43 lines
992 B
Rust
43 lines
992 B
Rust
/// Converts unsigned integers into a string representation with some base.
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/// Bases up to and including 36 can be used for case-insensitive things.
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use std::str;
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#[cfg(test)]
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mod tests;
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pub const MAX_BASE: usize = 64;
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pub const ALPHANUMERIC_ONLY: usize = 62;
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pub const CASE_INSENSITIVE: usize = 36;
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const BASE_64: &[u8; MAX_BASE] =
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b"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ@$";
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#[inline]
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pub fn push_str(mut n: u128, base: usize, output: &mut String) {
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debug_assert!(base >= 2 && base <= MAX_BASE);
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let mut s = [0u8; 128];
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let mut index = 0;
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let base = base as u128;
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loop {
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s[index] = BASE_64[(n % base) as usize];
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index += 1;
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n /= base;
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if n == 0 {
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break;
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}
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}
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s[0..index].reverse();
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output.push_str(str::from_utf8(&s[0..index]).unwrap());
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}
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#[inline]
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pub fn encode(n: u128, base: usize) -> String {
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let mut s = String::new();
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push_str(n, base, &mut s);
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s
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}
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