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Python library for indexing block offsets within LZO compressed files

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python3_lzo_indexer

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Python library for indexing block offsets within LZO compressed files. The implementation is largely based on that of the Hadoop Library. Index files are used to allow Hadoop to split a single file compressed with LZO into several chunks for parallel processing.

Since LZO is a block based compression algorithm, we can split the file along the lines of blocks and decompress each block on it’s own. The index is a file containing byte offsets for each block in the original LZO file.

This library is python3 fork of python-lzo-indexer.

Example

The python code below demonstrates how easy it is to index an LZO file. This library also supports indexing a string, and a method to return the individual block offsets should you need to create a file of your own format.

import lzo_indexer

with open("my-file.lzo", "r") as f, open("my-file.lzo.index", "rw") as index:
    lzo_indexer.index_lzo_file(f, index)

Command-line Utility

This library also includes a utility for indexing multiple lzo files, using the python indexer. This is a much faster alternative to the command line utility built into the hadoop-lzo library as it avoids the JVM.

$ lzo_indexer --help

Usage: lzo_indexer [OPTIONS] <files to index>

  Tool for indexing LZO compressed files

Options:
  -t, --threads INTEGER  Processing threads count
  -e, --extension TEXT   Index file extension
  -f, --force            Force re-creation of an index even if it exists
  -h, --help             Show this message and exit.

Contributions

I welcome any contributions, though I request that any pull requests come with test coverage.

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Python library for indexing block offsets within LZO compressed files

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