49 lines
1.4 KiB
Rust
49 lines
1.4 KiB
Rust
#[allow(dead_code)]
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#[derive(Debug)]
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pub struct LineNumbers {
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line_starts: Vec<usize>,
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length: usize,
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}
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impl LineNumbers {
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pub fn new(src: &str) -> Self {
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Self {
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length: src.len(),
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line_starts: std::iter::once(0)
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.chain(src.match_indices('\n').map(|(i, _)| i + 1))
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.collect(),
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}
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}
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/// Get the line number for a byte index
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pub fn line_number(&self, byte_index: usize) -> usize {
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self.line_starts
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.binary_search(&byte_index)
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.unwrap_or_else(|next_line| next_line - 1)
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+ 1
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}
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// TODO: handle unicode characters that may be more than 1 byte in width
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pub fn line_and_column_number(&self, byte_index: usize) -> LineColumn {
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let line = self.line_number(byte_index);
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let column = byte_index - self.line_starts.get(line - 1).copied().unwrap_or_default() + 1;
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LineColumn { line, column }
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}
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// TODO: handle unicode characters that may be more than 1 byte in width
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/// 0 indexed line and character to byte index
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#[allow(dead_code)]
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pub fn byte_index(&self, line: usize, character: usize) -> usize {
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match self.line_starts.get(line) {
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Some(line_index) => *line_index + character,
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None => self.length,
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}
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}
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}
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#[derive(Debug, Clone, Copy)]
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pub struct LineColumn {
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pub line: usize,
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pub column: usize,
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}
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