https://github.com/guzba/crunchy

SIMD-optimized hashing, checksums and CRCs.
https://github.com/guzba/crunchy

adler32 checksum crc32 crc32c cyclic-redundancy-check nim sha256 simd

Last synced: about 11 hours ago
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SIMD-optimized hashing, checksums and CRCs.

• Host: GitHub
• URL: https://github.com/guzba/crunchy
• Owner: guzba
• License: mit
• Created: 2022-06-12T17:05:59.000Z (over 2 years ago)
• Default Branch: master
• Last Pushed: 2024-01-26T03:20:13.000Z (about 1 year ago)
• Last Synced: 2024-11-28T07:24:11.120Z (about 2 months ago)
• Topics: adler32, checksum, crc32, crc32c, cyclic-redundancy-check, nim, sha256, simd
• Language: Nim
• Homepage:
• Size: 206 KB
• Stars: 31
• Watchers: 5
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Crunchy

![Github Actions](https://github.com/guzba/crunchy/workflows/Github%20Actions/badge.svg)

`nimble install crunchy`

[API reference](https://guzba.github.io/crunchy/)

## About

Crunchy provides pure Nim implementations of common hashes and data integrity checks (cyclic redundancy checks and checksums). These implementations are intended to be high-performance, including amd64 and arm64 SIMD implementations or using instruction set intrinsics.

Function | Scalar | SIMD: | amd64 | arm64

---       | ---   | ---   | ---   | ---:

SHA-1     | ✅   |       |  ⛔   | ⛔

SHA-256   | ✅   |       |  ✅   | ⛔

CRC-32    | ✅   |       |  ✅   | ✅

CRC-32C   | ⛔   |       |  ✅   | ⛔

Adler-32  | ✅   |       |  ✅   | ✅

Crunchy is a new repo so keep an eye on releases for more functions and SIMD optimization.

## Examples

Runnable examples using Crunchy can be found in the [examples/](https://github.com/guzba/crunchy/blob/master/examples) folder.

Here is a basic example that prints the hex-encoded SHA-256 of a string:

```nim

import crunchy

let data = "The quick brown fox jumps over the lazy dog"

echo sha256(data).toHex()

```

Or calculating the CRC-32 of a string:

```nim

import crunchy

let data = "The quick brown fox jumps over the lazy dog"

echo crc32(data)

```

Now, lets say you want to compute the CRC-32 of a file. Many approaches are possible, but lets look at these two:

First, the easy way. Just read the file into memory and compute:

```nim

import crunchy

let data = readFile("tests/data/zlib.rfc")

echo crc32(data)

```

Alternatively, to avoid copying the file, memory-map the file and compute instead:

```nim

import crunchy, std/memfiles

var memFile = memfiles.open("tests/data/zlib.rfc")

echo crc32(memFile.mem, memFile.size)

memFile.close()

```

Memory-mapping the file is great if the file is very large or you want to avoid copying a large file's contents. This uses Crunchy's pointer + len API.

## Testing

`nimble test`