ZipStream Class

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The ZipStream class is used to perform compression or decompression.

Class Name

IPWorksZip_ZipStream

Procedural Interface

 ipworkszip_zipstream_open();
 ipworkszip_zipstream_close($res);
 ipworkszip_zipstream_register_callback($res, $id, $function);
 ipworkszip_zipstream_get_last_error($res);
 ipworkszip_zipstream_get_last_error_code($res);
 ipworkszip_zipstream_set($res, $id, $index, $value);
 ipworkszip_zipstream_get($res, $id, $index);
 ipworkszip_zipstream_do_compressblock($res, $lastblock);
 ipworkszip_zipstream_do_compressdata($res);
 ipworkszip_zipstream_do_config($res, $configurationstring);
 ipworkszip_zipstream_do_decompressblock($res);
 ipworkszip_zipstream_do_decompressdata($res);
 ipworkszip_zipstream_do_reset($res);

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

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

Method List

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

Event List

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

Config Settings

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

CompressionLevel Property (IPWorksZip_ZipStream Class)

The compression level to use.

Object Oriented Interface

public function getCompressionLevel();
public function setCompressionLevel($value);

Procedural Interface

ipworkszip_zipstream_get($res, 1 );
ipworkszip_zipstream_set($res, 1, $value );

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.

Data Type

Integer

InputData Property (IPWorksZip_ZipStream Class)

Specifies the data to compress or decompress.

Object Oriented Interface

public function getInputData();
public function setInputData($value);

Procedural Interface

ipworkszip_zipstream_get($res, 2 );
ipworkszip_zipstream_set($res, 2, $value );

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.

When performing operations on multiple chunks of data, note that this property is not automatically cleared after each operation.

Data Type

Binary String

OutputData Property (IPWorksZip_ZipStream Class)

The output data after compression or decompression.

Object Oriented Interface

public function getOutputData();

Procedural Interface

ipworkszip_zipstream_get($res, 3 );

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 and not available at design time.

Data Type

Binary String

StreamFormat Property (IPWorksZip_ZipStream Class)

The stream format to use.

Object Oriented Interface

public function getStreamFormat();
public function setStreamFormat($value);

Procedural Interface

ipworkszip_zipstream_get($res, 4 );
ipworkszip_zipstream_set($res, 4, $value );

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).

Data Type

Integer

CompressBlock Method (IPWorksZip_ZipStream Class)

Compresses a block of data.

Object Oriented Interface

public function doCompressBlock($lastblock);

Procedural Interface

ipworkszip_zipstream_do_compressblock($res, $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 (IPWorksZip_ZipStream Class)

Compresses the specified data.

Object Oriented Interface

public function doCompressData();

Procedural Interface

ipworkszip_zipstream_do_compressdata($res);

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 (IPWorksZip_ZipStream Class)

Sets or retrieves a configuration setting.

Object Oriented Interface

public function doConfig($configurationstring);

Procedural Interface

ipworkszip_zipstream_do_config($res, $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 (IPWorksZip_ZipStream Class)

Decompresses a block of data.

Object Oriented Interface

public function doDecompressBlock();

Procedural Interface

ipworkszip_zipstream_do_decompressblock($res);

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 (IPWorksZip_ZipStream Class)

Decompresses the specified data.

Object Oriented Interface

public function doDecompressData();

Procedural Interface

ipworkszip_zipstream_do_decompressdata($res);

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 (IPWorksZip_ZipStream Class)

Resets the class.

Object Oriented Interface

public function doReset();

Procedural Interface

ipworkszip_zipstream_do_reset($res);

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 (IPWorksZip_ZipStream Class)

This event fires with compressed data.

Object Oriented Interface

public function fireCompressedData($param);

Procedural Interface

ipworkszip_zipstream_register_callback($res, 1, array($this, 'fireCompressedData'));

Parameter List

 '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 (IPWorksZip_ZipStream Class)

This event fires with decompressed data.

Object Oriented Interface

public function fireDecompressedData($param);

Procedural Interface

ipworkszip_zipstream_register_callback($res, 2, array($this, 'fireDecompressedData'));

Parameter List

 '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 (IPWorksZip_ZipStream Class)

Information about errors during data delivery.

Object Oriented Interface

public function fireError($param);

Procedural Interface

ipworkszip_zipstream_register_callback($res, 3, array($this, 'fireError'));

Parameter List

 'errorcode'
 'description'

Remarks

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

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 Class)

The class accepts one or more of the following configuration settings. Configuration 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.

No configuration settings defined.

Base Config Settings

Trappable Errors (ZipStream Class)

Note that the streams returned by GetCompressionStream and GetDecompressionStream will throw standard IOExceptions in case of error.

ZipStream Errors