated within the DecompressedData event.

Reset Method (ZipStream Module)

Resets the component.

Syntax

• Swift
• Objective-C

public func reset() throws -> Void

- (void)reset;

Remarks

Reset resets the state of the class. All properties will be set to their default values, and any files open will be closed.

CompressedData Event (ZipStream Module)

This event fires with compressed data.

Syntax

• Swift
• Objective-C

func onCompressedData(data: Data)

- (void)onCompressedData:(NSData*)data;

Remarks

The CompressedData event fires as compressed data is available when CompressData or CompressBlock is called. This may fire one or more times when data is compressed.

Data holds the current block of compressed data.

DecompressedData Event (ZipStream Module)

This event fires with decompressed data.

Syntax

• Swift
• Objective-C

func onDecompressedData(data: Data)

- (void)onDecompressedData:(NSData*)data;

Remarks

The DecompressedData event fires as compressed data is available when DecompressData or DecompressBlock is called. This may fire one or more times as data is decompressed.

Data holds the current block of decompressed data.

Error Event (ZipStream Module)

Information about errors during data delivery.

Syntax

• Swift
• Objective-C

func onError(errorCode: Int32, description: String)

- (void)onError:(int)errorCode :(NSString*)description;

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class .

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Config Settings (ZipStream Module)

No configuration settings defined.

Trappable Errors (ZipStream Module)

ZipStream Errors

	101   The data is of an invalid or unsupported format.
	111   Can't open file for read.
	150   An I/O error has occurred (details follow).