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IPWorks ZIP 2022 Python Edition

Version 22.0 [Build 8203]

ZipStream Class

Properties   Methods   Events   Configuration Settings   Errors  

The ZipStream class is used to perform compression or decompression.

Syntax

class 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 stream_format property specifies the algorithm to us. Possible values are:

  • Deflate
  • Zlib
  • Gzip

CompressBlock and DecompressBlock

The compress_block and decompress_block 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 output_data property is not applicable. Instead data is made available through the on_compressed_data and on_decompressed_data events.

If all data is available ahead of time compress_data and decompress_data may be called instead.

Compress Data

Set input_data to the current block to be compressed. Next call compress_block to compress the current block. Note that compress_block 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 on_compressed_data event will fire with the compressed data. Note that this event may not fire for every call to compress_block due to the way the compression algorithm operates. For example:

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

Note that output_data is not applicable when compressing block data.

Decompress Data

Set input_data to the current block to be decompressed. Next call decompress_block to decompress the current block.

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

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

Note that output_data is not applicable when decompressing block data.

CompressData and DecompressData

The compress_data and decompress_data methods operate on the complete blob of data. The entire compressed or decompressed data must be set to input_data before calling either method.

To compress and decompress data in blocks (chunks) see compress_block and decompress_block.

Compress Data

Set input_data to the decompressed data. This should be the entire data to be compressed. Next call compress_data. After compression output_data will hold the compressed data. For example:

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

In addition to output_data, the compressed data may also be accumulated within the on_compressed_data event.

Decompress Data

Set input_data to the compressed data. This should be the entire data to be decompressed. Next call decompress_data. After decompression output_data will hold the decompressed data. For example:

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

In addition to output_data, the compressed data may also be accumulated within the on_decompressed_data event.

Property List


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

compression_levelThe compression level to use.
input_dataSpecifies the data to compress or decompress.
output_dataThe output data after compression or decompression.
stream_formatThe stream format to use.

Method List


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

compress_blockCompresses a block of data.
compress_dataCompresses the specified data.
configSets or retrieves a configuration setting.
decompress_blockDecompresses a block of data.
decompress_dataDecompresses the specified data.
resetResets the class.

Event List


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

on_compressed_dataThis event fires with compressed data.
on_decompressed_dataThis event fires with decompressed data.
on_errorInformation about errors during data delivery.

Configuration Settings


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

BuildInfoInformation about the product's build.
CodePageThe system code page used for Unicode to Multibyte translations.
LicenseInfoInformation about the current license.
ProcessIdleEventsWhether the class uses its internal event loop to process events when the main thread is idle.
SelectWaitMillisThe length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.
UseInternalSecurityAPITells the class whether or not to use the system security libraries or an internal implementation.

compression_level Property

The compression level to use.

Syntax

def get_compression_level() -> int: ...
def set_compression_level(value: int) -> None: ...

compression_level = property(get_compression_level, set_compression_level)

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 get_compression_stream 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 compression_level will have no effect on existing streams.

input_data Property

Specifies the data to compress or decompress.

Syntax

def get_input_data() -> bytes: ...
def set_input_data(value: bytes) -> None: ...

input_data = property(get_input_data, set_input_data)

Default Value

""

Remarks

This property specifies the data to compress or decompress.

When decompressing this should be set to the compressed data before calling decompress_data or decompress_block.

When compressing this should be set to the decompressed data before calling compress_data or compress_block.

output_data Property

The output data after compression or decompression.

Syntax

def get_output_data() -> bytes: ...

output_data = property(get_output_data, None)

Default Value

""

Remarks

This property holds the compressed or decompressed data after compress_data or decompress_data is called.

This property is not applicable when calling compress_block or decompress_block.

This property is read-only.

stream_format Property

The stream format to use.

Syntax

def get_stream_format() -> int: ...
def set_stream_format(value: int) -> None: ...

stream_format = property(get_stream_format, set_stream_format)

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).

compress_block Method

Compresses a block of data.

Syntax

def compress_block(last_block: bool) -> None: ...

Remarks

This method compresses the block of data specified by input_data.

The on_compress_block and decompress_block 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 output_data property is not applicable. Instead data is made available through the on_compressed_data and on_decompressed_data events.

If all data is available ahead of time compress_data and decompress_data may be called instead.

Compress Data

Set input_data to the current block to be compressed. Next call on_compress_block to compress the current block. Note that on_compress_block 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 on_compressed_data event will fire with the compressed data. Note that this event may not fire for every call to on_compress_block due to the way the compression algorithm operates. For example:

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

Note that output_data is not applicable when compressing block data.

