https://github.com/brianpugh/micropython-fnv1a32

Micropython native module for the FNV1a hashing algorithm.
https://github.com/brianpugh/micropython-fnv1a32

fnv hash hashing micropython native native-module python

Last synced: 2 months ago
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Micropython native module for the FNV1a hashing algorithm.

• Host: GitHub
• URL: https://github.com/brianpugh/micropython-fnv1a32
• Owner: BrianPugh
• License: apache-2.0
• Created: 2024-06-15T01:41:55.000Z (6 months ago)
• Default Branch: main
• Last Pushed: 2024-07-07T21:00:02.000Z (6 months ago)
• Last Synced: 2024-10-10T22:22:14.562Z (2 months ago)
• Topics: fnv, hash, hashing, micropython, native, native-module, python
• Language: Python
• Homepage:
• Size: 28.3 KB
• Stars: 3
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# micropython-fnv1a32

[FNV1a32](http://www.isthe.com/chongo/tech/comp/fnv) is a simple 32-bit hash function that is optimized for speed while maintaining a low collision rate.

This repo implements a [micropython native module](https://docs.micropython.org/en/latest/develop/natmod.html) of the fnv1a32 hash function. To use a precompiled micropython native module, download the appropriate architecture/micropython-version [from the release page](https://github.com/BrianPugh/micropython-fnv1a32/releases).

Requires MicroPython `>1.22.0`.

# Usage

This library supplies a single function, `fnv1a32`, that can handle a variety of datatypes. The resulting hash is an `integer` object (not `bytes`!).

### Hashing Data In-Memory

To hash `bytes`/`bytearray`/`str` in-memory:

```python

from fnv1a32 import fnv1a32

fnv1a32_hash = fnv1a32(b"this is the data to be hashed")

```

To continue hashing, supply the previous hash into the next `fnv1a32` invocation:

```python

from fnv1a32 import fnv1a32

fnv1a32_hash = fnv1a32(b"this is the data to be hashed")

fnv1a32_hash = fnv1a32(b"more data", fnv1a32_hash)

```

### Hashing File

To hash a file:

```python

from fnv1a32 import fnv1a32

with open("foo.bin") as f:

    # Defaults to using 4096-byte chunks

    fnv1a32_hash = fnv1a32(f)

```

To read and hash bigger chunks at a time (uses more memory, may improve speed):

```python

from fnv1a32 import fnv1a32

with open("foo.bin") as f:

    fnv1a32_hash = fnv1a32(f, buffer_size=16384)

```

# Unit Testing

To run the unittests, install [Belay](https://github.com/BrianPugh/belay/tree/main) and run the following commands:

```bash

make clean

make

belay run micropython -m unittest tests/test_fnv1a32.py

```

# Benchmark

The following were benchmarked on an rp2040 hashing 50KB of data in-memory.

| Implementation             | Bytes/s   | Relative Speed |

|----------------------------|-----------|----------------|

| vanilla micropython        | 24,912    | 1.00x          |

| @micropython.native        | 26,619    | 1.07x          |

| @micropython.viper         | 2,438,786 | 97.90x         |

| micropython native module  | 8,744,316 | 351.01x        |

To run the benchmark, install [Belay](https://github.com/BrianPugh/belay/tree/main) and run the following commands:

```bash

export MPY_DIR=../micropython  # Replace with your micropython directory.

make clean

ARCH=armv6m make  # Change the arch if running on different hardware.

belay install /dev/ttyUSB0 --with=dev

belay sync /dev/ttyUSB0 fnv1a32.mpy

belay run /dev/ttyUSB0 benchmark/fnv1a32_benchmark.py

```