97 lines
2.6 KiB
Rust
97 lines
2.6 KiB
Rust
use anyhow::{anyhow, Result};
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pub trait SliceSubsequence<T> {
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fn trim_start(&self, needle: &[T]) -> &[T];
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fn first_index_of(&self, needle: &[T]) -> Result<usize>;
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fn replace(self, needle: &[T], replacement: &[T]) -> Vec<T>;
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fn contains_seq(&self, needle: &[T]) -> bool {
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self.first_index_of(needle).is_ok()
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}
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}
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fn last_index_of<T: PartialEq>(s: &[T], needle: &[T]) -> usize {
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let mut len = 0;
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for i in s {
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if needle.contains(i) {
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len += 1;
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} else {
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break;
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}
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}
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len
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}
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impl<T: PartialEq + Clone> SliceSubsequence<T> for &[T] {
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fn trim_start(&self, needle: &[T]) -> &[T] {
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&self[last_index_of(self, needle)..]
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}
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fn first_index_of(&self, needle: &[T]) -> Result<usize> {
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for i in 0..self.len() - needle.len() + 1 {
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if self[i..i + needle.len()] == needle[..] {
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return Ok(i);
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}
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}
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Err(anyhow!("not found"))
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}
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fn replace(self, needle: &[T], replacement: &[T]) -> Vec<T> {
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self.to_vec().replace(needle, replacement)
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}
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}
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impl<T: PartialEq + Clone> SliceSubsequence<T> for Vec<T> {
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fn trim_start(&self, needle: &[T]) -> &[T] {
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&self[last_index_of(self, needle)..]
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}
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fn first_index_of(&self, needle: &[T]) -> Result<usize> {
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return (self.as_slice()).first_index_of(needle);
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}
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fn replace(mut self, needle: &[T], replacement: &[T]) -> Vec<T> {
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while let Ok(idx) = self.first_index_of(needle) {
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self.splice(idx..(idx + needle.len()), replacement.iter().cloned());
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}
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self
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}
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}
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#[cfg(test)]
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mod tests {
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use crate::slicesubsequence::*;
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const WHITESPACE: &[u8] = b" \t\n\r";
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#[test]
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fn trim_start() {
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let buf = &b" bla"[..];
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let buf = buf.trim_start(WHITESPACE);
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assert_eq!(buf, b"bla");
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let buf = &b"\n\t\r \rbla"[..];
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let buf = buf.trim_start(WHITESPACE);
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assert_eq!(buf, b"bla");
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}
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#[test]
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fn replace() {
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let buf = b"bla to='tsnhaou' bla2".replace(b" to=", b" from=");
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assert_eq!(buf, b"bla from='tsnhaou' bla2");
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let buf = buf.replace(b" from=", b" to=");
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assert_eq!(buf, b"bla to='tsnhaou' bla2");
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let buf = buf.replace(b" to=", b" from=");
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assert_eq!(buf, b"bla from='tsnhaou' bla2");
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let buf = b"bla to='tsnhaou' bla2".replace(b"bla", b"boo");
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assert_eq!(buf, b"boo to='tsnhaou' boo2");
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let buf = buf.replace(b"boo", b"bla");
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assert_eq!(buf, b"bla to='tsnhaou' bla2");
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let buf = buf.replace(b" bla2", b"");
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assert_eq!(buf, b"bla to='tsnhaou'");
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}
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}
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