Decompress Data

Set input_data to the current block to be decompressed. Next call decompress_block to decompress the current block.

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

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

Note that output_data is not applicable when decompressing block data.

compress_data Method

Compresses the specified data.

Syntax

def compress_data() -> None: ...

Remarks

This method compresses the data specified by input_data. After calling this method output_data holds the compressed data.

The on_compress_data and decompress_data methods operate on the complete blob of data. The entire compressed or decompressed data must be set to input_data before calling either method.

To compress and decompress data in blocks (chunks) see compress_block and decompress_block.

Compress Data

Set input_data to the decompressed data. This should be the entire data to be compressed. Next call on_compress_data. After compression output_data will hold the compressed data. For example:

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

In addition to output_data, the compressed data may also be accumulated within the on_compressed_data event.

Decompress Data

Set input_data to the compressed data. This should be the entire data to be decompressed. Next call decompress_data. After decompression output_data will hold the decompressed data. For example:

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

In addition to output_data, the compressed data may also be accumulated within the on_decompressed_data event.

config Method

Sets or retrieves a configuration setting.

Syntax

def config(configuration_string: str) -> str: ...

Remarks

on_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 on_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.

decompress_block Method

Decompresses a block of data.

Syntax

def decompress_block() -> None: ...

Remarks

This method decompresses the block of data specified by input_data.

The compress_block and on_decompress_block 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 output_data property is not applicable. Instead data is made available through the on_compressed_data and on_decompressed_data events.

If all data is available ahead of time compress_data and decompress_data may be called instead.

Compress Data

Set input_data to the current block to be compressed. Next call compress_block to compress the current block. Note that compress_block 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 on_compressed_data event will fire with the compressed data. Note that this event may not fire for every call to compress_block due to the way the compression algorithm operates. For example:

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

Note that output_data is not applicable when compressing block data.

Decompress Data

Set input_data to the current block to be decompressed. Next call on_decompress_block to decompress the current block.

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

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

Note that output_data is not applicable when decompressing block data.

decompress_data Method

Decompresses the specified data.

Syntax

def decompress_data() -> None: ...

Remarks

This method decompresses the data specified by input_data. After calling this method output_data holds the decompressed data.

The compress_data and on_decompress_data methods operate on the complete blob of data. The entire compressed or decompressed data must be set to input_data before calling either method.

To compress and decompress data in blocks (chunks) see compress_block and decompress_block.

Compress Data

Set input_data to the decompressed data. This should be the entire data to be compressed. Next call compress_data. After compression output_data will hold the compressed data. For example:

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

In addition to output_data, the compressed data may also be accumulated within the on_compressed_data event.

Decompress Data

Set input_data to the compressed data. This should be the entire data to be decompressed. Next call on_decompress_data. After decompression output_data will hold the decompressed data. For example:

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

In addition to output_data, the compressed data may also be accumulated within the on_decompressed_data event.

reset Method

Resets the class.

Syntax

def reset() -> None: ...

Remarks

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

on_compressed_data Event

This event fires with compressed data.

Syntax

class ZipStreamCompressedDataEventParams(object):
  @property
  def data() -> bytes: ...

# In class ZipStream:
@property
def on_compressed_data() -> Callable[[ZipStreamCompressedDataEventParams], None]: ...
@on_compressed_data.setter
def on_compressed_data(event_hook: Callable[[ZipStreamCompressedDataEventParams], None]) -> None: ...

Remarks

The on_compressed_data event fires as compressed data is available when compress_data or compress_block is called. This may fire one or more times when data is compressed.

Data holds the current block of compressed data.

on_decompressed_data Event

This event fires with decompressed data.

Syntax

class ZipStreamDecompressedDataEventParams(object):
  @property
  def data() -> bytes: ...

# In class ZipStream:
@property
def on_decompressed_data() -> Callable[[ZipStreamDecompressedDataEventParams], None]: ...
@on_decompressed_data.setter
def on_decompressed_data(event_hook: Callable[[ZipStreamDecompressedDataEventParams], None]) -> None: ...

Remarks

The on_decompressed_data event fires as compressed data is available when decompress_data or decompress_block is called. This may fire one or more times as data is decompressed.

Data holds the current block of decompressed data.

on_error Event

Information about errors during data delivery.

Syntax

class ZipStreamErrorEventParams(object):
  @property
  def error_code() -> int: ...

