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uuid.gleam
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uuid.gleam
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//// A module for generating UUIDs (Universally Unique Identifiers).
////
//// The module currently supports UUID versions:
//// - Version 4 (random)
////
import gleam/bit_string
/// Generates a version 4 (random) UUID. The version 4 UUID produced
/// by this function is generated using a cryptographically secure
/// random number generator.
///
/// ### Usage
/// ```gleam
/// import ids/uuid
///
/// let assert Ok(id) = uuid.generate_v4()
/// ```
///
pub fn generate_v4() -> Result(String, String) {
let <<u0:size(48), _:size(4), u1:size(12), _:size(2), u2:size(62)>> =
crypto_strong_rand_bytes(16)
let <<
a1:size(4),
a2:size(4),
a3:size(4),
a4:size(4),
a5:size(4),
a6:size(4),
a7:size(4),
a8:size(4),
b1:size(4),
b2:size(4),
b3:size(4),
b4:size(4),
c1:size(4),
c2:size(4),
c3:size(4),
c4:size(4),
d1:size(4),
d2:size(4),
d3:size(4),
d4:size(4),
e1:size(4),
e2:size(4),
e3:size(4),
e4:size(4),
e5:size(4),
e6:size(4),
e7:size(4),
e8:size(4),
e9:size(4),
e10:size(4),
e11:size(4),
e12:size(4),
>> = <<u0:size(48), 4:size(4), u1:size(12), 2:size(2), u2:size(62)>>
let bitstr_id = <<
e(a1),
e(a2),
e(a3),
e(a4),
e(a5),
e(a6),
e(a7),
e(a8),
45,
e(b1),
e(b2),
e(b3),
e(b4),
45,
e(c1),
e(c2),
e(c3),
e(c4),
45,
e(d1),
e(d2),
e(d3),
e(d4),
45,
e(e1),
e(e2),
e(e3),
e(e4),
e(e5),
e(e6),
e(e7),
e(e8),
e(e9),
e(e10),
e(e11),
e(e12),
>>
case bit_string.to_string(bitstr_id) {
Ok(str_id) ->
str_id
|> Ok
Error(_) -> {
let error: String = "Error: BitString could not be converted to String."
error
|> Error
}
}
}
fn e(n: Int) -> Int {
case n {
0 -> 48
1 -> 49
2 -> 50
3 -> 51
4 -> 52
5 -> 53
6 -> 54
7 -> 55
8 -> 56
9 -> 57
10 -> 97
11 -> 98
12 -> 99
13 -> 100
14 -> 101
15 -> 102
}
}
external fn crypto_strong_rand_bytes(Int) -> BitString =
"crypto" "strong_rand_bytes"