The ZCompress class implements an LZC compressor and decompressor. It is compatible with the UNIX compress utility.
The LZC file format is used only to archive a single file. Accordingly, the operation of the class is simpler than that of the other classs.
To compress with the class, set archive_file to the name of the LZC compressed file to be created, and file_decompressed_name to the name of the file to be compressed. Finally, invoke compress. To extract the file, first set archive_file. file_decompressed_name may then be set; if not, it will automatically be set based on the archive_file name. Finally, invoke the extract method.
Example (Creating an LZC File)
ZipControl.ArchiveFile = "c:\test.Z"
ZipControl.FileDecompressedName = "c:\test.txt"
Example (Extracting from an LZC File)
ZipControl.ArchiveFile = "c:\test.Z"
ZipControl.FileDecompressedName = "c:\test.txt"
The following is the full list of the properties of the class with short descriptions. Click on the links for further details.
|archive_file||The name of the zip, gzip, tar, or jar archive.|
|file_decompressed_name||File name to decompress to, or compress from.|
|file_input_data||The data of the file to be compressed.|
|z_compress_data||(Decompression only) The LZC compressed file contents as a byte array.|
The following is the full list of the methods of the class with short descriptions. Click on the links for further details.
|abort||Aborts the current operation.|
|compress||Creates the compressed archive.|
|config||Sets or retrieves a configuration setting.|
|extract||Extracts the compressed file from the archive.|
|reset||Resets the class.|
The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.
|on_begin_file||Fired before a file is processed.|
|on_end_file||Fired after a file is processed.|
|on_error||Information about non-fatal errors.|
|on_overwrite||Fired whenever a file exists and may be overwritten.|
|on_progress||Fired as progress is made.|
The following is a list of configuration settings for the class with short descriptions. Click on the links for further details.
|WriteToProgressEvent||Whether or not to write data to the Progress Event.|
|BuildInfo||Information about the product's build.|
|CodePage||The system code page used for Unicode to Multibyte translations.|
|LicenseInfo||Information about the current license.|
|ProcessIdleEvents||Whether the class uses its internal event loop to process events when the main thread is idle.|
|SelectWaitMillis||The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.|
|UseInternalSecurityAPI||Tells the class whether or not to use the system security libraries or an internal implementation.|
The name of the zip, gzip, tar, or jar archive.
def get_archive_file() -> str: ... def set_archive_file(value: str) -> None: ...
archive_file = property(get_archive_file, set_archive_file)
This property specifies the name of the archive to be read or written. This property is required when extracting files.
When scan, extract, or extract_all is invoked, the file specified by archive_file will be opened for read. If the file does not exist, a trappable error will be generated.
When compress is called, the file named by archive_file will be written; if a file of this name already exists the on_overwrite event will be fired. If archive_file is set to the empty string (""), the archive will not be written to disk, and will be provided only through the on_progress event.
The filename may be specified with or without a path. Paths may be relative or absolute, and should be specified in the format native to the host operating system. The filename should be specified with the appropriate extension (such as "zip"); an extension will not automatically be appended by the class.
If the file cannot be read, or written, as appropriate, a trappable error will be generated.
Example (Creating an Archive)
ZipControl.ArchiveFile = "c:\test.zip"
ZipControl.RecurseSubdirectories = true
Note: an archive already open for read may be closed by setting archive_file to the empty string ("").
File name to decompress to, or compress from.
def get_file_decompressed_name() -> str: ... def set_file_decompressed_name(value: str) -> None: ...
file_decompressed_name = property(get_file_decompressed_name, set_file_decompressed_name)
file_decompressed_name contains the name of the file in the archive, as stored on the file system, outside the archive.
When compressing a file and set_file_input_stream has not been called with a valid input stream, this property should be specified with a path, if necessary, to allow the file to be found by the class. If the file cannot be found when compress is called, a trappable error will be generated, and the archive will not be correctly written.
When decompressing files, this property may be set prior to calling extract. If this property is set to the empty string when extract is called, extract will automatically set this property to an appropriate value.
Paths on the local file system should be specified in the format native to the host operating system. They may also be specified in standard (UNIX) format, in which case they will be immediately converted.
The data of the file to be compressed.
def get_file_input_data() -> bytes: ... def set_file_input_data(value: bytes) -> None: ...
file_input_data = property(get_file_input_data, set_file_input_data)
When this property is set, the class will read in the data from this property instead of reading from the file contained in the file_decompressed_name property.
(Decompression only) The LZC compressed file contents as a byte array.
def set_z_compress_data(value: bytes) -> None: ...
z_compress_data = property(None, set_z_compress_data)
Normally you should set archive_file before invoking extract. If you prefer to read the LZC compressed file from memory you may set z_compress_data instead. z_compress_data should be set to the entire contents of the LZC compressed file; this will allow you to read from the archive without writing any temporary files to disk.
If you would like to extract data from the archive without ever writing to disk you should also set WriteToProgressEvent to true, and you should set the value of file_decompressed_name to an empty string. Then, when you invoke extract the data will be provided in the on_progress event.
This property is write-only. Note that modifying a LZC compressed file stored in z_compress_data is not supported.
This property is write-only.
Aborts the current operation.
def abort() -> None: ...
on_abort may be used to immediately interrupt compression or decompression. Any files partially written by the class will be deleted.
Creates the compressed archive.
def compress() -> None: ...
Invoking on_compress creates the archive specified by archive_file. When the method is called, the file specified by file_decompressed_name will be opened, and the file specified by archive_file will contain the compressed output.
Sets or retrieves a configuration setting.
def config(configuration_string: str) -> str: ...
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.
Extracts the compressed file from the archive.
def extract() -> None: ...
