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https://github.com/lukateras/nanoid.h
Sitnik's Nano ID as a 199-byte C header
https://github.com/lukateras/nanoid.h
c c-library cli id-generator meson nanoid
Last synced: 28 days ago
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Sitnik's Nano ID as a 199-byte C header
- Host: GitHub
- URL: https://github.com/lukateras/nanoid.h
- Owner: lukateras
- License: other
- Created: 2022-10-24T20:54:24.000Z (over 2 years ago)
- Default Branch: trunk
- Last Pushed: 2025-01-04T04:38:04.000Z (about 1 month ago)
- Last Synced: 2025-01-08T05:47:09.749Z (30 days ago)
- Topics: c, c-library, cli, id-generator, meson, nanoid
- Language: C
- Homepage:
- Size: 62.5 KB
- Stars: 27
- Watchers: 2
- Forks: 3
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
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README
# Nano ID for C
A tiny, secure, URL-friendly unique string ID generator for C.
- **Small.** 199 bytes. Header-only. No dependencies other than libc.
- **Safe.** Uses [`getentropy(3)`][], a modern, reliable, secure randomness source.
- **Short IDs.** A default Nano ID is 15 characters shorter than a UUIDv4 while
encoding 4 bits more entropy.
- **Portable.** POSIX-compliant. Available in [29 programming languages][ports].
```c
#include
#include
#include
int main() {
char id[NANOIDLEN + 1] = "";
if (nanoidgen(id, NANOIDLEN))
return EXIT_FAILURE;
puts(id);
}
```
```
$ cc main.c -o example
$ ./example
V1StGXR8_Z5jdHi6B-myT
```
[ports]: https://github.com/ai/nanoid#other-programming-languages
## Overview
Nano IDs are unique string IDs where each character is an alphanumeric, a
hyphen, or an underscore. Think of them as random unpadded [Base64url][]
strings. You've already seen this format elsewhere: on YouTube!
A default Nano ID is 21 characters long, encoding 126 bits of entropy at 6 bits
per character.
[`nanoid.h`][] is a self-contained Nano ID generator built on top of the
[`getentropy(3)`][] randomness source. It's as portable as [`getentropy(3)`][]
itself, which is a part of the POSIX.1-2024 standard. Just grab the header and
use it wherever you wish!
[Base64url]: https://datatracker.ietf.org/doc/html/rfc4648#section-5
## Usage
Works out of the box on NetBSD, OpenBSD, Linux, Android, macOS, illumos,
Solaris, FreeBSD, DragonFly, Haiku, GNU Hurd, Fuchsia, Emscripten, and WASI.
Windows support requires a [`getentropy(3)`][] shim.
To include [`nanoid(3)`][] copy [`nanoid.h`][] and [`LICENSE.txt`][] to your
project.
To build [`nanoidgen(1)`][] run `make nanoidgen`.
To build and install the project use [Meson][]:
```sh
meson setup ../nanoid && \
ninja -C ../nanoid && \
sudo ninja -C ../nanoid install
```
[`nanoid.h`]: nanoid.h
[`LICENSE.txt`]: LICENSE.txt
[Meson]: https://meson.build
## Documentation
See the PDF manual at .
### [`nanoid(3)`][]
```c
#include
```
- macro `NANOIDLEN`
The default Nano ID length of 21.
- static inline function `int *nanoidgen(char *buffer, size_t length)`
Fills the buffer with a Nano ID of the specified length up to
`GETENTROPY_MAX` (256).
Returns the return value of [`getentropy(3)`][].
### [`nanoidgen(1)`][]
```
$ nanoidgen [length]
```
Generates a Nano ID of the default length (21), or the specified length within
1 and `GETENTROPY_MAX` (256), and prints it to the standard output.
[`getentropy(3)`]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/getentropy.html
[`nanoid(3)`]: https://lukateras.github.io/nanoid.h/man/nanoid.3.html
[`nanoidgen(1)`]: https://lukateras.github.io/nanoid.h/man/nanoidgen.1.html
## Attribution
Port of [Nano ID](https://github.com/ai/nanoid) by [Andrey Sitnik](https://sitnik.ru).
Original logo by [Anton Lovchikov](https://github.com/antiflasher).
Social preview background texture by [Tuomo](https://x.com/tuomodesign).
Social preview logo assistance by [Tanya Nevskaya](https://github.com/unparalloser).