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use errors::Result;
use std::io::Read;
const NL: u8 = '\n' as u8;
pub fn find_line<'a, R: AsMut<Read + 'a>>(
mut reader: R,
span: (usize, usize),
) -> Result<(String, usize, (usize, usize))> {
let r = reader.as_mut();
let mut line = 0usize;
let mut current = 0usize;
let mut buffer: Vec<u8> = Vec::new();
let start = span.0;
let end = span.1;
let mut it = r.bytes().peekable();
let mut read = 0usize;
while let Some(b) = it.next() {
let b = b?;
read += 1;
match b {
NL => {}
_ => {
buffer.push(b);
continue;
}
}
let start_of_line = current;
current += read;
if current > start {
let buffer = String::from_utf8(buffer)?;
let end = ::std::cmp::min(end, current);
let range = (start - start_of_line, end - start_of_line);
return Ok((buffer, line, range));
}
read = 0usize;
line += 1;
buffer.clear();
}
Err("bad file position".into())
}
pub fn find_range<'a, R: AsMut<Read + 'a>>(
mut reader: R,
span: (usize, usize),
) -> Result<(usize, usize, usize, usize)> {
let r = reader.as_mut();
let mut line_start = 0usize;
let mut line_end = 0usize;
let mut col_start = 0usize;
let mut col_end = 0usize;
let mut line = 0usize;
let mut col = 0usize;
let mut it = r.bytes().enumerate();
while let Some((c, b)) = it.next() {
let b = b?;
let mut new_line = b == NL;
if new_line {
line += 1;
col = 0;
}
if c == span.0 {
line_start = line;
col_start = col;
}
if c == span.1 {
line_end = line;
col_end = col;
break;
}
if !new_line {
col += 1;
}
}
Ok((line_start, line_end, col_start, col_end))
}