Invoking on_extract decompresses the archive specified by archive_file. The compressed file will be extracted, and written to disk.
Resets the class.
def reset() -> None: ...
on_reset resets the state of the class. All properties will be set to their default values, and any files open will be closed.
Fired before a file is processed.
class ZCompressBeginFileEventParams(object): @property def index() -> int: ... @property def skip() -> bool: ... @skip.setter def skip(value) -> None: ... # In class ZCompress: @property def on_begin_file() -> Callable[[ZCompressBeginFileEventParams], None]: ... @on_begin_file.setter def on_begin_file(event_hook: Callable[[ZCompressBeginFileEventParams], None]) -> None: ...
on_begin_file is fired before compression or decompression begins. Index will contain 0.
You may use the Skip parameter to tell the component to skip the file when compressing or decompressing.
Fired after a file is processed.
class ZCompressEndFileEventParams(object): @property def index() -> int: ... # In class ZCompress: @property def on_end_file() -> Callable[[ZCompressEndFileEventParams], None]: ... @on_end_file.setter def on_end_file(event_hook: Callable[[ZCompressEndFileEventParams], None]) -> None: ...
on_end_file is fired when compression or decompression finishes. Index will contain 0.
Information about non-fatal errors.
class ZCompressErrorEventParams(object): @property def description() -> str: ... @property def error_code() -> int: ... @property def index() -> int: ... @property def filename() -> str: ... @property def ignore() -> bool: ... @ignore.setter def ignore(value) -> None: ... # In class ZCompress: @property def on_error() -> Callable[[ZCompressErrorEventParams], None]: ... @on_error.setter def on_error(event_hook: Callable[[ZCompressErrorEventParams], None]) -> None: ...
The on_error event is fired when non-fatal errors occur during compression or decompression. Note that if this event is fired during decompression this may indicate that the archive is corrupt.
By default these errors will cause the component to fail with an exception. The exception may be overridden by setting Ignore to true. This will cause the error to be ignored, the file will be skipped if necessary, and the class will continue operation.
ErrorCode will correspond to one of the following errors:
|1||Bad or missing CRC-32 checksum.|
|2||Failed to set creation date of a file.|
|111||Can't open file for read (skipping).|
Description contains a textual description of the error. Index and Filename contain the array index (where appropriate) and filename of the file being processed at the time of the error.
Fired whenever a file exists and may be overwritten.
class ZCompressOverwriteEventParams(object): @property def filename() -> str: ... @filename.setter def filename(value) -> None: ... @property def overwrite() -> bool: ... @overwrite.setter def overwrite(value) -> None: ... # In class ZCompress: @property def on_overwrite() -> Callable[[ZCompressOverwriteEventParams], None]: ... @on_overwrite.setter def on_overwrite(event_hook: Callable[[ZCompressOverwriteEventParams], None]) -> None: ...
on_overwrite is fired when a file is about to be overwritten, and would overwrite an existing file. The event is fired during decompression.
Filename contains the full name of the file, specified with its pathname.
Overwrite specifies whether or not the file will be overwritten. For Zip, Jar, and Tar, this is equal by default to the value of the overwrite_files property. For Gzip, this value defaults to true.
Either of the parameters may be changed when the event is fired. Changing the value of Overwrite will override the default behavior of the class, and cause the file to be overwritten or not overwritten, depending on the value set. If Filename is changed, the value of Overwrite will be ignored, and the file will be written with the specified name. If a file of the new name also exists this file will be silently overwritten.
Fired as progress is made.
class ZCompressProgressEventParams(object): @property def data() -> bytes: ... @property def filename() -> str: ... @property def bytes_processed() -> int: ... @property def percent_processed() -> int: ... # In class ZCompress: @property def on_progress() -> Callable[[ZCompressProgressEventParams], None]: ... @on_progress.setter def on_progress(event_hook: Callable[[ZCompressProgressEventParams], None]) -> None: ...
The on_progress event is automatically fired as compression or decompression is performed. When WriteToProgressEvent is true, the output data is provided through the Data parameter, allowing for it to be streamed out.
Filename contains the name of the file being written. If no file is being written, Filename will contain an empty string, and the output data will be provided exclusively through this event.
BytesProcessed contains the total number of uncompressed bytes processed. PercentProcessed contains the percent of uncompressed bytes processed, corresponding roughly to the running time of the operation.
For Gzip extraction only, BytesProcessed and PercentProcessed will reflect the number of compressed bytes extracted, as it is generally impossible to predetermine the total uncompressed size.
If WriteToProgressEvent is false, Data will contain null.
ZCompress ConfigurationThe 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.
ZCompress Configuration Settings
Whether or not to write data to the Progress Event.If WriteToProgressEvent is set to true, then all data produced through invocations
of extract, extract_all, and compress will be written to the on_progress
event as well as to disk. Applications may stream out the compressed or decompressed
data by trapping this event and copying the data.
By default, this config is set to false.
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.|
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:
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:
|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.|
The following errors may be generated by the class. Note that frequently the error message will contain more specific information than what is listed here.
Note that some non-fatal errors may be trapped and explicitly ignored in the on_error event. This will allow the class to continue operation even in case of error.
|111 Can't open file for read.|
|112 Can't open file for write.|
|113 Can't create directory.|
|114 The file is too large.|
|115 Can't create empty archive.|
|116 The archive must be scanned prior to attempting this operation.|
|117 The array index is out of range.|
|118 The maximum size of the archive has been exceeded.|
|119 The archive must be specified, or streaming must be enabled.|
|120 The component is busy.|
|124 Must specify the compressed name.|
|127 Bad CRC-32 checksum.|
|128 Unable to set file date.|
|133 File already exists in the archive.|
|150 An I/O error has occurred (details follow).|