isal

1.8.0 · active · verified Sat Apr 11

isal (python-isal) provides faster zlib and gzip compatible compression and decompression by offering Python bindings for the Intel® Intelligent Storage Acceleration Library (ISA-L). It includes `isal_zlib` and `igzip` as high-performance, largely drop-in replacements for the standard library's `zlib` and `gzip` modules, respectively, along with `igzip_threaded` for multi-threaded streaming and `igzip_lib` for direct ISA-L API access. The current version is 1.8.0, and it maintains an active development and release cadence.

Warnings

breaking As of a recent release (likely 1.8.0), Python 3.8 and 3.9 are no longer officially supported, despite PyPI metadata potentially indicating support for `>=3.9`.
Fix: Ensure your project runs on Python 3.10 or newer.
gotcha Compression level `0` in `isal_zlib` and `igzip` corresponds to the *lowest* compression level, unlike `zlib` and `gzip` where `0` means 'no compression'.
Fix: Adjust compression level usage or explicitly choose a higher level if you expect actual compression.
gotcha `isal_zlib` primarily supports `Z_DEFAULT_STRATEGY`. While other strategies are exposed for compatibility, using them may result in warnings as ISA-L might not fully implement them.
Fix: Prefer `Z_DEFAULT_STRATEGY` or be aware that other strategies might behave differently or issue warnings.
gotcha `igzip_threaded`'s `open` function returns buffered read/write streams that are designed for streaming only and do not support seeking operations.
Fix: Use `igzip` for files requiring seeking, or manage your data in a strictly streaming fashion with `igzip_threaded`.
gotcha `igzip.open` returns an `IGzipFile` class instance, not the standard `GzipFile`. While `igzip.GzipFile` exists as an alias for compatibility, direct type checking or relying on `GzipFile`-specific internal behavior might break.
Fix: When using `igzip.open`, avoid strict type checks against `gzip.GzipFile` or use `igzip.GzipFile` alias if specific compatibility is needed.

Install

pip install isal Via pip
conda install python-isal Via Conda

Imports

isal_zlib
```
from isal import isal_zlib
```
Drop-in replacement for the standard `zlib` module.
igzip
```
from isal import igzip
```
Drop-in replacement for the standard `gzip` module.
igzip_threaded
```
from isal import igzip_threaded
```
Provides multi-threaded buffered read/write streams.
igzip_lib
```
from isal import igzip_lib
```
Direct access to ISA-L's compression functions.

Quickstart

This example demonstrates basic compression and decompression using `isal_zlib`, highlighting its direct compatibility with the standard `zlib` module's API.

from isal import isal_zlib

original_data = b"Python-isal offers faster compression and decompression." * 10

# Compress data
compressed_data = isal_zlib.compress(original_data)

# Decompress data
decompressed_data = isal_zlib.decompress(compressed_data)

assert original_data == decompressed_data

print(f"Original size: {len(original_data)} bytes")
print(f"Compressed size: {len(compressed_data)} bytes")
print("Data compressed and decompressed successfully using isal_zlib.")

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