  @property
  def description() -> str: ...

# In class ZipStream:
@property
def on_error() -> Callable[[ZipStreamErrorEventParams], None]: ...
@on_error.setter
def on_error(event_hook: Callable[[ZipStreamErrorEventParams], None]) -> None: ...

Remarks

The on_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.

ZipStream Configuration

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 Configuration Settings

BuildInfo:   Information about the product's build.

When queried, this setting will return a string containing information about the product's build.

CodePage:   The system code page used for Unicode to Multibyte translations.

The default code page is Unicode UTF-8 (65001).

The following is a list of valid code page identifiers:

IdentifierName
037IBM EBCDIC - U.S./Canada
437OEM - United States
500IBM EBCDIC - International
708Arabic - ASMO 708
709Arabic - ASMO 449+, BCON V4
710Arabic - Transparent Arabic
720Arabic - Transparent ASMO
737OEM - Greek (formerly 437G)
775OEM - Baltic
850OEM - Multilingual Latin I
852OEM - Latin II
855OEM - Cyrillic (primarily Russian)
857OEM - Turkish
858OEM - Multilingual Latin I + Euro symbol
860OEM - Portuguese
861OEM - Icelandic
862OEM - Hebrew
863OEM - Canadian-French
864OEM - Arabic
865OEM - Nordic
866OEM - Russian
869OEM - Modern Greek
870IBM EBCDIC - Multilingual/ROECE (Latin-2)
874ANSI/OEM - Thai (same as 28605, ISO 8859-15)
875IBM EBCDIC - Modern Greek
932ANSI/OEM - Japanese, Shift-JIS
936ANSI/OEM - Simplified Chinese (PRC, Singapore)
949ANSI/OEM - Korean (Unified Hangul Code)
950ANSI/OEM - Traditional Chinese (Taiwan; Hong Kong SAR, PRC)
1026IBM EBCDIC - Turkish (Latin-5)
1047IBM EBCDIC - Latin 1/Open System
1140IBM EBCDIC - U.S./Canada (037 + Euro symbol)
1141IBM EBCDIC - Germany (20273 + Euro symbol)
1142IBM EBCDIC - Denmark/Norway (20277 + Euro symbol)
1143IBM EBCDIC - Finland/Sweden (20278 + Euro symbol)
1144IBM EBCDIC - Italy (20280 + Euro symbol)
1145IBM EBCDIC - Latin America/Spain (20284 + Euro symbol)
1146IBM EBCDIC - United Kingdom (20285 + Euro symbol)
1147IBM EBCDIC - France (20297 + Euro symbol)
1148IBM EBCDIC - International (500 + Euro symbol)
1149IBM EBCDIC - Icelandic (20871 + Euro symbol)
1200Unicode UCS-2 Little-Endian (BMP of ISO 10646)
1201Unicode UCS-2 Big-Endian
1250ANSI - Central European
1251ANSI - Cyrillic
1252ANSI - Latin I
1253ANSI - Greek
1254ANSI - Turkish
1255ANSI - Hebrew
1256ANSI - Arabic
1257ANSI - Baltic
1258ANSI/OEM - Vietnamese
1361Korean (Johab)
10000MAC - Roman
10001MAC - Japanese
10002MAC - Traditional Chinese (Big5)
10003MAC - Korean
10004MAC - Arabic
10005MAC - Hebrew
10006MAC - Greek I
10007MAC - Cyrillic
10008MAC - Simplified Chinese (GB 2312)
10010MAC - Romania
10017MAC - Ukraine
10021MAC - Thai
10029MAC - Latin II
10079MAC - Icelandic
10081MAC - Turkish
10082MAC - Croatia
12000Unicode UCS-4 Little-Endian
12001Unicode UCS-4 Big-Endian
20000CNS - Taiwan
20001TCA - Taiwan
20002Eten - Taiwan
20003IBM5550 - Taiwan
20004TeleText - Taiwan
20005Wang - Taiwan
20105IA5 IRV International Alphabet No. 5 (7-bit)
20106IA5 German (7-bit)
20107IA5 Swedish (7-bit)
20108IA5 Norwegian (7-bit)
20127US-ASCII (7-bit)
20261T.61
20269ISO 6937 Non-Spacing Accent
20273IBM EBCDIC - Germany
20277IBM EBCDIC - Denmark/Norway
20278IBM EBCDIC - Finland/Sweden
20280IBM EBCDIC - Italy
20284IBM EBCDIC - Latin America/Spain
20285IBM EBCDIC - United Kingdom
20290IBM EBCDIC - Japanese Katakana Extended
20297IBM EBCDIC - France
20420IBM EBCDIC - Arabic
20423IBM EBCDIC - Greek
20424IBM EBCDIC - Hebrew
20833IBM EBCDIC - Korean Extended
20838IBM EBCDIC - Thai
20866Russian - KOI8-R
20871IBM EBCDIC - Icelandic
20880IBM EBCDIC - Cyrillic (Russian)
20905IBM EBCDIC - Turkish
20924IBM EBCDIC - Latin-1/Open System (1047 + Euro symbol)
20932JIS X 0208-1990 & 0121-1990
20936Simplified Chinese (GB2312)
21025IBM EBCDIC - Cyrillic (Serbian, Bulgarian)
21027Extended Alpha Lowercase
21866Ukrainian (KOI8-U)
28591ISO 8859-1 Latin I
28592ISO 8859-2 Central Europe
28593ISO 8859-3 Latin 3
28594ISO 8859-4 Baltic
28595ISO 8859-5 Cyrillic
28596ISO 8859-6 Arabic
28597ISO 8859-7 Greek
28598ISO 8859-8 Hebrew
28599ISO 8859-9 Latin 5
28605ISO 8859-15 Latin 9
29001Europa 3
38598ISO 8859-8 Hebrew
50220ISO 2022 Japanese with no halfwidth Katakana
50221ISO 2022 Japanese with halfwidth Katakana
50222ISO 2022 Japanese JIS X 0201-1989
50225ISO 2022 Korean
50227ISO 2022 Simplified Chinese
50229ISO 2022 Traditional Chinese
50930Japanese (Katakana) Extended
50931US/Canada and Japanese
50933Korean Extended and Korean
50935Simplified Chinese Extended and Simplified Chinese
50936Simplified Chinese
50937US/Canada and Traditional Chinese
50939Japanese (Latin) Extended and Japanese
51932EUC - Japanese
51936EUC - Simplified Chinese
51949EUC - Korean
51950EUC - Traditional Chinese
52936HZ-GB2312 Simplified Chinese
54936Windows XP: GB18030 Simplified Chinese (4 Byte)
57002ISCII Devanagari
57003ISCII Bengali
57004ISCII Tamil
57005ISCII Telugu
57006ISCII Assamese
57007ISCII Oriya
57008ISCII Kannada
57009ISCII Malayalam
57010ISCII Gujarati
57011ISCII Punjabi
65000Unicode UTF-7
65001Unicode UTF-8

