`compress.bzip2`

import compress

compress exposes this as compress.bzip2, so import compress is enough and the names are called as compress.bzip2.*. import compress.bzip2 reaches the same definitions directly.

The Bzip2 submodule for the compress module.

Functions

`compress()`

compress.bzip2.compress(data, level) -> bytes

Compress data using the default options for Bzip2.

Parameters

data (bytes|string)
level (?number) — Compression level (1..=9): Default 9.

Returns bytes

`decompress()`

compress.bzip2.decompress(data) -> bytes

Decompress Bzip2-compressed data.

Parameters

data (bytes|string)

Returns bytes

Note: This only decodes the first bzip2 stream in data. Some tools (pbzip2, Wikipedia data dumps, …) concatenate several independent bzip2 streams back to back (“multistreams”); use Bzip2Decoder in a loop with reset() to decode all of them.

Classes

`Bzip2Encoder`

class compress.bzip2.Bzip2Encoder

A streaming Bzip2 encoder.

Example:

%> import compress.bzip2
%> var encoder = bzip2.Bzip2Encoder()
%> encoder.write('hello world')
11
%> encoder.finish()
(42 5a 68 39 31 41 59 26 53 59 ...)

Constructor

compress.bzip2.Bzip2Encoder(level, work_factor)

Creates a new streaming Bzip2 encoder.

Parameters

level (?number) — Compression level (1..=9): Default 9.
work_factor (?number) — Controls when the compressor falls back from its standard sorting algorithm to a slower but more robust one on highly repetitive input. 0..=250: 0 (the default) means “use bzip2’s own default of 30”.

`Bzip2Encoder.finish()`

compress.bzip2.Bzip2Encoder.finish() -> bytes

Flushes remaining data, writes the stream footer, and returns the inner byte stream.

Returns bytes

Note: Once finish is called, the encoder can no longer be reused.

`Bzip2Encoder.close()`

compress.bzip2.Bzip2Encoder.close() -> bytes

Same as finish() for file API compartibility.

Returns bytes

Note: Once finish is called, the encoder can no longer be reused.

`Bzip2Encoder.reset()`

compress.bzip2.Bzip2Encoder.reset() -> bytes

Finishes the current stream and installs a fresh one for the next frame.

Returns the previous byte stream containing the completed frame.

Returns bytes

`Bzip2Encoder.write()`

compress.bzip2.Bzip2Encoder.write(data) -> number

Writes data into this encoder’s byte stream, returning how many bytes were written.

Parameters

data (bytes|string)

Returns number

`Bzip2Encoder.flush()`

compress.bzip2.Bzip2Encoder.flush() -> bytes

Flushes this output stream and returns the compressed data produced so far, without terminating the bzip2 stream.

Returns bytes

`Bzip2Encoder.available()`

compress.bzip2.Bzip2Encoder.available() -> number

Returns the number of compressed bytes currently waiting in the encoder’s output buffer.

Returns number

`Bzip2Encoder.finished()`

compress.bzip2.Bzip2Encoder.finished() -> bool

Returns whether finish() has completed the stream.

Returns bool

`Bzip2Encoder.total_in()`

compress.bzip2.Bzip2Encoder.total_in() -> number

Number of uncompressed bytes consumed by the encoder.

Returns number

`Bzip2Encoder.total_out()`

compress.bzip2.Bzip2Encoder.total_out() -> number

Number of compressed bytes generated by the encoder.

Returns number

`Bzip2Decoder`

class compress.bzip2.Bzip2Decoder

Streaming bzip2 decompressor implementation.

Wraps a byte stream of compressed data and yields decompressed bytes.

Example:

%> import compress.bzip2
%> var data = bzip2.compress('hello world')
%> var decoder = bzip2.Bzip2Decoder(data)
%> decoder.read_as_string()
hello world

Note: only decodes a single bzip2 stream: see decompress()’s note about “multistreams”.

Constructor

compress.bzip2.Bzip2Decoder(source)

Creates a Bzip2 decoder

Parameters

source (bytes)

`Bzip2Decoder.reset()`

compress.bzip2.Bzip2Decoder.reset(new_source)

Installs a new data source, discarding whatever remained of the previous one.

Parameters

new_source (bytes)

`Bzip2Decoder.close()`

compress.bzip2.Bzip2Decoder.close()

Closes the decoder by resetting it into an empty stream.

