pyzim.compression.DecompressingReader

class documentation

class DecompressingReader(object):

A helper class that helps with reading data selectively from a compressed stream.

Method	`__init__`	The default constructor.
Method	`iter_read`	Read n bytes iteratively.
Method	`read`	Read up to n bytes.
Method	`read_n`	Read until n bytes have been read (or until EOF has been encountered).
Method	`reseek`	Re-seek the wrapped file object to match the last read position.
Method	`skip`	Skip the next n bytes.
Method	`skip_to`	Skip bytes until the specified offset is reached.
Instance Variable	`read_compressed`	number of compressed bytes read.
Instance Variable	`read_decompressed`	number of decompressed bytes read
Property	`total_compressed_size`	Return the total size of the compressed data stream so far.
Instance Variable	`_buffer`	Undocumented
Instance Variable	`_decompressor`	Undocumented
Instance Variable	`_f`	Undocumented

def __init__(self, f, decompressor): ¶

The default constructor.

Parameters
f:file-like	file to read from
decompressor:decompressor-like	a decompressor-like object to decompress the data

def iter_read(self, n=-1, buffersize=4096): ¶

Read n bytes iteratively.

Parameters
n:`int`	number of bytes to read. If smaller than 0, read until EOF.
buffersize:`int`	size of chunks to read at once

Yields
`bytes`	the data read (may be less than n)

def read(self, n, extra_decompress=0): ¶

Read up to n bytes.

Similiar to file-like objects, this may return less bytes, but will return an empy string if and only if there's nothing left to read.

Parameters
n:`int`	maximum number of bytes to read
extra_decompress:`int`	decompress this many bytes more, mainly used for testing

Returns
`str`	the bytes read

def read_n(self, n): ¶

Read until n bytes have been read (or until EOF has been encountered).

This method will attempt to always return exactly n bytes. However, should the EOF be encountered before this, less bytes may be returned.

Parameters
n:`int`	number of bytes to read

Returns
`str`	the bytes read

def reseek(self, base_offset=0): ¶

Re-seek the wrapped file object to match the last read position.

This should be called whenever some other code may have read/seeked the underlying file object.

Parameters
base_offset:`int`	If specified, take this offset within the underlying file object as the actual start of this wrapper.

def skip(self, n): ¶

Skip the next n bytes.

Parameters
n:`int`	number of bytes to skip

def skip_to(self, offset): ¶

Skip bytes until the specified offset is reached.

Parameters
offset:`int`	offset to skip to

Raises
`IOError`	if offset points behind current position

read_compressed: int = ¶

number of compressed bytes read.

read_decompressed: int = ¶

number of decompressed bytes read

total_compressed_size: int = ¶

Return the total size of the compressed data stream so far.

This only works if the compressor has read until the end.

_buffer = ¶

Undocumented

_decompressor = ¶

Undocumented

Undocumented