The following is a list of valid code page identifiers for Mac OS only:

IdentifierName
1ASCII
2NEXTSTEP
3JapaneseEUC
4UTF8
5ISOLatin1
6Symbol
7NonLossyASCII
8ShiftJIS
9ISOLatin2
10Unicode
11WindowsCP1251
12WindowsCP1252
13WindowsCP1253
14WindowsCP1254
15WindowsCP1250
21ISO2022JP
30MacOSRoman
10UTF16String
0x90000100UTF16BigEndian
0x94000100UTF16LittleEndian
0x8c000100UTF32String
0x98000100UTF32BigEndian
0x9c000100UTF32LittleEndian
65536Proprietary

LicenseInfo:   Information about the current license.

When queried, this setting will return a string containing information about the license this instance of a class is using. It will return the following information:

  • Product: The product the license is for.
  • Product Key: The key the license was generated from.
  • License Source: Where the license was found (e.g., RuntimeLicense, License File).
  • License Type: The type of license installed (e.g., Royalty Free, Single Server).
  • Last Valid Build: The last valid build number for which the license will work.
ProcessIdleEvents:   Whether the class uses its internal event loop to process events when the main thread is idle.

If set to False, the class will not fire internal idle events. Set this to False to use the class in a background thread on Mac OS. By default, this setting is True.

SelectWaitMillis:   The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.

If there are no events to process when do_events is called, the class will wait for the amount of time specified here before returning. The default value is 20.

UseInternalSecurityAPI:   Tells the class whether or not to use the system security libraries or an internal implementation.

By default the class will use the system security libraries to perform cryptographic functions where applicable. Setting this to True tells the class to use the internal implementation instead of using the system's security API.

ZipStream Errors

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

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).

Copyright (c) 2022 /n software inc. - All rights reserved.
IPWorks ZIP 2022 Python Edition - Version 22.0 [Build 8203]