`Bzip2Decoder.read()`

compress.bzip2.Bzip2Decoder.read(length) -> bytes

Reads some bytes up to the amount of bytes specified by length from the current source. Returns an empty byte stream when there is no more data to read.

Parameters

length (number)

Returns bytes

`Bzip2Decoder.read_exact()`

compress.bzip2.Bzip2Decoder.read_exact(length) -> bytes

Reads the exact number of bytes from the buffer. This method will raise an error if it encounters an unexpected EOF (end of file) or there are insufficient data to read to complete the required number of bytes.

Parameters

length (number)

Returns bytes

`Bzip2Decoder.read_all()`

compress.bzip2.Bzip2Decoder.read_all() -> bytes

Reads all remaining bytes until EOF is encountered in the source.

Returns bytes

`Bzip2Decoder.read_as_string()`

compress.bzip2.Bzip2Decoder.read_as_string() -> string

Reads all remaining bytes until EOF is encountered in the source and returns the data read as a string instead of a byte stream.

Returns string

`Bzip2Decoder.available()`

compress.bzip2.Bzip2Decoder.available() -> number

Returns the number of compressed bytes still unread in the decoder’s source.

Returns number

`Bzip2Decoder.finished()`

compress.bzip2.Bzip2Decoder.finished() -> bool

Returns whether the decoder has reached the end of the stream.

Returns bool

`Bzip2Decoder.total_in()`

compress.bzip2.Bzip2Decoder.total_in() -> number

Number of compressed bytes consumed by the decoder.

Returns number

`Bzip2Decoder.total_out()`

compress.bzip2.Bzip2Decoder.total_out() -> number

Number of uncompressed bytes generated by the decoder.

Returns number

`BzFile`

class compress.bzip2.BzFile

The BzFile class implements a Bzip2 based I/O system that allows you to treat Bzip2 streams (bytes) as if they were a file.

The class implements the essentials of a file except those that ties it to the operating system filesystem such as symbolic links, chmod and set time.

See the chapter on files in The Zuri Programming Language for more information.

Constructor

compress.bzip2.BzFile(path: string, mode: ?string, _inner)

Returns a new BzFile object bounded to a physical file at the given path and opened in the given mode. See [[file]] for a description of the supported file modes.

Parameters

path (string)
mode (?string)

Returns BzFile

`BzFile.exists()`

compress.bzip2.BzFile.exists() -> bool

Returns true if the underlying file bounded to BzFile actually exists or false otherwise.

Returns bool

`BzFile.close()`

compress.bzip2.BzFile.close()

Closes the stream to an opened BzFile. You’ll rarely ever need to call this method yourself in most use cases.

`BzFile.flush()`

compress.bzip2.BzFile.flush() -> bytes

Flushes the remaning data into the BzFile underlying file and returns the byte stream returned.

Returns bytes

`BzFile.open()`

compress.bzip2.BzFile.open() -> bool

Opens the stream to a BzFile for the operation originally specified on the BzFile object during creation.

You may need to call this method after a call to read() if the length isn’t specified or write() if you wish to read or write again as the BzFile will already be closed.

Returns bool

`BzFile.read()`

compress.bzip2.BzFile.read(length: ?number) -> bytes

Reads the content of an opened BzFile up to the specified length and returns it as string or bytes if the BzFile was opened in the binary mode. If the length is not specified, the BzFile will be read to the end.

This method requires that the BzFile be opened in the read mode (default mode) or a mode that supports reading. If you aren’t reading the full length of the BzFile, you’ll need to call the close() method to free the BzFile for further reading, otherwise, the close() method will be automatically called for you.

Parameters

length (number) — Default = -1

Returns bytes

Raises Error

`BzFile.gets()`

compress.bzip2.BzFile.gets(length: ?number) -> bytes

Same as read(), but doesn’t close the BzFile automatically.

Parameters

length (?number) — Default = -1, meaning read to the end.

Returns bytes

Raises Error

`BzFile.write()`

compress.bzip2.BzFile.write(data: bytes|string) -> number

Writes a string or bytes to an opened BzFile at the current insertion point. When the BzFile is opened with the a mode enabled, write will always start from the end of the BzFile.

If the seek() method has been previously called, write will begin from the seeked position, otherwise it will start at the beginning of the BzFile.

