70 lines
2.1 KiB
Rust
70 lines
2.1 KiB
Rust
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use crate::RopeSlice;
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pub fn find_nth_next(text: RopeSlice, ch: char, pos: usize, n: usize) -> Option<usize> {
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// start searching right after pos
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let mut byte_idx = text.char_to_byte(pos + 1);
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let (mut chunks, mut chunk_byte_idx, _chunk_char_idx, _chunk_line_idx) =
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text.chunks_at_byte(byte_idx);
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let mut chunk = chunks.next().unwrap_or("");
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chunk = &chunk[(byte_idx - chunk_byte_idx)..];
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for _ in 0..n {
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loop {
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match chunk.find(ch) {
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Some(pos) => {
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byte_idx += pos;
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chunk = &chunk[pos + 1..];
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break;
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}
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None => match chunks.next() {
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Some(next_chunk) => {
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byte_idx += chunk.len();
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chunk = next_chunk;
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}
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None => {
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log::info!("no more chunks");
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return None;
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}
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},
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}
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}
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}
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Some(text.byte_to_char(byte_idx))
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}
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pub fn find_nth_prev(text: RopeSlice, ch: char, pos: usize, n: usize) -> Option<usize> {
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// start searching right before pos
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let mut byte_idx = text.char_to_byte(pos.saturating_sub(1));
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let (mut chunks, mut chunk_byte_idx, _chunk_char_idx, _chunk_line_idx) =
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text.chunks_at_byte(byte_idx);
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let mut chunk = chunks.prev().unwrap_or("");
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// start searching from pos
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chunk = &chunk[..=byte_idx - chunk_byte_idx];
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for _ in 0..n {
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loop {
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match chunk.rfind(ch) {
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Some(pos) => {
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byte_idx = chunk_byte_idx + pos;
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chunk = &chunk[..pos];
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break;
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}
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None => match chunks.prev() {
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Some(prev_chunk) => {
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chunk_byte_idx -= chunk.len();
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chunk = prev_chunk;
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}
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None => return None,
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},
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}
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}
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}
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Some(text.byte_to_char(byte_idx))
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}
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