---
id: bytesparse
version: "1.1.0"
license: BSD-2-Clause
license_treatment: permissive
maintenance: aging
---

# bytesparse — Library to handle sparse bytes within a virtual memory space

License: permissive · Maintenance: aging · Downloads: 225.3K/mo

## What it is and what it does

bytesparse is a Python library that implements a virtual memory container similar to bytearray but capable of storing sparse, non-contiguous chunks of data. Unlike bytearray, which requires contiguous allocation from address zero, bytesparse allows you to store data at arbitrary addresses with gaps in between—useful when emulating microcontroller memory spaces or handling other sparse data structures. The library provides two main classes: Memory (generic virtual memory with infinite address range) and bytesparse (a subclass that behaves more like bytearray). Both inherit from collections.abc.MutableSequence and MutableMapping, so they support familiar Python sequence and mapping operations.

The implementation is pure Python for maximum compatibility and leverages Python's arbitrary-precision integers to support even negative addresses. Data chunks are stored internally as bytearray objects, and the library provides a rich API for manipulating sparse memory: slicing, insertion, deletion, block management, memory views, cropping, shifting, and flooding empty spaces. The package also offers an experimental Cython implementation for performance-critical use cases.

Use it for:

- Emulate the address space of a microcontroller or embedded system where memory is sparse and non-contiguous.
- Store and manipulate binary data with gaps (e.g., firmware images with reserved regions or discontinuous segments).
- Implement a memory model for a debugger, simulator, or virtual machine that needs to track data at arbitrary addresses.
- Manage sparse binary patches or overlays where only certain address ranges contain meaningful data.
- Work with hex dump formats or binary file structures that have gaps or non-zero starting addresses.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides a bytearray-like class that stores sparse chunks of data in a virtual memory space with non-contiguous addressing, useful for emulating microcontroller memory or other sparse data structures.

Yes, if you need to work with sparse binary data at arbitrary addresses. The pure Python implementation, zero runtime dependencies, and bytearray-like interface make it easy to adopt. The lack of recent releases (406 days) is a minor concern but not a blocker given the stable, mature codebase and absence of known vulnerabilities. Best suited for embedded systems simulation, firmware manipulation, and memory emulation tasks.

## Install

pip install bytesparse
uv add bytesparse
poetry add bytesparse

## Installing bytesparse

Before you install: No runtime dependencies and a pure Python implementation make installation straightforward. The package is marked Production/Stable and has been maintained since 2021, though the last release was over a year ago.

License in practice: Licensed under BSD-2-Clause (permissive), allowing free use, modification, and distribution with minimal restrictions—suitable for both open-source and commercial projects.

Quickstart:

from bytesparse import bytesparse

m = bytesparse(b'Hello, World!')
print(len(m))  # 13
print(bytes(m))  # b'Hello, World!'
m.extend(b'!!')
print(bytes(m))  # b'Hello, World!!!'

Requires Python 3.9 or later.

Verify before relying:

- Whether the Cython implementation (cbytesparse) offers meaningful performance gains for typical use cases.
- How memory overhead compares to a contiguous bytearray when storing mostly-contiguous data.
- Real-world performance characteristics with very large address ranges or many fragmented blocks.

## Package facts

- License: BSD-2-Clause (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: aging
- Downloads: 225.3K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

sparse bytes virtual memory, non-contiguous memory blocks, bytearray with gaps, microcontroller memory emulation, sparse data storage, virtual addressing space, memory blocks management, memory-management, binary-data, embedded-systems

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