Parameters

`` (bytes|string)

Returns number

`BzFile.puts()`

compress.bzip2.BzFile.puts(data: bytes|string) -> number

Same as write(), but doesn’t open or close the BzFile automatically.

Parameters

`` (bytes|string)

Returns number

`BzFile.number()`

compress.bzip2.BzFile.number() -> number

Returns the integer file descriptor number that is used by the underlying implementation to request I/O operations from the operating system. This can be very useful for low-level interfaces that uses or act as BzFile descriptors.

Returns number

`BzFile.is_tty()`

compress.bzip2.BzFile.is_tty() -> bool

Returns true if the underlying file of BzFile is a TTY device or false otherwise.

Returns bool

`BzFile.is_open()`

compress.bzip2.BzFile.is_open() -> bool

Returns true if the BzFile is open for reading or writing and false otherwise.

Returns bool

`BzFile.is_closed()`

compress.bzip2.BzFile.is_closed()

Returns true if the BzFile is closed for reading or writing and false otherwise.

`BzFile.symlink()`

compress.bzip2.BzFile.symlink(path: string) -> bool

See [[file.symlink]]

Returns bool

`BzFile.stats()`

compress.bzip2.BzFile.stats() -> dict

Returns the statistics or details of the BzFile.

See the working with files documentation for more information about the stats() method.

Returns dict

`BzFile.delete()`

compress.bzip2.BzFile.delete() -> bool

Deletes the underlying file pointed to by BzFile

Any further attempt to perform most operations on the BzFile after calling delete() will raise an error.

Returns bool

`BzFile.rename()`

compress.bzip2.BzFile.rename(new_name) -> bool

Renames the underlying file pointed to by BzFile to the new name and returns true if it succeeds or false otherwise.

Returns bool

`BzFile.copy()`

compress.bzip2.BzFile.copy() -> [[compress.bzip2.BzFile]]

Returns a new BzFile reading (or writing) the same underlying path independently of this one, with its own decoder/encoder state and its own position.

Returns [[compress.bzip2.BzFile]]

`BzFile.path()`

compress.bzip2.BzFile.path() -> string

Returns the physical path of the file pointed to by BzFile.

Returns string

`BzFile.abs_path()`

compress.bzip2.BzFile.abs_path() -> string

Returns the absolute path of the physical file pointed to by BzFile.

Returns string

`BzFile.truncate()`

compress.bzip2.BzFile.truncate(length: ?int) -> bool

Truncates the entire BzFile if length is not given or truncates the BzFile such that only length number of bytes is left in it.

Returns bool

`BzFile.chmod()`

compress.bzip2.BzFile.chmod(number: int) -> bool

Updates the permission for the file bounded by BzFile.

Returns bool

`BzFile.set_times()`

compress.bzip2.BzFile.set_times(atime: int, mtime: int) -> bool

Sets the last access time and last modified time of the BzFile.

Returns bool

`BzFile.seek()`

compress.bzip2.BzFile.seek(position: int, seek_type: int) -> bool

Sets the position of a BzFile reader in the decompressed byte stream (not the raw, still-compressed bytes on disk, which have no useful correspondence to a decompressed offset). The seek_type argument must be one of [[io.SEEK_SET]], [[io.SEEK_CUR]] or [[io.SEEK_END]].

Seeking forward simply discards decompressed bytes until the target position, since a streaming decoder has no way to skip ahead without producing them. Seeking backward (or SEEK_END, which has to fully decode the stream once to learn its length) re-opens the underlying file and restarts decompression from the beginning, discarding up to the target position: an inherently expensive operation for a compressed stream, same as with any other streaming (de)compressor.

Not supported on a BzFile opened for writing.

Returns bool

`BzFile.tell()`

compress.bzip2.BzFile.tell() -> number

Returns the current position of the reader in the decompressed byte stream (bytes already consumed via read()/gets()/seek()), or of the writer in the uncompressed input already fed to write()/puts() for a BzFile opened for writing.

Returns number

`BzFile.mode()`

compress.bzip2.BzFile.mode() -> string

Returns the mode in which the current BzFile was opened.

Returns string

`BzFile.name()`

compress.bzip2.BzFile.name() -> string

Returns the name of the file pointed to by BzFile.

Returns string

2026, Richard Ore and Zuri contributors

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