# Zstd Class

TBD.

## Syntax

```text
class ipworkszip.Zstd
```

## Remarks

TBD

## 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_level](#compression_level-property) | The compression level to use. |
| [input_data](#input_data-property) | Specifies the data to compress or decompress. |
| [output_data](#output_data-property) | The output data after compression or decompression. |

## 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_block](#compress_block-method) | Compresses a block of data. |
| [compress_data](#compress_data-method) | Compresses the specified data. |
| [config](#config-method) | Sets or retrieves a configuration setting. |
| [decompress_block](#decompress_block-method) | Decompresses a block of data. |
| [decompress_data](#decompress_data-method) | Decompresses the specified data. |
| [reset](#reset-method) | Resets 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_data](#on_compressed_data-event) | This event fires with compressed data. |
| [on_decompressed_data](#on_decompressed_data-event) | This event fires with decompressed data. |
| [on_error](#on_error-event) | Information about errors during data delivery. |

## Config Settings

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

|  |  |
| --- | --- |
| [BuildInfo](#BuildInfo) | Information about the product's build. |
| [CodePage](#CodePage) | The system code page used for Unicode to Multibyte translations. |
| [LicenseInfo](#LicenseInfo) | Information about the current license. |
| [MaskSensitiveData](#MaskSensitiveData) | Whether sensitive data is masked in log messages. |
| [ProcessIdleEvents](#ProcessIdleEvents) | Whether the class uses its internal event loop to process events when the main thread is idle. |
| [SelectWaitMillis](#SelectWaitMillis) | The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process. |
| [UseInternalSecurityAPI](#UseInternalSecurityAPI) | Whether or not to use the system security libraries or an internal implementation. |

# compression_level property

The compression level to use.

## Syntax

```text
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

```text
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](#decompress_data-method) or [decompress_block](#decompress_block-method).

When compressing this should be set to the decompressed data before calling [compress_data](#compress_data-method) or [compress_block](#compress_block-method).

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

# output_data property

The output data after compression or decompression.

## Syntax

```text
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](#compress_data-method) or [decompress_data](#decompress_data-method) is called.

This property is not applicable when calling [compress_block](#compress_block-method) or [decompress_block](#decompress_block-method).

This property is read-only.

# compress_block method

Compresses a block of data.

## Syntax

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

## Remarks

This method compresses the block of data specified by [input_data](#input_data-property).

The compress_block and [decompress_block](#decompress_block-method) 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](#output_data-property) property is not applicable. Instead data is made available through the [on_compressed_data](#on_compressed_data-event) and [on_decompressed_data](#on_decompressed_data-event) events.

If all data is available ahead of time [compress_data](#compress_data-method) and [decompress_data](#decompress_data-method) may be called instead.

### Compress Data

Set [input_data](#input_data-property) 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](#on_compressed_data-event) 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:

```text
zipstream.InputDataB = MyDecompressedData;
zipstream.CompressBlock();
```

 Data is accumulated inside the [on_compressed_data](#on_compressed_data-event) event:

```text
private static void Zipstream_OnCompressedData(object sender, ZipstreamCompressedDataEventArgs e)
{
  DoSomethingWith(e.DataB);
}
```

Note that [output_data](#output_data-property) is not applicable when compressing block data.

### Decompress Data

Set [input_data](#input_data-property) to the current block to be decompressed. Next call [decompress_block](#decompress_block-method) to decompress the current block.

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

```text
zipstream.InputDataB = MyCompressedData;
zipstream.DecompressBlock();
```

 Data is accumulated inside the [on_decompressed_data](#on_decompressed_data-event) event:

```text
private static void Zipstream_OnDecompressedData(object sender, ZipstreamDecompressedDataEventArgs e)
{
  DoSomethingWith(e.DataB);
}
```

Note that [output_data](#output_data-property) is not applicable when decompressing block data.

# compress_data method

Compresses the specified data.

## Syntax

```text
def compress_data() -> None: ...
```

## Remarks

This method compresses the data specified by [input_data](#input_data-property). After calling this method [output_data](#output_data-property) holds the compressed data.

The compress_data and [decompress_data](#decompress_data-method) methods operate on the complete blob of data. The entire compressed or decompressed data must be set to [input_data](#input_data-property) before calling either method.

To compress and decompress data in blocks (chunks) see [compress_block](#compress_block-method) and [decompress_block](#decompress_block-method).

### Compress Data

Set [input_data](#input_data-property) to the decompressed data. This should be the entire data to be compressed. Next call compress_data. After compression [output_data](#output_data-property) will hold the compressed data. For example:

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

In addition to [output_data](#output_data-property), the compressed data may also be accumulated within the [on_compressed_data](#on_compressed_data-event) event.

### Decompress Data

Set [input_data](#input_data-property) to the compressed data. This should be the entire data to be decompressed. Next call [decompress_data](#decompress_data-method). After decompression [output_data](#output_data-property) will hold the decompressed data. For example:

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

In addition to [output_data](#output_data-property), the compressed data may also be accumulated within the [on_decompressed_data](#on_decompressed_data-event) event.

# config method

Sets or retrieves a configuration setting.

## Syntax

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

## Remarks

config is a generic method available in every class. It is used to set and retrieve [configuration settings](#zstd-config-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](#zstd-config-settings), you must call *Config("PROPERTY")*. The value will be returned as a string.

# decompress_block method

Decompresses a block of data.

## Syntax

```text
def decompress_block() -> None: ...
```

## Remarks

This method decompresses the block of data specified by [input_data](#input_data-property).

The [compress_block](#compress_block-method) 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](#output_data-property) property is not applicable. Instead data is made available through the [on_compressed_data](#on_compressed_data-event) and [on_decompressed_data](#on_decompressed_data-event) events.

If all data is available ahead of time [compress_data](#compress_data-method) and [decompress_data](#decompress_data-method) may be called instead.

### Compress Data

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

```text
zipstream.InputDataB = MyDecompressedData;
zipstream.CompressBlock();
```

 Data is accumulated inside the [on_compressed_data](#on_compressed_data-event) event:

```text
private static void Zipstream_OnCompressedData(object sender, ZipstreamCompressedDataEventArgs e)
{
  DoSomethingWith(e.DataB);
}
```

Note that [output_data](#output_data-property) is not applicable when compressing block data.

### Decompress Data

Set [input_data](#input_data-property) to the current block to be decompressed. Next call decompress_block to decompress the current block.

During decompression the [on_decompressed_data](#on_decompressed_data-event) 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:

```text
zipstream.InputDataB = MyCompressedData;
zipstream.DecompressBlock();
```

 Data is accumulated inside the [on_decompressed_data](#on_decompressed_data-event) event:

```text
private static void Zipstream_OnDecompressedData(object sender, ZipstreamDecompressedDataEventArgs e)
{
  DoSomethingWith(e.DataB);
}
```

Note that [output_data](#output_data-property) is not applicable when decompressing block data.

# decompress_data method

Decompresses the specified data.

## Syntax

```text
def decompress_data() -> None: ...
```

## Remarks

This method decompresses the data specified by [input_data](#input_data-property). After calling this method [output_data](#output_data-property) holds the decompressed data.

The [compress_data](#compress_data-method) and decompress_data methods operate on the complete blob of data. The entire compressed or decompressed data must be set to [input_data](#input_data-property) before calling either method.

To compress and decompress data in blocks (chunks) see [compress_block](#compress_block-method) and [decompress_block](#decompress_block-method).

### Compress Data

Set [input_data](#input_data-property) to the decompressed data. This should be the entire data to be compressed. Next call [compress_data](#compress_data-method). After compression [output_data](#output_data-property) will hold the compressed data. For example:

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

In addition to [output_data](#output_data-property), the compressed data may also be accumulated within the [on_compressed_data](#on_compressed_data-event) event.

### Decompress Data

Set [input_data](#input_data-property) to the compressed data. This should be the entire data to be decompressed. Next call decompress_data. After decompression [output_data](#output_data-property) will hold the decompressed data. For example:

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

In addition to [output_data](#output_data-property), the compressed data may also be accumulated within the [on_decompressed_data](#on_decompressed_data-event) event.

# reset method

Resets the class.

## Syntax

```text
def reset() -> None: ...
```

## Remarks

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

```text
class ZstdCompressedDataEventParams(object):
  @property
  def data() -> bytes: ...

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

## Remarks

The on_compressed_data event fires as compressed data is available when [compress_data](#compress_data-method) or [compress_block](#compress_block-method) 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

```text
class ZstdDecompressedDataEventParams(object):
  @property
  def data() -> bytes: ...

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

## Remarks

The on_decompressed_data event fires as compressed data is available when [decompress_data](#decompress_data-method) or [decompress_block](#decompress_block-method) 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

```text
class ZstdErrorEventParams(object):
  @property
  def error_code() -> int: ...

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

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

## Remarks

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

*error_code* 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](#zstd-errors) section.

# Zstd Config Settings

 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](#config-method) method.

*No configuration settings defined.*

### Base Config 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:

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

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

|  |  |
| --- | --- |
| Identifier | Name |
| 1 | ASCII |
| 2 | NEXTSTEP |
| 3 | JapaneseEUC |
| 4 | UTF8 |
| 5 | ISOLatin1 |
| 6 | Symbol |
| 7 | NonLossyASCII |
| 8 | ShiftJIS |
| 9 | ISOLatin2 |
| 10 | Unicode |
| 11 | WindowsCP1251 |
| 12 | WindowsCP1252 |
| 13 | WindowsCP1253 |
| 14 | WindowsCP1254 |
| 15 | WindowsCP1250 |
| 21 | ISO2022JP |
| 30 | MacOSRoman |
| 10 | UTF16String |
| 0x90000100 | UTF16BigEndian |
| 0x94000100 | UTF16LittleEndian |
| 0x8c000100 | UTF32String |
| 0x98000100 | UTF32BigEndian |
| 0x9c000100 | UTF32LittleEndian |
| 65536 | Proprietary |

**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.

**MaskSensitiveData**: Whether sensitive data is masked in log messages.In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to *True* to mask sensitive data. The default is *True*.

**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**: Whether or not to use the system security libraries or an internal implementation. When set to *False*, the class will use the system security libraries by default to perform cryptographic functions where applicable.

Setting this configuration setting to *True* tells the class to use the internal implementation instead of using the system security libraries.

 On Windows, this setting is set to *False* by default. On Linux/macOS, this setting is set to *True* by default.

 To use the system security libraries for Linux, OpenSSL support must be enabled. For more information on how to enable OpenSSL, please refer to the [OpenSSL Notes](platforms.md) section.

# Zstd 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). |